The PS398/PS399 are improved high precision analog multiplexers. The PS398, an 8-channel single-ended mux, selects one of eight inputs to a common output as determined by a 3-bit address A0-A2. An EN (enable) pin when low disables all switches, useful when stacking several devices. The PS399 is a 4-channel differential multiplexer. It selects one of four differential inputs to a common differential output as determined by a 2-bit address A0, A1. An EN pin may be driven low to disable all switches. These multiplexers operate with dual supplies from +3V to +8V. Single-supply operation is possible from +3V to +15V. With +5V power supplies, the PS398/PS399 guarantee <100-ohm on-resistance. On-Resistance matching between channels is within 6-ohm. On-Resistance flatness is less than 11-ohm over the specified signal range. Each switch conducts current equally well in either direction when on. In the off state each switch blocks voltages up to the powersupply rails. Both devices guarantee low leakage currents (<2.5nA at +85oC) and fast switching speeds (tTRANS <250ns). Break-before-make switching action protects against momentary crosstalk between channels.