Datasheet

TPS65930/TPS65920
www.ti.com SWCS037G–MAY 2008–REVISED APRIL 2011
6.2 Audio Uplink (TX) Module
The audio uplink path includes two input amplification stages:
• MIC_MAIN_P, MIC_MAIN_M (differential main handset input)
• AUXR (common terminal: single-ended auxiliary)
NOTE
If two audio inputs are needed, and mic bias is not needed, the AUXR input can be used
with MIC_MAIN to provide the two inputs.
6.2.1 Microphone Bias Module
A bias generator provides an external voltage of 2.2 V to bias the analog microphones (MICBIAS1
terminal). The typical output current is 1 mA.
6.2.1.1 Analog Microphone Bias Module Characteristics
Table 6-7 lists the characteristics of the analog microphone bias module.
Table 6-7. Analog Microphone Bias Module Characteristics With Bias Resistor
Parameter Test Conditions Min Typ Max Unit
Bias voltage 2.15 2.2 2.25 V
Load current 1 mA
Output noise P-weighted 20 Hz to 6.6 kHz 1.8 μV
RMS
External capacitor 0 200 pF
Internal resistance 50 60 70 kΩ
NOTE
If the external capacitor is higher than 200 pF, the analog microphone bias becomes
unstable. To stabilize it, add a serial resistor.
Table 6-8 lists the characteristics of the analog microphone bias module with a bias resistor.
Table 6-8. Analog Microphone Bias Module Characteristics With Bias Resistor
Parameter Test Conditions Min Typ Max Unit
C
B
< 200 pF 0
R
SB
C
B
= 100 pF 300 Ω
C
B
= 1 μF 500
R
B
+ R
SB
2.2 to 2.7 kΩ
Copyright © 2008–2011, Texas Instruments Incorporated Audio/Voice Module (TPS65930 Device Only) 61
Submit Documentation Feedback
focus.ti.com: TPS65930/TPS65920