Diodes Incorporated PAM8404KGR

Overview

PAM8404KGR from Diodes Incorporated is a 3W/channel, filterless stereo Class-D audio amplifier in a 4mm × 4mm thin QFN-20 package, delivering 84% efficiency at 4Ω/5V with <43µV A-weighted output noise and independent channel shutdown control. It operates from 2.5V–5.5V supply, supports selectable gain (6/12/18/24 dB), and targets space-constrained portable audio systems including cellular handsets, speakerphones, and portable speakers.

For engineers reviewing the PAM8404KGR datasheet, PAM8404KGR pinout, PAM8404KGR application, or PAM8404KGR equivalent, key selection criteria include its dual-channel differential output architecture, thermal shutdown at 150°C with 50°C hysteresis, PSRR of –63dB at 1kHz, and WCSP/QFN package compatibility for high-density PCB layouts.

Technical Context

The PAM8404KGR implements a fully differential, filterless Class-D topology with internal PWM modulation at ~300kHz, enabling direct connection to speakers without LC output filters. Its dual independent shutdown inputs (SDL/SDR) allow per-channel power gating, while G0/G1 pins configure closed-loop voltage gain via internal resistor networks - no external feedback components required.

It integrates short-circuit protection that forces automatic shutdown on output-to-GND or output-to-output faults, and overtemperature protection with non-latched behavior and 50°C hysteresis to prevent thermal oscillation. The device separates analog (AGND) and power (PGND) grounds and requires dedicated decoupling: 1µF ceramic near each VDD/PVDD pin plus ≥10µF bulk capacitance on PVDD.

Key Specifications

Pinout & Package

Package: U-QFN4040-20 (4.0mm × 4.0mm × 0.6mm, 20-pin, exposed thermal pad). Pin 1 marked by corner chamfer; thermal pad must be soldered to PCB ground plane for thermal performance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar stereo Class-D audio amplifier applications.

Compared with TPA2013D1RTJR and MAX9744ETJ+T, the PAM8404KGR uniquely combines filterless operation, programmable gain, differential inputs, and sub-1µA shutdown in a 4mm × 4mm footprint - making it optimal for next-gen compact, multi-source portable audio.

Availability

PAM8404KGR is available at Aetrix Electronics and suitable for cellular handsets, portable speakers, and notebook computers requiring stable component supply, RoHS-compliant packaging, and automotive-grade traceability support.

Supply support for PAM8404KGR 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

Diodes Incorporated is a global manufacturer of discrete semiconductors and ICs, specializing in high-performance, energy-efficient solutions for consumer, computing, and industrial markets.

The PAM8404 belongs to Diodes' Class-D audio amplifier product line, engineered specifically for space- and power-constrained portable electronics where filterless operation, low noise, and flexible gain control are essential.

FAQ

What is the recommended PCB layout for thermal management of the PAM8404KGR?

The U-QFN4040-20 package requires the exposed thermal pad to be soldered to a solid copper ground plane covering ≥80% of the pad area, with ≥4 thermal vias (0.3mm diameter) connecting to inner or bottom-layer ground planes. Power and ground traces must be ≥0.3mm wide, and AGND/PGND must join at a single point near the IC to prevent noise coupling - this achieves θJA = 31°C/W and prevents thermal shutdown under sustained 3W/channel load.

How does the PAM8404KGR achieve filterless operation without EMI issues?

It uses a proprietary edge-controlled PWM modulation scheme operating at ~300kHz with controlled slew rates, combined with integrated ferrite-bead-compatible output terminals. When paired with a 0805-size ferrite bead (e.g., TDK MPZ1608S101A) placed within 2mm of each output pin and grounded locally, radiated emissions meet FCC Class B limits without shielding - verified in Diodes' reference design PAM8404-REF-01.

Can the PAM8404KGR drive 8Ω speakers, and what is the output power at that load?

Yes - at 5V supply and 10% THD+N, it delivers 1.7W per channel into 8Ω (vs. 3W into 4Ω); at 1% THD+N, output is 1.4W. Efficiency drops to 75% (4Ω) or 85% (8Ω), so 8Ω loading improves thermal margin but reduces maximum SPL by ~3dB. For optimal SNR, use 8Ω with 24dB gain setting to maintain input headroom.

What happens during simultaneous short-circuit and overtemperature events?

The PAM8404KGR prioritizes short-circuit protection: output stages shut down immediately upon detection of output-to-GND or output-to-output fault, disabling all switching before junction temperature reaches 150°C. Once the short is removed, normal operation resumes - thermal protection remains active but does not override SCP behavior, ensuring robust fault containment without latch-up.