Texas Instruments SN74LVC16646ADGGR

Overview

SN74LVC16646ADGGR from Texas Instruments is a 16-bit bus transceiver and register with 3-state outputs, designed for bidirectional data flow control between two 8-bit buses (A and B) in mixed-voltage systems. It operates from 1.65 V to 3.6 V, accepts 5.5-V inputs, delivers ≤5.2 ns propagation delay at 3.3 V, and supports transparent or registered transfer modes - used in high-speed memory interface buffering and FPGA-to-ASIC interconnect.

For engineers reviewing the SN74LVC16646ADGGR datasheet, SN74LVC16646ADGGR pinout, SN74LVC16646ADGGR application, or SN74LVC16646ADGGR equivalent, key selection criteria include dual-clock edge-triggered register storage, Ioff partial-power-down support, mixed-mode 3.3-V/5-V signal translation capability, and TSSOP-56 package compatibility with dense PCB layouts.

Technical Context

The SN74LVC16646ADGGR integrates two independent 8-bit transceiver channels, each with D-type flip-flops clocked on low-to-high transitions of CLKAB/CLKBA. Its select-control logic (SAB/SBA) enables glitch-free multiplexing between real-time and registered data paths without decoding hazards.

Direction (DIR), output-enable (OE), and clock-select signals jointly determine data path routing: DIR selects bus direction when OE is active low; OE high places both A and B ports in high-impedance isolation while preserving register contents; Ioff circuitry blocks current backflow during partial power-down.

Key Specifications

Pinout & Package

TSSOP-56 (DGG) package: 13.9 mm × 6.1 mm body, 0.5-mm lead pitch, 1.2-mm maximum height, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC16646ADGGR, SN74LVC16245ADGGR omits clocked storage and multiplexing - reducing complexity but eliminating timing control; 74ALVCH16646QFG retains register functionality but sacrifices 5-V tolerance and changes package thermal profile, impacting layout reuse and mixed-voltage interoperability.

Availability

SN74LVC16646ADGGR is available at Aetrix Electronics and suitable for industrial PLC backplanes, FPGA-to-memory interfaces, test equipment signal routing, and embedded processor peripheral expansion requiring stable component supply and long-term manufacturability.

Supply support for SN74LVC16646ADGGR 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 interface IC design.

The SN74LVC16646A belongs to TI's Widebus™ family - engineered specifically for high-speed, low-voltage bus management in mixed-signal systems requiring precise timing control and robust voltage translation.

FAQ

What is the maximum clock frequency supported by the SN74LVC16646ADGGR?

The SN74LVC16646ADGGR supports up to 150 MHz at VCC = 3.3 V, as specified in the timing characteristics table. This maximum frequency applies to both CLKAB and CLKBA inputs under recommended operating conditions (TA = –40°C to +85°C, VCC = 3.3 V ± 0.3 V). At lower supply voltages (e.g., 1.8 V), the max clock rate reduces to 85 MHz due to slower internal switching speeds.

Does the SN74LVC16646ADGGR support 5-V input signals while powered from a 3.3-V supply?

Yes, the SN74LVC16646ADGGR accepts input voltages up to 5.5 V regardless of VCC level - enabling direct connection to 5-V TTL or CMOS outputs when VCC = 3.3 V. This mixed-mode capability is explicitly guaranteed in the Absolute Maximum Ratings and Recommended Operating Conditions tables, making the SN74LVC16646ADGGR suitable for bridging legacy and modern logic families without external level shifters.

How does the Ioff feature function in the SN74LVC16646ADGGR during partial power-down?

The Ioff circuitry in the SN74LVC16646ADGGR actively disables all I/O ports when VCC = 0 V, limiting off-state current to ±10 µA. This prevents damaging reverse current flow from live buses into a powered-down device - a critical requirement for hot-plug systems and multi-rail power architectures. Ioff behavior is guaranteed across the full temperature range and requires no external biasing or configuration.

Can the SN74LVC16646ADGGR operate as two independent 8-bit transceivers?

Yes, the SN74LVC16646ADGGR is internally partitioned into two fully independent 8-bit sections (1A/1B and 2A/2B), each with dedicated DIR, OE, CLKAB, CLKBA, SAB, and SBA controls. This allows concurrent operation - for example, transferring data from Bus A to Bus B on Channel 1 while simultaneously routing from Bus B to Bus A on Channel 2 - with no electrical or timing crosstalk between channels.

What is the purpose of the SAB and SBA pins on the SN74LVC16646ADGGR?

The SAB and SBA pins on the SN74LVC16646ADGGR control multiplexing between real-time (transparent) and registered data paths. When SAB = L, Channel 1 outputs real-time B-bus data; when SAB = H, it outputs stored B-bus data. Similarly, SBA selects real-time vs. stored A-bus data for output on the B bus. This hardware-select logic eliminates decoding glitches common in software-controlled muxes, ensuring deterministic timing in high-speed synchronous systems.