Document Outline
- S-8424A Series
- Cover
- Features
- Package
- Applications
- Selection Guide
- Block Diagram
- Pin Assignment
- Absolute Maximum Ratings
- Electrical Characteristics
- Test Circuit
- Operation Timing Chart
- Operation
- Transient Response
- Standard Circuit
- Package Power Dissipation
- Precautions
- Application Circuits
- Characteristics
- Package Drawings
Rev.1.3
_10
BATTERY BACKUP SWITCHING IC
S-8424A Series
Seiko Instruments Inc.
1
The S-8424A Series is a CMOS IC designed for use in the switching
circuits of primary and backup power supplies on a single chip. It
consists of two voltage regulators, three voltage detectors, a power
supply switch and its controller, as well as other functions.
In addition to the switching function between the primary and backup
power supply, the S-8424A Series can provide the micro controllers
with three types of voltage detection output signals corresponding to
the power supply voltage.
Moreover adopting a special sequence for switch control enables
the effective use of the backup power supply, making this IC ideal
for configuring a backup system.
Features
Low power consumption
Normal operation: 15
A Max. (V
IN
= 6 V)
Backup: 2.1
A Max.
Voltage regulator
Output voltage tolerance :
2 %
Output voltage:
Independently selectable in 0.1 V steps in the range of 2.3 V to 5.4 V
Three built-in voltage detectors (CS, PREEND , RESET )
Detection voltage precision:
2 %
Detection voltage:
Selectable in 0.1 V steps in the range of 2.4 V to 5.3 V (CS voltage detector)
Selectable in 0.1 V steps in the range of 1.7 V to 3.4 V (PREEND , RESET
voltage detector)
Switching circuit for primary power supply and backup power supply configurable on one chip
Efficient use of backup power supply possible
Special sequence
Backup voltage is not output when the primary power supply voltage does not reach the initial voltage at which
the switch unit operates.
Package
8-Pin TSSOP (Package drawing No.: FT008-A)
8-Pin SON(B) (Package drawing No.: PA008-B)
Applications
Video camera recorders
Still video cameras
Memory cards
SRAM backup equipment
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
2
Seiko Instruments Inc.
Selection Guide
Package
Output
Voltage
(V)
CS Voltage
(V)
RESET Voltage
(V)
PREEND
Voltage
(V)
Switch
Voltage
(V)
Part No.
Type
V
RO
V
OUT
-V
DET1
+V
DET1
-V
DET2
+V
DET2
-V
DET3
+V
DET3
V
SW1
S-8424AAAFT-TB
8-Pin TSSOP
3.000
3.000
3.300
3.401
2.200
2.312 2.600
2.748
+V
DET1
0.85
S-8424AAAPA-TF
8-Pin SON(B)
S-8424AABFT-TB
8-Pin TSSOP
3.300
3.300
4.000
4.129
2.300
2.420 2.500
2.640
+V
DET1
0.77
S-8424AACFT-TB
8-Pin TSSOP
3.200
3.200
3.300
3.401
2.400
2.528 2.600
2.748
+V
DET1
0.85
S-8424AADFT-TB
8-Pin TSSOP
5.000
5.000
4.600
4.753
2.300
2.420 2.500
2.640
+V
DET1
0.77
S-8424AAFFT-TB
8-Pin TSSOP
3.200
3.200
4.400
4.545
2.400
2.528 2.600
2.748
+V
DET1
0.77
S-8424AAGFT-TB
8-Pin TSSOP
2.800
2.800
4.400
4.545
2.400
2.528 2.600
2.748
+V
DET1
0.77
S-8424AAJFT-TB
8-Pin TSSOP
3.100
3.100
4.400
4.545
2.200
2.312 2.600
2.748
+V
DET1
0.77
S-8424AAKFT-TB
8-Pin TSSOP
3.200
3.200
4.600
4.753
2.400
2.528 2.600
2.748
+V
DET1
0.77
Caution Set the CS voltage so that the switch voltage (V
SW1
) is equal to or greater than the
RESET
detection voltage (
-
-
-
-V
DET2
).
Remark 1. The selection range is as follows.
V
RO
, V
OUT
: 2.3 to 5.4 V (0.1 V steps)
-V
DET1
:
2.4 to 5.3 V (0.1 V steps)
-V
DET2
:
1.7 to 3.4 V (0.1 V steps )
-V
DET3
:
1.7 to 3.4 V (0.1 V steps)
V
SW1
:
+V
DET1
0.85 or +V
DET1
0.77
2. If a product with a voltage other than above is required, contact our sales representative.
S-8424A xx xx - xx
IC direction in tape specification
TB: 8-Pin TSSOP
TF: 8-Pin SON(B)
Package code
FT: 8-Pin TSSOP
PA: 8-Pin SON(B)
Serial code
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
3
Block Diagram
VBAT
V
SW2
Detector
M1
CS
Voltage
detector
V
SW1
Detector
Switch
controller
VOUT
RESET
RESET
Voltage
detector
CS
VIN
REG2
REG1
VRO
PREEND
PREEND
Voltage
detector
VSS
Figure 1 Block Diagram
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
4
Seiko Instruments Inc.
Pin Assignment
Table 1 Pin description
Pin No.
Pin Name
Functions
1 VSS
Ground
2 PREEND Output pin of PREEND voltage detector
3 VBAT
*1
Backup power supply input pin
4
CS
Output pin of CS voltage detector
5 RESET
Output pin of RESET voltage detector
VSS
PREEND
VBAT
CS
VRO
VIN
VOUT
RESET
8-Pin TSSOP
Top View
1
2
3
4
8
7
6
5
6 VOUT
*2
Output pin of voltage regulator 2
Figure 2
7 VIN
*3
Primary power supply input pin
8
VRO
*4
Output pin of voltage regulator 1
*1 to *4. Mount capacitors between VSS (GND pin) and the VIN, VBAT,
VOUT, and VRO pins. (Refer to the "Standard Circuit")
Table 2 Pin description
Pin No.
Pin Name
Functions
1 VSS
Ground
2 PREEND Output pin of PREEND voltage detector
3 VBAT
*1
Backup power supply input pin
4
CS
Output pin of CS voltage detector
5 RESET
Output pin of RESET voltage detector
VSS
PREEND
VBAT
CS
VRO
VIN
VOUT
RESET
8-Pin SON(B)
Top View
8
7
6
5
1
2
3
4
6 VOUT
*2
Output pin of voltage regulator 2
Figure 3
7 VIN
*3
Primary power supply input pin
8
VRO
*4
Output pin of voltage regulator 1
*1 to *4. Mount capacitors between VSS (GND pin) and the VIN, VBAT,
VOUT, and VRO pins. (Refer to the "Standard Circuit")
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
5
Absolute Maximum Ratings
Table 3 Absolute Maximum Ratings
(Unless otherwise specified: Ta
= 25C)
Parameter Symbol Ratings Unit
Primary power supply input voltage
V
IN
V
SS
-0.3 to V
SS
+18
V
Backup power supply input voltage
V
BAT
Output voltage of voltage regulator
V
RO
, V
OUT
V
SS
-0.3 to V
IN
+0.3
CS output voltage
V
CS
V
SS
-0.3 to V
SS
+18
RESET output voltage
RESET
V
PREEND output voltage
PREEND
V
Power dissipation
P
D
8-Pin TSSOP
300
mW
8-Pin
SON(B)
300
Operating ambient temperature
T
opr
-40 to +85
C
Storage temperature
T
stg
-40 to +125
Caution The absolute maximum ratings are rated values exceeding which the product could suffer
physical damage. These values must therefore not be exceeded under any conditions.
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
6
Seiko Instruments Inc.
Electrical Characteristics
1. S-8424AAAxx
Table 4 Electrical Characteristics
(Unless otherwise specified: Ta
= 25C)
Parameter Symbol
Conditions
Min.
Typ.
Max.
Unit
Test
Circuit
Output voltage 1
V
RO
V
IN
= 7.2 V, I
RO
= 3 mA
2.940
3.000
3.060
V
1
Dropout voltage 1
V
drop1
V
IN
= 7.2 V, I
RO
= 3 mA
41 59 mV
Load stability 1
V
RO1
V
IN
= 7.2 V, I
RO
= 0.1 to 10 mA
50 100 mV
Input stability 1
V
RO2
V
IN
= 4 to 16 V, I
RO
= 3 mA
5 20 mV
Output voltage temperature coefficient 1
RO
RO
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Output voltage 2
V
OUT
V
IN
= 7.2 V, I
OUT
= 23 mA
2.940
3.000
3.060
V
Dropout voltage 2
V
drop2
V
IN
= 7.2 V, I
OUT
= 23 mA
187 252 mV
Load stability 2
V
OUT1
V
IN
= 7.2 V, I
OUT
= 0.1 to 60 mA
50 100 mV
Input stability 2
V
OUT2
V
IN
= 4 to 16 V, I
OUT
= 23 mA
5 20 mV
Output voltage temperature coefficient 2
OUT
OUT
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Primary power input voltage
V
IN
16 V
CS detection voltage
-V
DET1
V
IN
voltage
detection
3.234 3.300 3.366
V
2
CS release voltage
+V
DET1
3.319
3.401
3.482
V
RESET detection voltage
-V
DET2
V
OUT
voltage detection
2.156
2.200
2.244
V
RESET release voltage
+V
DET2
2.256 2.312 2.367
V
PREEND detection voltage
-V
DET3
V
BAT
voltage detection
2.548
2.600 2.652
V
PREEND release voltage
+V
DET3
2.682
2.748
2.814
V
Operating voltage
V
opr
V
IN
or
V
BAT
1.7
- 16 V
Detection voltage temperature coefficient
1
DET
1
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
2
DET
2
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
3
DET
3
DET
V
Ta
V
-
-
Ta = -40C to +85C
100
ppm/C
Sink current
I
SINK
V
DS
= 0.5 V, V
IN
= V
BAT
= 2.0 V
RESET
1.50 2.30
mA 3
PREEND
1.50 2.30
mA
CS
1.50 2.30
mA
Leakage
current
I
LEAK
V
DS
= 16 V, V
IN
= 16 V
0.1 A
Switch voltage
V
SW1
V
BAT
= 2.8 V, V
IN
voltage detection
+V
DET1
0.83
+V
DET1
0.85
+V
DET1
0.87
V 4
CS output inhibit voltage
V
SW2
V
BAT
= 3.0 V, V
OUT
voltage detection
V
OUT
0.93
V
OUT
0.95
V
OUT
0.97
V 5
V
BAT
switch leakage current
I
LEAK
V
IN
= 3.6 V, V
BAT
= 0 V
0.1 A 6
V
BAT
switch resistance
R
SW
V
IN
= Open, V
BAT
= 3.0 V, I
OUT
= 10 to 500 A
30 60 7
Switch voltage temperature coefficient
1
SW
1
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 4
CS output inhibit voltage temperature
coefficient
2
SW
2
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 5
Current consumption
I
SS1
V
IN
= 3.6 V, V
BAT
= 3.0 V, Unload
7 15 A 8
I
BAT1
0.26 0.50 A
I
BAT2
V
IN
= Open, V
BAT
= 3.0 V, Unload
Ta
= 25C
1.0 2.1 A
Ta
= 85C
3.5 A
Backup power supply input voltage
V
BAT
1.7
4.0 V 7
Remark The number in the Test Circuit column corresponds to the circuit number in the "Test Circuit"section.
V
o
l
t
age regul
ator
V
o
l
t
age detector
S
w
i
t
ch uni
t
To
t
a
l
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
7
2. S-8424AABxx
Table 5 Electrical Characteristics
(Unless otherwise specified: Ta
= 25C)
Parameter Symbol
Conditions
Min.
Typ.
Max.
Unit
Test
Circuit
Output voltage 1
V
RO
V
IN
= 6 V, I
RO
= 30 mA
3.234
3.300
3.366
V
1
Dropout voltage 1
V
drop1
V
IN
= 6 V, I
RO
= 30 mA
356 474 mV
Load stability 1
V
RO1
V
IN
= 6 V, I
RO
= 0.1 to 40 mA
50 100 mV
Input stability 1
V
RO2
V
IN
= 6 to 16 V, I
RO
= 30 mA
5 20 mV
Output voltage temperature coefficient 1
RO
RO
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Output voltage 2
V
OUT
V
IN
= 6 V, I
OUT
= 50 mA
3.234
3.300
3.366
V
Dropout voltage 2
V
drop2
V
IN
= 6 V, I
OUT
= 50 mA
401 540 mV
Load stability 2
V
OUT1
V
IN
= 6 V, I
OUT
= 0.1 to 60 mA
50 100 mV
Input stability 2
V
OUT2
V
IN
= 6 to 16 V, I
OUT
= 50 mA
5 20 mV
Output voltage temperature coefficient 2
OUT
OUT
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Primary power input voltage
V
IN
16 V
CS detection voltage
-V
DET1
V
IN
voltage
detection
3.920 4.000 4.080
V
2
CS release voltage
+V
DET1
4.030
4.129
4.228
V
RESET detection voltage
-V
DET2
V
OUT
voltage detection
2.254
2.300
2.346
V
RESET release voltage
+V
DET2
2.362
2.420
2.478
V
PREEND detection voltage
-V
DET3
V
BAT
voltage detection
2.450
2.500
2.550
V
PREEND release voltage
+V
DET3
2.576
2.640
2.703
V
Operating voltage
V
opr
V
IN
or
V
BAT
1.7
16 V
Detection voltage temperature coefficient
1
DET
1
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
2
DET
2
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
3
DET
3
DET
V
Ta
V
-
-
Ta = -40C to +85C
100
ppm/C
Sink current
I
SINK
V
DS
= 0.5 V, V
IN
= V
BAT
= 2.0 V
RESET
1.50 2.30
mA 3
PREEND
1.50 2.30
mA
CS
1.50 2.30
mA
Leakage
current
I
LEAK
V
DS
= 16 V, V
IN
= 16 V
0.1 A
Switch voltage
V
SW1
V
BAT
= 2.8 V, V
IN
voltage detection
+V
DET1
0.75
+V
DET1
0.77
+V
DET1
0.79
V 4
CS output inhibit voltage
V
SW2
V
BAT
= 3.0 V
V
OUT
voltage detection
V
OUT
0.93
V
OUT
0.95
V
OUT
0.97
V 5
V
BAT
switch leakage current
I
LEAK
V
IN
= 6V, V
BAT
= 0 V
0.1 A 6
V
BAT
switch resistance
R
SW
V
IN
= Open, V
BAT
= 3.0 V, I
OUT
= 10 to 500 A
30 60 7
Switch voltage temperature coefficient
1
SW
1
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 4
CS output inhibit voltage temperature
coefficient
2
SW
2
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 5
Current
consumption
I
SS1
V
IN
= 6 V, V
BAT
= 3.0 V, Unload
7 15 A 8
I
BAT1
0.26 0.50 A
I
BAT2
V
IN
= Open, V
BAT
= 3.0 V, Unload
Ta
= 25C
1.0 2.1 A
Ta
= 85C
3.5 A
Backup power supply input voltage
V
BAT
1.7
4.0 V 7
Remark The number in the Test Circuit column corresponds to the circuit number in the "Test Circuit" section.
V
o
l
t
age regul
ator
V
o
l
t
age det
ec
t
o
r
S
w
i
t
ch uni
t
To
t
a
l
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
8
Seiko Instruments Inc.
3. S-8424AACxx
Table 6 Electrical Characteristics
(Unless otherwise specified: Ta
= 25C)
Parameter Symbol
Conditions
Min.
Typ.
Max.
Unit
Test
Circuit
Output voltage 1
V
RO
V
IN
= 3.6 V, I
RO
= 15 mA
3.136
3.200
3.264
V
1
Dropout voltage 1
V
drop1
V
IN
= 3.6 V, I
RO
= 15 mA
181 243 mV
Load stability 1
V
RO1
V
IN
= 3.6 V, I
RO
= 0.1 to 20 mA
50 100 mV
Input stability 1
V
RO2
V
IN
= 3.6 to 16 V, I
RO
= 15 mA
5 20 mV
Output voltage temperature coefficient 1
RO
RO
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Output voltage 2
V
OUT
V
IN
= 3.6 V, I
OUT
= 15mA
3.136
3.200
3.264
V
Dropout voltage 2
V
drop2
V
IN
= 3.6 V, I
OUT
= 15 mA
123 167 mV
Load stability 2
V
OUT1
V
IN
= 3.6 V, I
OUT
= 0.1 to 20 mA
50 100 mV
Input stability 2
V
OUT2
V
IN
= 3.6 to 16 V, I
OUT
= 15 mA
5 20 mV
Output voltage temperature coefficient 2
OUT
OUT
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Primary power input voltage
V
IN
16 V
CS detection voltage
-V
DET1
V
IN
voltage
detection
3.234 3.300 3.366
V
2
CS release voltage
+V
DET1
3.319
3.401
3.482
V
RESET detection voltage
-V
DET2
V
OUT
voltage detection
2.352
2.400
2.448
V
RESET release voltage
+V
DET2
2.467
2.528
2.589
V
PREEND detection voltage
-V
DET3
V
BAT
voltage detection
2.548
2.600 2.652
V
PREEND release voltage
+V
DET3
2.682
2.748
2.814
V
Operating voltage
V
opr
V
IN
or
V
BAT
1.7
16 V
Detection voltage temperature coefficient
1
DET
1
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
2
DET
2
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
3
DET
3
DET
V
Ta
V
-
-
Ta = -40C to +85C
100
ppm/C
Sink current
I
SINK
V
DS
= 0.5 V, V
IN
= V
BAT
= 2.0 V
RESET
1.50 2.30
mA 3
PREEND
1.50 2.30
mA
CS
1.50 2.30
mA
Leakage
current
I
LEAK
V
DS
= 16 V, V
IN
= 16 V
0.1 A
Switch voltage
V
SW1
V
BAT
= 2.8 V, V
IN
voltage detection
+V
DET1
0.83
+V
DET1
0.85
+V
DET1
0.87
V 4
CS output inhibit voltage
V
SW2
V
BAT
= 3.0 V, V
OUT
voltage detection
V
OUT
0.93
V
OUT
0.95
V
OUT
0.97
V 5
V
BAT
switch leakage current
I
LEAK
V
IN
= 3.6 V, V
BAT
= 0 V
0.1 A 6
V
BAT
switch resistance
R
SW
V
IN
= Open, V
BAT
= 3.0 V, I
OUT
= 10 to 500 A
30 60 7
Switch voltage temperature coefficient
1
SW
1
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 4
CS output inhibit voltage temperature
coefficient
2
SW
2
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 5
Current consumption
I
SS1
V
IN
= 3.6 V, V
BAT
= 3.0 V, Unload
7 15 A 8
I
BAT1
0.26 0.50 A
I
BAT2
V
IN
= Open, V
BAT
= 3.0 V, Unload
Ta
= 25C
1.0 2.1 A
Ta
= 85C
3.5 A
Backup power supply input voltage
V
BAT
1.7
4.0 V 7
Remark The number in the Test Circuit column corresponds to the circuit number in the "Test Circuit" section.
V
o
l
t
age regul
ator
V
o
l
t
age detector
S
w
i
t
ch uni
t
To
t
a
l
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
9
4. S-8424AADxx
Table 7 Electrical Characteristics
(Unless otherwise specified: Ta
= 25C)
Parameter Symbol
Conditions
Min.
Typ.
Max.
Unit
Test
Circuit
Output voltage 1
V
RO
V
IN
= 6 V, I
RO
= 30 mA
4.900
5.000
5.100
V
1
Dropout voltage 1
V
drop1
V
IN
= 6 V, I
RO
= 30 mA
356 474 mV
Load stability 1
V
RO1
V
IN
= 6 V, I
RO
= 0.1 to 40 mA
50 100 mV
Input stability 1
V
RO2
V
IN
= 6 to 16 V, I
RO
= 30 mA
5 20 mV
Output voltage temperature coefficient 1
RO
RO
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Output voltage 2
V
OUT
V
IN
= 6 V, I
OUT
= 50mA
4.900
5.000
5.100
V
Dropout voltage 2
V
drop2
V
IN
= 6 V, I
OUT
= 50 mA
401 540 mV
Load stability 2
V
OUT1
V
IN
= 6 V, I
OUT
= 0.1 to 60 mA
50 100 mV
Input stability 2
V
OUT2
V
IN
= 6 to 16 V, I
OUT
= 50 mA
5 20 mV
Output voltage temperature coefficient 2
OUT
OUT
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Primary power input voltage
V
IN
16 V
CS detection voltage
-V
DET1
V
IN
voltage
detection
4.508 4.600 4.692
V
2
CS release voltage
+V
DET1
4.639 4.753 4.867
V
RESET detection voltage
-V
DET2
V
OUT
voltage detection
2.254
2.300
2.346
V
RESET release voltage
+V
DET2
2.362
2.420
2.478
V
PREEND detection voltage
-V
DET3
V
BAT
voltage detection
2.450
2.500
2.550
V
PREEND release voltage
+V
DET3
2.576
2.640
2.703
V
Operating voltage
V
opr
V
IN
or
V
BAT
1.7
16 V
Detection voltage temperature coefficient
1
DET
1
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
2
DET
2
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
3
DET
3
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
Sink current
I
SINK
V
DS
= 0.5 V, V
IN
= V
BAT
= 2.0 V
RESET
1.50 2.30
mA 3
PREEND
1.50 2.30
mA
CS
1.50 2.30
mA
Leakage
current
I
LEAK
V
DS
= 16 V, V
IN
= 16 V
0.1 A
Switch voltage
V
SW1
V
BAT
= 2.8 V, V
IN
voltage detection
+V
DET1
0.75
+V
DET1
0.77
+V
DET1
0.79
V 4
CS output inhibit voltage
V
SW2
V
BAT
= 3.0 V, V
OUT
voltage detection
V
OUT
0.93
V
OUT
0.95
V
OUT
0.97
V 5
V
BAT
switch leakage current
I
LEAK
V
IN
= 6 V, V
BAT
= 0 V
0.1 A 6
V
BAT
switch resistance
R
SW
V
IN
= Open, V
BAT
= 3.0 V, I
OUT
= 10 to 500 A
30 60 7
Switch voltage temperature coefficient
1
SW
1
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 4
CS output inhibit voltage temperature
coefficient
2
SW
2
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 5
Current
consumption
I
SS1
V
IN
= 6 V, V
BAT
= 3.0 V, Unload
7 15 A 8
I
BAT1
0.26 0.50 A
I
BAT2
V
IN
= Open, V
BAT
= 3.0 V, Unload
Ta
= 25C
1.0 2.1 A
Ta
= 85C
3.5 A
Backup power supply input voltage
V
BAT
1.7
4.0 V 7
Remark The number in the Test Circuit column corresponds to the circuit number in the "Test Circuit" section.
V
o
l
t
age regul
ator
V
o
l
t
age detector
S
w
i
t
ch uni
t
To
t
a
l
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
10
Seiko Instruments Inc.
5. S-8424AAFxx
Table 8 Electrical Characteristics
(Unless otherwise specified: Ta
= 25C)
Parameter Symbol
Conditions
Min.
Typ.
Max.
Unit
Test
Circuit
Output voltage 1
V
RO
V
IN
= 6 V, I
RO
= 30 mA
3.136
3.200
3.264
V
1
Dropout voltage 1
V
drop1
V
IN
= 6 V, I
RO
= 30 mA
356 474 mV
Load stability 1
V
RO1
V
IN
= 6 V, I
RO
= 0.1 to 30 mA
50 100 mV
Input stability 1
V
RO2
V
IN
= 6 to 16 V, I
RO
= 30 mA
5 20 mV
Output voltage temperature coefficient 1
RO
RO
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Output voltage 2
V
OUT
V
IN
= 6 V, I
OUT
= 50 mA
3.136
3.200
3.264
V
Dropout voltage 2
V
drop2
V
IN
= 6 V, I
OUT
= 50 mA
401 540 mV
Load stability 2
V
OUT1
V
IN
= 6 V, I
OUT
= 0.1 to 50 mA
50 100 mV
Input stability 2
V
OUT2
V
IN
= 6 to 16 V, I
OUT
= 50 mA
5 20 mV
Output voltage temperature coefficient 2
OUT
OUT
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Primary power input voltage
V
IN
16 V
CS detection voltage
-V
DET1
V
IN
voltage detection
4.312
4.400
4.488
V
2
CS release voltage
+V
DET1
4.436
4.545
4.654
V
RESET detection voltage
-V
DET2
V
OUT
voltage detection
2.352
2.400
2.448
V
RESET release voltage
+V
DET2
2.467
2.528
2.589
V
PREEND detection voltage
-V
DET3
V
BAT
voltage detection
2.548
2.600 2.652
V
PREEND release voltage
+V
DET3
2.682
2.748
2.814
V
Operating voltage
V
opr
V
IN
or
V
BAT
1.7
16 V
Detection voltage temperature coefficient
1
DET
1
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
2
DET
2
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
3
DET
3
DET
V
Ta
V
-
-
Ta = -40C to +85C
100
ppm/C
Sink current
I
SINK
V
DS
= 0.5 V, V
IN
= V
BAT
= 2.0 V
RESET
1.50 2.30
mA 3
PREEND
1.50 2.30
mA
CS
1.50 2.30
mA
Leakage
current
I
LEAK
V
DS
= 16 V, V
IN
= 16 V
0.1 A
Switch voltage
V
SW1
V
BAT
= 2.8 V, V
IN
voltage detection
+V
DET1
0.75
+V
DET1
0.77
+V
DET1
0.79
V 4
CS output inhibit voltage
V
SW2
V
BAT
= 3.0 V, V
OUT
voltage detection
V
OUT
0.93
V
OUT
0.95
V
OUT
0.97
V 5
V
BAT
switch leakage current
I
LEAK
V
IN
= 6 V, V
BAT
= 0 V
0.1 A 6
V
BAT
switch resistance
R
SW
V
IN
= Open, V
BAT
= 3.0 V, I
OUT
= 10 to 500 A
30 60 7
Switch voltage temperature coefficient
1
SW
1
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 4
CS output inhibit voltage temperature
coefficient
2
SW
2
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 5
Current
consumption
I
SS1
V
IN
= 6 V, V
BAT
= 3.0 V, Unload
7 15 A 8
I
BAT1
0.26 0.50 A
I
BAT2
V
IN
= Open, V
BAT
= 3.0 V, Unload
Ta
= 25C
1.0 2.1 A
Ta
= 85C
3.5 A
Backup power supply input voltage
V
BAT
1.7
4.0 V 7
Remark The number in the Test Circuit column corresponds to the circuit number in the "Test Circuit" section.
V
o
l
t
age regul
ator
V
o
l
t
age detector
S
w
i
t
ch uni
t
To
t
a
l
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
11
6. S-8424AAGxx
Table 9 Electrical Characteristics
(Unless otherwise specified: Ta
= 25C)
Parameter Symbol
Conditions
Min.
Typ.
Max.
Unit
Test
Circuit
Output voltage 1
V
RO
V
IN
= 6 V, I
RO
= 30 mA
2.744
2.800
2.856
V
1
Dropout voltage 1
V
drop1
V
IN
= 6 V, I
RO
= 30 mA
356 474 mV
Load stability 1
V
RO1
V
IN
= 6 V, I
RO
= 0.1 to 30 mA
50 100 mV
Input stability 1
V
RO2
V
IN
= 6 to 16 V, I
RO
= 30 mA
5 20 mV
Output voltage temperature coefficient 1
RO
RO
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Output voltage 2
V
OUT
V
IN
= 6 V, I
OUT
= 50 mA
2.744
2.800
2.856
V
Dropout voltage 2
V
drop2
V
IN
= 6 V, I
OUT
= 50 mA
401 540 mV
Load stability 2
V
OUT1
V
IN
= 6 V, I
OUT
= 0.1 to 50 mA
50 100 mV
Input stability 2
V
OUT2
V
IN
= 6 to 16 V, I
OUT
= 50 mA
5 20 mV
Output voltage temperature coefficient 2
OUT
OUT
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Primary power input voltage
V
IN
16 V
CS detection voltage
-V
DET1
V
IN
voltage detection
4.312
4.400
4.488
V
2
CS release voltage
+V
DET1
4.436
4.545
4.654
V
detection
voltage
-V
DET2
V
OUT
voltage detection
2.352
2.400
2.448
V
RESET release voltage
+V
DET2
2.467
2.528
2.589
V
PREEND detection voltage
-V
DET3
V
BAT
voltage detection
2.548
2.600 2.652
V
PREEND release voltage
+V
DET3
2.682 2.748 2.814
V
Operating voltage
V
opr
V
IN
or
V
BAT
1.7
16 V
Detection voltage temperature coefficient
1
DET
1
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
2
DET
2
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
3
DET
3
DET
V
Ta
V
-
-
Ta = -40C to +85C
100
ppm/C
Sink current
I
SINK
V
DS
= 0.5 V, V
IN
= V
BAT
= 2.0 V
RESET
1.50 2.30
mA 3
PREEND
1.50 2.30
mA
CS
1.50 2.30
mA
Leakage
current
I
LEAK
V
DS
= 16 V, V
IN
= 16 V
0.1 A
Switch voltage
V
SW1
V
BAT
= 2.8 V, V
IN
voltage detection
+V
DET1
0.75
+V
DET1
0.77
+V
DET1
0.79
V 4
CS output inhibit voltage
V
SW2
V
BAT
= 3.0 V, V
OUT
voltage detection
V
OUT
0.93
V
OUT
0.95
V
OUT
0.97
V 5
V
BAT
switch leakage current
I
LEAK
V
IN
= 6 V, V
BAT
= 0 V
0.1 A 6
V
BAT
switch resistance
R
SW
V
IN
= Open, V
BAT
= 3.0 V, I
OUT
= 10 to 500 A
30 60 7
Switch voltage temperature coefficient
1
SW
1
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 4
CS output inhibit voltage temperature
coefficient
2
SW
2
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 5
Current consumption
I
SS1
V
IN
= 6 V, V
BAT
= 3.0 V, Unload
7 15 A 8
I
BAT1
0.26 0.50 A
I
BAT2
V
IN
= Open, V
BAT
= 3.0 V, Unload
Ta
= 25C
1.0 2.1 A
Ta
= 85C
3.5 A
Backup power supply input voltage
V
BAT
1.7
4.0 V 7
Remark The number in the Test Circuit column corresponds to the circuit number in the "Test Circuit" section.
V
o
l
t
age regul
ator
V
o
l
t
age detector
S
w
i
t
ch uni
t
To
t
a
l
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
12
Seiko Instruments Inc.
7. S-8424AAJFxx
Table 10 Electrical Characteristics
(Unless otherwise specified: Ta
= 25C)
Parameter Symbol
Conditions
Min.
Typ.
Max.
Unit
Test
Circuit
Output voltage 1
V
RO
V
IN
= 6 V, I
RO
= 10 mA
3.038
3.100
3.162
V
1
Dropout voltage 1
V
drop1
V
IN
= 6 V, I
RO
= 10 mA
123 167 mV
Load stability 1
V
RO1
V
IN
= 6 V, I
RO
= 0.1 to 15 mA
50 100 mV
Input stability 1
V
RO2
V
IN
= 6 to 16 V, I
RO
= 10 mA
5 20 mV
Output voltage temperature coefficient 1
RO
RO
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Output voltage 2
V
OUT
V
IN
= 6 V, I
OUT
= 50
mA
3.038 3.100 3.162
V
Dropout voltage 2
V
drop2
V
IN
= 6 V, I
OUT
= 50 mA
401 540 mV
Load stability 2
V
OUT1
V
IN
= 6 V, I
OUT
= 0.1 to 60 mA
50 100 mV
Input stability 2
V
OUT2
V
IN
= 6 to 16 V, I
OUT
= 50 mA
5 20 mV
Output voltage temperature coefficient 2
OUT
OUT
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Primary power input voltage
V
IN
16 V
CS detection voltage
-V
DET1
V
IN
voltage detection
4.312
4.400
4.488
V
2
CS release voltage
+V
DET1
4.436
4.545
4.654
V
RESET detection voltage
-V
DET2
V
OUT
voltage detection
2.156
2.200
2.244
V
RESET release voltage
+V
DET2
2.256 2.312 2.367
V
PREEND detection voltage
-V
DET3
V
BAT
voltage detection
2.548
2.600 2.652
V
PREEND release voltage
+V
DET3
2.682
2.748
2.814
V
Operating voltage
V
opr
V
IN
or
V
BAT
1.7
16 V
Detection voltage temperature coefficient
1
DET
1
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
2
DET
2
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
3
DET
3
DET
V
Ta
V
-
-
Ta = -40C to +85C
100
ppm/C
Sink current
I
SINK
V
DS
= 0.5 V, V
IN
= V
BAT
= 2.0 V
RESET
1.50 2.30
mA 3
PREEND
1.50 2.30
mA
CS
1.50 2.30
mA
Leakage
current
I
LEAK
V
DS
= 16 V, V
IN
= 16 V
0.1 A
Switch voltage
V
SW1
V
BAT
= 2.8 V, V
IN
voltage detection
+V
DET1
0.75
+V
DET1
0.77
+V
DET1
0.79
V 4
CS output inhibit voltage
V
SW2
V
BAT
= 3.0 V, V
OUT
voltage detection
V
OUT
0.93
V
OUT
0.95
V
OUT
0.97
V 5
V
BAT
switch leakage current
I
LEAK
V
IN
= 6 V, V
BAT
= 0 V
0.1 A 6
V
BAT
switch resistance
R
SW
V
IN
= Open, V
BAT
= 3.0 V, I
OUT
= 10 to 500 A
30 60 7
Switch voltage temperature coefficient
1
SW
1
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 4
CS output inhibit voltage temperature
coefficient
2
SW
2
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 5
Current consumption
I
SS1
V
IN
= 6 V, V
BAT
= 3.0 V, Unload
7 15 A 8
I
BAT1
0.26 0.50 A
I
BAT2
V
IN
= Open, V
BAT
= 3.0 V, Unload
Ta
= 25C
1.0 2.1 A
Ta
= 85C
3.5 A
Backup power supply input voltage
V
BAT
1.7
4.0 V 7
Remark The number in the Test Circuit column corresponds to the circuit number in the "Test Circuit" section.
V
o
l
t
age regul
ator
V
o
l
t
age detector
S
w
i
t
ch uni
t
To
t
a
l
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
13
8. S-8424AAKxx
Table 11 Electrical Characteristics
(Unless otherwise specified: Ta
= 25C)
Parameter Symbol
Conditions Min.
Typ.
Max.
Unit
Test
Circuit
Output voltage 1
V
RO
V
IN
= 6 V, I
RO
= 10 mA
3.136
3.200
3.264
V
1
Dropout voltage 1
V
drop1
V
IN
= 6 V, I
RO
= 10 mA
123 167 mV
Load stability 1
V
RO1
V
IN
= 6 V, I
RO
= 0.1 to 15 mA
50 100 mV
Input stability 1
V
RO2
V
IN
= 6 to 16 V, I
RO
= 10 mA
5 20 mV
Output voltage temperature coefficient 1
RO
RO
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Output voltage 2
V
OUT
V
IN
= 6 V, I
OUT
= 50 mA
3.136
3.200
3.264
V
Dropout voltage 2
V
drop2
V
IN
= 6 V, I
OUT
= 50 mA
401 540 mV
Load stability 2
V
OUT1
V
IN
= 6 V, I
OUT
= 0.1 to 60 mA
50 100 mV
Input stability 2
V
OUT2
V
IN
= 6 to 16 V, I
OUT
= 50 mA
5 20 mV
Output voltage temperature coefficient 2
OUT
OUT
V
Ta
V
Ta
= -40C to +85C
100
ppm/C
Primary power input voltage
V
IN
16 V
CS detection voltage
-V
DET1
V
IN
voltage detection
4.508
4.600
4.692
V
2
CS release voltage
+V
DET1
4.639
4.753
4.867
V
RESET detection voltage
-V
DET2
V
OUT
voltage detection
2.352
2.400
2.448
V
RESET release voltage
+V
DET2
2.467
2.528
2.589
V
PREEND detection voltage
-V
DET3
V
BAT
voltage detection
2.548
2.600 2.652
V
PREEND release voltage
+V
DET3
2.682
2.748
2.814
V
Operating voltage
V
opr
V
IN
or
V
BAT
1.7
16 V
Detection voltage temperature coefficient
1
DET
1
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
2
DET
2
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
3
DET
3
DET
V
Ta
V
-
-
Ta
= -40C to +85C
100
ppm/C
Sink current
I
SINK
V
DS
= 0.5 V, V
IN
= V
BAT
= 2.0 V
RESET
1.50 2.30
mA 3
PREEND
1.50 2.30
mA
CS
1.50 2.30
mA
Leakage
current
I
LEAK
V
DS
= 16 V, V
IN
= 16 V
0.1 A
Switch voltage
V
SW1
V
BAT
= 2.8 V, V
IN
voltage detection
+V
DET1
0.75
+V
DET1
0.77
+V
DET1
0.79
V 4
CS output inhibit voltage
V
SW2
V
BAT
= 3.0 V, V
OUT
voltage detection
V
OUT
0.93
V
OUT
0.95
V
OUT
0.97
V 5
V
BAT
switch leakage current
I
LEAK
V
IN
= 6 V, V
BAT
= 0 V
- 0.1 A 6
V
BAT
switch resistance
R
SW
V
IN
= Open, V
BAT
= 3.0 V, I
OUT
= 10 to 500 A
30 60 7
Switch voltage temperature coefficient
1
SW
1
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 4
CS output inhibit voltage temperature
coefficient
2
SW
2
SW
V
Ta
V
Ta
= -40C to +85C
100
ppm/C 5
Current
consumption
I
SS1
V
IN
= 6 V, V
BAT
= 3.0 V, Unload
7 15 A 8
I
BAT1
0.26 0.50 A
I
BAT2
V
IN
= Open, V
BAT
= 3.0 V, Unload
Ta
= 25C
1.0 2.1 A
Ta
= 85C
3.5 A
Backup power supply input voltage
V
BAT
1.7
4.0 V 7
Remark The number in the Test Circuit column corresponds to the circuit number in the "Test Circuit" section.
V
o
l
t
age regul
ator
V
o
l
t
age detector
S
w
i
t
ch uni
t
To
t
a
l
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
14
Seiko Instruments Inc.
Test Circuit
1. 2.
V
10
F
VRO or VOUT
V
IN
VIN
VSS
VSS
RESET
VIN
VBAT
V
VOUT
V
V
CS
100 k
V
IN
100 k
PREEND
100 k
V
V
BAT
V
To measure V
DET3
, apply 6 V to VIN.
3. 4.
V
DS
V
IN
VIN
VSS
CS
RESET
A
A
VBAT VOUT
PREEND
A
V
BAT
V
IN
VOUT
VIN
VSS
VBAT
V
V
Measure the value after applying 6 V to VIN.
5. 6.
VOUT
VIN
VSS
CS
F.G
.
V
BAT
VBAT
Oscilloscope
Oscilloscope
100 k
VSS
A
V
IN
VIN
VBAT
7.
8.
I
OUT
V
BAT
VOUT
VIN
VSS
VBAT
V
V
IN
Leave open and measure the value after applying 6
V to VIN.
V
BAT
V
IN
VIN
VSS
VBAT
A
A
I
BAT
I
SS
To measure I
BAT2
, apply 6 V to VIN and then leave
VIN open and measure I
BAT
.
Figure 4 Test Circuit
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
15
Operation Timing Chart
V
IN
(V)
V
OUT
(V)
V
BAT
(V)
V
RO
(V)
V
CS
(V)
( )
V
V
RESET
( )
V
V
PREEND
Remark CS, PREEND and RESET are pulled up to V
OUT
. Y-axis is an arbitrary scale.
Figure 5 Operation Timing Chart
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
16
Seiko Instruments Inc.
Operation
The internal configuration of the S-8424A Series is as follows.
Voltage regulator 1, which stabilizes input voltage (V
IN
) and outputs it to V
RO
Voltage regulator 2, which stabilizes input voltage (V
IN
) and outputs it to V
OUT
CS voltage detector, which monitors input voltage (V
IN
)
PREEND voltage detector, which monitors output voltage (V
BAT
)
RESET voltage detector, which monitors output voltage (V
OUT
)
Switch unit
The functions and operations of the above-listed elements are described below.
1. Voltage Regulators
The S-8424A Series features on-chip voltage regulators with a small dropout voltage. The voltage of the VRO
and VOUT pins (the output pins of the voltage regulator) can separately be selected for the output voltage in
0.1 V steps between the range of 2.3 to 5.4 V.
[Dropout voltage V
drop1
, V
drop2
]
Assume that the voltage output from the VRO pin is V
RO(E)
under the conditions of output voltage 1
described in the electrical characteristics table. V
IN1
is defined as the input voltage at which output voltage
from the VRO pin becomes 98% of V
RO(E)
when the input voltage V
IN
is decreased. Then, the dropout
voltage V
drop1
is calculated by the following expression.
V
drop1
= V
IN1
- V
RO(E)
0.98
Similarly, assume that the voltage of the VOUT pin is V
OUT(E)
under the conditions of output voltage 2
described in the electrical characteristics table. V
IN2
is defined as the input voltage at which the output
voltage from the VOUT pin becomes 98% of V
OUT(E)
. Then, the dropout voltage V
drop2
is calculated by the
following expression.
V
drop2
= V
IN2
- V
OUT(E)
0.98
2. Voltage Detector
The S-8424A Series incorporates three high-precision, low power consuming voltage detectors with hysteresis
characteristics. The power of the CS voltage detector is supplied from the VIN and VBAT pins. Therefore, the
output is stable as long as the primary or backup power supplies are within the operating voltage range (1.7 to
16 V). All outputs are Nch open-drain, and need pull-up resistors of about 100 k
.
2.1 CS Voltage Detector
The CS voltage detector monitors the input voltage V
IN
(VIN pin voltage). The detection voltage can be
selected from between 2.4 and 5.3 V in 0.1 V steps. The result of detection is output at the CS pin: "Low"
for lower voltage than the detection level and "High" for higher voltage than the release level (however,
when the VOUT pin voltage is the CS output inhibit voltage (V
SW2
), a low level is output) .
Input voltage
Output voltage
Release voltage
Detection voltage
Figure 6 Definition of Detection and Release Voltages
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
17
2.2 PREEND Voltage Detector
The PREEND voltage detector monitors the input voltage V
BAT
(VBAT pin voltage). The detection voltage
can be selected from between 1.7 V and 3.4 V in 0.1 V steps. A higher voltage can also be seclected
keeping a constant difference with the RESET voltage. This function enables the warning that the backup
battery is running out. The detection result is output to the PREEND pin: "Low" for lower voltages than the
detection voltage and "High" for higher voltages than the release voltage. The power supply of the
PREEND voltage detector is supplied from the VIN pin. The output is valid only when the voltage is
supplied from the VIN pin to the VOUT pin (V
IN
V
SW1
). The ourput is the low level when the voltage is
supplied from the VBAT pin to the VOUT pin (V
IN
< V
SW1
).
2.3 RESET Voltage Detector
The RESET voltage detector monitors the output voltage V
OUT
(VOUT pin voltage). The detection voltage
can be selected from between 1.7 V and 3.4 V in 0.1 V steps. The result of detection is output at the
RESET pin: "Low" for lower voltages than the detection level and "High" for higher voltages than the
release level. RESET outputs the normal logic if the VOUT pin voltage is 1.0 V or more.
Caution The PREEND and RESET voltage detectors use the different pins, respectively.
Practically, the current is taken from the VBAT side, and consider the I/O voltage
difference (V
dif
) of M1 when M1 is ON.
3. Switch Unit
The switch unit consists of the V
SW1
and V
SW2
detectors, a switch controller, voltage regulator 2, and switch
transistor M1 (Refer to "Figure 7 Switch Unit").
REG2
VOUT
M1
VBAT
VIN
Switch
controller
V
SW1
detector
V
SW2
detector
Figure 7 Switch Unit
3.1 V
SW1
Detector
The V
SW1
detector monitors the power supply voltage V
IN
and sends the results of detection to the switch
controller. The detection voltage (V
SW1
) can be set to 77
2% or 85 2% of the CS release voltage +V
DET1
.
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
18
Seiko Instruments Inc.
3.2 V
SW2
Detector
The V
SW2
detector monitors the VOUT pin voltage and keeps the CS release voltage output low until the
VOUT pin voltage rises to V
SW2
voltage. The CS pin output then changes from low to high if the VIN pin
voltage is more than the CS release voltage (
+V
DET1
) when the VOUT pin voltage rises to 95
2% of the
output voltage of voltage regulator 2 (V
OUT
). The CS pin output changes from high to low regardless of the
V
SW2
voltage when the VIN pin voltage drops to less than the CS detection voltage (
-V
DET1
).
The CS pin output remains high if the VIN pin voltage stays higher than the CS detection voltage (
-V
DET1
)
when the VOUT pin voltage drops to less than the V
SW2
voltage due to an undershoot.
3.3 Switch Controller
The switch controller controls voltage regulator 2 and switch transistor M1. There are two statuses
corresponding to the power supply voltage V
IN
(or power supply voltage V
BAT
) sequence: a special
sequence status and a normal sequence status. When the power supply voltage V
IN
rises and becomes
equal to or exceeds the CS release voltage (
+V
DET1
), the normal sequence status is entered, but until then
the special sequence status is maintained.
(1) Special sequence status
The switch controller sets voltage regulator 2 ON and switch transistor M1 OFF from the initial status
until the primary power supply voltage V
IN
is connected and reaches more than the CS release voltage
(
+V
DET1
) in order to prevent consumption of the backup power supply regardless of the V
SW1
detector
status. This status is called the special sequence status.
(2) Normal sequence status
The switch controller enters the normal sequence status from the special sequence status once the
primary power supply voltage V
IN
reaches more than the CS release voltage (
+V
DET1
).
Once the normal sequence is entered, the switch controller switches voltage regulator 2 and switch
transistor M1 ON/OFF as shown in Table 12 according to the power supply voltage V
IN
. The time
required for voltage regulator 2 to be switched from OFF to ON is a few hundred
s at most. During
this interval, voltage regulator 2 and switch transistor M1 may both switch OFF and the VOUT pin
voltage may drop. To prevent this, connect a capacitor of 10
F or more to the VOUT pin.
When the VOUT pin voltage becomes lower than the RESET detection voltage, the status returns to
the special sequence status.
Table 12 ON/OFF Switching of Voltage Regulator 2 and
Switch Transistor M1 According to Power Supply Voltage (V
IN
)
Power Supply Voltage (V
IN
)
Voltage Regulator 2
Switch Transistor M1
VOUT Pin Voltage
V
IN
> V
SW1
ON OFF
V
OUT
V
IN
< V
SW1
OFF ON
V
BAT
- V
dif
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
19
3.4 Switch Transistor M1
Voltage regulator 2 is also used to switch from VIN pin to VOUT pin. Therefore, no reverse current flows
from VOUT pin to VIN pin when voltage regulator 2 is OFF. The output voltage of voltage regulator 2 can be
selected from between 2.3 V and 5.4 V in 0.1 V steps.
The on-resistance of switch transistor M1 is 60
or lower (I
OUT
= 10 to 500 A).
Therefore, when M1 is switched ON and VOUT pin is connected to VBAT pin, the voltage drop (V
dif
)
caused by M1 is 60
I
OUT
(output current) at maximum., and V
BAT
V
dif
(max.) is output to the VOUT pin at
minimum.
When voltage regulator 2 is ON and M1 is OFF, the leakage current of M1 is kept below 0.1
A max. (V
IN
=
6 V, Ta
= 25C) with the VBAT pin grounded (VSS pin).
VIN
VBAT
VOUT
M1
V
dif
REG2
Figure 8 Definition of V
dif
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
20
Seiko Instruments Inc.
Transient Response
1. Line Transient Response Against Input Voltage Variation
The input voltage variation differs depending on whether the power supply input (0 V to 10 V square wave) is
applied or the power supply variation (6 V and 10 V square waves) is applied. This section describes the
ringing waveforms and parameter dependency of each type. The test circuit is shown for reference.
Power supply application: 0 V to 10 V Square wave
Input voltage
Output voltage
0 V
10 V
Undershoot
Overshoot
S-8424A
Series
Fast amplifier
P.G.
VSS
VOUT
VIN
C
OUT
R
L
Oscilloscope
Figure 10 Test Circuit
Figure 9 Power Supply Application:
0 V to 10 V Square Wave
Power Supply Application
VOUT pin
VRO pin
Input Voltage
(5 V/div)
0 V
10 V
Output Voltage
(0.5 V/div)
(0.5 V/div)
C
OUT
= 22 F, I
OUT
= 50 mA, Ta = 25C
t (100
s/div)
Input Voltage
(5 V/div)
0 V
10 V
Output Voltage
(0.5 V/div)
t (100
s/div)
C
RO
= 22 F, I
RO
= 30 mA, Ta = 25C
Figure 11 Ringing Waveform of Power Supply
Application (VOUT Pin)
Figure 12 Ringing Waveform of Power Supply
Application (VRO Pin)
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
21
Power supply variation: 6 V and 10 V square waves
Overshoot
6 V
10 V
Input
voltage
Output
voltage
Undershoot
S-8424A Series
Fast amplifier
P.G.
VSS
VOUT
VIN
C
OUT
R
L
Oscillo-scope
Figure 14 Test Circuit
Figure 13 Power Supply Variation:
6 V and 10 V Square Waves
Power Supply Variation
VOUT pin
Input Voltage
(4 V/div)
Output Voltage
(50 mV/div)
6 V
10 V
10 V
6 V
C
OUT
=
=
=
= 22 F, I
OUT
=
=
=
= 50 mA, Ta ==== 25C
t (100
s/div)
Figure 15 Ringing Waveform of Power Supply Variation (VOUT Pin)
VRO pin
Input Voltage
(4 V/div)
Output Voltage
(50 mV/div)
6 V
10 V
C
RO
=
=
=
= 22 F, I
RO
=
=
=
= 30 mA, Ta ==== 25C
10 V
6 V
t (100
s/div)
Figure 16 Ringing Waveform of Power Supply Variation (VRO Pin)
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
22
Seiko Instruments Inc.
Reference data: Dependency of output current (I
OUT
), load capacitance (C
OUT
), input variation width (
V
IN
),
temperature (Ta)
For reference, the following pages describe the results of measuring the ringing amounts at the VOUT and
VRO pins using the output current (I
OUT
), load capacitance (C
OUT
), input variation width (
V
IN
), and temperature
(Ta) as parameters.
1.1 I
OUT
Dependency
(1) VOUT pin
(2) VRO pin
Ri
n
g
in
g a
m
ou
n
t
(
V
)
I
OUT
(mA)
0.00
0.05
0.10
0.15
0.20
0.25
0 20 40 60
C
OUT
=
22
F, V
IN
=
6 V and 10 V, Ta
=
25
C
Ri
n
g
in
g a
m
ou
n
t
(
V
)
I
RO
(mA)
0.00
0.05
0.10
0.15
0.20
0.25
0 20 40 60
C
RO
=
22
F, V
IN
=
6 V and 10 V, Ta
=
25
C
1.2 C
OUT
Dependency
(1) VOUT pin
(2) VRO pin
Ri
ng
ing
a
m
o
u
n
t
(
V
)
C
OUT
(
F)
0.00
0.10
0.20
0.30
0.40
0.50
0 10
40 50
20 30
I
OUT
=
50 mA, V
IN
=
6 V and 10 V, Ta
=
25
C
Ring
in
g am
ount (
V
)
C
RO
(
F)
0.00
0.10
0.20
0.30
0.40
0.50
0 10
40 50
20 30
I
RO
=
30 mA, V
IN
=
6 V and 10 V, Ta
=
25
C
Overshoot
Undershoot
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
23
1.3
V
IN
Dependency
V
IN
shows the difference between the low voltage fixed to 6 V and the high voltage.
For example,
V
IN
= 2 V means the difference between 6 V and 8 V.
(1) VOUT pin
(2) VRO pin
Ri
ng
ing
a
m
o
u
n
t
(
V
)
I
OUT
=50 mA, C
OUT
=22 F, Ta=25C
0.00
0.05
0.10
0.15
0.20
0.30
V
IN
(V)
0 1 2 3 4 5
0.25
Ri
n
g
in
g a
m
ou
n
t
(
V
)
I
RO
=30 mA, C
RO
=22 F, Ta=25C
V
IN
(V)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0 1 2 3 4 5
1.4 Temperature Dependency
(1) VOUT pin
(2) VRO pin
V
IN
=6 10 V,
I
OUT
=50 mA,
C
OUT
=22 F
0.00
0.05
0.10
0.15
0.20
0.25
0.30
50
0 50
100
Ta (
C)
Ri
ng
ing
a
m
o
u
n
t
(
V
)
V
IN
=6 10 V,
I
OUT
=30 mA,
C
RO
=22 F
0.00
0.05
0.10
0.15
0.20
0.25
0.30
50
0 50
100
Ri
n
g
in
g a
m
ou
n
t
(
V
)
Ta (
C)
Overshoot
Undershoot
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
24
Seiko Instruments Inc.
2. Load Transient Response Based on Output Current Fluctuation
The overshoot and undershoot are caused in the output voltage if the output current fluctuates between 10
A and
50 mA (V
RO
is between 10
A and 30 mA) while the input voltage is constant. Figure 17 shows the output voltage
variation due to the output current. Figure 18 shows the test circuit for reference. The latter half of this section
describes ringing waveform and parameter dependency.
10
A
50 mA
Undershoot
Overshoot
Output
current
Output
current
Figure 17 Output Voltage Variation due to Output
Current
Oscilloscope
VSS
VOUT
VIN
C
OUT
S-8424A
Series
Figure 18 Test Circuit
Figure 19 shows the ringing waveforms at the VOUT pin and Figure 20 shows the ringing waveforms at the VRO
pin due to the load variation, respectively.
VOUT pin
Output current
Output voltage
(50 mV/div)
50 mA
10
A
t (500 ms/div)
50 mA
10
A
V
IN
= 6.0 V, C
OUT
= 22 F, Ta = 25C
t (50
s/div)
Figure 19 Ringing Waveform due to Load Variation (VOUT Pin)
VRO pin
30 mA
Output current
Output voltage
(20 mV/div)
10
A
t (20 ms/div)
V
IN
=6.0 V, C
RO
=22 F, Ta=25C
t (50
s/div)
30 mA
10
A
Figure 20 Ringing Waveform due to Load Variation (VRO Pin)
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
25
Reference data: Dependency of input voltage (V
IN
), load capacitance (C
OUT
), output variation width (
I
OUT
), and
temperature (Ta)
2.1 V
IN
Dependency
(1) VOUT pin
(2) VRO pin
C
OUT
= 22 F, I
OUT
= 50 mA and 10 A, Ta = 25C C
RO
= 22 F, I
RO
= 30 mA and 10 A, Ta = 25C
Ring
i
ng am
oun
t
(
V
)
V
IN
(V)
0.00
0.04
0.06
0.08
0.10
0.12
4
5
8
10
6
7
0.02
9
Ring
i
ng am
oun
t
(
V
)
V
IN
(V)
0.00
0.04
0.06
0.08
0.10
0.12
4
5
8
10
6
7
0.02
9
2.2 C
OUT
Dependency
(1) VOUT pin
(2) VRO pin
Ri
n
g
in
g a
m
ou
n
t
(
V
)
C
OUT
(
F)
0.00
0.20
0.30
0.40
0.50
0.60
0 10
40
50
20 30
0.10
V
IN
= 6.0 V, I
OUT
= 50 mA and 10 A, Ta = 25C
Ri
n
g
in
g a
m
ou
n
t
(
V
)
C
OUT
(
F)
0.00
0.10
0.15
0.20
0.25
0.30
0 10
40
50
20 30
0.05
V
IN
= 6.0 V, I
RO
= 30 mA and 10 A, Ta = 25C
Overshoot
Undershoot
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
26
Seiko Instruments Inc.
2.3
I
OUT
Dependency
I
OUT
and
I
RO
show the fluctuation between the low current stabilized at 10
A and the high current. For
example,
I
OUT
= 10 mA means a fluctuation between 10 A and 10 mA.
(1) VOUT pin
(2) VRO pin
I
OUT
(mA)
C
OUT
= 22 F, V
IN
= 6 V, Ta = 25C
Ring
i
ng am
oun
t
(
V
)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0 10 20 30 40 50 60
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0 10 20 30 40 50 60
Ri
ng
i
i
ng
am
ou
nt
(
V
)
C
RO
=22 F, V
IN
=6.0 V, Ta=25C
I
RO
(mA)
2.4 Temperature Dependency
(1) VOUT pin
(2) VRO pin
Ta (
C)
V
IN
=6.0 V, I
OUT
=50 mA 10 A, C
OUT
=22 F
Ri
n
g
i
n
g
am
ou
nt
(
V
)
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
-50
0 50 100
Ta (
C)
V
IN
=6.0 V, I
RO
=30 mA 10 A, C
RO
=22 F
Ri
n
g
i
n
g
am
ou
nt
(
V
)
0.00
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
-50
0 50 100
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
27
Standard Circuit
VRO
V
RO
10
F
CS
VSS
6 V
3 V
VIN
VBAT
S-8424A
Series
0.1
F
+
+
1 k
10
F
V
OUT
VOUT
10
F
+
PREEND
RESET
V
OUT
100 k
100 k
V
OUT
100 k
V
OUT
Figure 21 Standard Circuit
Caution 1. Be sure to add a 10
F or more capacitor to the VOUT and VRO pins.
2. The above connections and values will not guarantee correct operation. Before setting these
values, perform sufficient evaluation on the application to be actually used.
Package Power Dissipation
0
100
200
300
400
25
50
75
Ambient temperature Ta (
C)
100
125
Po
w
e
r
di
s
s
i
p
a
t
i
on
P
D
(m
W
)
Not mounted
8-Pin TSSOP
8-Pin SON(B)
150
Figure 22 Power Dissipation
Caution The above graph in the "Figure 22" shows the power dissipation of the each package only.
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
28
Seiko Instruments Inc.
Precautions
In applications with small I
RO
or I
OUT
, the output voltages V
RO
and
V
OUT
may rise, causing the load stability to
exceed standard levels. Set I
RO
and I
OUT
to 10
A or more.
Attach the proper capacitor to the VOUT pin to prevent the RESET voltage detector (which monitors the VOUT
pin) from coming active due to undershoot.
Watch for overshoot and ensure it does not exceed the ratings of the IC chips and/or capacitors attached to the
VRO and VOUT pins.
Add a 10 F or more capacitor to the VOUT and VRO pins.
When V
IN
rises from the voltage more than V
SW1
, a low pulse of less than 4 ms flows through the PREEND pin
even when V
BAT
is more than the PREEND release voltage. Thus when monitoring the PREEND pin, make
sure to take the 4 ms interval or more after the rise of V
IN
.
Do not apply an electrostatic discharge to this IC that exceeds the performance ratings of the built-in electrostatic
protection circuit.
Application Circuits
1. When Using Timer Micro controllers for Backup to display PREEND in the primary CPU
Address data
VRO
10 F
RESET
CS
6 V
VIN
VBAT
VOUT
3 V
0.1 F
1 k
10 F
VSS
CS
RESET
VCC
100 k
100 k
Timer
microcontroller
S-8424A
Series
RESET
VCC
Main CPU
+
+
+
10
F
PREEND
INT
100 k
Figure 23 Application Circuit 1
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
29
2. When Using Secondary Battery as Backup Battery
VRO
10
F
RESET
CS
VSS
6 V
VIN
VBAT
VOUT
S - 8424 A
Series
+
+
3 V
0.1
F
VCC
INT
Microcontroller
10
F
+
100 k
10
F
100 k
RESET
Figure 24 Application Circuit 2
Remark The backup battery can be floating-recharged by using voltage regulator 1.
3. Memory Card
100 k
VSS
VIN
S-8424A
Series
RESET
VBAT
CS
VOUT
+
Card unit
+
0.1 F
3 V
SRAM
CS
V
IN
BDT1
CS
10
F
10 F
PREEND
BDT2
100 k
100 k
Figure 25 Application Circuit 3
Caution The above connections and values will not guarantee correct operation. Before setting these
values, perform sufficient evaluation on the application to be actually used.
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
30
Seiko Instruments Inc.
Characteristics
1. Voltage Regulator Unit (V
RO
=
=
=
= V
OUT
=
=
=
= 3.0 V)
1.1 Input Voltage (V
IN
) vs. Output Voltage (V
RO
) Characteristics (REG1)
(1) Ta
=
=
=
= 85C (2)
Ta
=
=
=
= 25C
I
RO
= 10 mA, 30 mA, 50 mA, 70 mA, 90 mA
I
RO
= 10 mA, 30 mA, 50 mA, 70 mA, 90 mA
2.0
2.4
2.8
3.2
2.0
3.0
4.0
5.0
V
IN
(V)
V
RO
(V)
I
RO
= 90 mA
I
RO
= 10 mA
2.0
2.4
2.8
3.2
2.0
3.0
4.0
5.0
V
IN
(V)
V
RO
(V
)
I
RO
= 90 mA
I
RO
= 10 mA
(3) Ta
=
=
=
= ----40C
I
RO
= 10 mA, 30 mA, 50 mA, 70 mA, 90 mA
2.0
2.4
2.8
3.2
2.0
3.0
4.0
5.0
V
IN
(V)
V
RO
(V)
I
RO
= 10 mA
I
RO
= 90 mA
1.2 Input Voltage (V
IN
) vs. Output Voltage (V
OUT
) Characteristics (REG2)
(1) Ta
=
=
=
= 85C (2)
Ta
=
=
=
= 25C
I
OUT
= 10 mA, 30 mA, 50 mA, 70 mA, 90 mA
I
OUT
= 10 mA, 30 mA, 50 mA, 70 mA, 90 mA
2.0
2.4
2.8
3.2
2.0
3.0
4.0
5.0
V
IN
(V)
V
OU
T
(V
)
I
OUT
= 90 mA
I
OUT
= 10 mA
2.0
2.4
2.8
3.2
2.0
3.0
4.0
5.0
V
IN
(V)
V
OU
T
(V
)
I
OUT
= 90 mA
I
OUT
= 10 mA
(3) Ta
=
=
=
= ----40C
I
OUT
= 10 mA, 30 mA, 50 mA, 70 mA, 90 mA
2.0
2.4
2.8
3.2
2.0
3.0
4.0
5.0
V
IN
(V)
V
OUT
(V)
I
OUT
= 10 mA
I
OUT
= 90 mA
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
31
1.3 Output Current (I
RO
) vs. Dropout Voltage (V
drop1
)
Characteristics
1.4 Output Current (I
OUT
) vs. Dropout Voltage (V
drop2
)
Characteristics
0.0
0.2
0.4
0.6
0.8
1.0
0
0.02
0.04
0.06
I
RO
(A)
V
dr
op
1
(V
)
Ta
=
85
C
25
C
-
40
C
0.0
0.2
0.4
0.6
0.8
1.0
0
0.02
0.04
0.06
I
OUT
(A)
V
drop2
(V)
Ta = 85C
25
C
-40C
1.5 Output Current (I
RO
) vs. Output Voltage (V
RO
)
Characteristics
1.6 Output Current (I
OUT
) vs. Output Voltage (V
OUT
)
Characteristics
2.85
2.95
3.05
3.15
3.25
1
100
10 m
1
I
RO
(A)
V
OU
T
(V
)
Ta
=
-
40
C
25
C
85
C
V
IN
=
6
V
2.85
2.95
3.05
3.15
3.25
1
100
10 m
1
I
RO
(A)
V
RO
(V
)
Ta
=
-
40
C
25
C
85
C
V
IN
=
6
V
1.7 Output voltage (V
RO
) Temperature
Characteristics
1.8 Output voltage (V
OUT
) Temperature
Characteristics
-30
-10
-20
0
30
20
10
-40 -20
0
20
40
60
80
100
Ta (
C)
V
RO
(m
V
)
V
IN
= 6 V, I
RO
= 30 mA
Based on V
RO
voltage when Ta is 25
C
-30
-10
-20
0
30
20
10
-40 -20
0
20
40
60
80 100
Ta (
C)
V
OU
T
(m
V
)
V
IN
= 6 V, I
OUT
= 50 mA
Based on V
OUT
voltage when Ta is 25
C
1.9 Input Stability (V
RO
) Temperature Characteristics 1.10 Input Stability (V
OUT
) Temperature
Characteristics
0
15
10
5
20
Ta (
C)
V
RO2
(m
V
)
-40 -20
0
20
40
80
60
100
0
15
10
5
20
Ta (
C)
V
OUT
2
(m
V
)
-40 -20
0
20
40
80
60
100
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
32
Seiko Instruments Inc.
1.11 Load Stability (V
RO
) Temperature
Characteristics
1.12 Load Stability (V
RO
) Temperature
Characteristics
Ta (
C)
0
10
20
30
40
V
RO
1
(m
V
)
-40
-20
0
20
40
80
60
100
Ta (
C)
0
10
20
30
40
V
OU
T
(m
V
)
-40
-20
0
20
40
80
60
100
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
33
2. Voltage Detector
2.1 CS Voltage Detector (
-
-
-
-V
DET1
=
=
=
= 3.3 V)
(1) Detection voltage (
-
-
-
-V
DET1
) temperature
characteristics
(2) Output current (I
SINK
) characteristics
-20
-10
0
10
20
CS
(
m
V
)
Ta (
C)
-40
-20
0
20
40
80
60
100
Based on CS (-V
DET1
) voltage when Ta is 25
C
0
5
10
15
20
25
30
0.0
1.0
2.0
3.0
4.0
V
DS
(V)
CS
I
SI
N
K
(m
A
)
V
IN
= 3 V
V
IN
= 1.7 V
Ta
= 25C
(3) Output current (I
SINK
) temperature characteristics
0
4
8
CS
I
S
INK
(m
A
)
Ta (
C)
-40 -20
0
20
40
80
60
100
2
6
10
V
IN
= V
BAT
= 2.0 V, V
DS
= 0.5 V
2.2 RESET Voltage Detector (
-
-
-
-V
DET2
=
=
=
= 2.2 V)
(1) Detection voltage (
-
-
-
-V
DET2
) temperature
characteristics
(2) Output current (I
SINK
) characteristics
-
20
-
10
0
10
20
RE
S
E
T
(
m
V
)
Ta (
C
)
-
40
-
20
0
20
40
80
60
100
Based on
RESET
(
-
V
DET2
)
voltage
when
Ta is 25
C
0
5
10
15
20
25
30
0.0
1.0
2.0
3.0
4.0
V
DS
(V)
R
ESE
T I
SI
N
K
(m
A
)
V
IN
= 1.7 V
V
IN
= 3 V
Ta = 25C
(3) Output current (I
SINK
) temperature characteristics
0
2
4
6
8
10
R
E
SET
I
SI
N
K
(
m
A
)
Ta (
C
)
-
40
-
20
0
20
40
80
60
100
V
IN
=
V
BAT
=
2.0 V, V
DS
=
0.5 V
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
34
Seiko Instruments Inc.
2.3 PREEND Voltage Detector (
-
-
-
-V
DET3
=
=
=
= 2.6 V)
(1) Detection voltage (
-
-
-
-V
DET3
) temperature
characteristics
(2) Output current (I
SINK
) characteristics
-
20
-
10
0
10
20
PR
EE
N
D
(m
V)
-
40
-
20
0
20
40
80
60
100
V
DS
(V)
Based on
PREEND
(
-
V
DET3
)
voltage
when
Ta is 25
C
V
IN
= 3 V
V
IN
= 1.7 V
V
DS
(V)
0
5
10
15
20
25
30
0.0
1.0
2.0
3.0
4.0
PR
EEN
D
I
SI
N
K
(m
A
)
Ta
= 25C
(3) Output current (I
SINK
) temperature characteristics
V
IN
=
V
BAT
=
2.0 V, V
DS
=
0.5 V
10
0
4
8
PR
E
E
N
D
I
SI
N
K
(
m
A)
Ta (
C
)
-
40
-
20
0
20
40
80
60
100
2
6
BATTERY BACKUP SWITCHING IC
Rev.1.3
_10
S-8424A Series
Seiko Instruments Inc.
35
3. Switch Unit
3.1 Switch Voltage (V
SW1
) Temperature Characteristics 3.2 CS Output Inhibit Voltage (V
SW2
) Temperature
Characteristics
V
SW
1
(m
V
)
Ta (
C)
-40
-20
0
20
40
80
60
100
-20
-10
0
10
20
Based on V
SW1
voltage when Ta is 25C
V
SW
2
(m
V
)
Ta (
C)
-40 -20
0
20
40
80
60
100
-20
-10
0
10
20
Based on V
SW2
voltage when Ta is 25
C
3.3 Input Voltage (V
BAT
) vs. VBAT Switch
Resistance(R
SW
) Characteristics
3.4 V
BAT
Switch Resistance (R
SW
) Temperature
Characteristics
0
10
20
30
40
50
60
1
2
3
4
5
V
BAT
(V)
R
SW
(
)
I
OUT
= 500 A
R
SW
(
)
Ta (
C)
-40 -20
0
20
40
80
60
100
0
10
20
30
40
50
60
V
BAT
= 3 V, I
OUT
= 500 A
3.5 V
BAT
Switch Leakage Current (I
LEAK
) Temperature
Characteristics
0
10
20
30
I
L
EAK
(n
A
)
Ta (
C)
-40
-20
0
20
40
80
60
100
5
15
25
V
IN
= 6.0 V, V
BAT
= 0 V
BATTERY BACKUP SWITCHING IC
S-8424A Series
Rev.1.3
_10
36
Seiko Instruments Inc.
4. Consumption Current
4.1 V
IN
vs. V
IN
Consumption Current (I
SS1
)
Characteristics
4.2 V
BAT
vs. V
BAT2
Consumption Current (I
BAT2
)
Characteristics
Ta = 85C
25
C
-40C
0
4
8
12
16
0
2
4
6
8
10
12 14
16
18
V
IN
(V)
I
SS1
(
A)
0.0
0.5
1.0
1.5
2.0
2.0
2.4
2.8
3.2
3.6
4.0
V
BAT
(V)
I
BAT
2
(
A)
Ta = 85C
25
C
-40C
4.3 Consumption Current Temperature
Characteristics
(1) I
SS1
(2)
I
BAT2
0
4
8
12
16
I
SS1
(
A)
Ta (
C)
-40 -20
0
20
40
80
60
100
V
IN
= 6.0 V, V
BAT
= 3.0 V
0.0
0.5
1.0
1.5
2.0
I
BAT
2
(
A)
Ta (
C)
-40
-20
0
20
40
80
60
100
V
IN
= open, V
BAT
= 3.0 V
No.
TITLE
SCALE
UNIT
mm
Seiko Instruments Inc.
0.170.05
3.00
+0.3
-0.2
0.65
0.20.1
1
4
5
8
TSSOP8-A-PKG Dimensions
No. FT008-A-P-SD-1.1
FT008-A-P-SD-1.1
No.
TITLE
SCALE
UNIT
mm
Seiko Instruments Inc.
1.550.05
2.00.05
8.00.1
1.55
+0.1
-0
(6.9)
4.0
+0.4
-0.2
6.6
1.40.1
0.30.05
7 max.
1
4
5
8
4.00.1(50 pitches:200.00.3)
Feed direction
TSSOP8-A-Carrier Tape
No. FT008-A-C-SD-3.1
FT008-A-C-SD-3.1
No.
TITLE
SCALE
UNIT
mm
Seiko Instruments Inc.
13.41.0
17.51.0
130.5
20.5
210.8
QTY.
3,000
Enlarged drawing in the central part
TSSOP8-A-Reel
No. FT008-A-R-SD-3.1
FT008-A-R-SD-3.1
No.
TITLE
SCALE
UNIT
mm
3.000.2
0.30
0.65
(2.4)
(1.0)
0.525typ.
+0.1
-0.05
Seiko Instruments Inc.
No. PA008-B-P-SD-1.1
PA008-B-P-SD-1.1
SON8B-B-PKG Dimensions
1.550.05
1.550.05
2.00.05
4.00.1
3.40.1
8.00.1
0.30.05
1.20.1
No.
TITLE
SCALE
UNIT
mm
1
4
5
8
Seiko Instruments Inc.
No. PA008-B-C-SD-1.1
PA008-B-C-SD-1.1
SON8B-B-Carrier Tape
Feed direction
20.3
13.50.5
130.2
No.
TITLE
SCALE
UNIT
mm
QTY.
3,000
Seiko Instruments Inc.
No. PA008-B-R-SD-1.1
PA008-B-R-SD-1.1
SON8B-B-Reel
Enlarged drawing in the central part
The information described herein is subject to change without notice.
Seiko Instruments Inc. is not responsible for any problems caused by circuits or diagrams described herein
whose related industrial properties, patents, or other rights belong to third parties. The application circuit
examples explain typical applications of the products, and do not guarantee the success of any specific
mass-production design.
When the products described herein are regulated products subject to the Wassenaar Arrangement or other
agreements, they may not be exported without authorization from the appropriate governmental authority.
Use of the information described herein for other purposes and/or reproduction or copying without the
express permission of Seiko Instruments Inc. is strictly prohibited.
The products described herein cannot be used as part of any device or equipment affecting the human
body, such as exercise equipment, medical equipment, security systems, gas equipment, or any apparatus
installed in airplanes and other vehicles, without prior written permission of Seiko Instruments Inc.
Although Seiko Instruments Inc. exerts the greatest possible effort to ensure high quality and reliability, the
failure or malfunction of semiconductor products may occur. The user of these products should therefore
give thorough consideration to safety design, including redundancy, fire-prevention measures, and
malfunction prevention, to prevent any accidents, fires, or community damage that may ensue.
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