AN 8-B, 40 MSAMPLES S SWITCHED-CURRENT-MODE TRACK-AND-HOLD CIRCUIT ONA BICMOS SEA-OF-GATES ARRAY/

A fully differential track-and-hold circuit based on the switched-curr ent processing has been integrated on a fully complementary 1.2 mu m-6 GHz BiCMOS sea of gates array, It is based on a BICMOS switched-curre nt memory cell which uses MOS transistors to store the analog informat ion and bipolar transistors to implement the switch, This improves the speed achievable and the distortion compared to a CMOS only switched- current memory cell, A differential configuration Is also presented wh ich made it possible to improve performances such as the hold mode fee dthrough (< -67 dB @ 10 MHz) or the pedestal error. The acquisition ti me for a full scale step is 22 ns, in order to reach the final value w ithin 0.1%, It achieves 8-b precision at a sample-rate of 40 MHz under Nyquist condition, a full scale track-mode bandwidth of 150 MHz and a consumption of 80 mW for a surface of 0.44 mm(2).