The CS42L52 is a highly integrated, low-power stereo CODEC with headphone and Class D speaker amplifiers. The CS42L52 offers many features suitable for low-power, portable system applications. The ADC input path allows independent channel control of a number of features. Input summing amplifiers mix and select line-level and/or microphone-level inputs for each channel. The microphone input path includes a selectable programmable-gain pre-amplifier stage and a low-noise MIC bias voltage supply. A PGA is available for line or microphone inputs and provides analog gain with soft-ramp and zero-cross transitions. The ADC also features a digital volume control with soft ramp transitions. A programmable ALC and Noise Gate monitor the input signals and adjust the volume levels appropriately. To conserve power, the ADC may be bypassed while still allowing full analog volume control. The DAC output path includes a digital signal processing engine with various fixed-function controls. Tone control provides bass and treble adjustment of four selectable corner frequencies. The Digital Mixer provides independent volume control for both the ADC output and PCM input signal paths, as well as a master volume control. Digital Volume controls may be configured to change on soft-ramp transitions while the analog controls can be configured to occur on every zero crossing. The DAC also includes de-emphasis, limiting functions and a BEEP generator, delivering tones selectable across a range of two full octaves. The stereo headphone amplifier is powered from a separate positive supply and the integrated charge pump provides a negative supply. This allows a ground-centered, analog output with a wide signal swing and eliminates external DC-blocking capacitors. The Class D stereo speaker amplifier does not require an external filter and provides the high-efficiency amplification required by power-sensitive portable applications. The speaker amplifier may be powered directly from a battery while the internal DC supply monitoring and compensation provides a constant gain level as the battery’s voltage decays. In addition to its many features, the CS42L52 operates from a low-voltage analog and digital core making it ideal for portable systems that require extremely low power consumption in a minimal amount of space.