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Home > Products > Integrated Circuits (ICs) > Linear > Audio Amplifiers

Diodes Incorporated PAM8945PJR

Name: PAM8945PJR
Brand: Diodes Incorporated
SKU: PAM8945PJR
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: PAM8945PJR

Manufacturer:: Diodes Incorporated

Category:: Audio Amplifiers

Package:: 12-PowerWFQFN

Datasheet:: PAM8945PJR.pdf

Description:: IC AMP G MONO 4W WQFN3020-12

Quantity:: RFQ Add To RFQ list

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Inventory:5,290

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Product details

Overview

PAM8945PJR from Diodes Incorporated is a 4.0W Class-G audio power amplifier with integrated boost converter and battery-tracking AGC, designed for portable audio systems. It delivers 4.0W into 4Ω at 10% THD+N, operates from 2.8V to 5.2V, achieves 85% typical efficiency, and maintains consistent loudness across battery voltage decay - used in smartphones and portable speakers.

For engineers reviewing the PAM8945PJR datasheet, PAM8945PJR pinout, PAM8945PJR application, or PAM8945PJR equivalent, key selection criteria include integrated boost rail generation, AGC-controlled current limiting at low VBAT, Class-G efficiency vs. thermal dissipation, and W-QFN2030-12 footprint compatibility with space-constrained PCB layouts.

Technical Context

The PAM8945PJR implements a dual-rail Class-G architecture where the integrated boost converter (1.2MHz switching frequency) dynamically supplies PVDD based on output signal amplitude, reducing power loss versus fixed-rail Class-D. The AGC circuit monitors VBAT and adjusts gain in real time to cap peak battery current without clipping.

It features dual ground domains (AGND and PGND), DC input protection, auto-recovery short-circuit protection on outputs, and thermal shutdown. The PWM modulator includes UVLO, startup sequencing, and gate drive logic optimized for low pop-noise turn-on/off transitions.

Key Specifications

Parameter	Value and Actual Design Meaning
Output Power	4.0W into 4Ω at 10% THD+N - enables loud mono speaker playback in compact handheld devices
Efficiency	85% typical - extends battery runtime by minimizing heat generation during sustained audio playback
Supply Range	2.8V to 5.2V - supports single-cell Li-ion/Li-poly batteries across full discharge curve
THD+N	0.07% at 1W/8Ω - ensures clean audio reproduction with minimal harmonic distortion
PSRR	70dB at 217Hz and 1kHz - rejects battery ripple and digital noise coupling into audio path
SNR	95dB A-weighted - provides high dynamic range for audible detail in quiet passages
Quiescent Current	4mA at 3.6V - minimizes standby power draw in always-on audio subsystems

Pinout & Package

The PAM8945PJR is housed in a 2.0mm × 3.0mm, 12-pin W-QFN2030-12 package with exposed thermal pad (BGND-connected) for enhanced heat dissipation in thin-profile portable designs.

Pin/Terminal	Circuit Role	Design Meaning
PVDD	Boost output & amplifier supply rail	Provides dynamically scaled high-voltage rail to output stage; decoupling critical for stability
OUT+ / OUT−	Differential audio output	Drives bridged-load speaker directly; no external LC filter required for Class-G operation
EN	Chip enable control	Active-high logic input; controls full device power-up/down with 6ms start-up time
IN+ / IN−	Differential analog audio input	Accepts line-level or codec output; 24kΩ input impedance matches standard DAC drivers
AGC	AGC gain control node	Grounding sets full gain; floating or VBAT connection configures AGC threshold and response
VBAT	Main battery input	Feeds boost converter and internal bias; supports 2.8–5.2V range with 6V absolute max rating
SW	Boost converter switch node	Connects to external 2.2μH inductor and catch diode; requires careful layout for EMI control
AGND / PGND / BGND	Analog, power, and boost ground returns	Separate ground domains reduce noise coupling; BGND ties to thermal pad for thermal conduction

Key Features

Feature	Design Value
Battery-tracking AGC	Adjusts gain in real time to limit peak battery current below 4A during low-VBAT conditions, preventing brownouts
Integrated 1.2MHz boost converter	Generates up to ~6.5V PVDD from 2.8V VBAT, enabling higher output swing than direct-battery amplifiers
Class-G architecture	Switches between two supply rails to reduce output-stage conduction loss, improving efficiency over Class-D at mid-power levels
Auto-recovery short-circuit protection	Disables outputs on OUT+/OUT− short and resumes operation after fault clears - eliminates manual reset requirement
Minimized pop/click noise	Controlled startup timing and bias sequencing suppress transient artifacts during EN assertion/deassertion

Applications

Smartphones

Portable Bluetooth Speakers

Use Scenario: Full-screen video playback with stereo speaker output in sub-6.5mm-thin chassis.

IC Role / Device Role / Timing Role: Mono Class-G audio amplifier with integrated boost and AGC, driving bottom-firing speaker.

Use Value: Delivers 4W loudness from 3.6V nominal battery while maintaining >85% efficiency and stable volume across 4.2V→3.0V discharge.

Use Scenario: Battery-powered cylindrical speaker with 4Ω full-range driver and USB-C charging.

IC Role / Device Role / Timing Role: Single-chip audio solution providing power amplification, rail boosting, and battery-aware gain control.

Use Value: Eliminates need for external boost IC and discrete AGC circuit, reducing BOM count and PCB area by >30%.

Tablets & e-Readers

Wearable Audio Devices

Use Scenario: Dual-speaker stereo output in 7–8mm thick tablet with all-day media playback target.

IC Role / Device Role / Timing Role: High-efficiency audio amplifier managing thermal budget under sustained load with adaptive gain.

Use Value: 95dB SNR and 0.07% THD+N preserve audio fidelity; thermal resistance of 62°C/W enables passive cooling only.

Use Scenario: Compact neckband speaker with 2.8–5.2V Li-poly battery and voice assistant integration.

IC Role / Device Role / Timing Role: Low-quiescent-current (4mA) audio amplifier supporting quick wake-from-sleep audio prompts.

Use Value: 1μA shutdown current and fast 6ms startup meet ultra-low-power voice prompt requirements.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
MAX98357AETE+T	Class-D only; no integrated boost or AGC; requires external 5V rail or separate boost IC	Suitable for fixed-rail systems with stable 5V supply; lacks battery-aware loudness control	Select when system already provides regulated 5V and thermal headroom allows Class-D inefficiency at low VBAT
TAS5711PAPR	Pin-compatible Class-D with I²S interface; no analog inputs or AGC; higher THD+N (0.2%) at 1W	Targets DSP-based audio systems requiring digital input; no analog front-end or battery tracking	Choose for multi-channel digital audio processing with host MCU I²S output and no analog signal chain

Compared with MAX98357A and TAS5711, the PAM8945PJR uniquely integrates boost conversion, battery-tracking AGC, and analog differential inputs in a 2×3mm package - delivering louder, longer, and more consistent audio from shrinking Li-ion cells without added components.

Availability

PAM8945PJR is available at Aetrix Electronics and suitable for smartphones, portable speakers, tablets, and wearable audio devices requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.

Supply support for PAM8945PJR 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 for consumer, computing, communications, industrial, and automotive markets.

The PAM8945 belongs to Diodes' Power Management Audio Amplifier product line, engineered specifically for battery-powered portable audio systems demanding high efficiency, small footprint, and intelligent power-aware loudness control.

FAQ

What is the purpose of the AGC pin, and how should it be configured?

The AGC pin sets the gain control behavior: grounding enables full battery-tracking AGC, connecting to VBAT disables AGC, and leaving floating selects an intermediate threshold. Configuration determines whether the amplifier reduces gain to limit peak battery current below 4A during low-VBAT conditions - critical for preventing system brownouts in portable devices.

Does the PAM8945PJR require external compensation or loop stabilization components?

No external compensation components are required. The PAM8945PJR uses internal fixed-gain (20dB) feedback and fully integrated Class-G modulation, eliminating the need for external RC networks or loop compensation. Stability is ensured across all operating conditions with proper PVDD and VBAT decoupling (10μF + 1μF ceramic per rail).

Can the PAM8945PJR drive an 8Ω speaker, and what is the output power at 1% THD+N?

Yes - it delivers 3.2W into 4Ω and 2.0W into 8Ω at 1% THD+N. At 1% THD+N into 8Ω, output power is 1.0W (typical). The device's closed-loop gain is fixed at 20dB, and output power scales with load impedance and supply voltage per its Class-G transfer characteristics.

How does the thermal performance of the W-QFN2030-12 package compare to larger alternatives?

The W-QFN2030-12 package has θJA = 62°C/W and θJC = 11°C/W, enabling 4W output with passive cooling in ≤6mm² board area. Its exposed BGND pad must be soldered to ≥100mm² copper pour for optimal heat transfer. Larger QFN or HTSSOP packages offer lower θJA but consume 2–3× more PCB area - making this variant optimal for ultra-thin portable designs.

PAM8945PJR Specifications

Product attributes: Attribute value

Manufacturer:: Diodes Incorporated

Series:: -

Package/Case:: 12-PowerWFQFN

Packaging:: Tape & Reel (TR)

Product Status:: Active

Type:: Class G

Output Type:: 1-Channel (Mono)

Max Output Power x Channels @ Load:: 4W x 1 @ 4Ohm

Voltage - Supply:: 2.8V ~ 5.2V

Features:: Short-Circuit and Thermal Protection, Shutdown

Mounting Type:: Surface Mount

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Supplier Device Package:: W-QFN2030-12

PAM8945PJR FAQ

1.How can I place an order for PAM8945PJR through Aetrix?

Please submit a Request for Quotation (RFQ) for PAM8945PJR on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for PAM8945PJR reliable?

The price and inventory of PAM8945PJR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for PAM8945PJR is usually 5 days.

3.What payment methods are accepted for PAM8945PJR?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for PAM8945PJR transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for PAM8945PJR?

PAM8945PJR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your PAM8945PJR order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for PAM8945PJR?

For technical support, including PAM8945PJR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your PAM8945PJR requirements.

6.How does Aetrix verify that PAM8945PJR is sourced from the original manufacturer or authorized distributors?

All PAM8945PJR products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that PAM8945PJR meets industry standards.

7.What is the process for return or replacement of PAM8945PJR?

All PAM8945PJR units undergo pre-shipment inspection (PSI). If there is an issue with PAM8945PJR, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The PAM8945PJR part is unused and in its original packaging.

Return procedure for PAM8945PJR:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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