The A21SP16 is a differential class-D BTL power amplifier. It is able to drive up to 2.3 W into a 4 Ω load and 1.4 W into a 8 Ω load at 5 V. It achieves outstanding efficiency (88% typ.) compared to classical Class-AB audio amps.
The gain of the device can be controlled via two external gain-setting resistors. Pop & click reduction circuitry provides low on/off switch noise while allowing the device to start within 5 ms. A standby function (active low) allows the reduction of current consumption to 10 nA typ.