Product Status Notice

CS42L55Not Recommended for New Designs
Recommended for New Designs: WM8750 WM8973

Ultra-Low Power Stereo Codec with Class H Headphone Amplifier

The CS42L55 is a highly integrated, 24-bit, ultra-low power stereo audio codec that delivers excellent audio performance. Both the ADC and DAC offer many feature suitable for low power portable system applications. The CS42L55 features Cirrus Logic’s patent-pending bi-modal Class H headphone amplifier which combines the efficiency of an integrated step-down and inverting charge pump with the linearity and low EMI of a Class AB amplifier. The amplifier delivers a ground-centered output with a large signal swing even at low voltages and eliminates the need for external DC-blocking capacitors.

The analog input path allows independent channel control of a variety of features. The Programmable Gain Amplifier (PGA) provides analog gain with zero cross transitions. The ADC path includes a digital volume attenuator with soft ramp transitions and a programmable ALC and noise gate monitor the input signals and adjust the volume appropriately. An analog passthrough also exists, accommodating a lower noise, lower power analog in to analog out path to the headphone and line amplifiers, bypassing the ADC and DAC.

The DAC output path includes a fixed-function digital signal processing engine. Tone control provides bass and treble adjustment at 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 path also includes de-emphasis, limiting functions and a beep generator delivering tones selectable across a range of two full octaves.

These features make the CS42L55 the ideal solution for portable applications that require extremely low power consumption in a minimal amount of space.

The CS42L55 is available in a 36-pin QFN package for the Commercial (-40°C to +85°C) grade. The CDB42L55 Customer Demonstration board is also available for device evaluation and implementation suggestions.

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Digital to Analog Features

  • 5 mW Stereo Playback Power Consumption
  • 99 dB Dyanmic Range
  • -86 dB THD+N
  • Digital Signal Processing Engine
    • Bass & Treble Tone Control, De-Emphasis
    • Master Volume Control (+12 to -102 dB in 0.5 dB steps)
    • Soft-Ramp & Zero-Cross Transitions
    • Programmable Peak-Detect and Limiter
    • Beep Generator w/ Full Tone Control
  • Step-Down/Inverting Charge Pump
  • Class H Amplifier – Automatic Supply Adjusting
    • High Efficiency
    • Low EMI
  • Pseudo-Differential Ground-Centered Outputs
  • High HP Power Output at -75 dB THD+N
    • 2 x 20 mW into 32 Ω @ 1.8 V
    • 2 x 20 mW into 16 Ω @ 1.8 V
  • 1 VRMS Line Output @ 1.8 V
  • Analog Volume Control (+12 to -55 dB in 1 dB steps)
  • Analog In to Analog Out Passthrough
  • Pop and Click Suppression

Analog to Digital Features

  • 3.5 mW Stereo Record Power Consumption
  • 95 dB Dynamic Range (A-wtd)
  • -87 dB THD+N
  • 2:1 Stereo Input MUX
  • Analog Programmable Gain Amplifier (PGA) (+12 to -6 dB in 0.5 steps)
  • +20 dB Boost
  • Programmable Automatic Level Control (ALC)
    • Noise Gate for Noise Suppression
    • Programmable Threshold & Attack/Release Rates
  • Independent ADC Channel Control
  • Digital Volume Control (0 to -96 dB in 1 dB steps)
  • High-Pass Filter Disable for DC Measurements
  • Pseudo Differential Inputs

System Features

  • 12 MHz USB Master Clock Input
  • Low Power Operation
    • Stereo Analog Passthrough: 3.3 mW @ 1.8 V
    • Stereo Record and Playback: 8.3 mW @ 1.8 V
  • Headphone Detect Input
  • High Performance 24-bit Converters
    • Multi-bit Delta-Sigma Architecture
  • Integrated High Efficient Power Management Reduces Power Consumption
    • Step-Down Charge Pump Improves Efficiency
    • Inverting Charge Pump Accommodates Low System Voltage by Providing Negative Rail for HP/Line Amp
    • LDO Regulator Provides Low Digital Supply Voltage
  • Digital Power Reduction
    • Very Low Oversampling Rate for Converters
    • Bursted Serial Clock Providing 24 Bits per Sample
  • Power Down Management
    • ADC, DAC, Codec, PGA, DSP
  • Analog & Digital Routing/Mixes
    • Line/Headphone Out = Analog In (ADC Bypassed)
    • Line/Headphone Out = ADC Out
    • Internal Digital Loopback
    • Mono Mixes
  • I²C Control Port
  • I²S Digital Interface Format
  • Flexible Clocking Options
    • Master or Slave Operation
    • High-Impedance Digital Output Select
    • 8.000, 11.029, 12.000, 16.000, 22.059, 24.000, 32.000, 44.118 and 48.000 kHz Sample Rates

Related Documents

Design Resources

Tools and Software

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CS42L55 - Related News Releases

October 28, 2008
CS42L55’s Combination of Audio Quality, Feature Integration, Size, and Low Power Consumption Tops Among Available Portable Audio ICs
Part Dynamic Range (dB) THD+N (dB) Sample Rate (kHz) Analog I/O Power Supply (V) Comments Package
CS42L55 Not Recommended for New DesignsRecommended for New Designs: WM8750+WM8973
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