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