STMicroelectronics Inc. (ST, Geneva, Switzerland) introduced a pair of compact mono audio amplifiers for driving 16 to 32O speakers and earpieces in cellular and cordless phones, personal digital assistants and other portable appliances. The TS419 and TS421 are available in space-saving MiniSO-8 and DFN8 packages. The parts will operate from a supply of just 2V and draw a maximum of 2.5mA. Standby current consumption can be as little as 10nA. Standby mode can be active high for the TS419 or active low for the TS421.
With a Vcc of 5V, the parts offer a typical output power of 295mW into 16O, at a total harmonic distortion plus noise (THD + N) figure of 1% maximum. With a 32O load, output power is 207mW. With a Vcc of 3.3V, the parts offer a typical output power of 113mW into 16O, at a total harmonic distortion plus noise (THD + N) figure of 1% maximum. With a 32O load, output power is 81mW.
The parts can be ordered with an external gain configuration or with fixed gain of 6dB, 12dB or 18 dB. They also have on/off click reduction circuitry. The products are now available in 1,000-unit quantities at prices ranging from $0.37 to $0.41 depending upon configuration and package type.