The LM4674 is a single supply, high efficiency, 2.5W/channel, filterless switching audio amplifier. A low noise PWM architecture eliminates the output filter, reducing external component count, board area consumption, system cost, and simplifying design. The LM4674 is designed to meet the demands of mobile phones and other portable communication devices. Operating from a single 5V supply, the device is capable of delivering 2.5W/channel of continuous output power to a 4Ω load with less than 10% THD+N. Flexible power supply requirements allow operation from 2.4V to 5.5V. The LM4674 features high efficiency compared to conventional Class AB amplifiers. When driving an 8Ω speaker from a 3.6V supply, the device features 85% efficiency at PO = 500mW. Four gain options are pin selectable through the G0 and G1 pins. Output short circuit protection prevents the device from being damaged during fault conditions. Superior click and pop suppression eliminates audible transients on power-up/down and during shutdown. Independent left/right shutdown control maximizes power savings in mixed mono/stereo applications.
The LM4674 is a single‑supply, high‑efficiency 2.5 W/channel filter‑less switching audio amplifier designed for mobile phones and other portable communication devices. It operates from a 2.4 V to 5.5 V supply and delivers up to 2.5 W per channel into a 4 Ω load with less than 10 % THD+N. Features such as output short‑circuit protection, click‑and‑pop suppression, and independent left/right shutdown control simplify design and reduce component count.
Key specifications include typical efficiencies of 80 % (100 mW into 8 Ω) and 85 % (500 mW into 8 Ω) at 3.6 V, a shutdown current of 0.03 pA, and four pin‑selectable gain options. The device is offered in space‑saving 2 mm × 2 mm × 0.6 mm TL and 4 mm × 4 mm × 0.8 mm LLP packages, making it suitable for compact audio applications.
| Supply voltage range | 2.4 V to 5.5 V |
|---|---|
| Shutdown current | 0.03 pA typ |
| Output power at Vpp = 5V | 2.5 W typ |
| THD+N | < 10 % |
| Gain options | Four pin‑selectable (GO and G1) |
The LM4674 operates from 2.4 V to 5.5 V.
There are four gain options that are selected via the GO and G1 pins.
The typical shutdown current is 0.03 pA.