The 34972 Multiple Switch Detection Interface with suppressed wake-up is designed to detect the closing and opening of up to 22 switch contacts. The switch status, either open or closed, is transferred to the microprocessor unit (MCU) through a serial peripheral interface (SPI). The device also features a 22-to-1 analog multiplexer for reading inputs as analog. The analog input signal is buffered and provided on the AMUX output pin for the MCU to read.

The 34972 device has two modes of operation, Normal and Sleep. Normal mode allows programming of the device and supplies switch contacts with pull-up or pull-down current as it monitors switch change of state. The Sleep mode provides low quiescent current, which makes the 34972 ideal for industrial products requiring low sleep-state currents. This device is powered by SMARTMOS technology.

Features

•Designed to operate 5.5 V  VPWR  26 V

•Switch input voltage range -14 V to VPWR, 40 V Max

•Interfaces directly to MPU using 3.3 V / 5.0 V SPI protocol

•Selectable wake-up on change of state

•Selectable wetting current (16 or 2.0 mA)

•Eight programmable inputs (switches to supply or ground)

•14 switch-to-ground inputs

•Typical standby current - VPWR = 100 A and VDD = 20 A

•Active interrupt (INT) on change-of-switch state