A 1.2-GS/s 8-b silicon bipolar track & hold IC

An Si bipolar all-NPN track & hold (T&H) IC is presented for operation up to 2 GS/s. It is based on a switched emitter-follower design. The total harmonic distortion is less than -52.4 dB, corresponding to 8.4 b, up to 1.2 GS/s over the full Nyquist band. Fabricated in a 25 GHz f/sub T/ 0.4 /spl mu/m emitter width production technology, the IC consumes 460 mW, excluding the test buffer. The transistor count is 67. The T&H lends itself as a building block for multistage high-speed 8-b A/D-converters.