CONEXANT CX20741

CX20741/45 I2S Audio Codec with 2W Class-D,
Capless HP, and Digital Microphone
Features
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2 pairs of independent DACs and 3
pairs of independent ADCs
Sampling rates include 16-bit, 44.1
kHz to 24-bit, 192 kHz for DACs, and
from 16-bit, 44.1 kHz to 24-bit; 96 kHz
for ADCs.
Integrated 2 WRMS (per channel)
class-D stereo speaker amplifier
Capless headphone eliminates BOM
Dedicated Line Output
Multiple input/output retaskable ports
Stereo Digital Microphone interface
Integrated boost for all microphones
Two independent SPDIF outputs
Integrated regulators maximize
performance
Microphone Security Control
Integrated headphone limiter (GS
Mark)
D-Flex Power Management
Wake on PC BEEP
PopShield eliminates pops and clicks
Fidelity exceeds Microsoft WHCK
requirements
Jack sense detects up to 8 jacks
Digital Mixer
Compliant with all Intel High Definition
Audio Specifications
Selectable 1.5V/3.3 V link signaling
Available in 48-/56-QFN and in 48-/
64-QFP packages
Software
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Linux
Android 3.x/4.x
DSP Plug-ins
Voice input processing
Overview
The CX20741/45 are I2S audio codecs with integrated stereo Class-D speaker
amplifiers, capless headphone amplifiers and provides 98 dB dynamic range. The
CX20745 supports the Industrial temperature range while the CX20741 supports the
Commercial temperature range.
The integrated filter-less Class-D stereo amplifier with Spread Spectrum EMI dispersion
technology is capable of driving up to 2W RMS per channel into 4 Ω speakers. Built-in,
fully configurable hardware EQ and Dynamic Range Compression improve frequency
response, maximize output volume, and get maximum audio performance from
integrated speakers while remaining independent of driver and OS.
A stereo pair of capless headphone drivers includes integrated short circuit protection
and auto-recovery. These high performance headphone drivers save cost by eliminating
external headphone amplifiers and DC blocking capacitors. The capless architecture
outputs a full-range frequency response of 98 dB or better. Both Apple and Nokia style
headsets are supported as well inline command sensing for headset button controls.
One single-ended analog line output can be used to drive powered speakers or external
devices. One stereo differential Microphone/Line In port is available and it is re-taskable
to single-ended. Programmable microphone boost and bias is provided. Local analog
loopbacks with EQ/DR from Line or Microphone inputs to the outputs can be configured.
A digital microphone interface allows interfacing to two digital microphones. That
interface includes a hardware DC-level filter that eliminates problems caused by digital
microphones with DC offset with programmable clock outputs. Hardware Automatic Gain
Control (AGC) is available for all microphone paths to normalize the capture levels in real
time. The digital I/Os, I2C and I2S interfaces support a wide range of and all run at 3.3V.
The Hardware Digital Volume Control supports up-down buttons as well as an infinity
volume control knob commonly found in high-end AV equipment.
Two integrated Low Dropout Regulators (LDOs) generate the internal clean power rails
needed for analog and digital. All output ports feature PopShield circuitry that eliminates
pops and clicks. Jack sensing is available that can detect up to four jacks with
programmable switch de-bounce times.
.
Block Diagram
Applications
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Tablets
Portable Media Players
Smartphones
Digital Docking Stations
Part Number CX20741/45
Description I2S Audio Codec
Analog Performance Characteristics
Parameter
Minimum
Nominal Maximum
Unit
Comments
Microphone/Line In
Gain
dB
In steps of 10 dB
Full scale input signal
0
1
Vrms
ac-coupled
Dynamic Range(1)
87
dBFS
A-weighted, 20 to 20 kHz
THD+N at -3 dB FS
-80
dBFS
20 to 20 kHz
kΩ
15 kΩ with 0 dB gain, 5 kΩ otherwise
Input resistance
40
5
15
Class-D
Power
2W
5 V mode:
Up to 2 W/ch 4 Ω when headphone is not in use
Up to 1.5 W/ch 4 Ω when headphone is in use
3 V mode:
Up to 1 W/ch 4 Ω
Output load
4
Dynamic Range
75
Ω
85
THD+N at -3 dB FS
90
-65
dBFS
A-weighted, 20 to 20kHz
dBFS
20 to 20 kHz into 4 Ω
Line Output
Full scale output signal
Output load
1
Vrms
10
AC-coupled
kΩ
Dynamic Range
98
dBFS
A-weighted, 20 to 20 kHz
THD+N at -3 dB FS
-85
dBFS
20 to 20 kHz into 10 kΩ load
Crosstalk
-70
dB
Full scale output signal
1.0
Headphone Output
Output offset
-8
0
Output load
16
32
Dynamic Range
95
Vrms
8
mV
Ω
Reduces to + 250 μV with offset cancellation
Can drive -3 dBFS into 16 Ω without clipping.
dBFS
A-weighted, 20 to 20 kHz
20 to 20 kHz into 10 kΩ load
THD+N at -3 dB FS
-85
dBFS
Crosstalk
-70
dB
Ordering Information
Model Number
Package
Description
CX20745-11Z*
48-Pin QFN
Industrial Temperature Range, –40 oC to +85 oC
CX20741-11Z*
48-Pin QFN
Commercial Temperature Range, 0 oC to +70 oC
*Lead-free (Pb Free) and RoHS compliant
© 2012 Conexant Systems, Inc. All Rights Reserved. Conexant and the
Conexant logo are registered trademarks of Conexant Systems, Inc. All other
trademarks are owned by their respective owners. Although Conexant strives
for accuracy in all its publications, this material may contain errors or
omissions and is subject to change without notice. THIS MATERIAL IS
PROVIDED AS IS AND WITHOUT ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING MERCHANT ABILITY, FITNESS FOR A
PAPARTICULAR PURPOSE AND NON-INFRINGEMENT. Conexant shall
not be liable for any special, indirect, incidental or consequential damages as
a result of its use.
www.conexant.com
General Information:
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International: 1+ (949) 483-3000
Headquarters
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Newport Beach, CA 92660
Doc# PBR-203101