Texas Instruments 74ACT16651DLR

Overview

74ACT16651DLR from Texas Instruments is a 16-bit bus transceiver with dual 8-bit registers, 3-state outputs, and independent A/B bus control logic. It operates at 5 V, supports 90 MHz clock frequency, delivers ±24 mA output drive, and features inverting data paths for real-time or stored-data transfer between parallel buses. It is used in high-speed backplane interface and modular system interconnect applications.

For engineers reviewing the 74ACT16651DLR datasheet, 74ACT16651DLR pinout, 74ACT16651DLR application, or 74ACT16651DLR equivalent, key selection criteria include bidirectional register-controlled data flow, simultaneous real-time/stored-mode operation, latch-up immunity (500 mA at 125°C), and SSOP-56 package compatibility with dense PCB layouts.

Technical Context

The 74ACT16651DLR implements two independent 8-bit D-type flip-flop banks-one per bus-with separate clock (CLKAB/CLKBA), select (SAB/SBA), and output-enable (OEAB/OEBA) controls. Its flow-through architecture enables glitch-free multiplexing between live bus signals and registered data without external decoding.

It uses TI's EPIC 1-µm CMOS process, features distributed VCC/GND pins to suppress switching noise, and provides TTL-voltage-compatible inputs. The device supports both isolated bus operation and concurrent A→B + B→A stored-data transfers via coordinated control input states.

Key Specifications

Pinout & Package

Packaged in a 56-pin Shrink Small-Outline Package (SSOP-DL), 300-mil body width, 0.025-inch pin pitch, RoHS-compliant CU NIPDAU finish, MSL Level-1 rated.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 16-bit registered transceiver applications.

Compared with 74FCT16651CTPAG and SN74ALVTH16651DGGR, the 74ACT16651DLR offers superior 90 MHz performance and 500 mA latch-up immunity at 125°C-critical for industrial backplanes-while maintaining full pin and functional compatibility with legacy Widebus™ 5 V systems.

Availability

74ACT16651DLR is available at Aetrix Electronics and suitable for industrial PLC expansion, modular test equipment, retro-computing restoration, and high-reliability backplane interconnect applications requiring stable component supply and long-term obsolescence management.

Supply support for 74ACT16651DLR 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 innovation in high-performance logic families.

The 74ACT16651DLR belongs to TI's Widebus™ ACT logic family-designed specifically for high-speed, low-noise, registered bus interfacing in industrial and telecom infrastructure equipment.

FAQ

What is the maximum operating frequency of the 74ACT16651DLR?

The 74ACT16651DLR supports a maximum clock frequency of 90 MHz across its recommended operating conditions (VCC = 4.5 V to 5.5 V, TA = –40°C to +85°C). This value is specified in the timing requirements table of the official SCAS449A datasheet and confirmed by measured tPLH/tPHL propagation delays down to 3 ns at 25°C.

Does the 74ACT16651DLR support true bidirectional data flow between two independent buses?

Yes, the 74ACT16651DLR supports fully independent bidirectional operation: A→B and B→A paths are separately controlled via OEAB/OEBA and SAB/SBA inputs. Each 8-bit segment can be configured for real-time pass-through, registered storage, or isolated high-Z - enabling simultaneous A-to-B stored-data transfer while B-to-A real-time monitoring occurs.

Is the 74ACT16651DLR pin-compatible with older 74FCT16651 devices?

Yes, the 74ACT16651DLR shares identical pinout, function mapping, and AC/DC specifications with the 74FCT16651 family in the DL (SSOP-56) package. Both use the same logic symbol, terminal numbering, and control signal behavior - making it a direct drop-in replacement where enhanced latch-up immunity (500 mA) and wider supply tolerance (4.5–5.5 V) are beneficial.

What is the purpose of the dual-clock architecture (CLKAB and CLKBA) in the 74ACT16651DLR?

The dual-clock architecture allows independent registration of data on each bus: CLKAB captures data from the A bus into the A-side registers, while CLKBA captures data from the B bus into the B-side registers. This enables asynchronous sampling - e.g., capturing sensor data on B while simultaneously logging control commands on A - without cross-bus timing dependencies.

Can the 74ACT16651DLR operate reliably in noisy industrial environments?

Yes, the 74ACT16651DLR is engineered for industrial noise resilience: distributed VCC/GND pins reduce simultaneous switching noise, EPIC CMOS process ensures 500 mA latch-up immunity at 125°C, and TTL-compatible inputs provide 0.8 V/2.0 V noise margins. Its 90 MHz timing budget also accommodates added trace inductance/capacitance in ruggedized PCB layouts.