--1--
E94433A49-TE
Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by
any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the
operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits.
Absolute Maximum Ratings (Ta=25C)
Supply voltage
V
CC
7.0
V
Write current
I
W
20
mAo-p
Operating temperature
Topr 20 to +75
C
Operating temperature at Simultaneous Write
Topr 20 to +30
C
Storage temperature
Tstg 55 to +150
C
Allowable power dissipation
P
D
480
mW
Recommended Operating Conditions
Supply voltage
V
CC
5V10%
V
Description
The CXA1829N is a Read/Write amplifier for hard
disk drive thin-film heads and is designed to handle
up to 8-channel heads.
Features
Operates on a single 5V power supply.
Low power consumption.
Read: 115 mW
Write (I
W
= 15 mA): 160 mW + I
W
5
Power Save: 7 mW
Write current can be varied through an external
resistor. Built-in stabilizer circuit provides stable
current, preventing voltage and temperature drift.
Drives up to 8 heads.
Supports thin film heads or 2-pin MIG heads.
Emitter follower-type Read amplifier features 290
times gain (typ.).
Write-unsafe detection circuit.
Damping resistance is switched at Write (315
).
Simultaneous Write function.
Supply voltage monitor circuit prohibits error
writing during power surge or abnormal voltage.
IC protection circuit for head-to-ground short circuit
protection.
Differential input capacitance at Read: 14 pF (typ.).
Write data input minimum pulse width: 10 ns
Read data output in Write mode becomes a high
impedance due to the improved Read data offset
when Write is switched to Read.
Non-selected head DC voltage falls to GND level.
Structure
Bipolar silicon monolithic IC
8ch. Read/Write Amplifier for Thin Film Heads of Hard Disk Drive
30 pin SSOP (Plastic)
CXA1829N
For the availability of this product, please contact the sales office.
--2--
CXA1829N
Block Diagram and Pin Configuration
DRIVER
AMP
DRIVER
AMP
DRIVER
AMP
DRIVER
AMP
DRIVER
AMP
DRIVER
AMP
DRIVER
AMP
DRIVER
AMP
GND
H0X
H0Y
H1X
H1Y
H2X
H2Y
H3X
H3Y
H4X
H4Y
H5X
H5Y
H6X
H6Y
MODE
CONTROL
WRITE
CURRENT
SOURCE
AMP
HEAD
SELECT
POWER
ON/OFF
DETECTOR
T - FF
WRITE
SERVO
WRITE
UNSAFE
DETECTOR
IC
PROTECTOR
H7Y
H7X
WUS
WDI
V
CC
HS2
HS1
HS0
RDX
RDY
WC
PS
GND
WSER
R/W
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
20
21
22
23
24
25
26
27
28
29
30
19
--3--
CXA1829N
Pin Description
1, 30
GND
2, 3
H0X, H0Y
4, 5
H1X, H1Y
6, 7
H2X, H2Y
8, 9
H3X, H3Y
10, 11
H4X, H4Y
12, 13
H5X, H5Y
14, 15
H6X, H6Y
16, 17
H7X, H7Y
19
WUS
20
WDI
21
V
CC
22
HS2
23
HS1
24
HS0
28
R/W
29
PS
V
CC
GND
2k
2k
200k
330
330
2
4
6
8
10
12
14
16
3
5
7
9
11
13
15
17
V
CC
GND
19
V
CC
GND
2.1V
1.4V
20
100k
V
CC
2.1V
GND
22
23
24
V
CC
2.1V
GND
28
29
GND connection.
Head input.
8 channels provided.
Write-unsafe detection output.
Open collector output. When it is
high in Write mode, an error is
detected.
Write data input.
When high changes to low, input
is triggered.
5 V power supply.
Head select signal input. Eight
heads are selected as shown in
Table 2.
Read/Write signal input.
Read at high; Write at low.
Power save signal input.
Power save at high.
No.
Symbol
Equivalent circuit
Description
--4--
CXA1829N
18
WSER
25
RDX
26
RDY
27
WC
100k
VCC
2.1V
GND
18
V
CC
GND
25
26
1.25V
GND
V
CC
27
Simultaneous Write signal input.
Set to low for simultaneous Write
mode.
Read amplifier output.
Becomes a high impedance at
Write.
A setting resistor for the Write
current value is connected
between this pin and GND.
No.
Symbol
Equivalent circuit
Description
--5--
CXA1829N
Measure-
Item
Symbol
Measurement conditions
ment
Min.
Typ.
Max.
Unit
point
Current consumption for
Read
Current consumption for
Write
Current consumption for
Servo
Current consumption for
Power save
Digital low input voltage
Digital high input voltage
Digital low input current
Digital high input current
Write-unsafe output
saturation voltage
Write-unsafe output leak
current
Power ON/OFF detector
threshold voltage
Write current setting
range
Write current accuracy
Read amplifier differential
voltage gain
Bandwidth (-3 dB)
Input conversion noise
voltage
Common mode rejection
ratio
I
R
I
W
I
SE
I
P
V
IL
V
IH
I
L
I
H
V
WUS
I
WUS
V
TH
I
W
I
w
A
V
B
W
E
N
CMRR
R/W="H"
R/W="L"
WSER="L"
PS="H"
High applied voltage: 5 V
Low applied voltage: 0 V
Output current: 1 mA
Current flowing between head pins.
When Write current is I
W
[mA], then:
I
W
=
Rw
___
K
(Rw:
),
Refer to Fig. 12 (Characteristics) for K.
Input voltage SG1:1mVp-p,300kHz
Load resistance (RDX, RDY): 1k
Frequency at which Av drops by 3dB
Head impedance: 0
In-phase input voltage SG2:100mVp-p,
10 MHz
E
17
23
33
E
24
32
45
+I
W
+I
W
+I
W
mA
E
71
91
111
+4
I
W
+4
I
W
+4
I
W
E
0.8
1.4
2.0
B
0.8
D
V
F
2.0
G
H
-70
I
A
J
70
C
0.5
V
C
10
A
V
CC
3.6
3.9
4.3
V
A
A
5
15
mAo-p
A
-8
8
%
K
245
290
335
V/V
K
60
MHz
K
0.55
0.7
nV
Hz
K
50
77
dB
Electrical Characteristics (unless otherwise specified, V
CC
= 5 V, Ta = 25C, Write current I
W
= 15 mA)
Refer to Measurement Circuit 1.
--6--
CXA1829N
Measure-
Item
Symbol
Measurement conditions
ment
Min.
Typ.
Max.
Unit
point
Supply voltage rejection
ratio
Channel separation
Non-selected head voltage
PSRR
CS
V
HUS
Ripple voltage SG3: 5 V 100 mVp-p,
10 MHz
When Read amplifier output is Vp
(mVp-p), then: PSRR = 20 log (100/Vp)
+ 20 log Av
Selected head input voltage: 0 mVp-p
Non-selected head input voltage SG1:
100 mVp-p, 10 MHz
When Read amplifier output is Vcs
(mVp-p), then: CS = 20 log (100/Vcs) +
20 log Av
K
45
55
dB
K
45
55
Non
selected
0.2
V
head
Refer to Measurement Circuit 1.
--7--
CXA1829N
Item
Symbol
Measurement conditions
Min.
Typ.
Max.
Unit
Head differential
voltage amplitude
Write-unsafe detection
maximum frequency
Mode switching time
Read to Write
Mode switching time
Read to Simultaneous
Write
Mode switching time
Write to Read
Mode switching time
Safe to Unsafe
Mode switching time
Unsafe to Safe
Mode switching time
Power save to Read
Head switching time
Write current
propagation delay time
Write current rise/fall
time
V
SW
F
WUS
T
RW
T
RS
T
WR
T
SA1
T
SA2
T
PR
T
H
T
PD
T
R
/T
F
Potential difference between HX and
HY pins when Write current is
switched.
FWUS is the Write data frequency
when WUS pin is high in Write mode.
Time required for Write current to
reach 90% after Read mode is
switched to Write mode.
Time required for Write current to
reach 90% after Read mode is
switched to Simultaneous Write
mode.
Time required for Write current to
reach 10% after Write mode is
switched to Read mode.
Time required for WUS pin to
become high after the Write data is
stopped in Write mode.
Time required for WUS pin to
become low after the Write data is
input in Write mode.
Time required for RD output to reach
90% after Power Save mode is
switched to Read mode.
Time required for RD output to reach
90% when the selected head is
changed in Read mode.
L
H
= 0, R
H
= 0
Time required for Write current to
reach 90% after the Write data falling
edge.
L
H
= 0, R
H
= 0
T
R
is the time required for Write
current to reach 90% from 10%; T
F
is
the time required for it to reach 10%
from 90%.
4.4
5.2
Vp-p
280
1000
kHz
0.6
0.6
0.6
s
3
7
11
1.0
1.0
0.6
16
30
ns
5
10
Unless otherwise specified, V
CC
= 5 V, Ta = 25 C, f
WD
(Write data frequency) = 5 MHz, I
W
= 15 mA, L
H
(head
inductance) = 1 H, R
H
(head DC resistance) = 30
Refer to Measurement Circuit 2 and Timing Chart.
--8--
CXA1829N
Measurement Circuit 1
Measurement Circuit 2
GND
PS
WC
RDY
RDX
HS0
HS1
HS2
V
CC
WDI
WUS
R/W
WSER
H7X
H7Y
GND
H0X
H1Y
H1X
H1Y
H2X
H2Y
H3X
H3Y
H4X
H4Y
H5X
H5Y
H6X
H6Y
I
10k
1k
1k
AMP
1
1
1
5V
SG3
SG2
SG1
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
20
21
22
23
24
25
26
27
28
29
30
19
V
CC
5V
J
I
H
G
F
D
C
B
A
A
A
E
K
1H
1H
1H
1H
1H
1H
1H
1H
GND
PS
WC
RDY
RDX
HS0
HS1
HS2
V
CC
WDI
WUS
R/W
WSER
H7X
H7Y
GND
H0X
H1Y
H1X
H1Y
H2X
H2Y
H3X
H3Y
H4X
H4Y
H5X
H5Y
H6X
H6Y
10k
1k
1k
AMP
1
1
1
3.9k
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
20
21
22
23
24
25
26
27
28
29
30
19
V
CC
5V
PG
PG
PG
PG
PG
K
--9--
CXA1829N
Timing Chart 1
Fig. 3
Timing Chart 2
Fig. 4
50%
50%
T
RW
(T
RS
)
90%
10%
90%
T
WR
T
PR
90%
10%
90%
50%
I
WX
I
WY
PS
RDX
RDY
R/W
(WSER)
WDI
T
WR
50%
10%
10%
50%
50%
50%
T
R
T
F
90%
90%
T
SA2
TPD
90%
WUS
IWX
IWY
WDI
T
SA1
--10--
CXA1829N
Description of Functions
Read amplifier
This is a low-noise amplifier for amplifying the faint signals from the heads, and is an emitter follower output. It
outputs the signals differentially to the RDX and RDY pins, and the X side of the head and RDX pin and the Y
side of the head and RDY pin have the same polarity. RDX and RDY outputs in Write mode become high
impedance. (The outputs should be capacitor-coupled.)
Write circuit
The Write data input to the WDI pin passes through a T flip-flop where its frequency is halved. It then drives
the Write switch circuit and supplies the Write current to the heads.
The Write data is triggered at the transition from high to low and the Write current is switched.
The Write current flows from the X side when the mode changes from Read to Write.
Mode control
The modes are set as shown in Table 1 by the R/W, PS and WSER pins.
Table 1. Mode selection
The WSER pin has a built-in pull-up resistor (100 k
).
Head selection
The heads are selected as shown in Table 2 by the HS0, HS1 and HS2 pins.
Table 2. Head selection
R/W
PS
WSER
HSO
Mode
L
L
H
X
Write
H
L
H
X
Read
X
H
X
X
Power save
X
L
L
L
0, 2, 4, 6-head simultaneous Write
X
L
L
H
1, 3, 5, 7-head simultaneous Write
HS0
HS1
HS2
Head
L
L
L
0
H
L
L
1
L
H
L
2
H
H
L
3
L
L
H
4
H
L
H
5
L
H
H
6
H
H
H
7
--11--
CXA1829N
Write-unsafe detection circuit (refer to the "Notes on Operation.")
This circuit detects write errors.
In normal Write mode, the WUS output is low; in the conditions listed below, it is high.
Head input is open.
Head input is shorted to GND or V
CC
.
Write data frequency is abnormally low.
There is no Write current.
In Read mode
In Power save mode
Supply voltage is abnormal (refer to the "Power supply ON/OFF detection.")
Power supply ON/OFF detection
This circuit monitors V
CC
to detect erroneous Writes.
The error status is established when V
CC
falls below the threshold voltage (V
TH
) of the power supply ON/OFF
detector, in which case the recording and playback functions are prohibited.
When V
CC
rises above VTH, the prohibition of these functions is released.
Application Circuit
Fig. 5
GND
PS
WC
RDY
RDX
HS0
HS1
HS2
V
CC
WDI
WUS
R/W
WSER
H7X
H7Y
GND
H0X
H1Y
H1X
H1Y
H2X
H2Y
H3X
H3Y
H4X
H4Y
H5X
H5Y
H6X
H6Y
10k
1
+5V
3.9k
PULSE
DETECTOR
R
W
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
20
21
22
23
24
25
26
27
28
29
30
19
Application circuits shown are typical examples illustrating the operation of the devices. Sony cannot assume responsibility for
any problems arising out of the use of these circuits or for any infringement of third party patent and other right due to same.
--12--
CXA1829N
Notes on Operation
This IC handles high frequency and high gain signals. Please note the following;
Connect V
CC
decoupling capacitor of approximately 1000 pF near the IC.
Make the grounding area as large as possible.
Short-circuit the X and Y sides of unused head pins or leave them open.
Write data pulse width
Set the pulse width to 10 ns or more at 1.5 V to prevent misoperation.
The WC pin is a constant voltage pin. When noise affects this pin, it creates noise in Write current.
Therefore, locate Rw as close to the IC as possible.
Write-unsafe detection circuit
The WUS detection circuit operates by voltage waveform of head pin.
Fig. 6
Use the IC at T1 > 10 ns for normal operation of the WUS detecting circuit.
Use the IC with V
FB
of 2V or more. If the V
FB
is less than 2V, the write-unsafe detection maximum
frequency may become 1 MHz or more.
Please apply to the reference mentioned on this back cover since the operation range of the write-
unsafe detection circuit is greatly affected by the head inductance, head DC resistance and Write
current.
Use the IC with Ta at 30C or less in Simultaneous Write mode.
GND
V
TH
V
TH
=2V
T1
1.5V
Write data waveform
Voltage waveform
of head pin
V
FB
--13--
CXA1829N
Item
Symbol Measurement conditions
Min.
Typ.
Max.
Unit
Differential
Write mode
output capacitance
Differential output
resistance
Differential input
capacitance
Read mode
Differential input
resistance
Output resistance
Non-selected head differential
current in Write mode
Write current symmetry
C
0
R
0
C
1
R
1
R
RD
I
US
T
AS
Between head input
pins
Between head input
pins
RDX or RDY
LH=1H, RH=30
I
W
=15mA
LH=0H, RH=0
I
W
=15mA
15
pF
235
315
395
14
20
pF
0.7
1.4
k
40
60
0.2
mAp-p
-1
1
ns
Application Notes
Use the following characteristics for reference.
V
CC
=5V, Ta=25C
--14--
CXA1829N
Example of Representative Characteristics
4.0
5.0
6.0
0.99
1.00
1.01
Fig. 7 Normalized Write current
vs. Supply voltage
Normalized Write current
V
CC
-Supply voltage (V)
-25
0
25
0.98
1.00
1.02
Fig. 8 Normalized Write current
vs. Ambient temperature
Normalized Write current
Ta-Ambient temperature (C)
50
75
0.94
0.96
1.06
Fig. 10 Normalized Read amplifier differential voltage gain
vs. Ambient temperature
Normalized Read amplifier differential voltage gain
0.98
1.00
1.02
1.04
-25
0
25
Ta-Ambient temperature (C)
50
75
5
10
15
140
142
K=I
W
R
W
I
W
: mA, R
W
: k
Fig. 12 Write current setting constant K
vs. Write current
K-Write current setting constant
I
W
-Write current (mA)
144
146
148
150
V
CC
=5V
Fig. 11 Power supply ON/OFF detector threshold voltage
vs. Ambient temperature
Power supply ON/OFF detector threshold voltage (V)
-25
0
25
Ta-Ambient temperature (C)
50
75
V
TH
ON
V
TH
OFF
3.8
3.9
4.0
4.0
5.0
6.0
0.94
0.96
1.06
Fig. 9 Normalized Read amplifier differential voltage gain
vs. Supply voltage
Normalized Read amplifier differential voltage gain
V
CC
-Supply voltage (V)
0.98
1.00
1.02
1.04
Ta=25C
R
W
=10k
V
CC
=5V
R
W
=10k
Ta=25C
Vin=1mVp-p
f=300kHz
V
CC
=5V
Vin=1mVp-p
f=300kHz
SONY CODE
EIAJ CODE
JEDEC CODE
PACKAGE STRUCTURE
PACKAGE MATERIAL
LEAD TREATMENT
LEAD MATERIAL
PACKAGE WEIGHT
EPOXY RESIN
SOLDER/PALLADIUM
COPPER/42 ALLOY
30PIN SSOP (PLASTIC)
9.7 0.1
5.6
0.1
0.65 0.12
0.22
+ 0.1
0.05
30
1
15
16
1.25
+ 0.2
0.1
7.6
0.2
0.15
+ 0.05
0.02
0.1 0.1
0.5
0.2
0 to 10
A
DETAIL A
SSOP-30P-L01
SSOP030-P-0056
0.1g
NOTE: "
" Dimension do not include mold protrusion.
PLATING
0.10
Package Outline Unit : mm
CXA1829N
--15--
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