2-4 Channel Pre-Amp, 240 MHz, 5 or 3V
Description:
The LD-PA-1000-049-1, LD-PA-1000-049-2 are BiCMOS devices that support a 2-channel
(4-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.
Features:
- Current Bias/Current
Sense Architecture
- +3.3 or +5V 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
- GMR resistor range: 25W
to 65W
- Programmable 5 bit GMR
head bias current:
Ib = 2mA-9.75mA
- Programmable gain control:
130V/V & 200V/V@Rmr
= 35W, Ib = 6mA
- Wide bandwidth:
BW = 150 MHz at -3dB @ Rmr = 35W
- Programmable booster
for wide bandwidth
- Equivalent input noise:
Vn = 0.8nV/ÖHz
@ Rmr = 35W
- 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 = 15W)
- 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
