GENERAL DESCRIPTION

The ADG508F and ADG509F are CMOS analog multiplexers, with the ADG508F comprising eight single channels and the ADG509F comprising four differential channels. These multiplexers provide fault protection. Using a series n-channel, p-channel, n-channel MOSFET structure, both device and signal source protection is provided in the event of an overvoltage or power loss. The multiplexer can withstand continuous overvoltage inputs from ?40 V to +55 V. During fault conditions with power supplies off, the multiplexer input (or output) appears as an open circuit and only a few nanoamperes of leakage current will flow. This protects not only the multiplexer and the circuitry driven by the multiplexer, but also protects the sensors or signal sources that drive the multiplexer.

FEATURES

All switches off with power supply off

Analog output of on channel clamped within power supplies if an overvoltage occurs

Latch-up proof construction

Low on resistance (270 Ω typical)

Fast switching times

tON: 230 ns maximum

tOFF: 130 ns maximum

Low power dissipation (3.3 mW maximum)

Fault and overvoltage protection (?40 V to +55 V)

Break-before-make construction

TTL and CMOS compatible inputs

APPLICATIONS

Existing multiplexer applications (both fault-protected and nonfault-protected)

New designs requiring multiplexer functions