A 200 MHz, 3 mW, 16-tap mixed-signal FIR filter

Abstract

We have built a 16-tap, 7-bit, 200 MHz, mixed-signal FIR filter that consumes 3 mW at 3.3 V. The filter uses p-channel synapse transistors to store the tap coefficients; electron tunneling and hot-electron injection to modify the tap weights; digital registers for the delay line; and multiplying digital-to-analog converters to multiply the digital delay-line values with the analog tap weights. The measured bandwidth is 225 MHz; the measured tap multiplier resolution is 7 bits at 200 MHz. The total die area is 0.13 mm/sup 2/; we can readily scale the design to higher bit resolutions and longer delay-lines.