AN2972 datasheet(5/25 Pages) STMICROELECTRONICS

Part #	AN2972

Description	Designing an antenna for the M24LRxx-R

PDF	25 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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5 / 25 page

AN2972

Operating mode

Doc ID 15629 Rev 6

5/25

Operating mode

Integrating the M24LRxx-R or M24LRxxE-R in an application is simple: on the I2C side,

there is no specific design requirement as the device interfaces exactly as any serial I2C

EEPROM device. On the RF side, the M24LRxx-R or M24LRxxE-R needs to be connected

to an external antenna to operate.

Figure 2.

M24LRxx-R or M24LRxxE-R operating modes

The design principle of the M24LRxx-R or M24LRxxE-R antenna is very simple: the external

antenna inductance (Lantenna) that needs to be designed on board the PCB should match

the M24LRxx-R or M24LRxxE-R internal tuning capacitance (Ctuning) in order to create a

circuit resonating at 13.56 MHz. The basic equation of the tuning frequency is:

tuning

antenna

tuning

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AN2972 Datasheet(PDF) 5 Page - STMicroelectronics