TDA5250D2_07 INFINEON [Infineon Technologies AG], TDA5250D2_07 Datasheet - Page 39

• Manufacturer Part Number: TDA5250D2_07
• Description: ASK/FSK 868MHz Wireless Transceiver
• Manufacturer: INFINEON [Infineon Technologies AG]

3
3.1
3.1.1
Figure 3-1
The RX/TX-switch combines the PA-output and the LNA-input into a single 50 Ohm SMA-
connector. Two pin-diodes are used as switching elements. If no current flows through a pin diode,
it works as a high impedance for RF with very low capacitance. If the pin-diode is forward biased, it
provides a low impedance path for RF. (some Ω)
3.1.2
The RX/TX-switch is set to the receive mode by either applying a high level or an open to the RX/
TX-jumper on the evalboard or by leaving it open. Then both pin-diodes are not biased and
therefore have a high impedance.
Data Sheet
Application
LNA and PA Matching
RX/TX Switch
Switch in RX-Mode
RX/TX Switch
SMA-connector
50 Ohm
RF I/O
RX/TX
C2
C1
D2
R1
C6
D1
C7
39
C3
L3
L2
C9
C4
L1
C10
VCC
C5
RX/TX
LNI
LNIX
PA
TDA5250 D2
Version 1.7
Application
RX/TX_Switch.wmf
2007-02-26