Texas Instruments SN74ABT623PWR

Overview

SN74ABT623PWR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data communication between A and B buses in 5-V TTL systems. It features dual output-enable controls (OEAB/OEBA), high-drive capability (–32 mA IOH / 64 mA IOL), and operates across –40°C to 85°C. Used in backplane interfaces, memory expansion, and system-level bus isolation.

For engineers reviewing the SN74ABT623PWR datasheet, SN74ABT623PWR pinout, SN74ABT623PWR application, or SN74ABT623PWR equivalent, key selection factors include its 20-pin TSSOP package, dual-enable logic for bus storage, ground-bounce performance (<1 V VOLP), and compatibility with standard 5-V TTL signaling levels.

Technical Context

This device implements a true bidirectional 8-bit transceiver architecture with independent OEAB (A-to-B enable) and OEBA (B-to-A enable) inputs, enabling flexible data flow control without external direction logic. Its EPIC-II^B BiCMOS process delivers low power dissipation while maintaining TTL-compatible input thresholds and high-current drive strength.

The dual-enable configuration supports bus-hold functionality: when both OEAB and OEBA are asserted, outputs reinforce their inputs, allowing stable latched states on both A and B buses (16 lines total) during isolation - critical for glitch-free bus arbitration and hot-swap readiness.

Key Specifications

Pinout & Package

TSSOP-20 (PW) package: 6.95 mm × 4.4 mm × 1.2 mm body, 0.65 mm lead pitch, exposed pad optional, RoHS-compliant NIPDAU finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar octal bus transceiver applications.

Compared with SN74ABT245PWR and 74LVC245APW, the SN74ABT623PWR uniquely supports true dual-enable bus storage and 5-V TTL interoperability - making it the only option for legacy-compatible, glitch-immune bidirectional bus isolation in industrial control backplanes.

Availability

SN74ABT623PWR is available at Aetrix Electronics and suitable for industrial PLCs, memory expansion subsystems, and backplane routing applications requiring stable component supply and long-term production continuity.

Supply support for SN74ABT623PWR 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 logic solutions with over 50 years of industrial-grade product development.

The SN74ABT623PWR belongs to TI's ABT logic family, engineered for high-speed, high-drive 5-V TTL bus interfacing in mission-critical industrial and communications infrastructure.

FAQ

What is the recommended power-up sequence for SN74ABT623PWR to avoid bus contention?

TI specifies that OEBA must be tied to VCC through a pullup resistor and OEAB to GND through a pulldown resistor to ensure high-impedance outputs during power ramp. For SN74ABT623PWR, this prevents unintended data leakage or bus conflicts before system initialization completes. Resistor values depend on driver sourcing/sinking capability but typically range from 4.7 kΩ to 10 kΩ.

Can SN74ABT623PWR operate reliably at 4.5 V supply voltage?

Yes - SN74ABT623PWR is fully characterized from 4.5 V to 5.5 V per its recommended operating conditions. At 4.5 V, it maintains guaranteed VOH ≥ 2.0 V (with IOH = –32 mA) and VOL ≤ 0.55 V (with IOL = 64 mA), meeting TTL interface requirements. Performance metrics like propagation delay and ground bounce remain within spec across this range.

Does SN74ABT623PWR support hot-swap or live-insertion in backplane applications?

SN74ABT623PWR supports controlled hot-swap operation when OEBA and OEAB are managed externally to force 3-state before insertion. Its robust ESD protection (>2000 V HBM), latch-up immunity (>500 mA), and power-rail sequencing tolerance make it suitable for modular backplane designs - provided board-level current limiting and slew-rate control are implemented per TI's application guidelines for SN74ABT623PWR.

What is the thermal resistance (θJA) of the SN74ABT623PWR in its TSSOP-20 package?

The SN74ABT623PWR in PW (TSSOP-20) package has a specified junction-to-ambient thermal resistance (θJA) of 128°C/W under standard JEDEC test conditions. This value assumes a 1-inch² copper pad with two vias; actual board layout significantly impacts thermal performance, and TI recommends using the exposed pad (if present) with ≥4 thermal vias for improved heat dissipation in sustained high-current operation.

How does the dual-enable function of SN74ABT623PWR differ from standard 74-series transceivers like 74LS245?

Unlike single-enable transceivers such as 74LS245, SN74ABT623PWR uses separate OEAB and OEBA inputs to independently control A→B and B→A paths. When both are active, outputs reinforce inputs - enabling true bus-hold behavior without external feedback. This eliminates metastability risks during bus arbitration and provides deterministic state retention, a capability absent in classic 74-series devices and critical for SN74ABT623PWR's use in fault-tolerant industrial systems.