NXP Semiconductors 74ABT646APW,112

Overview

74ABT646APW,112 from NXP Semiconductors is an octal bus transceiver/register with 3-state outputs, combining BiCMOS logic for high-speed bidirectional data transfer (up to 350 MHz), ±64 mA/−32 mA drive capability, and dual independent A/B registers. It enables real-time or registered bus communication between two 8-bit data buses in industrial control backplanes and memory-mapped I/O interfaces.

For engineers reviewing the 74ABT646APW,112 datasheet, 74ABT646APW,112 pinout, 74ABT646APW,112 application, or 74ABT646APW,112 equivalent, key selection criteria include direction-controlled 3-state operation, clocked register storage on both buses, isolation-mode register hold, and TSSOP24 packaging for high-density PCB layouts.

Technical Context

The 74ABT646APW,112 implements a dual-path architecture with separate CPAB/CPBA clock inputs and SAB/SBA select lines, allowing asynchronous latching of data from either bus into its respective register. Its DIR pin controls data flow direction during transceiver mode, while OE enables/disables all outputs independently of register clocking.

It supports live insertion/extraction and features power-up 3-state and power-up reset behavior. The device operates across −40 °C to +85 °C with 4.5 V to 5.5 V supply, meeting JESD78B Class II latch-up immunity (>500 mA) and HBM ESD protection (>2000 V).

Key Specifications

Pinout & Package

TSSOP24 package (SOT355-1): plastic thin shrink small outline, 24 leads, 4.4 mm body width, 0.65 mm pitch, lead-free and RoHS compliant.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74ABT646APW,112, the 74ABT245PW,112 offers lower propagation delay but no register storage, while the 74ABT373APW,112 provides stronger latching integrity but no bidirectional bus coupling - making the 74ABT646APW,112 uniquely suited for systems requiring both real-time and registered data routing between two independent buses.

Availability

74ABT646APW,112 is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory-mapped I/O expansion, hot-swappable module hubs, and dual-bus arbitration logic requiring stable component supply and long-term production continuity.

Supply support for 74ABT646APW,112 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

NXP Semiconductors is a global semiconductor company headquartered in Eindhoven, Netherlands, specializing in secure connectivity solutions for automotive, industrial, and IoT applications.

The 74ABT646APW,112 belongs to NXP's ABT-series advanced BiCMOS logic family, designed for high-speed, low-power, and robust bus interface applications in industrial control and modular electronic systems.

FAQ

What is the primary function of the 74ABT646APW,112?

The 74ABT646APW,112 is an octal bus transceiver/register with dual independent A/B registers, 3-state outputs, and direction-controlled bidirectional data routing. It supports real-time transfer, stored-data transfer, isolation-mode hold, and simultaneous register capture - all within a single TSSOP24 package. Its core function is to manage time-critical and deterministic data movement between two 8-bit buses in industrial and embedded systems.

Does the 74ABT646APW,112 support hot-swap operation?

Yes, the 74ABT646APW,112 supports live insertion and extraction due to its power-up 3-state behavior and controlled output disable via OE. During power-up, all outputs remain in high-impedance until VCC stabilizes, preventing bus contention. This makes the 74ABT646APW,112 suitable for modular backplane systems where boards are replaced without powering down the host controller.

What are the voltage and timing requirements for reliable operation of the 74ABT646APW,112?

The 74ABT646APW,112 requires a 4.5 V to 5.5 V supply (VCC), operates from −40 °C to +85 °C, and specifies VIH ≥ 2.0 V and VIL ≤ 0.8 V. Clock pulse widths must be ≥4.0 ns (HIGH/LOW), and data setup/hold times are ±0.0 ns to 3.0 ns depending on edge. These values ensure reliable register capture and transceiver switching across its full temperature and voltage range.

How does the DIR pin affect data flow in the 74ABT646APW,112?

The DIR pin determines bus direction only when OE is active (LOW). With DIR = LOW, data flows from B bus to A bus; with DIR = HIGH, data flows from A bus to B bus. DIR has no effect in isolation mode (OE = HIGH), where it is ignored and register storage proceeds independently via CPAB/CPBA clocks. This allows flexible, software-controllable bus topology reconfiguration using the 74ABT646APW,112.

Can the 74ABT646APW,112 replace discrete 74ABT245 and 74ABT373 devices?

Yes - the 74ABT646APW,112 integrates the core functionality of both the 74ABT245 (transceiver) and 74ABT373 (octal latch) into one device, reducing component count and PCB area. However, it does not provide identical pin compatibility or identical timing margins. System redesign is required to leverage its multiplexed real-time + stored data modes, but the 74ABT646APW,112 delivers higher functional density and greater bus management flexibility than using separate 74ABT245 and 74ABT373 devices.