Overview
The MC33978AES, produced by NXP USA Inc., is a 22-channel multiple switch detection interface designed to detect the closing and opening of up to 22 switch contacts. This SMARTMOS device is integrated with a serial peripheral interface (SPI) to transfer the switch status to a microprocessor unit (MCU). It also features a 24-to-1 analog multiplexer for reading input channels as analog inputs and includes a battery and temperature monitor accessible via the AMUX pin. The device operates in two modes: Normal mode and Low-power mode (LPM), making it suitable for applications requiring low sleep-state currents.
Key Specifications
| Parameter | Description | Min. | Max. | Unit |
|---|---|---|---|---|
| VBATP (Battery Voltage) | Battery voltage range | -0.3 | 40 | V |
| VDDQ (Supply Voltage) | Supply voltage range | -0.3 | 7.0 | V |
| SGx, SPx (Switch Input Range) | Switch input voltage range | -1.0 | 36 | V |
| Wetting Current | Programmable wetting current | 2 | 20 | mA |
| Operating Temperature (TA) | Operating temperature range | -40 | 125 | °C |
| Package | Package type | QFN (WF-TYPE) 32 pins | ||
| SPI Interface | SPI protocol compatibility | 3.3 V / 5.0 V | ||
| Standby Current (IBATP, IDDQ) | Typical standby current | 30 μA, 10 μA | μA | |
Key Features
- Detection of up to 22 switch contacts with programmable wetting current (2, 6, 8, 10, 12, 14, 16, or 20 mA)
- 24-to-1 analog multiplexer for reading input channels as analog inputs
- Battery and temperature monitoring available via the AMUX pin
- Two modes of operation: Normal mode and Low-power mode (LPM)
- Interfaces directly to an MCU using 3.3 V / 5.0 V SPI protocol
- Selectable wake-up on change of state and active interrupt (INT_B) on change-of-switch state
- Operating voltage range from 4.5 V to 36 V, with full parametric operation between 6.0 V and 28 V
Applications
- Automotive systems: Ideal for low sleep-state current requirements in automotive applications.
- Industrial control systems: Suitable for monitoring switch states in industrial environments.
- Embedded system monitoring: Used in various embedded systems requiring robust switch detection and low power consumption.
Q & A
- What is the primary function of the MC33978AES?
The MC33978AES is designed to detect the closing and opening of up to 22 switch contacts and transfer the switch status to a microprocessor unit (MCU) via a serial peripheral interface (SPI).
- What are the operating voltage ranges for the MC33978AES?
The device operates from 4.5 V to 36 V, with full parametric operation between 6.0 V and 28 V.
- What types of wetting currents are available on the MC33978AES?
The device offers programmable wetting currents of 2, 6, 8, 10, 12, 14, 16, or 20 mA.
- Does the MC33978AES support low power mode?
- What is the purpose of the 24-to-1 analog multiplexer in the MC33978AES?
The 24-to-1 analog multiplexer allows for reading the input channels as analog inputs, with the selected input signal buffered and provided on the AMUX output pin.
- How does the MC33978AES interface with a microprocessor unit (MCU)?
The device interfaces directly to an MCU using a 3.3 V / 5.0 V SPI protocol.
- What are the typical standby currents for the MC33978AES?
The typical standby currents are 30 μA for IBATP and 10 μA for IDDQ.
- Does the MC33978AES include battery and temperature monitoring?
- In what types of applications is the MC33978AES commonly used?
The MC33978AES is commonly used in automotive systems, industrial control systems, and embedded system monitoring.
- What is the package type of the MC33978AES?
The device is available in a QFN (WF-TYPE) 32-pin package.
