AN4409 datasheet(5/8 Pages) STMICROELECTRONICS

部件名	AN4409

功能描述	Using the same antenna for M24LRXXE-R and M24SRXX-Y Dual Interface EEPROM families

PDF	8 Pages

Scroll/Zoom	100%

制造商	STMICROELECTRONICS [STMicroelectronics]

网页	http://www.st.com

标志

5 / 8 page

DocID025583 Rev 1

5/8

AN4409

Tuning capacitance specification vs tuning reference value

Tuning capacitance specification vs tuning reference

value

Figure 2 shows the serial equivalent tuning capacitance typical variation of either the

M24LRXXE-R or M24SRXX-Y according to the VAC0-AC1 RF input voltage:

Figure 2. Typical tuning capacitance variation of M24LRXXE-R and M24SRXX-Y

VRF_min corresponds to the minimum RF voltage between AC0 and AC1 RF inputs of the

RFID memory chips. The corresponding tuning capacitance CS_VRF_min must be taken as

reference for antenna design: in other words, customers have to design antennas which

inductance satisfies the following relationship, showed by Equation 6:

Equation 6

Vdatasheet corresponds to the voltage level used for better correlation with measurements

in production.

ftun

M24SR

π LA CS

VRFmin

⋅

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

→

VRFmin

⋅

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

AN4409 数据表(PDF) 5 Page - STMicroelectronics