Document Number: MC33975 Freescale Semiconductor Rev 11.0, 01/2014 Technical Data Multiple Switch Detection 33975 Interface with Suppressed 33975A Wake-up and 32 mA Wetting Current MULTIPLE SWITCH The 33975 Multiple Switch Detection Interface with Suppressed Wake- DETECTION INTERFACE WITH up is designed to detect the closing and opening of up to 22 switch SUPPRESSED WAKE-UP 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 33975 device has two modes of operation, Normal and Sleep. Normal mode allows programming of the device and supplies switch contacts with pull-up or pull-down current as it monitors the switch change of state. The Sleep mode provides low quiescent current, which makes the 33975 ideal for automotive and industrial products requiring low sleep state currents. Improvements are a programmable interrupt timer for Sleep mode that can be disabled, switch detection currents of 32 mA and 4.0 mA for EK SUFFIX (PB-FREE) 98ASA10556D switch-to-ground inputs, and an interrupt bit that can be reset. This 32-PIN SOICW EP device is powered using SMARTMOS technology. Applications Features Automotive systems Designed to operate from 5.5 V V 28 V PWR Industrial control systems Switch input voltage: (33975: -14 to 38 V) (33975A: -14 to 40 V) Process control systems Interfaces to microprocessor using 3.3 V/5.0 V SPI protocol Security systems Selectable wake-up on change of state Systems requiring switch status verification for safety, operation, or process control purposes 14 switch-to-ground inputs 8 programmable inputs (switches to battery or ground) Selectable wetting current (32 mA or 4.0 mA for switch-to-ground inputs) Sleep State current V 100 A, V 20 A PWR DD VDD POWER SUPPLY V BAT V BAT LVI 33975 SP0 VPWR VDD SP1 V ENABLE BAT 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. 33975 Simplified Application Diagram Freescale Semiconductor, Inc., 2005 - 2014. All rights reserved.1 Orderable Parts Table 1. Orderable Part Variations Temperature (T ) Part Number Package Switch Input Voltage Range Reference Location A MC33975TEK/R2 -14 to 38 V 5 DC -40 to 125 C 32 SOICW-EP MC33975ATEK/R2 -14 to 40 V 5 DC 33975 Analog Integrated Circuit Device Data 2 Freescale Semiconductor