P3065

ETALDOC 479/14

Page 3 of 5

February 2006

PERFORMANCE CHARACTERISTICS

Figure 3 gives flat RX and TX responses against

the reference impedance (typically around ±0.5dB

300Hz - 3.4kHz).

Return loss is typically better

than 20dB.

The 120nF capacitor should be of a

temperature stable dielectric.

In practice, the

100ohm resistor will normally connect to a low

impedance TX output.

For circuits with existing board drillings, figure 4

gives good return loss

(>20dB) against

the

reference impedance, but TX and RX flatness are

degraded by the use of this topology.

In practice, the 820ohm resistor will normally

connect to a low impedance TX output. The 68nF

capacitor, which should be of a temperature

stable dielectric, should be placed in parallel with

the 820ohm resistor (rather than in parallel with

the transformer winding) to obtain good TX

flatness.

For recommended matching to other reference

impedances please contact Profec Technologies.

Recommended Circ uit

Fig 2

470

LINE

600

22nF

10nF

μ

4.7 F

600

MATCH

Ω

EUROPEAN CTR21 COMPLEX MATCH

Recommended Circ uit

Fig 3

100

LINE

270

750

750

47nF

120nF

150nF

μ

2.2 F

Recommended Circ uit

Fig 4

820

LINE

270

750

68nF

33nF

150nF

μ

2.2 F