Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
1
ANPEC reserves the right to make changes to improve reliability or manufacturability without notice, and advise
customers to obtain the latest version of relevant information to verify before placing orders.
1A Low Dropout Fast Response Positive Adjustable Regulator and Fixed 3.3V
NC
V
IN
V
OUT
NC
ADJ/GND
APL1541-33
4
3
2
1
8
7
6
5
V
OUT
V
OUT
V
OUT
Guaranteed Output Voltage Accuracy within 2%
Fast Transient Response
Guaranteed Dropout Voltage at Multiple Cur-
rents
Load Regulation : 0.1% Typ.
Line Regulation : 0.03% Typ.
Low Dropout Voltage : 1.1V Typ. at I
OUT
=1A
Current Limit : 1A Typ. at T
J
=125
C
On-Chip Thermal Limiting : 150
C Typ.
Adjustable Output : 1.25~7.75V
Standard 8-pin SO Power Package
Features
Applications
Peripheral Cards
Active SCSI Terminators
Low Voltage Logic Supplies
Post Regulator for Switching Power Supply
General Description
The APL1541 is a low dropout three-terminal adjust-
able regulators with 1A output current capability. In
order to obtain lower dropout voltage and faster tran-
sient response, which is critical for low voltage ap-
plications , the APL1541 has been optimized.
The device is available in an adjustable version and
fixed output voltages of 3.3V, the output available
voltage range is from 1.25~7.75V with an input sup-
ply below 12V. Dropout voltage is guaranteed at a
maximum of 1.3V at 1A.
Current limit is trimmed to ensure specified output
current and controlled short-circuit current. On-chip
thermal limiting provides protection against any com-
bination of overload that would create excessive junc-
tion temperatures.
The APL1541 is available in the industry standard 8-
pin SO power package which can be used in appli-
cations where space is limited.
Pin Description
Front View for SO - 8
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
2
Ordering and Marking Information
Symbol
Parameter
Rating
Unit
V
I
Input Voltage
13.2
V
T
J
Operating Junction Temperature Range
Control Section
Power Transistor
0 to 125
0 to 150
C
T
STG
Storage Temperature Range
-65 to +150
C
T
L
Lead Temperature (Soldering, 10 second)
260
C
Absolute Maximum Ratings
Electrical Characteristics
APL1541
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
V
REF
Reference Voltage
APL1541
10mA
I
OUT
1A, 1.4V
(V
IN
-V
OUT
)
9.75V,
T
J
=0~125
C
1.225
1.250
1.275
V
V
OUT
Output Voltage
APL1541-33
T
J
=0~125
C,
0
I
OUT
1A, 4.75V
V
IN
12V,
3.235
3.300
3.365
V
REG
LINE
Line Regulation
APL1541
APL1541-33
T
J
=0~125
C
I
OUT
=
10mA, 1.5V
(V
IN
-V
OUT
)
9.75V, (note1)
I
OUT
=
0A, 4.75V
(V
IN
-V
OUT
)
7.75V, (note 1)
0.03
1
0.2
6
%
mV
REG
LOAD
Load Regulation
APL1541
APL1541-33
T
J
=0~125
C
(V
IN
-V
OUT
)
=3V, 0
I
OUT
1A ,(note 1)
V
IN
=4.75V, 0
I
OUT
1A ,(note 1)
0.1
1
0.4
10
%
mV
I
OUT
=100mA ,T
J
=0~125
C
1
1.1
V
D
Dropout Voltage
I
OUT
=500mA ,T
J
=0~125
C
I
OUT
=1A ,T
J
=0~125
C
1.05
1.1
1.2
1.3
V
P a c k a g e C o d e
K : S O P -8
T e m p . R a n g e
C : 0 to 7 0 C
H a n d lin g C o d e
T U : T u b e
T R : T a p e & R e e l
V o lta g e C o d e
3 3 : 3 .3 V B la n k : A d ju s ta b le V e rs io n
L e a d F re e C o d e
L : L e a d F re e D e vic e B la n k : O rig in a l D e v ic e
A P L 1 5 4 1 -
H a n d lin g C o d e
T e m p . R a n g e
P a c k a g e C o d e
V o lta g e C o d e
A P L 1 5 4 1
XX XX X
XX XX X - D a te C o d e
A P L 1 5 4 1 -
A P L 1 5 4 1
XX XX X3 3
XX XX X - D a te C o d e
A P L 1 5 4 1 - 3 3 :
L e a d F re e C o d e
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
3
Electrical Characteristics Cont.
APL1541
Symbol
Parameter
Test Conditions
Min.
Typ.
Max.
Unit
I
LIMIT
Current Limit
(V
IN
-V
OUT
)=5V, T
J
=25
C
1
A
I
ADJ
Adjust Pin Current
APL1541
(V
IN
-V
OUT
)
=3V, I
OUT
=10mA, T
J
=0~125
C
60
120
A
I
ADJ
Adjust Pin Current
Change
APL1541
T
J
=
0~125
C, 10mA
I
OUT
1A,
1.4V
(V
IN
-V
OUT
)
9.75V
0.2
5
A
I
O
Minimum Load
Current
APL1541
T
J
=0~125
C, (V
IN
-V
OUT
)=9.75V, (note 3)
1.7
mA
PSRR
Ripple Rejection
F
RIPPLE
=120Hz, V
RIPPLE
=1V
P-P,
(V
IN
-V
OUT
)
=3V, T
J
=0~125
C
60
75
dB
T
R
Thermal
Regulation
T
J
=25
C, 30ms Pulse
0.01
0.02
%/ W
T
S
Temperature
Stability
0.5
%
L
S
Long -Term
Stability
T
J
=125
C,1000Hrs.
0.3
%
V
N
RMS Output
Noise
T
J
=25
C,10Hz
F
10kHz,
(% of V
OUT
)
0.003
%
th
Thermal
Resistance
Junction to Case, at Tab
Junction to ambient
15
50
C/ W
I
q
Quiescent Current
APL1541-33
T
J
=0~125
C,
V
IN
12V
5.5
10
mA
Note 1: See thermal regulation specifications for changes in output voltage due to heating effects. Load line regulations are mea-
sured at a constant junction temperature by low duty cycle pulse testing.
Note 2: Dropout voltage is specified over the full output current range of the device. Dropout voltage is defined as the minimum input/
output differential measured at the specified output current. Test points and limits are also shown on the Dropout Voltage curve.
Note 3: Minimum load current is defined as the minimum output current required to maintain regulation.
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
4
Application Circuits
A P L 1 5 4 1
I N
O U T
A D J
V
I N
V
O U T
1 0 u F
C
1 *
R 1
1 2 1
1 0 0 u F
C
2 *
R 2
1 K
1.25V to 7.75V Adjustable Regulator
*Needed if device is far from filter capacitors
V
OUT
= 1.250V x
R 1 + R 2
R 1
A P L 1 5 4 1 -3 3
IN
O U T
G N D
V
IN
= 5 V
1 0 u F
1 0 u F
V
O U T
= 3 .3 V
A P L 1 5 4 1
IN
O U T
A D J
V
IN
V
O U T
R 2
3 6 5
1 %
C 1
1 0 u F
1 5 0 u F
R 1
1 2 1
1 0 u F
Improving Ripple Rejection
*C1 improves ripple rejection.XC should be approximately
equal to R1 at ripple frequency
A P L 1 5 4 1
I N
O U T
A D J
V
I N
5 V
1 0 u F
1 2 1
1 %
1 0 0 u F
1 K
3 6 5
1 %
T T L
1 K
5V Regulator with Shutdown
Simple 5V to 3.3V Regulation
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
5
0
0.5
1
1.5
2
2.5
3
3.5
0
1
2
3
4
5
6
7
8
9
0.9
0.95
1
1.05
1.1
1.15
1.2
1.25
0
0.2
0.4
0.6
0.8
1
0
1
2
3
4
5
6
-20
30
80
130
180
-0.05
0
0.05
0.1
0.15
0
0.5
1
1.5
2
2.5
3
3.5
4
4.5
5
-100
100
300
500
700
900
-0.03
-0.02
-0.01
0
0.01
0.02
Typical Characteristics
Load Transietn Response
Output Current (A)
Time (
S)
C
IN
=10
F
C
OUT
=10
F Tantalum
V
IN
=5V
APL1541-33
Line Transient Response
APL1541-33
Input V
oltage (V)
Time (
S)
C
IN
=10
F
C
OUT
=10
F Tantalum
I
OUT
=0.1A
Dropout Voltage vs. Output Current
Dropout V
oltage (V)
Output Current (A)
APL1541-33
Output V
oltage (V)
Input Voltage (V)
Output Voltage vs. Input Voltage
APL1541-33
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
6
3
3.1
3.2
3.3
3.4
-50
-25
0
25
50
75
100
125
50
52
54
56
58
60
62
64
66
68
70
-50
-25
0
25
50
75
100
125
1
1.2
1.4
1.6
1.8
2
2.2
2.4
5
7
9
11
13
0
1
2
3
4
5
6
0
2
4
6
8
10
12
Typical Characteristics Cont.
Input Current vs. Input Voltage
Input Current (mA)
Input Voltage (V)
APL1541-33
Current Limit vs. Input Voltage
Input Voltage (V)
Current Limit (A)
APL1541-33
Output Voltage vs. Temperature
Temperature (C)
Output V
oltage (V)
Adjustable Pin Current vs. Temperature
Adjustable Pin Current (
A)
Temperature (C)
APL1541-33
APL1541-Adj
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
7
1
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
-50
0
50
100
150
2
3
4
5
6
7
8
-50
-25
0
25
50
75
100
125
Typical Characteristics Cont.
Temperature (C)
APL1541-33
Input Current vs. Tmeperature
Temperature (C)
Input Current (mA)
Current Limit vs. Temperature
Current Limit (A)
APL1541-33
V
IN
-V
OUT
=5V
PSRR vs. Frequency
Frequency (Hz)
PSRR (dB)
-100
+0
-90
-80
-70
-60
-50
-40
-30
-20
-10
10
200k
20
50 100 200
500 1k 2k
5k 10k 20k
50k
V
IN
-V
OUT
>=Vdropout
V
IN
-V
OUT
>=3V
C
adj
=22
F
I
OUT
=0.1A
Vripple=1V
p
-
p
APL1541-Adj
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
8
Application Information
Output Voltage
The APL1541 develops a 1.25V reference voltage be-
tween the output and the adjust terminal. By placing
a resistor between these two terminals, a constant
Current is caused to flow through R1 and down through
R2 to set the overall output voltage. Normally this
current is chosen to be the specified minimum load
current of 10mA. For fixed voltage devices R1 and R2
are included in the device.
V
IN
APL1541
O UT
IN
ADJ
V
REF
R1
R2
V
OUT
I
ADJ
60
A
Figure 1. Basic Adjustable Regulator
V
O U T
= V
R E F
(1+ )+I
A D J
R 2
R 2
R 1
Load Regulation
When the adjustable regulator is used. Load regula-
tion will be limited by the resistance of the wire con-
necting the regulator to the load. The data sheet speci-
fication for load regulation is measured at the output
pin of the device. Best load regulation is obtained
when the top of the resistor divider (R1) is tied directly
to the output pin of the device, not to the load. For
fixed voltage devices the top of R1 is internally con-
nected to the output, and the ground pin can be con-
nected to low side of the load. If R1 were connected
to the load, RP is multiplied by the divider ratio, the
effective resistance between the regulator and the load
would be:
Rp X (1+ ), Rp = Parasitic Line Resistance
R2
R1
V
IN
A P L 1 5 4 1
O U T
IN
A D J
R 1
R 2
R p
P A R A S IT IC
L IN E R E S IS T A N C E
C O N N E C T
R 1 T O C A S E
C O N N E C T
R 2 T O L O A D
R
L
Figure 2. Connections for Best Load Regulation
Input Capacitor
An input capacitor of 10
F or greater is recommended.
Tantalum, or aluminum electrolytic capacitors can be
used for bypassing. Larger Values will improve ripple
rejection by bypassing the input to the regulator.
Output Capacitor
The APL1541 requires an output capacitor to main-
tain stability and improve transient response. Proper
capacitor selection is important to ensure proper
operation. The APL1541 output capacitor selection
is dependent upon the ESR (equivalent series
resistance) of the output capacitor to maintain stability.
When the output capacitor is 10uF or greater, the out-
put capacitor should have an ESR less than 1
.
This
will improve transient response as well as promote
stability. A low-ESR solid tantalum capacitor works
extremely well and provides good transient response
and stability over temperature.
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
9
Application Information (Cont.)
Output Capacitor (Cont.)
Aluminum electrolytics can also be used, as long as
the ESR of the capacitor is <1
. The value of the
output capacitor can be increased without limit. Higher
capacitance values help to improve transient response
and ripple rejection and reduce output noise.
Ripple Rejection
The curves for Ripple Rejection were generated using
an adjustable device with the adjust pin bypassed.
With a 22
F bypassing capacitor 75dB ripple rejec-
tion is obtainable at any output level. The impedance
of the adjust pin capacitor, at the ripple frequency,
should be < R1. R1 is normally in the range of 100
-
200
. The size of the required adjust pin capacitor is
a function of the input ripple frequency. At 120Hz,
with R1=100
, the adjust pin capacitor should be
13
F. For fixed voltage devices, and adjustable de-
vices without an adjust pin capacitor, the output ripple
will increase as the ratio of the output voltage to the
reference voltage (V
OUT
/V
REF
).
APL1541 has thermal protection which limits junction
temperature to 150C. However, device functionality
is only guaranteed to a maximum junction tempera-
ture of +125C. The thermal resistance for each ap-
plication will be affected by thermal interactions with
other components on the board. Some experimenta-
tion will be necessary to determine the actual value.
The power dissipation of APL1541 is equal to :
Thermal Considerations
P
D
= (V
IN
- V
OUT
) x I
OUT
Maximum junction temperature is equal to :
T
JUNCTION
= T
AMBIENT
+ (P
D
x
JA
)
Note: T
JUNCTION
must not exceed 125C
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
10
Packaging Information
M i ll i m e t er s
I n c h e s
D i m
M i n .
M a x .
M i n .
M a x .
A
1 . 3 5
1 . 7 5
0 . 0 5 3
0 . 0 6 9
A 1
0 . 1 0
0 . 2 5
0 . 0 0 4
0 . 0 1 0
D
4 . 8 0
5 . 0 0
0 . 1 8 9
0 . 1 9 7
E
3 . 8 0
4 . 0 0
0 . 1 5 0
0 . 1 5 7
H
5 . 8 0
6 . 2 0
0 . 2 2 8
0 . 2 4 4
L
0 . 4 0
1 . 2 7
0 . 0 1 6
0 . 0 5 0
e 1
0 . 3 3
0 . 5 1
0 . 0 1 3
0 . 0 2 0
e 2
1 . 2 7 B S C
0 . 5 0 B S C
1
8
8
H
E
e 1
e 2
0.015X45
D
A
A 1
0 . 0 0 4 m a x .
1
L
SOP-8 pin ( Reference JEDEC Registration MS-012)
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
11
t 25 C to P ea k
tp
R am p-up
t
L
R am p-do w n
ts
P reheat
T sm ax
T sm in
T
L
T
P
25
Tem
p
e
r
at
ur
e
T im e
C ritical Z one
T
L
to T
P
Physical Specifications
Terminal Material
Solder-Plated Copper (Solder Material : 90/10 or 63/37 SnPb), 100%Sn
Lead Solderability
Meets EIA Specification RSI86-91, ANSI/J-STD-002 Category 3.
Reflow Condition
(IR/Convection or VPR Reflow)
Classificatin Reflow Profiles
Sn-Pb Eutectic Assembly
Pb-Free Assembly
Profile Feature
Large Body
Small Body
Large Body
Small Body
Average ramp-up rate
(T
L
to T
P
)
3
C/second max.
3
C/second max.
Preheat
-
Temperature Min (Tsmin)
-
Temperature Mix (Tsmax)
-
Time (min to max)(ts)
100
C
150
C
60-120 seconds
150
C
200
C
60-180 seconds
Tsmax to T
L
- Ramp-up Rate
3
C/second max
Tsmax to T
L
-
Temperature(T
L
)
-
Time (t
L
)
183
C
60-150 seconds
217
C
60-150 seconds
Peak Temperature(Tp)
225 +0/-5
C 240
+0/-5
C 245
+0/-5
C 250
+0/-5
C
Time within 5
C of actual Peak
Temperature(tp)
10-30 seconds
10-30 seconds
10-30 seconds 20-40 seconds
Ramp-down Rate
6
C/second max.
6
C/second max.
Time 25
C to Peak Temperature
6 minutes max.
8 minutes max.
Note: All temperatures refer to topside of the package. Measured on the body surface.
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
12
Reliability test program
Test item
Method
Description
SOLDERABILITY
MIL-STD-883D-2003
245
C , 5 SEC
HOLT
MIL-STD-883D-1005.7
1000 Hrs Bias @ 125
C
PCT
JESD-22-B, A102
168 Hrs, 100 % RH , 121
C
TST
MIL-STD-883D-1011.9
-65
C ~ 150
C, 200 Cycles
ESD
MIL-STD-883D-3015.7
VHBM > 2KV, VMM > 200V
Latch-Up
JESD 78
10ms , I
tr
> 100mA
Carrier Tape
A
J
B
T 2
T 1
C
t
A o
E
W
P o
P
K o
B o
D 1
D
F
P 1
Application
A
B
C
J
T1
T2
W
P
E
330
1
62 +1.5
12.75+
0.15
2
0.5
12.4
0.2
2
0.2
12
0. 3
8
0.1
1.75
0.1
F
D
D1
Po
P1
Ao
Bo
Ko
t
SOP- 8
5.5
1
1.55 +0.1 1.55+ 0.25 4.0
0.1
2.0
0.1
6.4
0.1
5.2
0. 1
2.1
0.1
.3
0.013
(mm)
Copyright
ANPEC Electronics Corp.
Rev. A.2 - Oct., 2003
APL1541
www.anpec.com.tw
13
Customer Service
Anpec Electronics Corp.
Head Office :
5F, No. 2 Li-Hsin Road, SBIP,
Hsin-Chu, Taiwan, R.O.C.
Tel : 886-3-5642000
Fax : 886-3-5642050
Taipei Branch :
7F, No. 137, Lane 235, Pac Chiao Rd.,
Hsin Tien City, Taipei Hsien, Taiwan, R. O. C.
Tel : 886-2-89191368
Fax : 886-2-89191369
Cover Tape Dimensions
Application
Carrier Width
Cover Tape Width
Devices Per Reel
SOP- 8
12
9.3
2500
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