Monolithic Power Systems Inc. AX5688GRK-P

Overview

AX5688GRK-P from Monolithic Power Systems is a 2-channel BTL digital Class-D amplifier controller IC with 4 low-latency differential ADCs (115 dB DR), 4 programmable digital loop-filter slices, 4 CMOS-level PWM outputs, and I²S/TDM serial audio interface supporting up to 768 kHz sample rate. It enables closed-loop feedback across loudspeaker nodes for error suppression in the audio band (20 Hz–20 kHz) and is used in high-resolution soundbar and active loudspeaker systems.

For engineers reviewing the AX5688GRK-P datasheet, AX5688GRK-P pinout, AX5688GRK-P application, or AX5688GRK-P equivalent, key selection criteria include its 4-channel ADC latency (<1 MCLK cycle), 111 dB typical SNR, dual control interfaces (SPI/I²C), 64-pin QFN package with exposed pad, and compatibility with third-party power stages for scalable output power.

Technical Context

The AX5688GRK-P implements a fully digital, multi-input/multi-output (MIMO) control architecture: four independent low-latency ADCs feed into configurable loop-filter slices, which drive four PWM generators routed via an output crossbar to CMOS-level outputs. Feedback is processed digitally after the output filter, enabling high loop gain across 20 Hz–20 kHz.

Its serial audio subsystem supports 16 downstream/8 upstream TDM channels at 32–768 kHz with 16–32-bit resolution; control is handled via SPI (up to 10 MHz) or fast-mode I²C (400 kHz), with JTAG for debug. Power domains are segregated: 1.2 V analog/digital cores, 3.3 V I/O and PWM supplies, and dedicated analog/digital grounds.

Key Specifications

Pinout & Package

AX5688GRK-P is housed in a 64-pin QFN package (9 mm × 9 mm, 0.5 mm pitch) with exposed thermal pad (EPAD) requiring connection to PCB ground for thermal and electrical integrity.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar digital audio amplifier controller applications.

Compared with AX5688GRK-P, AX5688C offers identical functionality with improved thermal resistance and active lifecycle support, while TAS5825M trades programmability and external power stage control for integration and reduced BOM count-making it suitable only for fixed-configuration, lower-power systems.

Availability

AX5688GRK-P is available at Aetrix Electronics and suitable for streaming audio amplifier solutions, TV soundbars, and active loudspeakers requiring stable component supply despite its end-of-life status.

Supply support for AX5688GRK-P 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

Monolithic Power Systems (MPS) is a fabless semiconductor company specializing in high-performance power management and audio ICs, headquartered in Kirkland, WA, with global design and support centers.

The AX5688 product line delivers programmable digital audio controller ICs targeting high-fidelity, low-latency Class-D amplifier systems with flexible feedback architectures and multi-vendor power stage interoperability.

FAQ

Is AX5688GRK-P still in production?

No-AX5688GRK-P is officially end-of-life per MPS documentation, with migration directed to AX5688C. Aetrix Electronics maintains limited legacy stock with full traceability and provides transition support, including pin-compatible replacement guidance and firmware compatibility verification.

What power stages are compatible with AX5688GRK-P?

AX5688GRK-P supports discrete MOSFET half/full-bridge stages from Infineon, STMicroelectronics, and ON Semiconductor via its 4 CMOS PWM outputs and dedicated PSTART/PFAULT_N signaling. Compatibility is confirmed for IRS2092S, STGAP2S, and NCP51561 gate drivers per MPS application notes.

Can AX5688GRK-P operate without external feedback?

Yes-it supports open-loop operation using digital input only, but closed-loop mode (with ADC feedback across speaker terminals) is required to achieve specified 111 dB SNR and distortion suppression below –100 dB THD+N. Open-loop use forfeits dynamic error correction.

What is the minimum MCLK frequency requirement?

The AX5688GRK-P requires MCLK ≥ 45.1584 MHz for all supported audio sample rates (32–768 kHz). Lower frequencies violate timing margins for internal PLL lock and ADC decimation, causing loss of synchronization or invalid data in serial output streams.

Does AX5688GRK-P support DSD audio input?

No native DSD support-the serial interface accepts PCM only (I²S/TDM, 16–32-bit, 32–768 kHz). However, external DSD-to-PCM conversion (e.g., via FPGA or dedicated converter IC) feeding into SDI enables DSD playback in system-level designs.

How is thermal management implemented on the AX5688GRK-P PCB layout?

The exposed pad (EPAD) must be soldered to a minimum 200 mm² copper pour tied to system ground. Thermal vias (≥8×0.3 mm) under the pad connect to inner-layer ground planes. MPS recommends 2 oz copper and 4-layer stackup with dedicated analog/digital ground splits referenced to EPAD.

What JTAG debugging capabilities does AX5688GRK-P provide?

AX5688GRK-P supports IEEE 1149.1 JTAG for boundary-scan testing, register read/write, and real-time debug of control registers. TDO output reflects internal status bits (e.g., fault latches, PLL lock), and TCK supports up to 10 MHz for high-speed programming during development.