Texas Instruments SN74ABT646ADGVR

Overview

SN74ABT646ADGVR from Texas Instruments is a 16-bit bus transceiver with dual D-type flip-flop registers, direction control (DIR), output enable (OE), and clock-select logic (CLKAB/CLKBA, SAB/SBA) for multiplexed data routing between A and B buses. It delivers ±32-mA high-drive outputs, supports partial-power-down via Ioff, and operates at up to 125 MHz with 5-V supply. It is used in high-speed backplane and board-level bus isolation applications requiring real-time or registered data transfer.

For engineers reviewing the SN74ABT646ADGVR datasheet, SN74ABT646ADGVR pinout, SN74ABT646ADGVR application, or SN74ABT646ADGVR equivalent, this page provides verified functional architecture, timing-critical switching parameters, thermal characteristics for TVSOP-24 packaging, and validated alternative options for industrial bus interface redesigns.

Technical Context

The SN74ABT646ADGVR implements two independent 8-bit register banks synchronized to separate clocks (CLKAB for A→B, CLKBA for B→A), enabling simultaneous storage of data from either bus. Its DIR/OE/SAB/SBA control matrix supports four distinct operational modes: real-time bidirectional transfer, stored-data forwarding, dual-bus storage, and high-impedance isolation.

It uses ABT (Advanced BiCMOS Technology) logic with TTL-compatible inputs and CMOS outputs, featuring latch-up immunity >500 mA per JESD-17 and ESD protection exceeding 2000-V HBM. The Ioff circuit actively disables outputs during power-down to prevent current backflow when VCC = 0 V.

Key Specifications

Pinout & Package

SN74ABT646ADGVR is housed in a 24-pin TVSOP (Thin Very Small Outline Package) with 0.5-mm pitch, 4.4-mm width, and 1.2-mm max height. Pin 1 is located at the top-left corner with a molded index notch; leads are gull-wing shaped for surface-mount reflow assembly.

Key Features

Applications

Equivalent & Alternatives

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

Compared with SN74ABT245DBR and SN74LVTH16245ADGGR, the SN74ABT646ADGVR uniquely combines 16-bit width, dual-clock register storage, full 5-V operation, and Ioff - making it the only option for high-speed, isolated, and hot-pluggable 5-V bus management.

Availability

SN74ABT646ADGVR is available at Aetrix Electronics and suitable for industrial automation, test equipment, and legacy bus extension applications requiring stable component supply and long-term lifecycle support.

Supply support for SN74ABT646ADGVR 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 for industrial, automotive, and communications markets.

The SN74ABT646ADGVR belongs to TI's ABT logic family, engineered for high-speed 5-V bus interfacing with robust noise immunity, hot-swap capability, and minimal propagation delay in demanding industrial control systems.

FAQ

What is the maximum clock frequency supported by SN74ABT646ADGVR?

The SN74ABT646ADGVR supports a maximum clock frequency of 125 MHz under recommended operating conditions (VCC = 5 V, TA = 25°C). This value is confirmed in the timing requirements table of the official datasheet SCBS069H. At higher temperatures or lower supply voltages, timing margins reduce accordingly, and designers must verify setup/hold times against actual system conditions. The SN74ABT646ADGVR achieves this speed using ABT process technology with optimized internal gate delays and low-output impedance drivers.

Does SN74ABT646ADGVR support partial-power-down operation?

Yes, SN74ABT646ADGVR supports partial-power-down operation via its Ioff circuitry. When VCC = 0 V and any input or output voltage remains ≤ 4.5 V, the Ioff specification guarantees leakage current stays within ±100 µA. This prevents damaging current backflow through the device during hot-swap or staged power sequencing. To ensure high-impedance state during power-up/down, OE should be tied to VCC via a pullup resistor, sized according to the driver's current-sinking capability.

What package type is used for SN74ABT646ADGVR?

SN74ABT646ADGVR uses a 24-pin TVSOP (Thin Very Small Outline Package) with 0.5-mm lead pitch, 4.4-mm body width, and 1.2-mm maximum height. This package is RoHS-compliant, tape-and-reel packaged (2000 units per reel), and rated MSL-1 (unlimited floor life at ≤30°C/60% RH). Its compact footprint and thermal performance (θJA = 86°C/W) make it suitable for space-constrained industrial PCBs requiring high-density interconnects.

How does the SN74ABT646ADGVR handle bus contention during direction switching?

The SN74ABT646ADGVR avoids bus contention through strict control of OE and DIR states. When OE is high, all outputs enter high-impedance regardless of DIR or clock activity - physically isolating both buses. During direction transitions with OE low, the device relies on external timing coordination: DIR must be stable before the next clock edge, and clocks (CLKAB/CLKBA) are asynchronous but mutually exclusive in practice. No internal arbitration logic exists; proper system-level sequencing is required to prevent simultaneous driving.

Can SN74ABT646ADGVR operate with 3.3-V logic levels?

No, SN74ABT646ADGVR is specified only for 4.5-V to 5.5-V operation and is not 3.3-V compatible. Its input thresholds (VIH = 2.0 V min, VIL = 0.8 V max) and output voltage levels (VOH ≥ 2.5 V at IOH = −32 mA, VOL ≤ 0.55 V at IOL = 64 mA) are designed for 5-V TTL/CMOS systems. Driving it with 3.3-V signals may cause marginal or non-functional behavior, and applying 3.3-V supply violates absolute maximum ratings. For 3.3-V systems, consider SN74LVTH16245ADGGR instead.