AN3394

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

Doc ID 018754 Rev 5

7/29

1.2

Output impedance of the DEMO-CR95HF-A

demonstration board output circuit

To generate the magnetic field, the antenna is excited by the two CR95HF differential

generators (see Figure 2: CR95HF equivalent output impedance).

Each generator has an output impedance of 13.5

Ω.

simplified equivalent impedance:

Z

out

R

out

27

Ω

==

3V

()

Figure 2.

CR95HF

equivalent output

impedance

Figure 3.

Chip simplified equivalent

impedance

Ω

Ω

Ω

Where

Matching impedance. [

Ω]

Matching resistor. [

Ω]

Supply voltage of the chip. [V]