Texas Instruments SN74LVC16646ADLRG4

Overview

SN74LVC16646ADLRG4 from Texas Instruments is a 16-bit bus transceiver and register with 3-state outputs, designed for 1.65 V to 3.6 V operation. It supports mixed-mode signaling (5-V inputs with 3.3-V VCC), features dual 8-bit register-controlled data paths, and delivers 5.2 ns max propagation delay at 3.3 V in transparent mode - enabling high-speed bidirectional data routing in memory interfaces and FPGA I/O expansion.

For engineers reviewing the SN74LVC16646ADLRG4 datasheet, SN74LVC16646ADLRG4 pinout, SN74LVC16646ADLRG4 application, or SN74LVC16646ADLRG4 equivalent, key selection criteria include its dual-clock register architecture, Ioff partial-power-down support, 56-pin SSOP (DL) package, and guaranteed 3.6-V tolerant inputs - critical for voltage-level translation in industrial control backplanes and programmable logic interconnects.

Technical Context

The SN74LVC16646ADLRG4 implements two independent 8-bit transceiver/register blocks (A/B), each with dedicated direction (DIR), clock (CLKAB/CLKBA), select (SAB/SBA), and output-enable (OE) controls. Its register stage captures data on low-to-high clock transitions, while the transceiver stage routes either real-time or stored data based on SAB/SBA state - eliminating multiplexer glitches during mode switching.

It integrates Ioff circuitry to disable outputs during power-down, preventing backflow current, and supports 5.5-V-tolerant inputs across all control and data pins regardless of VCC level - enabling seamless interfacing between 3.3-V logic domains and legacy 5-V peripherals without external level shifters.

Key Specifications

Pinout & Package

SN74LVC16646ADLRG4 is housed in a 56-pin SSOP (DL) package with 0.5-mm lead pitch, 13.9 mm × 6.0 mm body size, and 1.2-mm maximum height - optimized for space-constrained industrial PCBs requiring thermal reliability and reflow compatibility.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC16646ADLRG4, SN74LVC16245ADLR omits register and select logic - limiting it to basic bus driving - while SN74ALVC16646DLR retains full functional equivalence with enhanced speed and ruggedness, making it a direct upgrade path without PCB changes.

Availability

SN74LVC16646ADLRG4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, FPGA I/O expansion, memory subsystem buffering, and modular test equipment interconnects requiring stable component supply and long-term lifecycle support.

Supply support for SN74LVC16646ADLRG4 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 SN74LVC16646ADLRG4 belongs to TI's Widebus™ family of advanced bus-interface ICs, engineered specifically for high-speed, low-voltage bidirectional data routing in industrial, communications, and computing systems requiring mixed-voltage interoperability.

FAQ

What is the maximum clock frequency supported by SN74LVC16646ADLRG4?

The SN74LVC16646ADLRG4 supports up to 150 MHz clock frequency at VCC = 3.3 V, as specified in the timing requirements table. This applies to both CLKAB and CLKBA inputs under recommended operating conditions, enabling high-throughput register loading in synchronous bus architectures. The device maintains this rating across its full –40°C to +85°C temperature range.

Does SN74LVC16646ADLRG4 support partial power-down operation?

Yes, SN74LVC16646ADLRG4 includes Ioff circuitry that disables outputs when VCC = 0 V, limiting current backflow to ±10 µA even with 5.5-V signals applied. This feature ensures safe operation during hot-swap events or staged power sequencing in modular systems - a requirement explicitly verified in the Absolute Maximum Ratings and Electrical Characteristics sections of the datasheet.

Can SN74LVC16646ADLRG4 be used as two independent 8-bit transceivers?

Yes, SN74LVC16646ADLRG4 is architecturally divided into two independent 8-bit sections (1A/1B and 2A/2B), each with dedicated DIR, OE, CLKAB/CLKBA, and SAB/SBA controls. This allows simultaneous operation - for example, one section transferring real-time data while the other routes registered data - without functional crosstalk or timing dependency between blocks.

What is the purpose of the SAB and SBA pins on SN74LVC16646ADLRG4?

The SAB and SBA pins on SN74LVC16646ADLRG4 control multiplexing between real-time and registered data paths per 8-bit section. When SAB = L, real-time B-bus data passes to A; when SAB = H, previously clocked B-data is output - all without output glitches due to internal synchronous select logic. This enables deterministic data routing in systems requiring both immediate and pipeline-delayed responses.

Is SN74LVC16646ADLRG4 pin-compatible with other Widebus™ transceivers?

SN74LVC16646ADLRG4 shares the same 56-pin SSOP (DL) footprint and core signal mapping (e.g., DIR, OE, CLK, S) with SN74ALVC16646DLR and SN74LVC16245ADLR, but differs in register/control pin count and function. Only SN74ALVC16646DLR is functionally and pin-compatible; SN74LVC16245ADLR omits register-related pins and cannot substitute for registered operation.