33975A

Notes
1. ESD testing is performed in accordance with the Human Body Model (CZAP = 100 pF, RZAP = 1500 ), the Machine Model (CZAP = 200 pF, RZAP = 0 ), and the Charge Device Model.
2. All Programmable Switches (SP) and Switch-to-Ground (SG) input terminals when tested individually.
3. Maximum power dissipation at T_J =150°C junction temperature with no heatsink used.
4. Thermal resistance between the die and the exposed die pad.
5. Terminal soldering temperature limit is for 10 seconds maximum duration. Not designed for immersion soldering. Exceeding these limits may cause malfunction or permanent damage to the device.

Freescale offers multiple Switch Detection Interface Devices. The 33975A 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 33975A also features a 22-to-1 analog multiplexer for reading inputs as analog.

The 33975A 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, 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 switch-to-ground inputs, and an interrupt bit that can be reset.