MC34978AES

MC34978AES is a 22-channel multiple-switch detection interface with a programmable wetting current. It 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). This SMARTMOS device also features a 24-to-1 analogue multiplexer for reading the input channels as analogue inputs. The analogue selected input signal is buffered and provided on the AMUX output pin for the MCU to read. The application includes heating ventilation and air conditioning (HVAC), lighting, central gateway/in-vehicle networking, gasoline engine management (automotive), programmable logic control (PLC), process control, temperature control, input-output control (I/O Control), single board computer, Ethernet switch (industrial).

• Fully functional operation 4.5V ≤ VBATP ≤ 36V, full parametric operation 6V ≤ VBATP ≤ 28V
• Operating switch input voltage range from -1.0V to 36V
• Eight programmable inputs (switches to battery or ground), 14 switch-to-ground inputs
• Interfaces directly to an MCU using 3.3V / 5.0V SPI protocol
• Active interrupt (INT-B) on change-of-switch state, integrated battery and temperature sensing
• Supply voltage range from 3.0 to 5.25V
• VBATP supply current is 7.0mA typ (TA = - 40°C to +125°C, VDDQ = 3.1V to 5.25V)
• Ground offset range from -1.0 to 1.0V (TA = - 40°C to +125°C)
• Switch detection threshold is 4.0V typ (TA = - 40°C to +125°C, VDDQ = 3.1V to 5.25V)
• 32 pins SOICW-EP package, temperature range from -40°C to 105°C