Document Number: MC33972 Freescale Semiconductor Rev. 19.0, 3/2012 Technical Data Multiple Switch Detection Interface with Suppressed 33972/A/T Wake-up MULTIPLE SWITCH The 33972 Multiple Switch Detection Interface with suppressed DETECTION INTERFACE 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 33972 device has two modes of operation, Normal and Sleep. Normal mode allows programming of the device and supplies switch EW SUFFIX (Pb-FREE) EK SUFFIX (Pb-FREE) contacts with pull-up or pull-down current as it monitors switch change 98ARH99137A 98ASA10556D of state. The Sleep mode provides low quiescent current, which makes 32-PIN SOICW 32-PIN SOICW EP the 33972 ideal for automotive and industrial products requiring low sleep-state currents. ORDERING INFORMATION Features Temperature Designed to operate 5.5 V V 26 V PWR Device Package Range (T ) A Switch input voltage range -14 V to V , 40 V Max PWR Interfaces directly to MPU using 3.3 V / 5.0 V SPI protocol MC33972TEW/R2 32 SOICW Selectable wake-up on change of state -40 C to 125 C MC33972ATEW/R2 Selectable wetting current (16 or 2.0 mA) MC33972ATEK/R2 32 SOICW EP 8 programmable inputs (switches to battery or ground) 14 switch-to-ground inputs Typical standby current - V 100 A and V = 20 A PWR = DD Active interrupt (INT) on change-of-switch state VDD POWER SUPPLY VBAT VBAT LVI 33972 SP0 VPWR VDD SP1 VBAT ENABLE VDD SP7 WAKE SG0 SG1 MCU SI MOSI WATCHDOG SCLK SCLK RESET SG12 CS CS SO MISO SG13 INT INT AMUX AN0 GND Figure 1. 33972 Simplified Application Diagram Freescale Semiconductor, Inc. reserves the right to change the detail specifications, as may be required, to permit improvements in the design of its products. Freescale Semiconductor, Inc., 2009-2012. All rights reserved.DEVICE VARIATIONS DEVICE VARIATIONS Table 1. Device Variations Device Switch Input Voltage Range Reference Location 33972 5, 6 -14 to 38 V DC 33972A 5, 6 -14 to 40 V DC 33972 Analog Integrated Circuit Device Data 2 Freescale Semiconductor