Datasheet

DigitalPGA
Gain=0to31dB
Amp
0to
30dB
ADC
Amp
CEA
–1.02dB
MCPC
0.56dB
032-041
TPS65950
www.ti.com SWCS032E–OCTOBER 2008–REVISED JANUARY 2011
Table 6-21. Uplink Amplifier Characteristics
Parameter Test Conditions Min Typ Max Unit
Speech delay Voice path 0.5 ms
Gain range
(1)
0 61 dB
Absolute gain 0 dBFs at 1.02 kHz –1 1 dB
Peak-to-peak differential input voltage (0 dBFs) For differential input 1.5 V
PP
0 dB gain setting
Peak-to-peak single-ended input voltage (0 dBFs) For single-ended input 1.5 V
PP
0 dB gain setting
Input impedance
(2)
40k 70k Ω
Total harmonic distortion (sine wave at 1.02 kHz) At –1 dBFs –80 –75 dB
At –6 dBFs –74 –69
At –10 dBFs –70 –65
At –20 dBFs –60 –55
At –60 dBFs –20 –15
Idle channel noise 20 Hz to 20 kHz, A-weighted, gain = 0 dB –85 –78 dBFs
16 kHz: < 20 Hz to 7 kHz, gain = 0 dB –90
8 kHz: P-weighted voice, gain = 18 dB –87
16 kHz: < 20 Hz to 7 kHz, gain = 18 dB –82
Crosstalk A/D to D/A Gain = 0 dB –80 dB
Crosstalk path between two microphones –70 dB
Intermodulation distortion Two-tone method –60 dB
(1) Gain range is defined by: Preamplifier = 0 to 30 dB; Filter = 0 to 31 dB (1-dB steps)
(2) Impedance varies in the specified range with gain selection.
6.2.7 Microphone Amplification Stage
Microphone amplification stages perform single-to-differential conversion for single-ended inputs. Two
programmable gains from 0 to 30 dB can be set:
• Automatic level control for main microphone or submicrophone input. The gain step is 1 dB.
• Level control by register for line-in or carkit input, or headset microphone. The gain step is 6 dB.
The amplification stage outputs are connected to the ADC input (ADC left and right).
6.2.8 Carkit Input
The USB-CEA carkit uses the DP pad to input the audio signal.
The MCPC carkit uses the TXAF analog pad to input the audio signal.
Figure 6-28 shows the uplink carkit full path uplink characteristics for audio and USB.
Figure 6-28. Carkit Input Uplink Path Characteristics
Table 6-22 lists the electrical characteristics of the MCPC and USB-CEA carkit audio.
Copyright © 2008–2011, Texas Instruments Incorporated Audio/Voice Module 93
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