SN55107A, SN75107A, SN75107B, SN75108A

DUAL LINE RECEIVERS

SLLS069D – JANUARY 1977 – REVISED APRIL 1998

11

POST OFFICE BOX 655303

APPLICATION INFORMATION

C

RT

RT

RT

RT

Drivers

SN55110A, SN75110A,

SN75112

Receiver 1

Receiver 2

Receiver 4

Driver 1

Driver 3

Driver 4

Location 1

Location 3

Location 4

Strobes

Receivers

‘107A, SN75107B,

SN75108A

Location 2

Data

Input

Inhibit

A

B

C

D

A

BB

A

C

DD

YY

Y

Strobes

Strobes

Figure 12. Typical Differential Party Line

unbalanced or single-line systems

These dual line circuits also can be used in unbalanced or single-line systems. Although these systems do not

offer the same performance as balanced systems for long lines, they are adequate for very short lines where

environmental noise is not severe.

The receiver threshold level is established by applying a dc reference voltage to one receiver input terminal.

The signal from the transmission line is applied to the remaining input. The reference voltage should be

optimized so that signal swing is symmetrical about it for maximum noise margin. The reference voltage should

be in the range of – 3 V to 3 V. It can be provided by a voltage supply or by a voltage divider from an available

supply voltage.

A single-ended output from a driver can be used in single-line systems. Coaxial or shielded line is preferred for

minimum noise and crosstalk problems. For large signal swings, the high output current (typically 27 mA) of the

SN75112 is recommended. Drivers can be paralleled for higher current. When using only one channel of the

line drivers, the other channel should be inhibited and/or have its outputs grounded.

Input

Vref

Input

Inhibit

SN55110A, SN75110A, SN75112

A

B

C

D

Output

VO = – IO • R

R

‘107A, SN75107B, SN75108A

Strobes

Output

Figure 13. Single-Ended Operation