Texas Instruments 74ACT16646DLRG4

Overview

74ACT16646DLRG4 from Texas Instruments is a 16-bit bus transceiver and register IC with 3-state outputs, TTL-voltage-compatible inputs, dual independent registers (A/B), and flow-through architecture for optimized PCB layout. It operates from –40°C to 85°C at 4.5–5.5 V, supports real-time and stored-data multiplexing, and is used in high-speed digital backplanes and memory interface buffering.

For engineers reviewing the 74ACT16646DLRG4 datasheet, 74ACT16646DLRG4 pinout, 74ACT16646DLRG4 application, or 74ACT16646DLRG4 equivalent, key selection criteria include its 90 MHz max clock frequency, ±24 mA drive strength, distributed V_CC/GND pin configuration for noise reduction, and support for isolated storage of A- and B-bus data without bus contention.

Technical Context

The 74ACT16646DLRG4 implements two independent 8-bit D-type flip-flop banks (A and B) with synchronous clocking on CLKAB/CLKBA edges, enabling simultaneous or selective latching of data from either bus. Its select controls (SAB/SBA) eliminate decoding glitches during transitions between transparent and stored modes.

Direction (DIR), output-enable (OE), and clock-select logic allow four distinct bus-management functions: real-time A→B or B→A transfer, bidirectional storage from A/B, and stored-data output to A and/or B - all while maintaining input functionality even when outputs are disabled.

Key Specifications

Pinout & Package

74ACT16646DLRG4 is housed in a 56-pin Shrink Small-Outline Package (SSOP-DL), 300-mil body width, 25-mil pin pitch, with distributed V_CC and GND pins to minimize switching noise.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74ACT16646DLRG4, the 74ACT16245DLR omits storage capability and multiplexing control, limiting it to basic bus extension, while SN74LVC16646ADLR offers superior speed and density at 3.3 V but sacrifices 5 V interoperability and military-grade temperature range.

Availability

74ACT16646DLRG4 is available at Aetrix Electronics and suitable for industrial control systems, memory subsystems, and digital backplane designs requiring stable component supply, long-lifecycle support, and guaranteed 5 V TTL compatibility.

Supply support for 74ACT16646DLRG4 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 decades of experience in high-reliability industrial and automotive ICs.

The 74ACT16646DLRG4 belongs to TI's Widebus™ family of advanced bus-interface devices, engineered specifically for high-speed, noise-resilient data routing in demanding industrial and computing applications.

FAQ

What is the maximum operating frequency of the 74ACT16646DLRG4?

The 74ACT16646DLRG4 supports a maximum clock frequency of 90 MHz under recommended operating conditions (V_CC = 4.5–5.5 V, T_A = –40°C to +85°C). This rating applies to both CLKAB and CLKBA inputs and is validated by TI's switching characteristics data, including t_w (pulse width) ≥ 5.5 ns and propagation delays as low as 3.4 ns (t_PHL). The device maintains timing integrity across its full industrial temperature range.

Does the 74ACT16646DLRG4 support true bidirectional operation on the same pin pair?

Yes, the 74ACT16646DLRG4 supports true bidirectional I/O on each A/B pin pair (e.g., A1/B1), enabled by independent DIR and OE controls per register bank. When OE is low and DIR is asserted, data flows in the selected direction; when OE is high, all outputs go high-impedance while inputs remain active - allowing concurrent storage and monitoring without bus contention.

Can the 74ACT16646DLRG4 operate with a 3.3 V supply?

No, the 74ACT16646DLRG4 is specified only for 4.5 V to 5.5 V operation. Its EPIC CMOS process and TTL-compatible input thresholds require nominal 5 V supply for guaranteed logic-level compliance and timing performance. For 3.3 V systems, TI recommends the pin-compatible SN74LVC16646ADLR, which is rated for 1.65–3.6 V and shares identical functionality and pinout.

How does the 74ACT16646DLRG4 handle simultaneous access to A and B buses?

The 74ACT16646DLRG4 prevents bus contention by enforcing strict one-bus-driven-at-a-time operation via DIR and OE logic. Its function table confirms that only one bus (A or B) may be actively driven at any time; attempting concurrent drive results in undefined output states. Internal design enforces this through gated output drivers and priority-encoded control paths.

What package type and RoHS status does the 74ACT16646DLRG4 use?

The 74ACT16646DLRG4 uses a 56-pin Shrink Small-Outline Package (SSOP-DL) with 25-mil pitch and is RoHS-compliant (lead-free NiPdAu finish). It carries JEDEC MSL Level-1 rating (unlimited floor life at ≤30°C/60% RH) and is qualified for reflow up to 260°C peak. The "G4" suffix denotes TI's green, lead-free, and halogen-free packaging standard.