NXP Semiconductors 74ABT646ADB,112

Overview

74ABT646ADB,112 from NXP Semiconductors is an octal bus transceiver/register with 3-state outputs, combining BiCMOS high-speed operation (up to 350 MHz), ±64 mA/−32 mA output drive, and independent A/B bus registers for real-time or stored-data transfer. It operates across −40 °C to +85 °C with 4.5 V–5.5 V supply and supports live insertion in industrial backplane and memory interface applications.

For engineers reviewing the 74ABT646ADB,112 datasheet, 74ABT646ADB,112 pinout, 74ABT646ADB,112 application, or 74ABT646ADB,112 equivalent, this device delivers multiplexed bus management with dual-clock control (CPAB/CPBA), direction-selectable data flow (DIR), and isolation-mode register storage-critical for deterministic timing in legacy parallel bus systems.

Technical Context

The 74ABT646ADB,112 implements a dual-latch architecture where CPAB clocks data from A to B registers and CPBA clocks from B to A registers, while SAB/SBA select real-time or registered path routing. DIR determines active bus direction during transceiver mode, and OE enables/disables all outputs independently of input functionality.

Its BiCMOS process enables simultaneous low static current (250 µA max at 5.5 V) and high dynamic drive (64 mA sink, 32 mA source), with propagation delays as low as 1.5 ns (An→Bn) and 2.2 ns (CPAB→Bn). Power-up 3-state and latch-up protection (>500 mA) ensure robust system initialization and fault tolerance.

Key Specifications

Pinout & Package

74ABT646ADB,112 uses SSOP24 (SOT340-1) package: plastic shrink small outline, 24 leads, 5.3 mm body width, 0.65 mm pitch.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74ABT646ADB,112, the SO24 variant offers identical performance in a wider package for legacy layouts, while the PDIP version trades speed and robustness for ease of manual prototyping-neither provides pin-compatible drop-in replacement without mechanical or timing revalidation.

Availability

74ABT646ADB,112 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy memory subsystems, and telecom line card control requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for 74ABT646ADB,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 leader specializing in secure connectivity solutions for automotive, industrial, and IoT applications, with deep expertise in high-performance logic and interface ICs.

The 74ABT646ADB,112 belongs to NXP's ABT-series advanced BiCMOS logic family, designed specifically for high-speed, low-power parallel bus interfacing in industrial and telecom infrastructure where reliability and timing determinism are critical.

FAQ

What is the maximum operating frequency of the 74ABT646ADB,112?

The 74ABT646ADB,112 achieves a maximum clock frequency of 350 MHz under recommended conditions (VCC = 5.0 V ± 0.5 V, −40 °C to +85 °C). This applies to CPAB/CPBA-controlled register loading; real-time data path (An↔Bn) supports up to 125 MHz maximum frequency per the dynamic characteristics table. The 74ABT646ADB,112 datasheet specifies these limits with test conditions and waveform definitions in Section 10.

Does the 74ABT646ADB,112 support hot-swap or live insertion?

Yes, the 74ABT646ADB,112 supports live insertion and extraction as explicitly stated in its features list. This is enabled by power-up 3-state behavior (outputs remain high-impedance until VCC stabilizes) and continuous input enable-even when OE is HIGH, A0–A7 and B0–B7 remain functional for data capture. The 74ABT646ADB,112 meets this requirement without external circuitry.

What are the absolute maximum ratings for supply voltage and junction temperature of the 74ABT646ADB,112?

The 74ABT646ADB,112 has an absolute maximum supply voltage (VCC) of −0.5 V to +7.0 V and a maximum junction temperature (Tj) of 150 °C. These values are defined in Table 4 (Limiting Values) of the NXP datasheet Rev. 03. Operation beyond these limits risks permanent damage. The 74ABT646ADB,112 must be operated within recommended conditions (4.5 V–5.5 V, −40 °C to +85 °C ambient) for reliable performance.

How does the DIR pin interact with OE and SAB/SBA in the 74ABT646ADB,112?

In the 74ABT646ADB,112, DIR controls data direction only when OE is LOW (output enabled). When OE is HIGH (isolation mode), DIR has no effect on transceiver action but remains relevant for register storage control. SAB and SBA determine whether data flows in real-time (L) or from registers (H), independent of DIR state. All three pins jointly define the four fundamental bus functions shown in Figure 5 of the 74ABT646ADB,112 datasheet.

Is the 74ABT646ADB,112 pin-compatible with other packages in the same family?

Yes-the 74ABT646ADB,112 (SSOP24), 74ABT646AD,118 (SO24), and 74ABT646APW,118 (TSSOP24) share identical pin numbering, pin functions, and logic behavior per Table 2 and Figures 4–5 in the datasheet. Mechanical differences (body width, pitch, thermal profile) require separate PCB footprints, but schematic symbols and netlist assignments are fully interchangeable. The 74ABT646ADB,112 is electrically and functionally identical to its family members.