L6327
L6332
6 / 4 CHANNEL VOLTAGE SENSE GMR PREAMPLIFIER
PRODUCT PREVIEW
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Power Supplies +5Vdc, -5Vdc
Current bias or voltage bias (selectable) /
Differential Voltage Sense architecture
6 or 4 channel versions
38-pin TSSOP package (for either 6 or 4
channels)
Internal reference Resistor for read and write
currents
Read channel -3dB bandwidth > 400MHz
(Rmr=50 ohm no interconnect)
Input equivalent preamplifier voltage noise
0.5nV/rtHz nominal
Input equivalent MR bias current noise 10 pA/
rtHz nominal
MR bias current programmable (5 bit DAC) 1.5-
7.0mA nominal MR bias voltage programmable
(5 bit DAC) 65-335mV nominal
Programmable gain (100V/V, 150, 200 and
250V/V) and read bandwidth
Write frequency up to 300 MHz (Lh=70nH,
Rh=20 ohms, Ch=2pF, VEE=-5V)
Rise/Fall time 0.6ns ( Iw =40mA 0-pk, Lh=70nH,
Rh=20 ohms, Ch=2pF, VEE=-5V)
Write current programmable (5 bit DAC) 15-60mA
PECL write data input
Bi-directional 16-bit TTL Serial interface for
head selection, read/write currents selection,
chip parameters modification, chip enable,
vendor code and fault status read back registers
2-pin mode selection (R/W, MRR)
Bank write feature for servo write
Digital buffered head voltage DBHV / Analog
buffered head voltage ABHV pin (gain 5)
Thermal asperity detection & correction with
adjustable sensitivity level (6 bit DAC)
Automatic successive approximation digital
measurement of temperature and Rmr (7 bits)
Read and write head open/short detection, low
low supply detect and temperature monitoring
(high temperature warning and Analog
Temperature Diode Voltage measurement)
Low write frequency detection.
WRITE to READ fast recovery 150ns (same
TSSOP38
ORDERING NUMBERS: L6327
L6332
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head, including 100ns blanking period)
Head-to-head switch in READ mode - 10碌s (nom)
Head and MR bias current switching transient
current head protection
READ-to-WRITE switching 50ns (same head)
Programmable read bias during write and bank
write operation
ESD diode for GMR head protection
DESCRIPTION
L6327/L6332 is a BICMOS monolithic integrated cir-
cuit GMR differential preamplifier designed for use
with four-terminal magneto-resistive GMR read/in-
ductive write heads. It is available as either a six
(L6327) or four (L6332) channel device. The devices
consist of a voltage-sense, current-bias or voltage-
bias (selectable), differential input and differential
output, low-noise, high bandwidth read amplifier and
include fast current switching write drivers which sup-
port data rates in excess of 550 Mb/s with 70nH write
heads.
The GMR preamplifier provides programmable read
current / voltage bias and write current (5 bit DAC for
the read bias, 5 bit DAC for the write current), fault
detection circuitry and servo writing features. Read
amplifier gain, write current wave shape (overshoot,
undershoot and damping) can be adjusted and a
thermal asperity detection and correction circuit can
be enabled and programmed with different thresh-
olds (6 bit DAC) through a 16-bit bi-directional serial
interface (SDEN, SDATA, SCLK). The device oper-
ates from a +5V supply and a -5V supply (nominal).
No external components are required as a trimmed
or untrimmed resistor for reference current setting is
employed.
1/4
February 2001
This is preliminary information on a new product now in development. Details are subject to change without notice.
STMICROELECTRONICS
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