Design of a 1 V 250 MHz current-mode filter in conventional CMOS process

The design of a 1 V 250 MHz 8th-order continuous-time current mode filter with on-chip automatic digital frequency tuning is presented. The low voltage filter is realized using simple current amplifiers and cascade connection of current mode Sallen-Key biquads, whose configuration is modified to achieve Q switching between finite and infinite independent on the filter pole frequency for tuning. The frequency response tuning is achieved by using programmable capacitor arrays and digital tuning methods. The IM3 was simulated to be -52.5 dB for a 200 MHz and 250 MHz two-tone signal with a 300 mV p-p voltage. Simulations show frequency tuning range between 237 MHz and 325 MHz in conjunction with low power consumption (less than 27 mW) for a 1 V supply.