TDA5251XT Infineon Technologies, TDA5251XT Datasheet - Page 72

• Manufacturer Part Number: TDA5251XT
• Manufacturer: Infineon Technologies

Specifications of TDA5251XT

• Operating Temperature (min): -40C
• Operating Temperature (max): 85C
• Operating Temperature Classification: Industrial
• Product Depth (mm): 4.4mm
• Product Length (mm): 9.7mm
• Operating Supply Voltage (min): 2.1V
• Operating Supply Voltage (max): 5.5V
• Lead Free Status / Rohs Status: Compliant

TDA5251 F1
Version 1.1
Application
The best sensitivity performance can be achieved using a data filter bandwidth of 1.25 times the
maximum occuring data frequency.
The IQ filter setting is depending on the modulation type. ASK needs an IQ filter of 50kHz, 30kHz
deviation at FSK recommend a 50kHz IQ filter.
A very practicable configuration is to set the chip-internal adjustable IQ filter to the sum of FSK peak
deviation and maximum datafrequency. Concerning these aspects the bandwidth should be chosen
small enough. With respect to both, the crystal tolerances and the tolerances of the crystal oscillator
circuit of receiver and transmitter as well, a too small IQ filter bandwidth will reduce the sensitivity
again. So a compromise has to be made. For further details on chip tolerances see also Section
3.2.7
3.10.2
BER performance depending on Supply Voltage
Due to the wide supply voltage range of this transeiver chip also the sensitivity behaviour over this
parameter is documented is the subsequent graph.
BER_VCC.wmf
Figure 3-35
BER supply voltage
Please notice the tiny sensitivity changes of less than 1dB, when variing the supply voltage.
Data Sheet
72
2007-02-26