NXP Semiconductors 74ABT651D,118

Overview

74ABT651D,118 from NXP Semiconductors (formerly Philips) is an octal inverting transceiver/register with 3-State outputs, designed for bidirectional data bus interfacing between two 8-bit buses (A and B) in high-speed TTL-compatible systems. It supports real-time transfer, stored-data transfer, independent A/B register storage, and operates at up to 300 MHz clock frequency with 3.8 ns typical propagation delay (CPAB to Bn). It delivers ±64 mA/–32 mA output drive and features power-up 3-State and latch-up protection exceeding 500 mA.

For engineers reviewing the 74ABT651D,118 datasheet, 74ABT651D,118 pinout, 74ABT651D,118 application, or 74ABT651D,118 equivalent, key selection criteria include its dual-clock (CPAB/CPBA), dual-select (SAB/SBA), dual-OE (OEAB/OEBA) control architecture, inverting logic behavior, BiCMOS process enabling low-power/high-speed operation, and compatibility with 5 V ±10 % supply across –40 °C to +85 °C.

Technical Context

The 74ABT651D,118 implements a dual-path 8-bit transceiver with integrated D-type flip-flops on both A and B sides, enabling simultaneous or staggered latching of data from either bus. Its inverting function applies to all data paths: A→B, B→A, and register-to-bus transfers.

Control is managed via four dedicated pins per direction: clock (CPAB/CPBA), select (SAB/SBA), and active-low output enable (OEAB/OEBA). The select pins determine whether data flows in real time or from internal registers; OE pins define directionality and 3-State state. Power-up reset ensures outputs enter high-impedance before valid logic levels stabilize.

Key Specifications

Pinout & Package

74ABT651D,118 is housed in a 24-pin plastic small outline (SO) package (SOT137-1), 7.5 mm body width, surface-mount compatible with standard reflow profiles.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ABT651N and 74ABT652D,118, the 74ABT651D,118 uniquely combines SO packaging, inverting functionality, and full register/transceiver multiplexing - making it optimal for space-constrained industrial boards requiring polarity inversion and real-time/stored data flexibility.

Availability

74ABT651D,118 is available at Aetrix Electronics and suitable for industrial PLC backplanes, legacy bus bridges, automated test equipment, and automotive diagnostic interfaces requiring stable component supply, long-term lifecycle assurance, and guaranteed traceable sourcing.

Supply support for 74ABT651D,118 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, formerly Philips Semiconductors, is a global leader in high-performance logic, analog, and interface ICs, with deep heritage in industrial-grade 5 V TTL-compatible solutions.

The 74ABT651D,118 belongs to the ABT (Advanced BiCMOS Technology) logic family - engineered for high-speed, low-noise, high-drive 5 V digital interfacing in demanding industrial and communications infrastructure applications.

FAQ

What is the logic polarity behavior of the 74ABT651D,118 during data transfer?

The 74ABT651D,118 performs inverting data transfer on all paths: A→B, B→A, and register-to-bus outputs. When data is passed in real time or retrieved from internal registers, each bit is complemented. This is inherent to the device's architecture and cannot be disabled. Designers must account for this inversion in system-level timing and logic equations - for example, pairing with non-inverting receivers or adjusting firmware bit-mapping. The 74ABT651D,118 datasheet confirms inversion applies identically across all operating modes defined in the Function Table.

Does the 74ABT651D,118 support live insertion in powered-backplane systems?

Yes, the 74ABT651D,118 supports live insertion and extraction due to its power-up 3-State feature and controlled output-enable sequencing. At power-on, all outputs default to high-impedance regardless of OEAB/OEBA pin states, preventing bus contention during voltage ramp-up. This behavior is verified in the "Power-up 3-State" feature and confirmed by the DC Electrical Characteristics table showing ICCZ = 110 µA (quiescent current with outputs disabled). The 74ABT651D,118 is therefore suitable for hot-pluggable modules in industrial backplanes and telecom line cards.

What are the minimum pulse width requirements for CPAB and CPBA clocks on the 74ABT651D,118?

The 74ABT651D,118 requires a minimum HIGH and LOW pulse width of 4.0 ns for CPAB and CPBA clocks at Tamb = +25 °C and VCC = +5.0 V, per the AC Set-up Requirements table. Over the full temperature range (–40 °C to +85 °C) and supply (4.5 V to 5.5 V), the minimum pulse width remains 1.2 ns. These values ensure reliable edge detection and register clocking. Violating these widths risks metastability or missed latches - especially critical when using the 74ABT651D,118 in high-frequency bus arbitration or test pattern generation where precise clock alignment is essential.

How does the 74ABT651D,118 handle simultaneous clocking of both A and B registers?

The 74ABT651D,118 permits simultaneous clocking of both A and B registers only when both SAB and SBA are LOW - i.e., when both buses are configured for stored-data output mode. If either SAB or SBA is HIGH (enabling real-time transfer), clocks must be staggered to avoid undefined behavior, as stated in the Function Table note (**). This constraint ensures deterministic register loading and prevents race conditions between overlapping clock edges. Designers implementing dual-bus synchronization must verify SAB/SBA states before asserting CPAB/CPBA - a requirement explicitly documented in the 74ABT651D,118 datasheet on page 4.

Is the 74ABT651D,118 pin-compatible with the 74ABT652D,118?

Yes, the 74ABT651D,118 is pin-compatible with the 74ABT652D,118 - they share identical 24-pin SO package (SOT137-1), pin numbering, and pin functions. The sole functional difference is logic polarity: the 74ABT651D,118 is inverting, while the 74ABT652D,118 is non-inverting. All timing parameters, drive strength, supply ranges, and control logic (clock, select, OE) are identical. This allows direct substitution in layouts where polarity can be compensated at the system level - for example, by inverting firmware data writes or adding a single inverter gate.