Texas Instruments SN74LVT16646DLR

Overview

SN74LVT16646DLR from Texas Instruments is a 16-bit bus transceiver and register IC designed for 3.3-V operation with 5-V tolerant I/O, supporting mixed-mode signal interfacing between 3.3-V logic and legacy 5-V systems. It features dual 8-bit or single 16-bit bidirectional data flow, clocked storage on CLKAB/CLKBA edges, and real-time or stored-data multiplexing via SAB/SBA controls. Used in high-speed backplane and motherboard bus isolation, level translation, and data buffering.

For engineers reviewing the SN74LVT16646DLR datasheet, SN74LVT16646DLR pinout, SN74LVT16646DLR application, or SN74LVT16646DLR equivalent, key selection criteria include 3.3-V VCC with 5-V input tolerance, bus-hold inputs eliminating external pullups, hot-insertion support via Ioff and power-up 3-state, distributed VCC/GND for noise reduction, and 150-MHz maximum clock frequency.

Technical Context

The SN74LVT16646DLR implements two independent 8-bit transceiver/register blocks (A/B), each with dedicated direction (DIR), output-enable (OE), clock (CLKAB/CLKBA), and select (SAB/SBA) controls. Data is latched on low-to-high clock transitions, and multiplexing between real-time and stored data avoids decoding glitches during mode switching.

Its ABT BiCMOS process enables 2.7-V to 3.6-V supply operation, supports unregulated battery inputs, delivers <0.8-V output ground bounce at 3.3 V, and provides latch-up immunity >500 mA per JESD-17. Bus-hold circuitry maintains valid logic states on undriven A/B port pins without external resistors.

Key Specifications

Pinout & Package

SN74LVT16646DLR is housed in a 56-pin SSOP (Shrink Small Outline Package) with 0.635-mm lead pitch, optimized for high-density PCB layouts and thermal performance (θJA = 56°C/W).

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC16646DGGR and SN74ALVCH16646DLR, the SN74LVT16646DLR uniquely combines 5-V-tolerant I/O, bus-hold, hot-insertion support, and 150-MHz operation in a single 3.3-V supply solution - making it the only option among the three that fully replaces discrete level shifters and pullup networks in mixed-voltage industrial backplanes.

Availability

SN74LVT16646DLR is available at Aetrix Electronics and suitable for backplane bus isolation, memory subsystem buffering, legacy system interface bridging, and configurable I/O expansion requiring stable component supply, long-term lifecycle assurance, and consistent parametric performance across production batches.

Supply support for SN74LVT16646DLR 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 SN74LVT16646DLR belongs to TI's Widebus™ family of advanced BiCMOS transceivers, engineered specifically for robust, high-speed bus management in mixed-voltage industrial, telecom, and computing infrastructure.

FAQ

What voltage levels does the SN74LVT16646DLR support on its I/O pins?

The SN74LVT16646DLR supports 5-V tolerant inputs and outputs while operating from a 2.7-V to 3.6-V VCC supply. Its I/O pins accept voltages up to 5.5 V, enabling direct connection to 5-V TTL buses without external level shifters. This capability is confirmed in the Absolute Maximum Ratings and Recommended Operating Conditions tables of the SCBS149D datasheet.

Does the SN74LVT16646DLR require external pullup resistors on its A/B bus pins?

No, the SN74LVT16646DLR includes active bus-hold circuitry on all A and B port inputs, which maintains the last-valid logic state without external pullup or pulldown resistors. The datasheet explicitly states that using external resistors with bus-hold is not recommended, as it may interfere with the internal hold current (±75 µA at 3 V).

Can the SN74LVT16646DLR be used in hot-insertion applications?

Yes, the SN74LVT16646DLR is fully specified for hot-insertion use via integrated Ioff and power-up 3-state circuitry. When VCC = 0, Ioff limits current backflow to ±100 µA; during power-up/down, outputs remain in high-impedance state to prevent bus conflicts - both features validated per JEDEC standards and documented in the datasheet's "Features" and "Electrical Characteristics" sections.

What is the maximum clock frequency supported by the SN74LVT16646DLR?

The SN74LVT16646DLR supports a maximum clock frequency of 150 MHz under recommended operating conditions (VCC = 3.3 V ± 0.3 V, TA = 25°C). This value is specified in the "Timing Requirements" table of the SCBS149D datasheet and verified across temperature and voltage ranges down to 2.7 V.

How many independent transceiver/register blocks does the SN74LVT16646DLR contain?

The SN74LVT16646DLR contains two independent 8-bit transceiver/register blocks (labeled Block 1 and Block 2), each with dedicated DIR, OE, CLKAB, CLKBA, SAB, and SBA controls. This architecture allows flexible configuration as either two 8-bit units or one unified 16-bit unit, as confirmed in the Functional Description and Logic Diagram sections of the datasheet.