73M1903C-EVM Maxim Integrated Products, 73M1903C-EVM Datasheet - Page 25

• Manufacturer Part Number: 73M1903C-EVM
• Description: BOARD DEMO 73M1903C WORLDWIDE
• Manufacturer: Maxim Integrated Products

Specifications of 73M1903C-EVM

• Main Purpose: Interface, Analog Front End (AFE)
• Utilized Ic / Part: *
• Primary Attributes: *
• Secondary Attributes: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Embedded: -

DS_1903C_033
With the transmit code word of +/- 32,767, the nominal differential swing at the transmit pins at dc is:
When DTMFBST bit is set, Vout (V) = 1.166 * 2.31= 2.693Vpk diff.
When TXBST0 bit is set, Vout (V) = 1.21 * 2.31= 2.795Vpk diff.
When both DTMFBST and TXBST0 are set to 1, Vout (V) = 2.795 * 1.166 = 3.259Vpk diff.
[1] If not limited by power supply or internal reference.
6.5
To calculate the analog output power, the peak voltage must be calculated and the peak to rms ratio
(crest factor) must be known. The following formula can be used to calculate the output power, in dBm
referenced to 600 Ω.
Pout (dBm) = 10 * log [ ( Vout (V) / cf )
The following example demonstrates the calculation of the analog output power given a 1.2 kHz FSK tone
(sine wave) with a peak code word value of 11,878 sent out by the DSP.
The differential output voltage at TXAP-TXAN will be:
With FreqFctr = 1.02, (See Figure 8)
Vout (V) = 2 * (11,878/32,767) * 0.6640625 * 0.8889 * 1.36 * 1.0 * 1.4454 * 1.02 = 0.841 V
The output signal power will be:
Pout (dBm) = 10 * log [(0.841 / 1.41)
Rev. 5.0
Vout (V) = 2 * code/32,767 * DSDMgain * dacGAIN * VREF * TLPFgain * SMFLTgain * FreqFctr
= 2 * 32,767/32767 * 0.6640625 * 0.8889 * 1.36 * 1.0 * 1.4454 * 1.0 = 2.31Vpk diff.
Transmit Power – dBm
Table 10: Peak to RMS Ratios and Maximum Transmit
Transmit Type Crest Factor
DPSK
DTMF
Levels for Various Modulation Types
QAM
V.90
FSK
2
/ (0.001 * 600) ] = - 2.29 dBm.
2
/ ( 0.001 * 600 ) ]
2.31
1.81
1.41
1.99
4.0
Max Line Level
(1)
-5.7 dBm
-12 dBm
-9 dBm
-9 dBm
-9 dBm
73M1903C Data Sheet
pk
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