Diodes Incorporated ZXCD50STEVAL

Overview

ZXCD50STEVAL from Zetex is a 50W music power (4Ω load), stereo Class D audio amplifier evaluation board built around the ZXCD1000 controller IC and ZXM64-series MOSFETs. It delivers <0.5% THD+N at 90% power, >90% efficiency, flat 20Hz–20kHz frequency response, and includes pop suppression, over-current protection, and active-low mute with 54dB attenuation - designed for rapid prototyping of high-fidelity, single-rail audio amplifiers.

For engineers reviewing the ZXCD50STEVAL datasheet, ZXCD50STEVAL pinout, ZXCD50STEVAL application, or ZXCD50STEVAL equivalent, this board supports quick validation of Class D amplifier performance under real-world conditions including bridge-tied load (BTL) operation, 13–25V single-supply input, and 18kΩ input impedance matching.

Technical Context

The ZXCD50STEVAL implements two synchronized Class D channels - one master (with triangle waveform generation) and one slave - each using a NE5532-based input phase splitter to drive the ZXCD1000 IC. The output stage employs complementary ZXM64P035G (PMOS) and ZXM64N035G (NMOS) SOT223 MOSFETs in BTL configuration, delivering up to 50W into 4Ω with L-C filtering to recover audio from PWM.

On-board 12V regulation (via ZTX692B transistors and Zener diodes) powers the ZXCD1000 and op-amps from the 25V bridge supply; over-current sensing uses 10mΩ resistors (R20/R120) feeding FMMT591A comparators to disable modulation on fault, while Q10-based soft-start circuitry ensures turn-on/turn-off pop suppression.

Key Specifications

Availability

ZXCD50STEVAL is available at Aetrix Electronics and suitable for audio product development, Class D amplifier reference design validation, and high-efficiency speaker driver qualification requiring stable component supply and documented performance benchmarks.

Supply support for ZXCD50STEVAL 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

Zetex (now part of Diodes Incorporated) specialized in high-performance analog and power semiconductor solutions, with expertise in Class D audio, MOSFETs, and precision analog ICs for industrial and consumer applications.

The ZXCD50STEVAL belongs to Zetex's Class D audio evaluation platform family, engineered to accelerate adoption of efficient, low-distortion switching amplifiers in professional audio equipment, active speakers, and multimedia systems.

FAQ

What power supply is required for full 50W output?

A regulated 25V DC single-rail supply capable of delivering ≥2.3A is required to achieve 50W music power into a 4Ω load. Supply voltage must remain between 13V and 25V; exceeding 25V risks permanent damage to the board's MOSFETs and regulator circuitry.

How is speaker connection implemented on this board?

The ZXCD50STEVAL uses Bridge-Tied Load (BTL) topology: both speaker terminals are actively driven - neither connects to ground. This doubles effective voltage swing across the load, enabling higher power from lower supply rails. Correct polarity is essential to prevent phasing errors.

Can the board drive 8Ω speakers, and what modifications are needed?

Yes - it delivers 25W music power into 8Ω with the same 25V supply. To maintain flat 20Hz–20kHz frequency response when using 8Ω loads, capacitor C2/102 (1nF) must be removed per channel as specified in the operation guide.

What protection features does the ZXCD50STEVAL include?

The board integrates turn-on/turn-off pop suppression via Q10 soft-start circuitry, over-current protection triggered by R20/R120 sense resistors that disable ZXCD1000 modulation during shorts, and active-low mute with 54dB attenuation - all implemented with discrete Zetex transistors and comparators.