Diodes Incorporated PAM8403DR-H

Overview

PAM8403DR-H from Diodes Incorporated is a filterless 3W Class-D stereo audio amplifier in SOP-16 package, delivering 3.2W output into 4Ω at 5V with 0.15% THD+N, 90% efficiency, and integrated short-circuit/thermal protection. It drives speakers directly without LC filters, reducing BOM cost and PCB area in portable audio systems.

For engineers reviewing the PAM8403DR-H datasheet, PAM8403DR-H pinout, PAM8403DR-H application, or PAM8403DR-H equivalent, key selection criteria include filterless operation, dual-channel differential output architecture, mute/shutdown control logic, thermal shutdown hysteresis (30°C), and 2.5–5.5V supply range compatibility with Ni-MH or 3-cell alkaline battery configurations.

Technical Context

The PAM8403DR-H implements a two-stage closed-loop Class-D architecture: first-stage gain is externally configurable (up to 24dB via RF/RI ratio), second-stage gain is fixed at 2×, yielding differential outputs with 180° phase shift. Its filterless operation relies on high-frequency PWM switching (260kHz) and integrated EMI suppression techniques including ferrite bead recommendations and bypass capacitor optimization.

It integrates analog reference regulation (VREF pin requiring 0.47–1.0μF ceramic bypass), under-voltage lockout (UVLO activates below 2.0V, releases at ≥2.2V), and non-latched thermal protection tripping at 140°C with 30°C hysteresis. MUTE and SHDN pins are active-low with internal pull-ups, enabling low-quiescent-current standby (≤1µA shutdown current).

Key Specifications

Pinout & Package

The PAM8403DR-H is housed in a 16-pin SOP package (SO-16, 10.0 × 6.1 mm body, 1.27 mm pitch) with exposed thermal pad (not electrically connected). Pin assignments support dual-channel differential output, independent analog/digital power domains (VDD/PVDD), and robust control signaling.

Key Features

Applications

Equivalent & Alternatives

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

Compared with TPA2013D1RTJR and PAM8302AHR, the PAM8403DR-H uniquely delivers true differential 3W stereo output in SOP-16 with VREF-based noise control and 0.15% THD+N-making it optimal for portable stereo systems prioritizing fidelity, efficiency, and filterless simplicity.

Availability

PAM8403DR-H is available at Aetrix Electronics and suitable for portable speakers, notebook computers, LCD monitors, and portable DVD players requiring stable component supply, consistent SOP-16 sourcing, and long-term lifecycle support for consumer audio programs.

Supply support for PAM8403DR-H 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 semiconductor company specializing in discrete, analog, and mixed-signal solutions, with emphasis on power management, signal integrity, and precision components for industrial, computing, and consumer markets.

The PAM8403DR-H belongs to Diodes' Class-D audio amplifier product line, engineered specifically for battery-powered stereo audio systems demanding high efficiency, low EMI, and minimal external components without compromising THD+N performance.

FAQ

What is the recommended bypass capacitor for the VREF pin?

A 0.47µF to 1.0µF X7R ceramic capacitor must be placed between VREF and GND, located within 2 mm of the pin. This capacitor stabilizes the internal analog reference during startup and shutdown, reduces power-supply-induced noise on the output, and minimizes pop/click artifacts. Values outside this range degrade THD+N and PSRR performance per DS36439 Rev. 2–3 Section 8.

Can the PAM8403DR-H drive 8Ω speakers at full rated power?

No-it delivers 1.8W into 8Ω at 10% THD+N and 5V supply, not 3W. The 3W rating applies only to 4Ω loads. Attempting to force 3W into 8Ω exceeds safe operating area limits and risks thermal shutdown or output clipping. For 8Ω systems, design for ≤1.8W continuous output or use lower supply voltage to maintain THD+N compliance.

Is the SOP-16 package thermally adequate for 3W continuous output?

Yes-the SOP-16 package has θJA = 110°C/W. At 3.2W output and 87% efficiency, power dissipation is ~0.42W, resulting in ~46°C junction-to-ambient rise above ambient. With 85°C max ambient, junction temperature reaches ~131°C-within the 125°C max operating junction limit only if PCB copper area and airflow meet datasheet layout guidelines (e.g., 1-in² 2-oz copper pour under thermal pad).

Why does the datasheet state "NOT RECOMMENDED FOR NEW DESIGN"?

Diodes recommends the PAM8406 as a drop-in upgrade offering higher output power (5W), improved PSRR (−70dB), and enhanced EMI performance. However, the PAM8403DR-H remains fully qualified, in active production, and supported for legacy designs, cost-sensitive programs, or applications where its 3W/0.15% THD+N specification meets requirements without needing PAM8406's added features.