The AN7551Z is an audio power IC developed as a car audio output (35 W x 4-ch). CR to stop oscillation is built in between the output pin and GND so that a space saving of set is possible. Also, it is incorporating a perfect muting circuit which does not make a shock noise so that a shock noise design in the set transitional state can be made easily when used together with its standby function. In addition, it is incorporating various protective circuits to protect the IC from destruction by GND-open earth short-circuiting and power supply surge which are the important subject of power IC, and the IC will largely contribute to a high reliability design of equipment.