CX20787
Features
Processing Features
NEW
Cap-less Stereo class G
Headphone driver
Two Stereo Differential 10 kΩ Line
(or Single Ended)
Stereo Differential Speaker -
Class D Amplifier 2 Wrms 4Ω @
5 V.0 or 1 Wrms 4
Ω
@3.2 V
No pops, clicks, or zipper noise
during any change of state
Single-ended External Mono Mic
(Headset Jack)
Three Differential Mic / Line -
shared with digital mic ports
2 Mic Bias
Nokia / Apple headset type
detection & mic/Gnd switch
control
Inline command sensing
Stereo 24-b ADCs, & 1 digital
ADC
Stereo 24-b DACs
HW Audio Signal Processing
– 5-band bi-quad EQ on stereo
output
– 2-knee stereo DRC
Digital Mic support, clk support:
1.5,3 MHz,
Two 4-wire bi-directional I
2
S/PCM,
1 Aux (pass-thru)
SPI (5 MHz)/I
2
C (100/400 kHz)
4 GPIO
Writer Sequencer to minimize
setup
MCLK clock input (10-48 MHz) for
reference to 2 PLLs
1.8 V +/- 0.5 V, 3.3 V
4x3.9x1mm 72-p WLCSP, 0.4mm
ball pitch
-40 to +85 deg C ambient, -40 to
+125 C junction
Ult
ra Low-Power I
2
S Audio Codec with Integrated Digital Signal
Overview
The CX20787 is an ultra low-power, I
2
S stereo audio codec with integrated Class-D
speaker amplifiers and power-efficient Class G headphone amplifiers with in- line
DSP features. Combined with our software driver and design support, this is an ideal
turnkey solution for Tablets, Ultrabooks, Smartphones etc.
The device features a pair of ProCousticTM headphone drivers. The high-
performance headphone drivers eliminate the need for an external headphone
amplifier and DC blocking capacitors. The capless architecture outputs a full-range
frequency response at 97 dB dynamic range. CX20787 supports both Apple and
Nokia style headset jacks with fully integrated auto detect and switch and inline
command button sensing. All output ports feature PopShield circuitry that eliminates
pops or clicks.
The integrated stereo filter-less Class-D amplifier with Spread Spectrum EMI
dispersion technology is capable of outputting 2W-rms into a 4
Ω
speaker with 5 V
supply rail. The device can be completely powered by a 3.3 V supply rail with
reduced Class-D output power. All other internal supply rails are generated by the
integrated LDOs.
The digital I/Os, such as I
2
S ports, Conexant Audio Bus, etc., support a wide range
of topologies for connections to both the application processor and baseband
processor simultaneously. Additional salient features of CX20787 include Write
Sequencer for ease of use.
CX20787 features Hardware Digital Volume Control, similar to an infinite volume
control knob commonly found in high-end AV equipment. There is also a single-bit
stream digital microphone interface that connects up to 3 digital microphones for
dual microphone array implementations. The Digital Microphone Interface (DMI) is
optimized with a hardware DC-level filter, which compliments and improves the
compatibility with more digital microphones. A fully configurable hardware EQ and
dual knee Dynamic Range Control with reconfigurable inputs is integrated to improve
frequency response, maximize output volume, and protect speakers from over
driving.
Functional Block Diagram
Digital
Microphone
3 x I
2
S Interfaces
Capless Class-G
Headphone/Headset
Gain/Mute
3 Diff/SE
Microphone/
Line Inputs
Mixer/MUX
PGA
ADC
DAC
Mixer
Outputs
2 Diff/SE
Line Outputs
Applications
Smartphones
Tablets
Ultrabooks
Portable Media Player
ADC
Speaker
EQ/DRC
ADC
DAC
2W RMS
Stereo Speaker
(Class-D)
PLL
I
2
C/SPI Bus
GPIOs and
Jack Sense
CONEXANT [ CONEXANT SYSTEMS, INC ]
