CS42L55 Datasheet, PDF (2/73 Pages) Cirrus Logic – Ultra Low Power, Stereo CODEC w/Class H Headphone Amp

SYSTEM FEATURES
 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 Reg. 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
(used for easy MUXing between CODEC
and other data sources)
– 8.000, 11.029, 12.000, 16.000, 22.059,
24.000, 32.000, 44.118 and 48.000 kHz
Sample Rates
APPLICATIONS
 HDD & Flash-Based Portable Audio Players
 MD Players/Recorders
 PDAs
 Personal Media Players
 Portable Game Consoles
 Digital Voice Recorders
 Digital Camcorders
 Digital Cameras
 Smart Phones
2
CS42L55
GENERAL DESCRIPTION
The CS42L55 is a highly integrated, 24-bit, ultra-low
power stereo CODEC based on multi-bit delta-sigma
modulation. Both the ADC and DAC offer many features
suitable for low power portable system applications.
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 at-
tenuator 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 ana-
log 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 frequen-
cies. 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 vol-
ume 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 in-
cludes de-emphasis, limiting functions and a beep
generator delivering tones selectable across a range of
two full octaves.
The Class H stereo headphone amplifier combines the
efficiency of an integrated step-down and inverting
charge pump with the linearity and low EMI of a Class
AB amplifier. A step-down/inverting charge pump oper-
ates in two modes: +/-VCP mode or +/-(VCP/2) mode.
Based on the amplifier’s output signal, internal logic au-
tomatically adjusts the output of the charge pump,
+VHPFILT and –VHPFILT, to optimize efficiency. With
these features, 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.
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 sug-
gestions. Please see “Ordering Information” on page 73
for complete details.
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