TDA5251F1_07 datasheet(44/88 Pages) INFINEON

Part #	TDA5251F1

Description	ASK/FSK 315MHz Wireless Transceiver

Download	88 Pages

Scroll/Zoom	100%

Manufacturer	INFINEON [Infineon Technologies AG]

Direct Link	http://www.infineon.com

Logo

44 / 88 page

TDA5251 F1

Version 1.1

Application

Data Sheet

44

2007-02-26

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 output power. This diagram

shows the data for the circuit of the test board at the frequency of 315MHz. The effective load

resistor of this circuit is RL= 250Ohm, which is the optimum impedance for operation at 3V. This will

lead to a dip of the collector current of approx. 20%.

pout_vs_frequ_315.wmf

Figure 3-8

Power output and collector current vs. frequency

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.

Semirigid cable works best.

3. Use the „Port Extension“ feature of your network analyzer to shift the reference plane of your

network analyzer to the open end of the cable.

4. Connect the center-conductor of the cable to the solder pad of the pin „PA“ of the IC. The shield

has to be grounded. Very short connections must be used. Do not remove the IC or any part of

the matching-components!

5. Screw a 50Ohm-dummy-load on the RF-I/O-SMA-connector

6. The TDA5251 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

Similar Part No. - TDA5251F1_07

Manufacturer	Part #	Datasheet	Description
Infineon Technologies A...	TDA5251F1	2Mb / 88P	ASK/FSK 315MHz Wireless Transceiver Version 1.0, 2003-02-18

Manufacturer	Part #	Datasheet	Description
Infineon Technologies A...	TDA5251F1	2Mb / 88P	ASK/FSK 315MHz Wireless Transceiver Version 1.0, 2003-02-18
Melexis Microelectronic...	TH72006	339Kb / 16P	315MHz FSK/ASK Transmitter
Infineon Technologies A...	TDA5250D2	2Mb / 94P	ASK/FSK 868MHz Wireless Transceiver Version 1.7, 2007-02-26
	TDA5252G2	2Mb / 86P	ASK/FSK 915MHz Wireless Transceiver Version 1.1, 2007-02-26
	TDA5255E1	2Mb / 93P	ASK/FSK 434MHz Wireless Transceiver Version 1.1, 2002-11-28
	TDA5255E1	2Mb / 91P	ASK/FSK 434MHz Wireless Transceiver Version 1.2, 2007-02-26
	TDA5250D2	2Mb / 97P	ASK/FSK 868MHz Wireless Transceiver Version 1.6 July 2002
Melexis Microelectronic...	TH72005	555Kb / 20P	315MHz FSK/ASK Transmitter
Melexis Microelectronic...	TH72005	1Mb / 21P	315MHz FSK/ASK Transmitter
Infineon Technologies A...	TDA7255V	2Mb / 109P	ASK/FSK 434 MHz Wireless Transceiver Revision 1.1, 2010-11-10