Audio Amplifier with Logarithmic Digital Volume Control
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The X9314 with the low voltage LM386 power amplifier is shown on figure below. 250mW of audio power will be produced by this circuit with only a 5V DC source. Plenty of sound for intercom, communications, or monitoring applications will be provided by this circuit.
It’s require a 74HC132 quad Schmidt NAND gate (U2) plus a few discrete components to interface to U1, the X9314W 10Kohm XDCP. U2A output will be HIGH when either push-button switch, S1 or S2 is depressed. This immediately brings U2B output LOW which enables the XDCP. The astable multivibrator (U2C) will begin generating increment pulses after a short delay determined by R3 and C3. [Source: Intersil Application Note]