Low-Power Stereo Analog-to-Digital Converter

The CS53L21 is a highly integrated, 24-bit, 96 kHz, low power stereo audio A/D converter (ADC). Based on multibit, Delta Sigma modulation, it allows infinite sample rate adjustment between 4 kHz and 96 kHz and offers many features suitable for low power, portable-system applications. The ADC input path allows independent channel control of a number of features. An input multiplexer selects between line-level 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 attenuator with soft ramp transitions. A programmable ALC and Noise Gate monitor the input signals and adjust the volume levels appropriately. The Signal Processing Engine (SPE) controls left/right channel volume mixing, channel swap and channel mute functions. All volume-level changes may be configured to occur on soft ramp and zero cross transitions. In addition to its many features, the CS53L21 operates from a single, low-voltage analog and digital core power supply, making this ADC ideal for applications such as portable audio players, digital microphones, digital voice recorders, voice recognition systems and audio/video capture cards.



  • Operates from a single 1.8 V or 2.5 V supply
  • Supports direct interface to logic levels from 1.8 V to 3.3 V
  • 3:1 Stereo input selector
  • Analog gain controls
    • PGA, +12 dB to -3 dB in 0.5 dB steps
    • +32 dB or +16 dB stereo MIC pre-amp with bias supply
  • Programmable automatic level control
    • Noise gate for noise suppression
    • Programmable threshold and attack/release rates
  • Independent left/right channel control
  • Digital volume control with soft ramp and zero cross
  • Flexible power-down management – chip/block selectable

Parametric Specifications

Channels (Inputs) 2
Resolution (bits) 24
Dynamic Range (dB) 98
THD+N (dB) -88
Sample Rate (kHz) 96
Analog Inputs/Outputs Differential
Analog Power Supply (V) 1.8;
Digital Power Supply (V) 1.8;
Logic Power Supply (V) 1.8;
Operational Power Consumption (mW) 7.1-22.5
Package 32 QFN

Design Resources

WAN-0118 Guidelines

WAN_0118 rev 2.5 : 740 kb


Comprehensive Solutions