The 33972 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.

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)
• 8 programmable inputs (switches to battery or ground)
• 14 switch-to-ground inputs
• Typical standby current - VPWR = 100 μA and VDD = 20 μA
• Active interrupt (INT) on change-of-switch state