Texas Instruments AM26LS31CNS-H

Overview

AM26LS31CNS-H from Texas Instruments is a quadruple differential line driver IC compliant with ANSI TIA/EIA-422-B and ITU V.11 standards, operating from a single 5V supply with TTL-compatible inputs, complementary outputs, and dual active-high/active-low enable control. It delivers ±30mA output drive capability and maintains high-impedance outputs during power-off or disable states, enabling robust RS-422 communication in industrial encoder interfaces.

For engineers reviewing the AM26LS31CNS-H datasheet, AM26LS31CNS-H pinout, AM26LS31CNS-H application, or AM26LS31CNS-H equivalent, this page provides verified electrical specifications, SO package mechanical data, functional mode truth table, thermal metrics for PCB layout, and real-world use cases in motor encoder signal transmission and field sensor interfacing.

Technical Context

The AM26LS31CNS-H integrates four independent 3-state differential drivers with complementary Y/Z outputs per channel and shared G/G̅ enable logic. Its low-power Schottky architecture supports propagation delays of 14–20 ns (tPLH/tPHL) and output enable/disable times under 45 ns at 5V, with built-in current limiting for line fault protection.

Each driver accepts TTL-level inputs (VIH = 2V min, VIL = 0.8V max), drives balanced lines up to ±30mA, and exhibits off-state leakage ≤±20 µA. The device operates across –40°C to +85°C and meets ESD ratings of ±2000V HBM and ±1000V CDM.

Key Specifications

Pinout & Package

AM26LS31CNS-H uses a 16-pin SO (Small Outline) package measuring 10.3 mm × 5.3 mm, with gull-wing leads and surface-mount compatibility. Thermal resistance R_θJA is 88.5°C/W, supporting moderate power dissipation in compact layouts.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar differential line driver applications.

Compared with SN65LVDS31DR and MAX3080CSA+, the AM26LS31CNS-H provides proven RS-422 compliance, TTL input compatibility, and dual-enable logic ideal for legacy industrial encoder and sensor interfaces where voltage swing and protocol alignment matter more than raw speed or bus topology.

Availability

AM26LS31CNS-H is available at Aetrix Electronics and suitable for motor encoder interfaces, field sensor transmission, military imaging data links, and Modbus RTU signal conditioning requiring stable component supply and long-term industrial availability.

Supply support for AM26LS31CNS-H includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Texas Instruments is a global semiconductor company headquartered in Dallas, Texas, specializing in analog, embedded processing, and connectivity technologies for industrial, automotive, and communications markets.

The AM26LS31 product line was designed specifically for robust, low-cost RS-422 differential transmission in industrial automation, motion control, and sensor interface applications where reliability and legacy protocol compatibility are critical.

FAQ

What is the maximum data rate supported by the AM26LS31CNS-H?

The AM26LS31CNS-H supports reliable data transmission up to 25 Mbps in typical point-to-point configurations. This is derived from its 14–20 ns propagation delay and ≤6 ns output skew, which maintain signal integrity on properly terminated 100Ω twisted-pair lines. Actual achievable rate depends on cable length, termination, and noise environment - for 100m runs, 1–10 Mbps is commonly used in industrial encoder applications.

Does the AM26LS31CNS-H require external pull-up or pull-down resistors on its inputs?

No, the AM26LS31CNS-H does not require external pull-up or pull-down resistors on its A-inputs or G/G̅ enable pins. Its TTL-compatible inputs have defined VIH (≥2V) and VIL (≤0.8V) thresholds with input currents under ±0.36 mA, allowing direct connection to microcontroller GPIOs or logic gates. However, unused inputs should be tied to VCC or GND to prevent floating states.

Can the AM26LS31CNS-H be used with RS-485 receivers?

Yes, the AM26LS31CNS-H can drive RS-485 receivers because both RS-422 and RS-485 share the same differential voltage specification (±1.5V to ±6V). The AM26LS31CNS-H's ±30mA drive strength exceeds RS-485's ±1.5V minimum requirement into 54Ω loads. However, it lacks RS-485's tri-state capability for multi-drop half-duplex operation - use it only in point-to-point or RS-422-style configurations.

What is the purpose of the complementary G and G̅ enable inputs on the AM26LS31CNS-H?

The complementary G (active-high) and G̅ (active-low) enable inputs on the AM26LS31CNS-H provide flexible system-level control: either pin can independently enable all four drivers. This allows direct interface with controllers offering only active-high or only active-low GPIOs without external inverters. When both are asserted oppositely (G=H, G̅=L), outputs are enabled; when both match (G=G̅=H or G=G̅=L), outputs go high-impedance.

Is the AM26LS31CNS-H pin-compatible with other members of the AM26LS31 family?

Yes, the AM26LS31CNS-H is pin-compatible with all 16-pin SO, SOIC, SSOP, PDIP, CDIP, and CFP variants of the AM26LS31 family (e.g., AM26LS31CD, AM26LS31CDB, AM26LS31CN-E), sharing identical pinout, function mapping, and electrical behavior. Differences are limited to package type, temperature grade, and screening - the NS suffix denotes SO package, and the -H suffix indicates enhanced quality screening per TI's internal standards.