Page 1
LD3501-XX
2, 4, 6, 8, up to 16-Channel
+5V, MR Head Preamplifier
version 1.5
DESCRIPTION
The LD3508 is a 5-Volt only 8-channel MR Pre-Amp,
one of the families of LD35XX MR Pre-Amp
integrated circuit products designed for use with
Magneto-Resistive recording heads. It is based on
external component design to provide maximum
programmability. These devices support 2, 4, 6, 8, 10
up to 16-channel MR Heads. It contains an MR low
noise read amplifier, a thin film head write driver and
mode select to provide the ability to control the
multiple operation modes. External components
provide programmable Read Gain, Programmable
Thermal Asperity Threshold Detection, and Correction,
Write Currents and MR bias current. This product
family requires 5V-supply voltage. These devices are
available in VQFP, or flip chip.
FEATURES
Ø 70 to 120Mhz - 3db Bandwidth
Ø Typical write current rise/fall time = 3.5ns (typical
conditions)
Ø Programmable Read Amplifier Gain through
external voltage.
Ø Programmable Thermal Asperity Threshold
Detection and correction through external resistor.
Ø MR Head: Differential current bias, Voltage sense
MR Head Read Amp.
Ø Programmable MR head bias current range 6-16
mA
Ø MR read input noise = 0.6nv/√Hz
Ø Programmable write current range 15 - 45 mA
Ø Write head unsafe sensing
Ø Head Swing = 8Vp-p differential
Ø Servo write capability
Ø Power on Reset
Ø Power supply fault protection
Write
Interface
Read
Interface
Read
Bias
Source
Write
Data
Control
Block
8 - Channel R/W, MR Bias
Write Driver
Dummy
Head
Interface/Command Control Block
WDY CN GNDR GND
VCC HUS
RDX
RDY
CBX CBY
HR0
HW0X
HW0Y
HR7
HW7X
HW7Y
SWSBY
WRN
CHEN
WI
BLOCK DIAGRAM
WDX TAEN
RG
Head
Select
HS0 HS1 HS2
RI
RDMY
POR
Current
Generator
Head
Unsafe
Prog.
Thermal
Asp. Detc.
Amplifier
Prog. Gain
Post Pre
Amplifier
CZX CZY
Page 2
LD3501-XX
2, 4, 6, 8, up to 16-Channel
+5V, MR Head Preamplifier
Page 10 version 1.5
1 2 3 4 5 6 7 8 9 10
11
12
13
14
15
16
17
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20
21
22
23
24
34 33 32 31 30 29 28 27 26 25
48
47
46
45
44
43
42
41
40
39
38
37
36
35
HS1
HS2
CHEN
RWN
SWSBY
HR7
HW7Y
HW7X
HR6
HW6Y
RDMYRGTAENCNGNDR
HW0X
HW0Y
HR0
HW1X
HW1Y
HW6X
HW5Y
HR5
HW5X
HR4
HW4Y
HR3
HW4X
HW3Y
HW3X
HR2
HW2X
HW2Y
HR1
HS0
WDY
HUS
WDX
WI
RI
GND
VCC
RDY
RDX
CBY
CZY
CBX
CZX
LD3501-XX
8-channel
FLIP CHIP (C4) PAD
FRAME
(C4 BUMPS UP)
Preliminary (Subject to change)
Page 3
LD3501-XX
2, 4, 6, 8, up to 16-Channel
+5V, MR Head Preamplifier
Page 11 version 1.5
Preliminary (Subject to change)
7 8 9 10 11 12
13
14
16
15
17
20
18
19
21
22
23
24
1 2 3 4 5 6
30 29 28 27 26 2536 35 34 33 32 31
48
47
45
46
44
41
43
42
40
39
38
37
HW0X
HW0Y
HR0
HW1X
HW1Y
HR1
HW2X
HW2Y
HR2
HW3X
HW5X
HR4
HW4Y
HR3
HW4X
HW3Y
HW6X
HR5
HW5Y
HW7Y
HR6
HW7X
HW6Y
RWN
SWSBY
HUS
WDX
WDYWIHR7
CHEN
TAEN
HS2
HS1
HS0
VCC
GND
RDX
RDY
CZX
RG
CZY
CBX
CBY
RICNGNDR
RDMY
LD3501-XX
8-Channel
VQFP Package
This document may contain preliminary information and is subject to change by LDIC without notice. LDIC assumes no responsibility or liability for any use of this information herein. Nothing in this
document shall operate as an express or implied license of indemnity under the intellectual property rights of LDIC or third parties. NO WARRENTIES OF ANY KIND, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIES WARRENTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, ARE OFFERED IN THIS DOCUMENT.
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