A 160-MHz analog equalizer for magnetic disk read channels

This paper presents a 160-MHz five-tap adaptive analog equalizer for magnetic recording disk drive read channels. The design is based on a direct form finite impulse response (FIR) architecture which includes four key features: signal shuffling in the analog domain to improve noise performance, use of a master sample-and-hold stage to improve the dynamic performance and clock jitter of the clock recovery loop, use of an additional sample-and-hold stage to accommodate settling time requirements and reduce power, and use of a time interleaved sign-sign LMS algorithm which permits coefficient adaptation at low power and area. This equalizer occupies 1.36 mm² and consumes only 240 mW with 5-V supply voltage. It is fabricated in BiCMOS technology with 0.8-μm CMOS and 0.72-μm² NPN, 3LM, and DP capacitor