22 channel multiple switch detection interface

The CD1020 is a cost optimized switch detection interface device (MSDI) 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 22-to-1 analog multiplexer for reading the input channels as analog inputs. The analog selected input signal is buffered and provided on the AMUX output pin for the MCU to read.

FEATUREs
• Fully functional operation 6.0 V ≤ VBATP ≤ 36 V
• Full parametric operation 6.0 V ≤ VBATP ≤ 28 V
• Operating switch input voltage range from –1.0 V to 36 V
• Eight programmable inputs (switches to battery or ground)
• 14 switch-to-ground inputs
• Selectable wetting current (2, 8, 12, 16 mA)
• Interfaces directly to an MCU using 3.3 V / 5.0 V SPI protocol
• Selectable wake-up on change of state
• Typical standby current IBATP = 30 μA and IDDQ = 10 μA
• Active interrupt (INT_B) on change-of-switch state

APPLICATIONs
• Automotive
   • Heating ventilation and air conditioning (HVAC)
   • Lighting
   • Central gateway/in-vehicle networking
   • Gasoline engine management