Datasheet

Functional Description
MC13783 Technical Data, Rev. 3.5
Freescale Semiconductor 33
4.3.5.2 Programmable Gain Amplifiers
The gain of the audio in both left and right channels is independently controlled in the programmable gain
amplifiers to allow for balance control. The input level from the external stereo source can be pre-amplified
by Arxin of 18 dB and the programmable gain amplifier PGArxin to get it at the same level as the other
sources before going into the audio input mixer block. The amplifiers are programmable in 3 dB steps from
–33 dB to +6 dB.
4.3.5.3 Balance, Mixer, Mono Adder and Selector Block
The mixer is a summing amplifier where the different input signals can be summed. The relative level
between the input signals is to be controlled via the PGArx, PGAst, and PGArxin amplifiers respectively.
The mono adder in the stereo channel can be used in four different modes: stereo (right and left channel
independent), stereo opposite (left channel in opposite phase), mono (right and left channel added), mono
opposite (as mono but with outputs in opposite phase).
The balance control allows for attenuating either the right or the left channel with respect to the other
channel. The balance control setting is applied independent of which input channel is selected.
The selector opens the audio path to the audio amplifiers and can be seen as an analog switch.
4.3.5.4 Earpiece Speaker Amplifier Asp
The Asp amplifier drives the earpiece of the phone in a bridge tied load configuration. The feedback
network of the Asp amplifier is fully integrated.
Table 18. Amplifier Asp Performance Specifications
Parameter Condition Min Typ Max Units
Differential Output Swing — — 4.0 — — V
PP
Gain Single Ended, 1.0 kHz Vin = 100 mVpp 3.8 4.0 4.2 dB
THD (2
nd
and 3
rd
) 1.0 kHz V
OUT
= 2 Vp — — 0.1 %
1.0 kHz V
OUT
= 100 mVp — — 0.1 %
1.0 kHz V
OUT
= 10 mVp — — 0.1 %
PSRR with respect to BP
20 Hz – 20 kHz
inputs AC grounded
A Weighted
— 90——dB
Input Noise A weighted
Including PGA Noise
———20μV
RMS
Load Impedance — — — 16 — Ω