An Implementation of Current-Mode Continuous-Time Transvesal Filter
Details
The recording density of modern hard-disk drives is high in order to provide low-cost data storage. As a result, adjacent bits are stored close together on the disk media and intersymbol interference (ISI) is severe. This paper presents a current-mode continuous-time transversal filter with the aim of equalization to a baseband communication digital channel like hard-disk drives. Delay blocks are main block for the transversal filter. We describe an analog delay circuit which is 3-pole lowpass filter and propose multiple phase lock loop (MPLL) locking the delay charactristic. The delay circuit consists of integrator, current mirror and OTA and it realizes5ns constant time delay on wide bandwidth (0〜50MHz) with 4.7mW power consumption. We disigned an integrator decreasing the influence of parasitic conductance and the integrator has high DC gain more than 60dB. The CMOS circuit is fabricated in 1.48μm CMOS process and it operates in 3V power supply.
