Switch Monitor Interface

The MC33884 Switch Monitor Interface is a monolithic silicon integrated circuit (IC) that performs switch monitoring functions. The device provides efficient interface between electrical switches and low voltage microprocessors. The MC33884 supplies switch contact pull–up and pull–down current while monitoring the input voltage level. All inputs are protected for transients when implemented with an appropriate static discharge capacitor used on the inputs.

The MC33884 has the following features:

• Full Operation with 7.0 V ≤ VPWR ≤ 26 V,

Limited Operation with 5.5 V ≤ VPWR ≤ 7.0 V

• Input Voltage Range: –14 V to 40 V

• Interfaces Directly to Microprocessors Using SPI Protocol

• 24–Lead Wide Body SOIC Package

• Wake–up on Change of Monitored Switch Status

• Programmable Wetting Current

• 4 Programmable Inputs to Monitor 4 Switch–to–Battery or

4 Switch–to–Ground Switches

• 6 (fixed function) Inputs to Monitor 6 Switch–to–Ground Switches

• 2 (fixed function) Inputs to Monitor 2 Switch–to–Battery Switches

• Standby Current During Normal Mode = 100 μA

• Quiescent Current in Sleep Mode < 10 μA

• Reset (RST) Input Defaults the Device to Sleep Mode

• Active Interrupt (INT) on Change of Switch State in Normal Mode

• 4 Modes of Operation

(Sleep, Normal, Polling, Polling + INT Timer)

• Designed to Operate –40°C ≤ TA ≤ 105°C