1Z

1Y

G

G

1A

4

12

1

2

3

2Z

2Y

2A

7

6

5

3Z

3Y

3A

9

10

11

4Z

4Y

4A

15

14

13

Copyright © 2016, Texas Instruments Incorporated

9

AM26LS31, AM26LS31C, AM26LS31I, AM26LS31M

www.ti.com

SLLS114L – JANUARY 1979 – REVISED OCTOBER 2018

Product Folder Links: AM26LS31 AM26LS31M

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Copyright © 1979–2018, Texas Instruments Incorporated

8 Detailed Description

8.1 Overview

The AM26LS31x differential bus transmitter is a monolithic integrated circuit designed for unidirectional data

communication on transmission lines. It is designed for balanced transmission lines and meets ANSI Standard

EIA/TIA-422-B and ITU Recommendation V.11.

The AM26LS31x has a four 3-state differential line drivers that operate from a single 5-V power supply. The

driver also integrates active-high and active-low enables for precise device control.

The driver is designed to handle loads of a minimum of ±30 mA of sink or source current. The driver features

positive- and negative-current limiting for protection from line fault conditions.

8.2 Functional Block Diagram

8.3 Feature Description

8.3.1 Complementary Output-Enable Inputs

The AM26LS31x can be configured using the G and G logic inputs to control transmitter outputs. Setting either G

to a logic HIGH or G to an logic LOW enables the transmitter outputs. If G is set to logic LOW and G is set to

logic HIGH, the transmitter outputs are disabled. See Table 1 for a complete truth table.

8.3.2 High Output Impedance in Power-Off Conditions

When the AM26LS31x transmitter outputs are disabled using G and G, the outputs are set to a high impedance

state.

8.3.3 Complementary Outputs

The AM26LS31x is the driver half of a pair of devices, with the AM26LS32 being the complementary receiver. TI

recommends using these devices together for optimal performance, but any RS-422 compliant receive must

ensure proper RS-422 communication and logic level translation.