Texas Instruments SN74LVC16646ADGVR

Overview

SN74LVC16646ADGVR from Texas Instruments is a 16-bit bus transceiver and register with 3-state outputs, designed for bidirectional data flow between two 8-bit buses (A and B) in mixed-voltage systems. It operates from 1.65 V to 3.6 V VCC, accepts 5.5-V inputs, supports transparent and registered transfer modes, and features Ioff partial-power-down protection. It is used in high-speed board-level interconnects requiring clocked data staging and voltage translation.

For engineers reviewing the SN74LVC16646ADGVR datasheet, SN74LVC16646ADGVR pinout, SN74LVC16646ADGVR application, or SN74LVC16646ADGVR equivalent, key selection criteria include its dual 8-bit register/transceiver architecture, 3.3-V/5-V mixed-mode I/O compatibility, 5.2-ns max tpd at 3.3 V, and TSSOP-56 package with 0.5-mm pitch.

Technical Context

The SN74LVC16646ADGVR integrates two independent 8-bit transceiver channels, each with D-type flip-flops clocked on CLKAB/CLKBA rising edges, select-control logic (SAB/SBA) for real-time or stored-data routing, and direction (DIR) and output-enable (OE) control. Its Ioff circuitry disables outputs during power-down to prevent backflow current.

It supports four fundamental bus-management functions: real-time A→B and B→A transfer, storage of A/B data independently or jointly, and isolation with hold capability. Input thresholds are VIL ≤ 0.35×VCC and VIH ≥ 0.65×VCC across 1.65–3.6 V, enabling robust noise margin in 3.3-V systems interfacing with 5-V peripherals.

Key Specifications

Pinout & Package

TSSOP-56 package (DGV), 13.9 mm × 6.1 mm × 1.2 mm max height, 0.5-mm lead pitch, RoHS-compliant NiPdAu finish, MSL Level-1 (260°C peak reflow).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC16646ADGVR, SN74LVC16245ADGVR offers lower cost and simpler control but forfeits clocked registration and mixed-mode flexibility; SN74ALVC164245DGGR delivers higher speed in narrow VCC range but lacks Ioff and register capability-making SN74LVC16646ADGVR uniquely suited for mixed-voltage, register-assisted interconnects.

Availability

SN74LVC16646ADGVR is available at Aetrix Electronics and suitable for industrial PLC backplanes, automotive body control modules, PCIe slot interfaces, and test equipment digital pattern generators requiring stable component supply and long-term lifecycle assurance.

Supply support for SN74LVC16646ADGVR 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 connectivity technologies, with decades of experience in high-reliability logic and interface solutions.

The SN74LVC16646A belongs to TI's Widebus™ family of advanced bus-interface devices, engineered specifically for high-speed, mixed-voltage board-level interconnects requiring both translation and register-based data staging.

FAQ

What is the maximum clock frequency supported by the SN74LVC16646ADGVR in registered mode?

The SN74LVC16646ADGVR supports up to 150 MHz clock frequency at VCC = 3.3 V in registered mode, as specified in the timing requirements table. This is validated across the full operating temperature range (–40°C to +85°C) and ensures reliable setup/hold timing margins for synchronous data capture. The device achieves this performance while maintaining 5.2-ns max propagation delay in transparent mode, making it suitable for demanding high-speed interconnect applications.

Can the SN74LVC16646ADGVR be used to interface a 3.3-V microcontroller with 5-V sensors without external level shifters?

Yes, the SN74LVC16646ADGVR can directly interface a 3.3-V microcontroller with 5-V sensors because its inputs tolerate up to 5.5 V regardless of VCC (1.65–3.6 V). When VCC = 3.3 V, the device outputs swing rail-to-rail (0 V to 3.3 V), so external pull-ups or translators are required only if the 5-V sensors require 5-V logic-high inputs. For sensing-only use cases where the microcontroller reads 5-V signals, no additional components are needed.

How does the Ioff feature of the SN74LVC16646ADGVR protect system-level power domains?

The Ioff feature of the SN74LVC16646ADGVR disables all outputs when VCC = 0 V, limiting leakage current to ±10 µA even if 5.5-V signals remain present on A/B ports. This prevents reverse current flow from powered subsystems into unpowered ones-critical during hot-swap, partial shutdown, or battery-backed backup scenarios. It eliminates the risk of unintended power injection that could disrupt voltage regulators or damage downstream logic in multi-rail systems.

What is the purpose of the SAB and SBA pins on the SN74LVC16646ADGVR?

The SAB and SBA pins on the SN74LVC16646ADGVR control multiplexing between real-time (transparent) and registered (stored) data paths for each 8-bit channel. SAB selects between real-time or stored data from bus B to bus A; SBA selects between real-time or stored data from bus A to bus B. Their dedicated hardware logic eliminates output glitches during mode transitions-unlike software-controlled muxes-ensuring deterministic timing in safety-critical or high-speed applications.

Is the SN74LVC16646ADGVR pin-compatible with other devices in the SN74LVC16xxx family?

No, the SN74LVC16646ADGVR is not pin-compatible with other SN74LVC16xxx devices such as SN74LVC16245 or SN74LVC16373. Its 56-pin TSSOP (DGV) footprint and signal assignment-including dual DIR/OE/CLK/S control sets and split A/B I/O banks-are unique to the 16646A functional architecture. Substitution requires PCB layout revision; functional alternatives must be evaluated case-by-case based on register presence, voltage tolerance, and control interface requirements.