Patent ID: 6369637
Filing Date: 2002-04-09
Classification: H03K

Abstract:
A BiCMOS analog multiplexer circuit with CMOS control circuitry comprising:multiple pairs of bipolar transistors and resistors for converting multiple differential input signals to current; a pair of output resistors through which said current is presented to develop a differential output signal; a first plurality of NMOS control switch transistors for selecting desired input signal; a second plurality of NMOS control switch transistors for dumping unselected input signal currents to circuit ground; multiple current sources to maintain appropriate paths for current to continuously flow; and bipolar emitter follower pair at circuit output to provide output drive capability; wherein the circuit improvement comprises: said first plurality of NMOS control switch transistors having lower parasitic capacitance accomplished by said NMOS control switch transistors having their gates split into even number of fingers.