DS_1903_032
73M1903 Data Sheet
8.4 Analog Specifications
8.4.1 DC Specifications
VREF should be connected to an external bypass capacitor with a minimum value of 0.1 μF. This pin is
not intended for any other external use.
Table 15: Reference Voltage Specifications
Parameter
VREF
Test Condition
VDD= 3.0 V - 3.6 V.
300Hz-3.3 kHz
Min
Nom
1.36
-86
Max
Units
V
VREF Noise
-80
dBm600
dB
VREF PSRR 300Hz-30 kHz
40*
8.4.2 AC Specifications
Table 16 shows the maximum transmit levels that the output drivers can deliver before distortion through
the DAA starts to become significant. The loss though the DAA transmit path is assumed to be 7 dB.
The signals presented at TXAP and TXAN are symmetrical. The transmit levels can be increased by
setting either TXBST0 (+1.5 dB) or/and TXBST1 (+0.83 dB) for the combined total gain of 2.33 dB.
These can be used where higher-level DTMF tones are required.
Table 16: Maximum Transmit Levels
Transmit Type
Maximum Different Maximum Single-
Peak to
Single-Ended Single-Ended
Line Level (dBm0)
Ended Level at
TXA Pins (dBm)
rms Ratio rms Voltage at Peak Voltage
TXA Pins (V) at TXA Pins (v)
VPA=2.7 V to 3.6 V. All rms and peak voltages are relative to VREF.
V.90
-12.0
-11.0
-6.3
-4.1
-2.0
-6.8
-8.8
4
0.2175
0.377
0.481
0.616
0.354
0.283
0.87
0.87
QAM
-7.3
-5.1
-3.0
-7.8
-9.8
2.31
1.81
1.41
1.41
1.41
DPSK
0.87
FSK
0.87
DTMF (high tone)
DTMF (low tone)
0.500
0.400
Rev. 2.0
29