Specifications

XT55 Hardware Interface Description
Confidential / Preliminary
s
mo b i l e
XT55_hd_v00.02 Page 103 of 116 17.03.2004
6.6.5 Voiceband transmit path
Test conditions:
· The values specified below were tested to 1kHz and 0dB gain stage, unless otherwise
stated.
· Parameter setup: Audio mode = 5 for GSM_MICP1 to GSM_MICN1 and 6 for
GSM_MICP2 to GSM_MICN2, inBbcGain= 0, inCalibrate = 32767, outBbcGain = 0,
OutCalibrate = 16384, sideTone = 0
Table 33: Voiceband transmit path
Parameter Min Typ Max Unit Test condition/Remark
Input voltage (peak to peak)
GSM_MICP1 to GSM_MICN1,
GSM_MICP2 to GSM_MICN2
1.03 V
Input amplifier gain in 6dB steps
(inBbcGain)
0 42 dB Set with AT^SNFI
Fine scaling by DSP (inCalibrate) -$ 0 dB Set with AT^SNFI
Input impedance GSM_MIC1 50 k"
Input impedance GSM_MIC2 2.0 k"
Microphone supply voltage ON
Ri = 4k" (GSM_MIC2 only)
2.57
2.17
1.77
2.65
2.25
1.85
2.73
2.33
1.93
V
V
V
no supply current
@ 100µA
@ 200µA
Microphone supply voltage OFF;
Ri = 4k" (GSM_MIC2 only)
0 V
Microphone supply in POWER
DOWN mode
See Figure 18