tda5251f1 Infineon Technologies Corporation, tda5251f1 Datasheet - Page 41

• Manufacturer Part Number: tda5251f1
• Description: Ask/fsk 315mhz Wireless Transceiver
• Manufacturer: Infineon Technologies Corporation

Confidential
Figure 3-4
R1 does not influence the matching because of its very high resistance. Due to the large
capacitance of C1, C6 and C5 the circuit can be further simplified for RF:
Figure 3-5
The LNA-matching is RF-grounded now, so no power is lost in the LNA-input. The PA-matching
consists of C2, C3 L2, C4 and L1.
When designing the matching of the PA, C2 must not be changed anymore because its value is
already fixed by the LNA-input-matching.
Preliminary Specification
TX_Mode
TX_Mode_simplified
41
TDA5251 F1
TX_Mode_simplified.wmf
Version 1.0
Application
2003-02-18
TX_Mode.wmf