GENERAL DESCRIPTION

The SZA1000 is a single chip digital equalizer for single channel QIC (Quarter Inch Cartridge) systems with MR (Magneto Resistive) heads. It can be used with QIC 3010, QIC 3020, QIC 3080, QIC 3095, Travan 2, 3, 4 and 5, and similar formats.

It replaces a pulse detector, programmable filter and data synchronizer, and adds a FIR filter to the conventional analog solution. This makes it possible to equalize yoke-type MR heads as well as SIG (Sensor In Gap) MR heads.

FEATURES

• 3-wire serial interface for programming and status reading

• Suitable for MFM (Modified Frequency Modulation), RLL 1,7 (Run Length Limited) and similar codes

• Transfer rates with MFM code from 250 kbits/s to 4 Mbits/s

• Transfer rates with RLL(1,7) code from 500 kbits/s to 12 Mbits/s

• Programmable FIR (Finite Impulse-Response) filter makes it possible to equalize complex and asymmetric channel impulse responses

• Programmable fixed and tracking qualification thresholds provide reliable data recovery in read mode, and reliable bad sector detection in verify mode

• Read pulse output for floppy tape drives

• Digital data synchronizer based on digital PLL with maximum likelihood detector for a better error rate than can be achieved with conventional analog circuits

• Data verification can be used (with the maximum likelihood detector switched off) to find bad sectors on drives with conventional read electronics

• Servo stripe detection for TR4, QIC3080 and similar formats

• Gap detector

• 2 programmable current sources

• Peak-to-peak amplitude detector with lowpass filter for servo burst reading

• Fully digital PLL for clock and data recovery:

– Fully programmable behaviour

– No external components, no tolerance problems

– Programmable window shift

– Fast run-in capability

– Ideal zero phase restart.

• Parallel 8-bit input and output for product development and production testing

• Programmable WEQ (write equalization) circuit with transfer rates of up to 2 Mbits/s for floppy tape drives and up to 8 Mbits/s for drives with internal controllers.