Copyright © 2016, Texas Instruments Incorporated

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AM26LS32AC, AM26LS32AI, AM26LS32AM

AM26LS33AC, AM26LS33AM

SLLS115F – OCTOBER 1980 – REVISED SEPTEMBER 2016

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Product Folder Links: AM26LS32AC AM26LS32AM AM26LS33AM

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Copyright © 1980–2016, Texas Instruments Incorporated

9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

When using AM26LS32A as a receiver, the AM26LS31AC can allow multiple AM26LS32As to be used causing

an increase in the amount of outputs.

9.2 Typical Application

Figure 17 shows a configuration with no termination. Although reflections are present at the receiver inputs at a

data signaling rate of 200 kbps with no termination, the RS-422-compliant receiver reads only the input

differential voltage and produces a clean signal at the output.

†R

T equals the characteristic impedance of the line.

Figure 17. Application Diagram

9.2.1 Design Requirements

Resistor and capacitor (if used) termination values are shown for each laboratory experiment, but vary from

system to system. For example, the termination resistor, RT, must be within 20% of the characteristic impedance,

ZO, of the cable and can vary from about 80 Ω to 120 Ω.

9.2.2 Detailed Design Procedure

Add a VCC bypass capacitor (0.1 µF or more). Either enable (G pin) input can turn on the receivers, so connect

the desired enable to a compatible logic line output. The other enable input must be tied to the inactive state

supply rail. If the receivers must always be active, then connect both enables to the supply rail such that at least

one is set to an active-state rail. VCC must be 5 V within 10% and logic inputs must provide TTL-compatible

voltage levels A & B Inputs can lead to an external connector or can be left unconnected. The last receiver on a

cable requires termination, either on-board or use as an external resistor. Unused Y outputs can be left

unconnected.