茂達(dá)電子推出立體聲喇叭放大器-APA4863，晶片本身為Class AB架構(gòu)，可操作在3.0V到5.5V的供給電源下，采用SOP-16P，TSSOP-20與 TSSOP-20P封裝，可以讓APA4863不需外接散熱片也可以有輸出高速3瓦的功率（VDD＝5V，RL＝3W）。APA4863可以借由HP-IN輸入控制管腳來切換放大器為橋接(Bridge-Tied Loads) ，或單端負(fù)載操作的模式來驅(qū)動(dòng)喇叭和耳機(jī)，需外接輸入與迴授電阻方便客戶自行設(shè)定放大器的增益值，具備噪音（Pop and Click）消除電路可消除啟動(dòng)與開關(guān)時(shí)的噪音，短路及過熱保護(hù)，操作溫度范圍為-40℃到+85℃，以及0.5微安的超低待機(jī)電流，快速的開機(jī)時(shí)間與小型的封裝，適合筆記本電腦及便攜式設(shè)備。

APA4863 : Stereo 2.2-W Audio Power Amplifier

The APA4863 is a stereo bridge-tied audio power amplifier in various power packages, including SOP, TSSOP, and TSSOP-P. When connecting to a 5V voltage supply, the APA4863 is capable of delivering 2.2W/1.8W/1.2W of continuous RMS power per channel into 3W/4W/8W bridge-tied loads with less than 1% THD+N respectively. When APA4863 operates in the single-ended load, it is capable of delivering 90mW of continuous RMS power per channel into 32W load. The APA4863 simplifies design and frees up board space for other features. The APA4863 also served well in low-voltage applications, which provides 750mW (1% THD+N) per channel into 4W loads with a 3.3V supply voltage. Both of the depop circuitry and the thermal shutdown protection circuitry are integrated in the APA4863, which reduces pops and clicks noise during power up and when using the shutdown mode and protects the chip from being destroyed by over-temperature failure. To simplify the audio system design in notebook computer applications, the APA4863 combines a stereo bridge-tied loads mode for speaker drive and a stereo single-end mode for headphone drive into a single chip, where both modes are easily switched by the HP-IN input control pin signal. For power sensitive applications, the APA4863 also features a shutdown function which keeps the supply current only 0.5 µA (typ.).