The 33993 Multiple Switch Detection Interface 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 Microprocessor Using 3.3 V/5.0 V SPI Protocol
• Selectable Wake-Up on Change of State
• Selectable Wetting Current (16 mA or 2.0 mA)
• 8 Programmable Inputs (Switches to Battery or Ground)
• 14 Switch-to-Ground Inputs
• VPWR Standby Current 100 µA Typical, VDD Standby Current 20 µA Typical
• Active Interrupt (INT) on Change-of-Switch State