MC33972

Freescale Semiconductor, Inc. MOTOROLA SEMICONDUCTOR TECHNICAL DATA Document order number: MC33972 Rev 3.0, 12/2004 Advance Information 33972 Multiple Switch Detection Interface with Suppressed Wake-Up 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 terminal for the MCU to read. MULTIPLE SWITCH DETECTION INTERFACE WITH SUPPRESSED WAKE-UP Freescale Semiconductor, Inc... The 33972 device has two modes of operation, Normal and Sleep. Normal mode allows programming of the device and supplies switch contacts with pullup or pulldown current as it monitors switch change of state. The Sleep mode provides low quiescent current, which makes the 33972 ideal for automotive and industrial products requiring low sleep state currents. 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...