SSM2142

–4–

THD PERFORMANCE

The following data, taken from the THD test circuit on an

Audio Precision System One using the internal 80 kHz noise

filter, demonstrates the typical performance of a balanced pair

system based on the SSM2142/SSM2141 chip set. Both dif-

ferential and single-ended modes of operation are shown, under

a number of output load conditions which simulate various

application situations. Note also that there is no adverse effect

on system performance when using the optional series feedback

capacitors, which reject dc cable offsets in order to maintain

optimal ac noise rejection. The large signal transient response of

the system to a 100 kHz square wave input is also shown,

demonstrating the stability of the SSM2142 under load.

V

IN

SSM

2142

4

3

+18V

6

5

7

8

1

2

–18V

10µF*

10µF*

R1

R2

R

L

A

B

SSM

2141

C

*USED ONLY IN THD PLOTS AS NOTED.

ALL CABLE MEASUREMENTS USE BELDEN 8451 CABLE.

Figure 7. THD Test Circuit

Figure 8. THD+N vs. Frequency at Point B

(Differential Mode)

Figure 9. THD+N vs. Frequency at Point B

(Differential Mode)

Figure 10. THD+N vs. Frequency at Point A

(Single Ended)

Figure 11. THD+N vs. Frequency at Point C

(SSM2141 Output)

REV. C