AN3394 datasheet(11/29 Pages) STMICROELECTRONICS

Part #	AN3394

Description	Antenna design and impedance matching guidelines for CR95HF multiprotocol contactless transceiver IC

PDF	29 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

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11 / 29 page

AN3394

Description of DEMO-CR95HF-A and criteria for impedance matching

Doc ID 018754 Rev 5

11/29

capacitance C22 = (C3+ C17).Cinput,and RRX can be transformed in a parallel equivalent

circuit (see Figure 9: CR95HF parallel matching circuit intermediate simplification).

Figure 9.

CR95HF parallel matching circuit intermediate simplification

The resulting equivalent circuit allows to calculate the matching circuit composed of C11 and

C22 that satisfies the condition Zout= Zeq

* where Z

* is the complex conjugate of Z

eq.

Figure 10.

CR95HF final equivalent circuit

The calculation described in Equation (A.I.7) and Equation (A.I.9) leads to:

Where

Equivalent circuit.

--------------------

out

-----------

–

⎝⎠

⎛⎞

----------------------

–

input

–

AN3394 Datasheet(PDF) 11 Page - STMicroelectronics