22 I/O MSDI Programmable Current Analog Mux

MC33978

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The NXP® MC33978 is a multiple switch detection interface (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 through a SPI in automotive environments.

  • This SMARTMOS® device features a 24-to-1 analog multiplexer for reading analog inputs
  • The analog input signal is buffered and provided on the analog multiplexer (AMUX) output pin for the MCU to read
  • Individually selectable input currents are available in Normal and Low-Power Mode
  • Battery and temperature monitor are included in the IC and available via the AMUX pin
  • Interfaces with any MCU that supports SPI communications

Product Details

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Block Diagram

MC33978: 22 I/O Switch Detection Interface, Programmable Wetting Current, Analog Mux

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Features

Key Features

  • Designed to operate 4.5 V ≤ VBATP ≤ 36 V
  • Switch input voltage range -14 V to VPWR, 36 V Max.
  • Interfaces directly to an MCU using 3.3 V / 5.0 V SPI protocol
  • Selectable wake-up on change of state
  • Selectable wetting current (2, 6, 8, 10, 12, 14, 16, or 20 mA)
  • 8 programmable inputs (switches to battery or ground) and 14 switch-to-ground inputs
  • Typical standby current - VBATP = 30 uA and VDD = 10 uA
  • Integrated battery and temperature sensing
  • Switch monitoring device function
  • 32 and 48 package termination count
  • HLQFP48, HSOP32 and HVQFN32 package type
  • Ambient operating temperature -40 to 125 °C

Product Longevity Program

  • This product is included in the NXP Product Longevity Program ensuring a stable supply of products for your embedded designs. The The MC33978 is included in the 15-year program

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