TDA5210 View Datasheet(PDF) - Infineon Technologies

Part Name

Description

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TDA5210

ASK/FSK Single Conversion Receiver

Infineon Technologies 

TDA 5210

Applications

4.2 Data Filter Design

Utilising the on-board voltage follower and the two 100kΩ on-chip resistors a

2nd order Sallen-Key low pass data filter can be constructed by adding 2 exter-

nal capacitors between pins 19 (SLP) and 22 (FFB) and to pin 21 (OPP) as

depicted in the following figure and described in the following formulas1.

C1

C2

Pins:

22

21

19

R

R

100k

100k

Figure 4-3 Data Filter Design

(1)(2)

C1 = ----2----Q---------b-----

R2Πf3dB

C2 = ---------------b------------

4QRΠf3dB

with

Q = -----b-

a

(3)the quality factor of the poles

where

in case of a Bessel filter a = 1.3617, b = 0.618

and thus Q = 0.577

and in case of a Butterworth filter a = 1.414, b = 1

and thus Q = 0.71

Example: Butterworth filter with f3dB = 5kHz and R = 100kΩ:

C1 = 450pF, C2 = 225pF

Filter_Design.wmf

1. taken from Tietze/Schenk: Halbleiterschaltungstechnik, Springer Berlin, 1999

Wireless Components

4-4

Specification, May 2001

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