NXP Semiconductors MC33972APEWR2

Overview

MC33972APEWR2 from NXP Semiconductors is a 32-pin SOICW EP automotive-grade multiple switch detection interface IC with suppressed wake-up functionality. It monitors up to 22 switch contacts (8 programmable SPx + 14 fixed SGx), delivers status via 3.3/5.0 V SPI, and provides analog multiplexed input reading via AMUX pin. Designed for ultra-low sleep current (70 µA typ), it supports VPWR = 5.5–26 V and switch input range of –14 V to 40 V.

For engineers reviewing the MC33972APEWR2 datasheet, MC33972APEWR2 pinout, MC33972APEWR2 application, or MC33972APEWR2 equivalent, key selection considerations include its dual-mode operation (Normal/Sleep), configurable wetting current (2.0/16.0 mA), open-drain INT/WAKE outputs, 22-to-1 analog mux capability, and automotive temperature range (–40 °C to 125 °C).

Technical Context

The MC33972APEWR2 implements a dedicated switch monitoring architecture with two independent input groups: 8 programmable SPx pins (switch-to-battery or switch-to-ground) and 14 fixed SGx pins (switch-to-ground only), all compared against a 4.0 V internal reference. Its SPI interface operates up to 6.0 MHz with 24-bit frame structure, supporting both parallel and daisy-chained multi-device configurations.

Sleep mode uses a calibrated scan timer (100–300 µs per channel, ±10% accuracy) to achieve 70 µA typical VPWR supply current while maintaining wake-up capability on switch change, WAKE pin edge, or INT pin edge. Normal mode enables full register programming-including wetting current selection, interrupt masking, analog channel selection, and tri-state control-only when VDD is applied.

Key Specifications

Pinout & Package

MC33972APEWR2 is housed in a 32-pin SOICW EP (exposed pad) package, Pb-free, with thermal pad recommended to be connected to GND for optimal thermal performance and EMI suppression.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar switch detection interface applications.

Compared with MC33972APEWR2, MC33971APEWR2 offers identical architecture at reduced channel count and lower cost, while TPS65381A-Q1 trades analog flexibility for integrated safety features-making MC33972APEWR2 optimal for cost-sensitive, analog-diagnostic-capable automotive body electronics.

Availability

MC33972APEWR2 is available at Aetrix Electronics and suitable for automotive body control modules, seat electronics, steering column interfaces, and roof console designs requiring stable component supply, AEC-Q100 qualification, and long-term production continuity.

Supply support for MC33972APEWR2 includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors is a global semiconductor leader focused on automotive, industrial, and IoT applications, delivering secure, scalable silicon solutions with deep domain expertise in vehicle electrification and connectivity.

The MC33972APEWR2 belongs to NXP's automotive system basis chip (SBC) and interface IC portfolio, designed specifically for robust, low-power switch monitoring in harsh automotive environments with extended temperature and voltage requirements.

FAQ

What is the maximum VPWR voltage rating for MC33972APEWR2?

The MC33972APEWR2 has a maximum VPWR rating of 40 V, with absolute maximum ratings specifying 50 V for short-duration transients. However, the device is characterized for normal operation between 5.5 V and 26 V, and sustained operation above 38 V requires use of the 33972A variant. For MC33972APEWR2, design margin should maintain VPWR ≤ 38 V under all conditions to avoid permanent damage.

Does MC33972APEWR2 support both 3.3 V and 5.0 V SPI communication?

Yes, MC33972APEWR2 supports 3.3 V and 5.0 V SPI communication through its VDD pin, which sets the logic level for SI, SO, CS, and SCLK interfaces. The SO driver output voltage is referenced to VDD (VSO(HIGH) ≥ VDD – 0.8 V), and input thresholds are compatible with both 3.3 V and 5.0 V CMOS logic families, eliminating need for external level shifters in mixed-voltage systems.

How does the wetting current function on MC33972APEWR2?

The MC33972APEWR2 provides selectable wetting current of either 2.0 mA or 16.0 mA per switch input, applied briefly (15–20 ms) upon closure detection to break through oxide layers on mechanical contacts. This function is programmable per channel via the Metallic Command register and applies identically to both SPx and SGx inputs, ensuring reliable detection in high-humidity or low-use automotive environments.

Can MC33972APEWR2 operate without VDD applied?

MC33972APEWR2 can remain in Sleep mode without VDD applied, drawing only 70 µA from VPWR, but cannot enter Normal mode or perform SPI communication without VDD. Wake-up via WAKE pin edge remains functional without VDD, but wake-up from CS or INT requires VDD to be present. Therefore, VDD is mandatory for configuration, diagnostics, and interrupt-driven operation.

What is the purpose of the AMUX pin on MC33972APEWR2?

The AMUX pin on MC33972APEWR2 is a buffered analog multiplexer output that provides the raw voltage of any selected SPx or SGx input channel. It enables diagnostic verification of switch voltage levels, detection of partial closures or floating inputs, and interfacing with external sensors-all using a single MCU ADC channel. Offset voltage is guaranteed ≤ ±10 mV, supporting accurate analog measurements across the full –14 V to 40 V input range.