Texas Instruments 74AC16646DL

Overview

74AC16646DL from Texas Instruments is a 16-bit advanced CMOS bus transceiver with dual independent registers, 3-state outputs, flow-through architecture, and operation from −40°C to 85°C. It supports real-time or stored data multiplexing between A and B buses, clocked on low-to-high transitions of CLKAB/CLKBA, with DIR/OE/SAB/SBA control. Used in high-density PCBs for bidirectional data routing in industrial control backplanes and memory interface buffers.

For engineers reviewing the 74AC16646DL datasheet, 74AC16646DL pinout, 74AC16646DL application, or 74AC16646DL equivalent, key selection criteria include its 75 MHz max clock frequency at 5 V, ±24 mA output drive, 5.5 V absolute max supply, distributed V_CC/GND pinning for noise reduction, and DL-package shrink small-outline footprint optimized for space-constrained layouts.

Technical Context

The 74AC16646DL implements two independent 8-bit register banks (A/B) with D-type flip-flops, enabling simultaneous storage and selective multiplexing of real-time or latched data. Its flow-through architecture eliminates propagation bottlenecks by allowing direct bus-to-bus transfer without internal register staging delays.

Control logic uses asynchronous OE and DIR inputs plus synchronous SAB/SBA select lines to manage four distinct bus functions: real-time A→B, real-time B→A, stored-data transfer, and isolation mode. Clock inputs CLKAB and CLKBA trigger edge-sensitive latching only on low-to-high transitions, ensuring deterministic timing alignment across all 16 channels.

Key Specifications

Pinout & Package

74AC16646DL is housed in a 56-pin plastic shrink small-outline (DL) package with 25-mil center-to-center pin spacing and twice the functionality per unit PCB area versus standard SOIC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with 74AC16646DL, 74ACT16646DL offers improved 3.3 V input compatibility and slightly faster output disable timing, while SN74LVC16646DGGR reduces power and footprint at the cost of 5 V operation - making 74AC16646DL the optimal choice for legacy 5 V industrial systems requiring robust noise immunity and wide voltage margin.

Availability

74AC16646DL is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory expansion buffers, test equipment data muxing, and DSP co-processor interfaces requiring stable component supply across extended product lifecycles.

Supply support for 74AC16646DL 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 heritage in high-reliability industrial and automotive components.

The 74AC16646DL belongs to TI's Widebus™ family of advanced CMOS bus interface ICs, engineered specifically for high-density, high-speed PCB layouts in industrial automation, instrumentation, and communications infrastructure.

FAQ

What is the maximum clock frequency supported by the 74AC16646DL?

The 74AC16646DL supports a maximum clock frequency of 75 MHz when operated at V_CC = 5 V ± 0.5 V across the full industrial temperature range. At 3.3 V, the maximum clock rate drops to 65 MHz. These values are specified in the timing requirements section of the SCAS241A datasheet and reflect guaranteed performance under recommended operating conditions - critical for synchronizing data capture in real-time industrial interfaces using the 74AC16646DL.

Does the 74AC16646DL support 3.3 V operation?

Yes, the 74AC16646DL operates over a supply range of 3 V to 5.5 V, making it fully functional at 3.3 V nominal. At 3.3 V, it delivers 75% of its 5 V output drive (±12 mA typical) and maintains full logic compatibility with 3.3 V systems. The 74AC16646DL datasheet specifies timing parameters including 65 MHz max clock frequency and 13.2 ns max propagation delay at 3.3 V - confirming reliable use in mixed-voltage designs where the 74AC16646DL bridges legacy 5 V and modern 3.3 V subsystems.

How does the 74AC16646DL handle bus contention during direction switching?

The 74AC16646DL prevents bus contention through strict directional control: DIR determines data flow direction (A→B or B→A) only when OE is active (low), and OE must be high to place outputs in high-impedance state during direction changes. The 74AC16646DL's architecture ensures that only one bus (A or B) may be driven at any time, enforced by internal logic that disables conflicting paths - eliminating shoot-through current and signal corruption during dynamic reconfiguration in applications like hot-swappable backplanes using the 74AC16646DL.

What is the purpose of the SAB and SBA pins on the 74AC16646DL?

The SAB (Select A-to-B) and SBA (Select B-to-A) pins on the 74AC16646DL control whether the output presents real-time (transparent) bus data or previously latched register contents. They enable glitch-free multiplexing between live and stored data streams by eliminating decoding hazards during transitions - a key feature confirmed in the functional table and Figure 1 of the 74AC16646DL datasheet. This capability allows the 74AC16646DL to serve as a flexible data router in test equipment and protocol analyzers where synchronized switching between live and buffered data is required.

Is the 74AC16646DL pin-compatible with other members of the Widebus family?

Yes, the 74AC16646DL shares identical pinout and function with the 74ACT16646DL and 74F16646 - all packaged in the 56-pin DL format. This pin compatibility allows direct substitution in existing designs when upgrading drive strength (ACT) or speed grade (F), provided voltage and timing margins are verified. The 74AC16646DL datasheet explicitly confirms mechanical and electrical compatibility within the Widebus™ family, simplifying second-source qualification and long-term supply chain resilience for designs relying on the 74AC16646DL.