TX_OUT
Pin 5
L1
L2
C2 and C3
Combination
C4, C4, and C7
Combination
C8, C9, C10, and C11
Combination
50
W
(4.00 + j0.00)
at 13.6 MHz
W
Z
L
3.0 nF
150.0 nH
1.2 nF
330.0 nH
256.0 pF
Z
IN
78
SLOS743L – AUGUST 2011 – REVISED MARCH 2017
Product Folder Links:
Applications, Implementation, and Layout
Copyright © 2011–2017, Texas Instruments Incorporated
Figure 7-2. Impedance Matching Circuit
Figure 7-3. Smith Chart Simulation
Resulting power out can be measured with a power meter or spectrum analyzer with power meter function
or other equipment capable of making a "hot" measurement. Observe maximum power input levels on test
equipment and use attenuators whenever available to avoid damage to equipment. Expected output
power levels under various operating conditions are shown in
.
7.4
Reader Antenna Design Guidelines
For HF antenna design considerations using the TRF7970A, see these documents:
•
Antenna Matching for the TRF7960 RFID Reader
•