National Semiconductor Corp, Santa Clara is claiming the first monolithic hard-disk read-channel electronics, combining four independent functions in one device. The DP8491 Integrated Read Channel is a single-chip mixed analogue and digital device that is designed to integrate all the functions needed for read-channel electronics while maintaining flexibility for a variety of applications. It uses a pulse-servo detector, a data synchroniser, frequency synthesiser and write pre-compensation circuitry into a single chip that runs at up to 33Mbps rates. For notebook builders, it is designed to operate from a single 5V power supply, and supports zoned data recording techniques for increasing useful capacity of disk drives by dividing the disk into zones with matched data rates to make more efficient use of the outer portions of the disk – increasing storage by 45%. The DP8491 costs $35 each in 100-piece packs.
