AN3249 Datasheet, PDF (1/7 Pages) STMicroelectronics – M24LR series internal capacitance considerations for antenna tuning

AN3249
Application note
M24LR series internal capacitance considerations
for antenna tuning
1
Introduction
The datasheet of the M24LR series devices^(a) specifies a typical internal tuning capacitance
value of 27.5 pF measured at 0.5 V_PEAK. While this value is correct in production test
conditions, more considerations have to be taken into account for tuning the antenna in an
real application environment. This document describes the M24LR series tuning
capacitance variation as a function of input voltage, explains the M24LR series tuning
capacitance specification and gives a robust tuning capacitance target for the inductive loop
antenna design.
Table 1: Applicable products
Type
Applicable products
Dual Interface EEPROM
M24LR series⁽¹⁾
1. While the considerations introduced in this document applies to the entire M24LR series, the M24LR64-R
has been used hereafter for specific measurements purpose.
a. I²C/ISO15693 Dual Interface EEPROM IC
December 2013
DocID017760 Rev 2
1/7
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