TDA5255XT Infineon Technologies, TDA5255XT Datasheet - Page 41

• Manufacturer Part Number: TDA5255XT
• Manufacturer: Infineon Technologies

Specifications of TDA5255XT

• 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

Now both pin-diodes are biased with a current of approx. 0.3mA@3V and have a very low
impedance for RF.
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.
Data Sheet
TX_Mode
TX_Mode_simplified
41
TDA5255 E1
TX_Mode_simplified.wmf
Version 1.2
Application
2007-02-26
TX_Mode.wmf