NXP Semiconductors NX1A4WPZ

Overview

NX1A4WPZ from NXP Semiconductors is an A4WP-compliant high-frequency wireless power receiver front-end IC for 6.78 MHz resonant charging systems. It integrates a 20 V-tolerant active rectifier, 5 V/1.2 A DC-DC buck regulator, dual LDOs (1.8 V/3.3 V @ 100 mA), 12-bit 7-channel ADC, four GPIOs, and Fast-Mode I²C interface - enabling full system control in compact portable devices.

For engineers reviewing the NX1A4WPZ datasheet, NX1A4WPZ pinout, NX1A4WPZ application, or NX1A4WPZ equivalent, this device delivers verified A4WP receiver functionality with integrated protection (OVP, OCP, OTP), programmable rectifier modes, and real-time telemetry via I²C for host MCU coordination in space-constrained wireless charging designs.

Technical Context

The NX1A4WPZ implements a digitally controlled A4WP receiver architecture centered on a high-efficiency active rectifier operating at 6.78 MHz, coupled with a synchronous DC-DC buck converter delivering regulated 5 V output. Its digital controller reads ADC-sampled parameters (V_RECT, I_RECT, V_DCOUT, I_DCOUT, chip temperature, and external NTC voltage) to autonomously manage power transfer and protection states.

Protection logic includes automatic AC-clamp over-voltage response (triggered at >18 V on LDRECT), over-power shutdown via GPIO-driven CTUNE grounding, and configurable thermal management using on-die OTP sensors (125 °C trip) and external NTC monitoring (10–60 °C range). All functions are accessible and configurable via 400 kHz I²C with fixed slave address 0x40.

Key Specifications

Pinout & Package

Package: WLCSP42 - wafer-level chip-scale package, 3.56 × 3.41 × 0.57 mm, 0.5 mm pitch, back-side coating included.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar wireless power receiver applications.

Compared with MP-A21 and BQ51222, the NX1A4WPZ uniquely delivers A4WP compliance, on-die 6.78 MHz rectification, dual LDOs, and hardware-accelerated NTC/OTP protection - reducing component count, firmware complexity, and thermal validation effort in certified 6.78 MHz receiver designs.

Availability

NX1A4WPZ is available at Aetrix Electronics and suitable for smartphone wireless charging receivers, wearable health monitors, TWS earbud cases, and medical sensor patches requiring stable component supply across industrial temperature ranges and long production lifecycles.

Supply support for NX1A4WPZ 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 secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in RF, power management, and embedded security.

The NX1A4WPZ belongs to NXP's A4WP wireless power receiver product line, designed specifically to accelerate development of compact, standards-compliant 6.78 MHz wireless charging systems for portable electronics with integrated thermal and electrical protection.

FAQ

What is the primary wireless charging standard supported by the NX1A4WPZ?

The NX1A4WPZ is explicitly designed for A4WP (Alliance for Wireless Power) compliance at 6.78 MHz. It integrates a matched active rectifier, digital controller, and telemetry subsystem optimized for A4WP protocol handshaking and power negotiation. It does not support Qi or PMA standards, and its 6.78 MHz architecture is incompatible with lower-frequency inductive charging systems.

Does the NX1A4WPZ require external components to operate as a complete wireless power receiver?

The NX1A4WPZ integrates core receiver functions - including 6.78 MHz active rectification, 5 V/1.2 A DC-DC regulation, dual LDOs, 12-bit ADC, GPIOs, and I²C interface - minimizing external parts. Required externals include: CTUNE capacitors (for resonance tuning), bypass capacitors on LDRECT/VOUT (35–100 µF), decoupling on LDODCPL (10 µF), and external NTC with bias resistors. No external MOSFETs, regulators, or ADCs are needed.

How does the NX1A4WPZ handle over-voltage protection on its antenna inputs?

The NX1A4WPZ implements dual OVP mechanisms: automatic AC-clamp shorts AC1/AC2 to ground when LDRECT exceeds 18 V (Vovp(en)), and over-power protection drives GPIO1/GPIO2 to ground CTUNE capacitors when VO(rect) > 18 V. Both trigger the INT pin and set status flags (OVP/OVD). The AC-clamp remains active until VO(rect) drops below Vovp(dis) (~17 V), ensuring robust field resilience during multi-receiver interference.

Can the NX1A4WPZ monitor external temperature using an NTC thermistor?

Yes, the NX1A4WPZ supports one external NTC thermistor via the TEMP pin, biased by an internal 3.3 V reference (VREF33). Two comparators detect thresholds at ~10 °C (NTCL) and ~60 °C (NTCU), setting status flags and asserting INT. The ADC also digitizes the NTC voltage for precise calibration. This enables hardware-enforced thermal limits without host MCU polling, critical for wearable and medical applications.

What GPIO voltage tolerances does the NX1A4WPZ provide, and how are they assigned?

The NX1A4WPZ provides four GPIOs: GPI01 and GPI02 are rated to 60 V for high-voltage control (e.g., AC-clamp switching), while GPI03 and GPI04 are rated to 25 V for general-purpose communication and signaling. All four are software-configurable as open-drain inputs/outputs via I²C registers IOCONL/IOCONU, and their states are readable in real time through the IOCONU register.