The NC8353 stereo Class D audio power can deliver a continuous power of up 20 W/ch into an 8-Ω bridge tied load. It can be powered from the existing 24-V rail in flat-panel television systems. Features include 87% efficiency, selectable gains of 20, 26, 32, 36 dB, and a shutdown feature that reduces the quiescent current of the amplifier to 100 μA typ. The PWM technique used within the Class D architecture permits filter-less operation in certain circumstances by using the speakers themselves as an LC filter.
In order to permit uninterruptible audio operation at lower output powers, should the internal temperature rise above the junction threshold of 150°C, the internal gain of the device is slowly reduced. The combination of gain reduction and internal power dissipation results in a stable maximum junction temperature of approximately 140°C. The output stage will completely shut down if the junction temperature rises above 160°C. The power stage is re-enabled once the device junction temperature cools to below 130°C.
An integrated digital power limiter can be set, using two external bits, to deliver a specific output (10, 12, 15, or 20 W/ch). Housed in a 32-pin QFN package, the part also features a mute function, pop and click suppression, auto-recovery short-circuit protection, and overtemperature protection. ($0.78 ea/10,000 — available now)
By Christina Nickolas
ON Semiconductor , Phoenix , AZ
Sales 602-244-6600
www.onsemi.com
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