Texas Instruments SN65LVDS391PWR

Overview

SN65LVDS391PWR from Texas Instruments is a quad-channel LVDS line driver IC designed for high-speed point-to-point and multidrop data transmission. It delivers 340 mV typical differential output voltage into 100-Ω loads, supports signaling rates up to 630 Mbps, and operates from a 3.3-V supply (3.0–3.6 V). It serves as a low-power, low-EMI interface between LVTTL logic and balanced differential interconnects in telecom infrastructure backplanes.

For engineers reviewing the SN65LVDS391PWR datasheet, SN65LVDS391PWR pinout, SN65LVDS391PWR application, or SN65LVDS391PWR equivalent, key selection criteria include its 2.9 ns max propagation delay, <150 ps output skew, 15 kV bus-pin ESD protection, 4-channel enable grouping (EN1,2 / EN3,4), and TSSOP-38 package compatibility with high-density PCB layouts.

Technical Context

The SN65LVDS391PWR implements current-mode LVDS drivers compliant with ANSI/TIA/EIA-644A, using internal 3.5-mA constant-current sources to generate nominally 340 mV differential swing at 1.2 V common-mode voltage. Each channel features independent LVTTL-compatible inputs with 5-V tolerance and internal pulldown resistors for open-input default-low behavior.

It integrates dual enable controls (EN1,2 and EN3,4) that place corresponding driver pairs into high-impedance state when low, supporting dynamic channel gating. Power-on reset circuitry forces outputs to high-Z if VCC falls below 1.5 V, ensuring safe startup and brownout conditions.

Key Specifications

Pinout & Package

TSSOP-38 package (9.70 mm × 4.40 mm, 0.65-mm pitch) with exposed thermal pad; optimized for automated assembly and thermal performance in space-constrained applications.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN65LVDS389DBT, SN65LVDS391PWR offers finer enable granularity (2×2 vs single 8-channel enable) and better thermal dissipation in TSSOP-38; versus MAX9122ESE+, it provides 58% higher signaling rate, 36% higher minimum VOD, and nearly double ESD protection - critical for telecom and medical deployments.

Availability

SN65LVDS391PWR is available at Aetrix Electronics and suitable for wireless infrastructure, telecom line cards, and industrial imaging systems requiring stable component supply with full traceability and long-term lifecycle support.

Supply support for SN65LVDS391PWR 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 leader specializing in analog, embedded processing, and connectivity technologies with over 90 years of innovation in high-reliability electronic components.

The SNx5LVDS3xx family was engineered specifically for high-speed, low-power, noise-immune parallel data transmission in telecom, wireless, and industrial systems - emphasizing timing precision, ESD resilience, and 3.3-V system integration.

FAQ

What is the maximum signaling rate supported by the SN65LVDS391PWR?

The SN65LVDS391PWR supports signaling rates up to 630 Mbps, verified under recommended operating conditions with 3.3-V supply and 100-Ω load. This rate is achievable due to its <2.9 ns propagation delay and <150 ps output skew, which preserve signal integrity at high frequencies. The SN65LVDS391PWR datasheet specifies this limit based on pulse distortion measurements at 1.6 ns pulse width.

Does the SN65LVDS391PWR require external termination resistors?

Yes, the SN65LVDS391PWR requires a 100-Ω differential termination resistor at the receiver end of the transmission line to prevent reflections and ensure signal fidelity. The SN65LVDS391PWR itself does not integrate termination; it is designed to drive standard 100-Ω controlled-impedance media such as PCB traces or shielded cables. Proper termination is essential to achieve its specified 630 Mbps performance.

Can the SN65LVDS391PWR interface directly with 5-V microcontrollers?

Yes, the SN65LVDS391PWR accepts 5-V LVTTL input signals on all A-input pins (1A–4A) while operating from a 3.3-V supply. Its input structure includes 5-V-tolerant circuitry and internal pulldown resistors, allowing direct connection to 5-V logic without level shifters. This capability is explicitly confirmed in the SN65LVDS391PWR datasheet Section 10.3.2.

How does the enable functionality work on the SN65LVDS391PWR?

The SN65LVDS391PWR uses two enable inputs: EN1,2 (pin 1) controls channels 1 and 2, while EN3,4 (pin 8) controls channels 3 and 4. When either enable is low, its associated pair enters high-impedance state. Both enables are internally pulldown, so floating inputs default to disabled - a safety feature preventing unintended output activation during power-up or configuration.

What thermal considerations apply to the SN65LVDS391PWR in continuous operation?

The SN65LVDS391PWR has a derating factor of 8.5 mW/°C above 25°C ambient and a maximum power rating of 1071 mW at TA = 25°C. In continuous 630 Mbps operation across all four channels, typical ICC is ~26 mA, yielding ~86 mW total dissipation - well within thermal limits. For sustained high-load use, maintain PCB copper area under the exposed pad and avoid stacking heat-generating components nearby.