Full-swing complementary BiCMOS logic circuits

Abstract

Full-swing BiCMOS logic circuits for complementary MOS/bipolar technologies are described. The circuits utilize a complementary emitter-follower driver configuration for efficient driving, switched base-emitter shutting to achieve full swing, and CMOS diodes for base-to-base clamping. The performance of the circuits has been demonstrated in a BiCMOS technology featuring 0.8-μm design rules and a single-poly (poly-emitter) npn-BJT (bipolar junction transistor) with an fT of 15 GHz. Using an n-well-base substrate-pnp-BJT (fT ≅ 500 MHz), a gate delay (fan-in = 2, fan-out = 1) of 232 ps was obtained with a 3.6-V supply. Low-voltage operation has been demonstrated down to 1.4 V.