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 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 contacts with pull-up or pull-down current as it monitors switch change of state. The sleep mode provides low quiescent current, making the 33972 ideal for automotive and industrial products requiring low sleep state currents.
Freescale recommends the use of the "A" version devices for new designs.
Features
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Interfaces directly to microprocessor using 3.3 V / 5.0 V SPI protocol
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Selectable wake-up on change of state
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Eight programmable inputs (switches to battery or ground)
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Fourteen switch-to-ground inputs
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Active Interrupt (INT) on change-of-switch state
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Switch Voltage Range -14 – VPWR
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Operating Voltage 5.5 V – 26 V (VPWR)
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This product is included in Freescale’s , with assured supply for a minimum of 15 years after launch
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