Texas Instruments has introduced two Class-D amplifiers with volume control, automatic gain control (AGC), and programmable dynamic range compression (DRC). The devices allow designers to compress the dynamic range of the audio to match the dynamic range of the speaker in applications like cell phones, notebook PCs and other portables.
The mono TPA2028D1 drives 3 W at 5 V into 4 Ω or 880 mW at 3.6 V into 8 Ω. The stereo TPA2026D2 can drive 3.2 W/ch at 5 V into 4 Ω or 750 mW/ch at 3.6 V into 8 Ω. Both devices are filter free.
The devices' DRC/AGC function is programmable via an I2 C interface and can be configured to automatically prevent distortion of the audio signal and enhance quiet passages that are normally not heard. Gain can be selected in 1-dB steps from 0 dB to +30 dB for the TPA2026D2 and from –28 dB to +30 dB for the TPA2028D1. AGC start-up time is 5 ms.
The TPA2028D1 is available in a 1.63 x 1.63-mm 9-ball WCSP and is priced at $0.90 in 1,000-unit quantities. The TPA2026D2 is available in a 2.2 x 2.2-mm 16-ball WCSP and is priced at $1.30 in 1,000-unit quantities.