TDA5252XT Infineon Technologies, TDA5252XT Datasheet - Page 44

• Manufacturer Part Number: TDA5252XT
• Manufacturer: Infineon Technologies

Specifications of TDA5252XT

• 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

As Figure 3-8 shows, detuning beyond the bandwidth of the matching circuit results in a significant
increase of collector current of the power amplifier and in some loss of power. This diagram shows
the data of the circuit of the test board around the center frequency of 915MHz.
Figure 3-8
C4, L2 and C3||C2 are the main matching components which are used to transform the 50 Ohm
load at the SMA-RF-connector to a higher impedance at the PA-output (250Ohm@3V). L1 can be
used for finetuning of the resonance frequency but should not be too low in order to keep its loss
low.
The transformed impedance of 250Ohm+j0 at the PA-output-pin can be verified with a network
analyzer using this measurement procedure:
1. Calibrate your network analyzer.
2. Connect a short, low-loss 50 Ohm cable to your network analyzer with an open end on one side.
3. Use the „Port Extension“ feature of your network analyzer to shift the reference plane of your
4. Connect the center-conductor of the cable to the solder pad of the pin „PA“ of the IC. The shield
5. Screw a 50Ohm-dummy-load on the RF-I/O-SMA-connector
6. The TDA5255 has to be in ASK-TX-Mode, Data-Input=LOW.
7. Be sure that your network analyzer is AC-coupled and turn on the power supply of the IC.
8. Measure the S-parameter
Data Sheet
Semirigid cable works best.
network analyzer to the open end of the cable.
has to be grounded. Very short connections must be used. Do not remove the IC or any part of
the matching-components!
PA-out & I-collector vs. frequency
44
PA-out_&_I-collector_vs_frequency.wmf
TDA5252 G2
Version 1.1
Application
2007-02-26