LD4000
PR4/EPR4 Read/Write Controller
GENERAL DESCRIPTION
The part is a high performance BICMOS read channel IC that provides all of the functions needed to
implement an entire Partial Response Class 4 (PR4) read channel for zoned recording hard disk drive
systems with data rates from 67 to 212 Mbps.
Functional blocks include a serial port, an automatic gain control amplifier, a programmable filter, an
offset canceller, a peak detecting pulse qualifier, an adaptive transversal filter, a Viterbi qualifier, a 8/9
GCR ENDEC, a data synchronizer, a time base generator, an integrating servo demodulator, as shown in
figure 1.
The part requires a single +5V power supply. The part utilizes an advanced BiCMOS process technology
along with advanced circuit design techniques which results in a high performance device with low power
consumption.
FEATURES
GENERAL
AUTOMATIC GAIN CONTROL
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Dual mode AGC, continuous time during
acquisition, sampled during data reads
Separate AGC level storage pins for data and
servo
Dual rate attack and decay charge pump for
rapid AGC recovery in continuous time mode
Programmable, symmetric, charge pump
currents for data reads in sampled mode
Charge pump currents track programmable
data rate during data reads
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Register programmable data rates from 67 to
212 Mbit/s
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Sampled data read channel with Viterbi
qualification
Programmable filter for PR4 equalization
Five tap transversal filter with adaptive PR4
equalization
8/9 GCR ENDEC
Data Scrambler / Descrambler
Presettable Precoder state
Programmable write precompensation
Low operating power - 1000mW maximum
at 5.5V to allow use of TOFP packages.
Active power management is applied to
achieve this target
Register programmable power management
(<5 mW power down mode)
4-bit nibble and byte wide bi-directional
NRZ data interface
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Low drift AGC hold circuitry
Low-Z circuitry at AGC input provides for
rapid external coupling capacitor recovery
AGC Amplifier squelch during Low-Z
Wide bandwidth amplitude feedback circuit
to allow improved stability of AGC level vs.
frequency
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Programmable AGC controls
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Separate external input pins for AGC
hold, fast recovery, and Low-Z control
or
8 bit direct write mode automatically
configured for CLK=VCO/8
Serial Interface port for access to internal
program storage registers
Single power supply (5V ± 10%)
Small package footprint: 100 lead TOFP
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Internal Low-Z and fast recovery timing
for rapid transient recovery and AGC
acquisition. Timing set with external
resistors (2). Ultra fast decay current set
with external resistor.
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version 2.1