NXP Semiconductors MPR031EPR2

Overview

MPR031EPR2 from NXP Semiconductors (formerly Freescale) is a 2- or 3-pad proximity capacitive touch sensor controller IC designed for low-power handheld electronics. It operates from 1.71V to 2.75V, draws 8 μA in active two-electrode mode with 64 ms response and IRQ enabled, and uses an I²C interface to manage electrode status changes in Bluetooth headsets, remote controls, and mobile phones.

For engineers reviewing the MPR031EPR2 datasheet, MPR031EPR2 pinout, MPR031EPR2 application, or MPR031EPR2 equivalent, key selection factors include its uDFN-8 package size (2 × 2 × 0.65 mm), independent auto-calibration per electrode, separate touch/release thresholds, interrupt-driven electrode reporting, and support for either two electrodes with IRQ or three electrodes without IRQ.

Technical Context

The MPR031EPR2 implements a dedicated CMOS state machine architecture-not software-based-enabling deterministic, low-latency touch detection without host MCU intervention. Its internal logic handles continuous auto-calibration, hysteresis via independent trip thresholds, and electrode multiplexing control.

It supports two operational configurations: (1) two electrodes + IRQ output for event-driven wake-up, or (2) three electrodes with IRQ disabled-both using the same I²C interface and sharing identical supply voltage (1.71–2.75 V) and temperature range (−40°C to +85°C) specifications.

Key Specifications

Pinout & Package

MPR031EPR2 is housed in an 8-pin ultra-thin dual flat no-lead (uDFN) package with wettable flank terminations, measuring 2.0 mm × 2.0 mm × 0.65 mm and specified for reflow soldering per JEDEC J-STD-020.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar proximity touch sensing applications.

Compared with MPR031EPR2, MPR032EPR2 offers identical performance with added I²C address flexibility, while AT42QT1070-MAHR provides more channels at the cost of larger footprint and higher minimum supply voltage-making MPR031EPR2 optimal for space- and power-constrained 2–3 zone interfaces.

Availability

MPR031EPR2 is available at Aetrix Electronics and suitable for remote controls, Bluetooth headsets, and mobile phone side-key interfaces requiring stable component supply and long-term lifecycle support.

Supply support for MPR031EPR2 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 company formed from the spin-off of Philips' semiconductor division, specializing in secure connectivity solutions, automotive MCUs, and sensor ICs.

The MPR031EPR2 belongs to NXP's proximity capacitive touch sensor family, engineered specifically for ultra-low-power, small-form-factor human interface applications in portable consumer electronics.

FAQ

What is the maximum number of electrodes supported by the MPR031EPR2?

The MPR031EPR2 supports up to three electrodes, but only two electrodes may be used simultaneously when the IRQ output is enabled. When IRQ is disabled via configuration register, all three electrodes (ELE0–ELE2) become active and independently monitored with auto-calibration and separate touch/release thresholds.

Does the MPR031EPR2 require an external microcontroller to operate?

No, the MPR031EPR2 contains a dedicated CMOS state machine and requires no external firmware. It autonomously monitors electrodes, performs calibration, and reports status via I²C registers. The host MCU reads results or responds to IRQ assertions - no real-time processing is needed on the MPR031EPR2 itself.

What is the purpose of separate touch and release thresholds in the MPR031EPR2?

Separate thresholds provide built-in hysteresis to prevent oscillation near detection boundaries. For each electrode, the MPR031EPR2 uses a higher capacitance value to trigger 'touch' and a lower value to register 'release', ensuring stable, noise-immune switching behavior under varying environmental conditions without requiring host-side debouncing logic.

Can the MPR031EPR2 be used with non-standard PCB trace geometries?

Yes - the MPR031EPR2 supports customizable electrode sensitivity and baseline tracking. Application Note AN3747 details pad layout guidelines, including trace width, spacing, and ground guard ring implementation. Electrode geometry affects raw capacitance range, but the MPR031EPR2's auto-calibration adapts to variations within its 0.1–30 pF input range.

Is the MPR031EPR2 RoHS compliant and halogen-free?

Yes, the MPR031EPR2 meets RoHS Directive 2011/65/EU and is halogen-free per IEC 61249-2-21. The uDFN package uses lead-free matte tin terminations and complies with JEDEC J-STD-020 moisture sensitivity level 1 (MSL1) for unlimited floor life at ≤30°C/60% RH.