Datasheet

DigitalPGA
gain=0to31dB
Amp
0to
30dB
ADC
Amp
CEA
–1.02dB
037-009
TPS65930/TPS65920
www.ti.com SWCS037G–MAY 2008–REVISED APRIL 2011
6.2.5 Carkit Input
The USB-CEA carkit uses the DP pad to input the audio signal.
Figure 6-11 shows the uplink carkit full path uplink characteristics for audio and USB.
Figure 6-11. Carkit Input Uplink Path Characteristics
Table 6-11 lists the USB-CEA carkit audio electrical characteristics.
Table 6-11. USB-CEA Carkit Audio Uplink Electrical Characteristics
Parameter Test Conditions Min Typ Max Unit
Gain range
(1)
–1 60 dB
Absolute gain, 0 dBFs at 1.02 kHz
(1) (2)
USB-CEA default gain setting –1.5 1.5 dB
Speech delay Voice path 0.5 ms
Input common mode voltage
(3)
USB-CEA 1.3 1.9 V
Phone microphone amplifier input impedance at 1 kHz USB-CEA 8 120 kΩ
Peak-to-peak single-ended input voltage (0 dBFs) Default setting 1.414 V
PP
Total harmonic distortion (sine wave at 1 kHz), default gain setting At –1 dBFs –74 –60 dB
At –6 dBFs
At –10 dBFs
At –20 dBFs
At –60 dBFs
THD+N (20 Hz to 20 kHz, A-weighted) At 0 dBFs 60 dB
Signal noise ratio (20 Hz to 20 kHz, A-weighted) At 0 dBFs 60 dB
Idle channel noise (20 Hz to 20 kHz, A-weighted), default gain USB-CEA –77
dBFs
setting
Output PSRR (20 Hz to 20 kHz, A-weighted) USB-CEA 50 dB
(1) Gain range is defined by: CEA amplifier = 0.56 to –1.02 dB; Preamplifier = 0 to 30 dB; Filter = 0 to 31 dB (1-dB steps).
(2) The CEA default gain setting assumes 0 dB on the preamplifier, 1 dB on digital filter, and CEA amplifier at –1.02 dB.
(3) Full-scale input voltage is 1 V minimum.
Copyright © 2008–2011, Texas Instruments Incorporated Audio/Voice Module (TPS65930 Device Only) 67
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