SSM2143

REV. 0

–8–

LINE DRIVER/RECEIVER SYSTEM

The SSM2143 and SSM2142 provide a fully integrated line driver/

receiver system. The SSM2142 is a high performance balanced

line driver IC that converts an unbalanced input into a balanced

output signal. It can drive large capacitive loads on long cables

making it ideal for transmitting balanced audio signals. When com-

bined with an SSM2143 on the receiving end of the cable, the sys-

tem maintains high common-mode rejection and ultralow THD.

The SSM2142 is designed with a gain of +2 and the SSM2143

with a gain of 1/2, providing an overall system gain of unity.

The following data demonstrates the typical performance of the

two parts together, measured on an Audio Precision at the

SSM2143’s output. This configuration was tested with 500 feet

Figure 30. THD+N vs. Frequency of SSM2142/SSM2143

±18 V, V

Figure 31. SSM2142/SSM2143 System Headroom–

Figure 32. SSM2142/SSM2143 System

DIM-100 Dynamic Intermodulation

of cable between the ICs as well as no cable. The combination

of the two parts results in excellent THD+N and SNR and a noise

floor of typically –105 dB over a 20 Hz to 20 kHz bandwidth.

A comment on SSM2142/SSM2143 system headroom is neces-

sary. Figure 31 shows a maximum signal handling of approximately

±22 dBu, but it must be kept in mind that this is measured be-

tween the SSM2142’s input and SSM2143’s output, which has

been attenuated by one half. Normally, the system would be shown

as actually used in a piece of equipment, whereby the SSM2143 is

at the input and SSM2142 at the output. In this case, the system

could handle differential signals in excess of +24 dBu at the input

and output, which is consistent with headroom requirements of

most professional audio equipment.

Figure 33. SSM2142/SSM2143 System Frequency

10

90

100

0%

5V

10

µs

Figure 34. SSM2142/SSM2143 System Large Signal Pulse

OUTLINE DIMENSIONS

Dimensions shown in inches and (mm).

500' CABLE

NO CABLE

500' CABLE

NO CABLE

N-8

0.200 (5.05)

0.125 (3.18)

0.150

(3.81)

MIN

0.210

(5.33)

MAX

0.430 (10.92)

0.348 (8.84)

0.280 (7.11)

0.240 (6.10)

4

5

8

1

0.070 (1.77)

0.045 (1.15)

0.022 (0.558)

0.014 (0.356)

0.325 (8.25)

0.300 (7.62)

0 - 15

0.100

(2.54)

BSC

0.015 (0.381)

0.008 (0.204)

SEATING

PLANE

0.060 (1.52)

0.015 (0.38)

SO-8

SEATING

PLANE

SEE DETAIL

ABOVE

4

5

8

1

0.0688 (1.75)

0.0532 (1.35)

0.0098 (0.25)

0.0075 (0.19)

0.1574 (4.00)

0.1497 (3.80)

0.2440 (6.20)

0.2284 (5.80)

0.1968 (5.00)

0.1890 (4.80)

0.0192 (0.49)

0.0138 (0.35)

0.0500

(1.27)

BSC

0.0098 (0.25)

0.0040 (0.10)

× 45°

0.0196 (0.50)

0.0099 (0.25)

0.0500 (1.27)

0.0160 (0.41)

PIN 1

0

°- 8°