Texas Instruments SN74LVCH16646ADGVR

Overview

SN74LVCH16646ADGVR 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-tolerant inputs, delivers 5.7-ns max propagation delay at 3.3 V, and supports real-time or registered data transfer via dual clock (CLKAB/CLKBA) and select (SAB/SBA) controls - used in high-speed memory interface buffering and FPGA-to-ASIC interconnects.

For engineers reviewing the SN74LVCH16646ADGVR datasheet, SN74LVCH16646ADGVR pinout, SN74LVCH16646ADGVR application, or SN74LVCH16646ADGVR equivalent, key selection criteria include its dual 8-bit register-transceiver architecture, Ioff partial-power-down support, bus-hold inputs eliminating external resistors, and guaranteed 3.3-V/5-V mixed-mode signal compatibility without level shifters.

Technical Context

The SN74LVCH16646ADGVR integrates two independent 8-bit transceiver channels, each with D-type flip-flops clocked on low-to-high transitions of CLKAB or CLKBA. Its control logic enables four bus-management functions: real-time A↔B transfer, stored-data A↔B transfer, simultaneous A/B register storage, and isolation mode with hold retention.

Direction (DIR), output-enable (OE), and select (SAB/SBA) inputs jointly determine data path routing and timing behavior. The device implements glitch-free multiplexing between transparent and registered paths using dedicated select-control circuitry, and features Ioff protection that disables outputs during power-down to prevent backflow current.

Key Specifications

Pinout & Package

TSSOP-56 (DGV) package: 13.9 mm × 6.1 mm × 1.2 mm body, 0.5-mm lead pitch, gull-wing leads, RoHS-compliant NiPdAu finish, MSL Level-1.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74LVC16646A and 74ALVCH16646, the SN74LVCH16646ADGVR uniquely combines 5.5-V input tolerance, integrated bus-hold, Ioff protection, and full 1.65–3.6-V operation - making it the only option qualified for robust mixed-voltage, hot-plug-capable, and space-constrained industrial designs.

Availability

SN74LVCH16646ADGVR is available at Aetrix Electronics and suitable for memory interface buffering, FPGA-to-ASIC interconnect, industrial backplane data routing, and test equipment signal conditioning requiring stable component supply across extended temperature ranges.

Supply support for SN74LVCH16646ADGVR 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 over 50 years of innovation in high-reliability interface and signal-path components.

The SN74LVCH16646ADGVR belongs to TI's Widebus™ family of advanced bus-interface devices, engineered specifically for high-speed, low-voltage, mixed-signal system interconnect in industrial, communications, and computing infrastructure.

FAQ

What is the maximum clock frequency supported by the SN74LVCH16646ADGVR?

The SN74LVCH16646ADGVR supports a maximum clock frequency of 150 MHz across its recommended operating range (1.65 V to 3.6 V). This specification is validated under standard load conditions (CL = 50 pF) and reflects the device's ability to reliably latch data on every low-to-high clock transition without setup/hold violations. The 5.7-ns propagation delay at 3.3 V directly enables this high-speed performance in real-world PCB layouts.

Does the SN74LVCH16646ADGVR require external pullup resistors on its data inputs?

No, the SN74LVCH16646ADGVR does not require external pullup or pulldown resistors on its A1–A8 or B1–B8 inputs because it integrates active bus-hold circuitry on all data terminals. This feature maintains a valid logic state on unused or unterminated inputs, eliminating floating nodes and associated noise susceptibility. Using external resistors with enabled bus-hold is explicitly discouraged in the datasheet due to potential contention and increased power draw.

Can the SN74LVCH16646ADGVR interface between a 5-V microcontroller and a 3.3-V FPGA?

Yes, the SN74LVCH16646ADGVR can safely interface a 5-V microcontroller with a 3.3-V FPGA. Its inputs tolerate up to 5.5 V regardless of VCC level, allowing direct connection of 5-V outputs to A/B ports while operating at 3.3 V. Outputs swing rail-to-rail within the 3.3-V domain, meeting VIH/VIL thresholds of standard 3.3-V CMOS inputs. No external level-shifting components are needed, simplifying design and improving signal integrity.

What is the purpose of the Ioff feature in the SN74LVCH16646ADGVR?

The Ioff feature in the SN74LVCH16646ADGVR disables all outputs when VCC = 0 V, preventing damaging current backflow through the device during partial power-down or hot-swap events. This is critical in modular systems where one board may be powered while adjacent boards are off. Ioff ensures that powered A/B buses cannot source current into unpowered sections, protecting both the SN74LVCH16646ADGVR and downstream components from latch-up or overstress conditions.

How does the SN74LVCH16646ADGVR handle simultaneous data storage on both A and B buses?

The SN74LVCH16646ADGVR supports simultaneous storage of data from both A and B buses using the isolation mode: when OE is high and both CLKAB and CLKBA receive low-to-high transitions, data present on A1–A8 and B1–B8 is latched into their respective internal registers. This dual-register capability enables deterministic data capture for time-critical applications like synchronized sensor sampling or parallel bus arbitration, with no cross-talk or timing dependency between the two 8-bit channels.