±3

±2

±1

0

1

2

3

4

5

0

0.1

0.2

0.3

0.4

0.5

Time ( s)

Y

A/B

C001

12

AM26LS31, AM26LS31C, AM26LS31I, AM26LS31M

SLLS114L – JANUARY 1979 – REVISED OCTOBER 2018

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Product Folder Links: AM26LS31 AM26LS31M

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Copyright © 1979–2018, Texas Instruments Incorporated

Typical Application (continued)

9.2.1 Design Requirements

This example requires the following:

•

5-V power source

•

RS-485 bus operating at 10 Mbps or less

•

Connector that ensures the correct polarity for port pins

9.2.2 Detailed Design Procedure

Place the device close to bus connector to keep traces (stub) short to prevent adding reflections to the bus line.

If desired, add external fail-safe biasing to ensure 200 mV on the A-B port, if the drive is in high impedance state

(see Failsafe in RS-485 data buses).

9.2.3 Application Curve

Figure 13. Differential 120-Ω Terminated Output Waveforms (Cat 5E Cable)