The amplifier shown in figure 2 is based on the MAX9715 integrated circuit from Maxim (www.maxim-ic.com) providing an output power of up to 2.8 W with supply voltages in the range of 4.5 to 5.5 V with 4 ohm load. The circuit operates in Class d which guarantees an efficiency that reaches 87%. The distortion is very low, only 0.06% at 1 kHz. For this amplifier it is possible to program the gain at +10.5 dB or +9.0 dB and the PSRR is 71 dB at 1 kHz. In addition, the integrated circuit used has short-circuit protection and thermal protection. The housing is the 16-pin QFN-EP. Among the applications suggested by Maxim we have LCD projectors, portable sound, multimedia stations and notebooks. In figure 1 we have the MAX9715 enclosure. Given the high performance of the circuit, there is no need to install it in a heat sink.
