LD3301-X
1 and 2-Channel
5V or 3.3V GMR Head Preamplifier
DESCRIPTION
The LD3301-1, LD3301-2 are BiCMOS devices that
support a 1-channel (2-channel) GMR Preamplifier.
They are designed for use with 4-terminal magneto-
resistive recording heads, providing a low noise
GMR head amplifier, GMR bias current control, thin
film write driver, write current control, thermal
asperity detection and correction. Fast recovery mode
can be also programmed to put the chip faster in read
mode from any other existing modes. The device is
programmable for read gain, GMR resistance
measurement, and thermal asperity threshold level.
The device allows multiple channel write functions
for servo writing. Half or all of the heads can be
simultaneously selected in the servo write mode.
Features and thresholds are controlled through a
serial port interface. This product requires +3.3V or
+5V supply voltage. Available in flip-chip or TSSOP
packages.
GMR resistor range: 25鈩?to 65鈩?/div>
Programmable 5 bit GMR head bias current:
Ib = 2mA-9.75mA
Programmable gain control: 130V/V & 200V/V
@ Rmr = 35鈩? Ib = 6mA
Wide bandwidth:
BW = 250 MHz at -1dB @ Rmr = 35鈩?/div>
Programmable booster for wide bandwidth
Equivalent input noise: Vn = 0.8nV/鈭欻z
@ Rmr = 35鈩?/div>
Impedance matched differential inputs for WDX
and WDY
Programmable 5 bit write head current:
Iw = 15 mA to 60 mA
Servo Bank Write Mode
Rise/Fall Time: 1ns@5V / 2ns@3.3V Typical
(Iw = 40mA (0-p), Ltf = 50nH, Rtf = 15鈩?
Fast recovery times: W/R = 200ns @ 5V supply,
W/R= 400ns @ 3.3V supply
Programmable write current overshoot control
Read fault and Write fault detection
Rmr value measurement mode
GMR Head Open/Short and TF Head Protection
Programmable (7 bits) thermal asperity detection
threshold control and programmable thermal
asperity compensation
Serial port read back capability
GMR ESD protection diodes on reader
Internal capacitor
FEATURES
Current Bias/Current Sense Architecture
+5V or +3.3V Supply
3.3V CMOS compatible Logic Interface
Power Management
Integrated reference resistor
Single ended input to reader with one side
grounded externally
Differential read output
RGND
GND
RREF
VCC
SDEN
SCLK
SDATA
SERIAL PORT
AND DATA
REGISTER
HEAD
SELECT
2K
READ BIAS
CONTROL
DUMMY HEAD
RBW
MRRB
MODE
CONTROL
POWER
MANAGEMENT
LOW VOLTAGE
FAULT
MR BIAS
CURRENT
5-BIT DAC
WRITE
CURRENT
5-BIT DAC
TA DETECTION
THRESHOLD
7-BIT DAC
THERMAL
ASPERITY
DETECTION AND
CORRECTION
W0X
W0Y
R0
MRGND
PREAMPS AND
WRITE
DRIVERS
RDX
RDY
READ
OUTPUT
BUFFER
WDX
WDY
PECL
INPUT
BUFFER
HEAD UNSAFE
DETECT
HEAD
VOLTAGE
MEASUREMENT
FLT
LDIC Confidential
1
version 1.6.2
1
