Send an Inquiry

To receive a quote for your project, please fill in the following information, and we’ll get back to you promptly.

Submit Inventory List

Please fill in the following information, and we’ll get back to you promptly.

Home > Products > Integrated Circuits (ICs) > Logic > Buffers, Drivers, Receivers, Transceivers

Texas Instruments SN74ABT646PW

Name: SN74ABT646PW
Brand: Texas Instruments
SKU: SN74ABT646PW
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

Compare

Part No.:: SN74ABT646PW

Manufacturer:: Texas Instruments

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: 24-TSSOP (0.173", 4.40mm Width)

Datasheet:: SN74ABT646PW.pdf

Description:: IC TXRX NON-INVERT 5.5V 24TSSOP

Quantity:: RFQ Add To RFQ list

Payment:

Shipping:

Inventory:419

Please send an inquiry. Send us your inquiry, and we will respond immediately.

Product details

Overview

SN74ABT646PW from Texas Instruments is a 16-bit bus transceiver with D-type flip-flop registers, direction control (DIR), output enable (OE), and dual-clock (CLKAB/CLKBA) and select (SAB/SBA) logic for multiplexed data routing between A and B buses. It delivers ±32-mA high-drive outputs, supports partial-power-down via Ioff, and operates across −40°C to 85°C at 4.5–5.5 V. It is used in backplane interface, memory expansion, and programmable logic interconnect systems.

For engineers reviewing the SN74ABT646PW datasheet, SN74ABT646PW pinout, SN74ABT646PW application, or SN74ABT646PW equivalent, this page provides verified functional architecture, real-time vs. registered transfer timing, Ioff behavior during power sequencing, thermal resistance (θJA = 88°C/W), and TSSOP-24 package layout compatibility.

Technical Context

The SN74ABT646PW integrates eight independent bidirectional channels, each with transparent and registered data paths controlled by CLKAB/CLKBA edges and SAB/SBA select logic. Its DIR input determines bus direction during OE-active mode, while OE high enables isolation with register hold capability.

It implements true TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V), achieves 125-MHz maximum clock frequency, and features ground-bounce-limited VOLP < 1 V. The Ioff circuit ensures ≤±100 µA leakage when VCC = 0 V and any I/O is biased ≤4.5 V.

Key Specifications

Parameter	Value and Actual Design Meaning
VCC Range	4.5 V to 5.5 V - Ensures compatibility with 5-V TTL and mixed-voltage system rails.
IOH / IOL	−32 mA / +64 mA - Enables direct drive of heavy capacitive loads or multiple TTL inputs without buffers.
fmax	125 MHz - Supports high-speed synchronous bus transfers in FPGA/CPLD interface applications.
tPLH / tPHL	1.5 ns to 5.6 ns - Guarantees sub-6-ns propagation for real-time or registered path selection in timing-critical designs.
Ioff	±100 µA at VCC = 0 V - Prevents backflow current during hot-swap or partial power-down, protecting upstream drivers.
θJA	88°C/W (TSSOP-PW) - Requires thermal-aware PCB layout with exposed pad grounding and copper pour for sustained 64-mA sink operation.
ESD Rating	2000-V HBM, 200-V MM - Meets industrial-level ESD robustness without external protection diodes.

Pinout & Package

TSSOP-24 package (PW), 7.8 mm × 4.4 mm × 1.2 mm body height, 0.65-mm lead pitch, exposed thermal pad (non-electrical).

Pin/Terminal	Circuit Role	Design Meaning
1, 2, 4, 5, 6, 7, 8, 9	A1–A8 bus I/O	Input/output port for side-A data; high-impedance when OE high or direction mismatched.
13, 14, 15, 16, 17, 18, 19, 20	B1–B8 bus I/O	Input/output port for side-B data; driven only when DIR and OE jointly enable B→A or A→B path.
21	OE	Active-low output enable; forces all A/B outputs to high-Z when high, retaining register state.
3	DIR	Direction control: low = B→A transfer, high = A→B transfer (when OE low).
1, 23	CLKAB, CLKBA	Low-to-high edge clocks data from A→register or B→register respectively; asynchronous to DIR/OE.
2, 22	SAB, SBA	Select controls: determine whether real-time or registered data appears on output bus during transfer.
10, 12	NC	No internal connection - must be left unconnected per TI design guidance.
11, 24	GND, VCC	Power pins - require local 0.1-µF ceramic decoupling within 3 mm of each pin for noise suppression.

Key Features

Feature	Design Value
High-Drive Outputs	−32 mA source / +64 mA sink capability eliminates need for external line drivers in dense backplane routing.
Ioff Partial-Power-Down	Enables safe insertion/removal in live systems by disabling outputs and blocking reverse current when VCC = 0 V.
Dual-Clock Register Architecture	Independent CLKAB and CLKBA allow concurrent latching of A and B bus data without cross-talk or arbitration delay.
Multiplexed Transfer Modes	Four distinct operational modes (real-time A↔B, stored A↔B, dual storage, isolation) reduce external logic count.
Bus-Hold Inputs	Internal weak pull-ups on A/B ports prevent floating states during high-Z periods, eliminating external resistors.

Applications

Industrial Backplane Interface	FPGA-to-ASIC Data Bridge
Use Scenario: Interfacing legacy 5-V parallel buses between PLC controller modules and field I/O cards. IC Role / Device Role / Timing Role: Bidirectional level-consistent transceiver with registered hold for glitch-free handshaking across noisy industrial environments. Use Value: Eliminates need for discrete bus buffers and latch ICs; Ioff prevents damage during hot-swap maintenance cycles.	Use Scenario: Connecting Xilinx Spartan FPGA GPIO banks to ASIC-based signal conditioning subsystems. IC Role / Device Role / Timing Role: Synchronous data multiplexer with selectable real-time or pipeline-delayed transfer using CLKAB/CLKBA edges. Use Value: Achieves 125-MHz throughput with sub-6-ns propagation, enabling full-bandwidth utilization of FPGA I/O resources.
Memory Expansion Subsystem	Programmable Logic Interconnect
Use Scenario: Adding external SRAM or Flash memory to microcontroller-based embedded systems with limited address/data pins. IC Role / Device Role / Timing Role: Registered bus transceiver that latches address/data on rising CLKAB/CLKBA to extend timing margins. Use Value: Allows use of slower, lower-cost memory devices while maintaining system clock speed via pipelined access.	Use Scenario: Routing configurable logic signals between CPLD clusters in modular test equipment chassis. IC Role / Device Role / Timing Role: Direction-controlled multiplexer supporting dynamic reconfiguration of signal paths under firmware control. Use Value: Reduces PCB layer count by consolidating four bus management functions into one 24-pin TSSOP device.

Industrial Backplane Interface

FPGA-to-ASIC Data Bridge

Use Scenario: Interfacing legacy 5-V parallel buses between PLC controller modules and field I/O cards.

IC Role / Device Role / Timing Role: Bidirectional level-consistent transceiver with registered hold for glitch-free handshaking across noisy industrial environments.

Use Value: Eliminates need for discrete bus buffers and latch ICs; Ioff prevents damage during hot-swap maintenance cycles.

Use Scenario: Connecting Xilinx Spartan FPGA GPIO banks to ASIC-based signal conditioning subsystems.

IC Role / Device Role / Timing Role: Synchronous data multiplexer with selectable real-time or pipeline-delayed transfer using CLKAB/CLKBA edges.

Use Value: Achieves 125-MHz throughput with sub-6-ns propagation, enabling full-bandwidth utilization of FPGA I/O resources.

Memory Expansion Subsystem

Programmable Logic Interconnect

Use Scenario: Adding external SRAM or Flash memory to microcontroller-based embedded systems with limited address/data pins.

IC Role / Device Role / Timing Role: Registered bus transceiver that latches address/data on rising CLKAB/CLKBA to extend timing margins.

Use Value: Allows use of slower, lower-cost memory devices while maintaining system clock speed via pipelined access.

Use Scenario: Routing configurable logic signals between CPLD clusters in modular test equipment chassis.

IC Role / Device Role / Timing Role: Direction-controlled multiplexer supporting dynamic reconfiguration of signal paths under firmware control.

Use Value: Reduces PCB layer count by consolidating four bus management functions into one 24-pin TSSOP device.

Equivalent & Alternatives

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

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74ABT245PW	Octal (8-bit), no internal registers; lacks CLKAB/CLKBA, SAB/SBA, and DIR-controlled bidirectional flow.	Suitable only for simple unidirectional or manually controlled bidirectional transfers without storage.	Choose when register functionality is unnecessary and board space allows two devices for 16-bit width.
SN74LVTH16245ADGGR	16-bit, 3.3-V only (VCC = 2.7–3.6 V); LVCMOS-compatible inputs; no Ioff support; θJA = 56°C/W.	Requires level-shifting for 5-V systems; not suitable for mixed-voltage hot-swap scenarios.	Prefer for new 3.3-V designs where lower power and higher integration density outweigh 5-V compatibility needs.

Compared with SN74ABT245PW and SN74LVTH16245ADGGR, the SN74ABT646PW uniquely combines 16-bit width, dual-clock register storage, Ioff-enabled hot-swap safety, and native 5-V operation-making it irreplaceable in legacy industrial backplanes requiring glitch-free, state-retentive bus management.

Availability

SN74ABT646PW is available at Aetrix Electronics and suitable for industrial backplane interface, FPGA-to-ASIC bridging, and memory expansion subsystems requiring stable component supply, long-term lifecycle assurance, and RoHS-compliant TSSOP packaging.

Supply support for SN74ABT646PW 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 ICs.

The SN74ABT646PW belongs to TI's ABT logic family, engineered for high-speed, high-drive 5-V bus interfacing in industrial, telecom, and computing infrastructure where signal integrity and power sequencing robustness are critical.

FAQ

What is the maximum clock frequency supported by the SN74ABT646PW?

The SN74ABT646PW supports a maximum clock frequency of 125 MHz under recommended operating conditions (VCC = 5 V, TA = 25°C). This value is validated across the full commercial temperature range (−40°C to 85°C) and applies to both CLKAB and CLKBA inputs. Timing parameters such as tsu (3 ns setup) and th (0 ns hold) ensure reliable capture at this rate without external synchronization aids.

Does the SN74ABT646PW support partial-power-down operation?

Yes, the SN74ABT646PW supports partial-power-down via its Ioff circuitry. When VCC = 0 V and any I/O voltage remains ≤4.5 V, Ioff limits current to ±100 µA, preventing damaging backflow through powered-down sections. This feature is explicitly characterized in the datasheet and enables safe hot-plug operation in modular systems.

What is the thermal resistance (θJA) of the SN74ABT646PW in its TSSOP package?

The SN74ABT646PW in the PW (TSSOP-24) package has a junction-to-ambient thermal resistance (θJA) of 88°C/W, measured per JESD 51-7. This value assumes standard JEDEC 2-layer board conditions. For continuous 64-mA sink operation, designers must implement thermal vias under the exposed pad and ≥1 in² copper pour to maintain junction temperature within safe limits.

How does the SN74ABT646PW handle bus contention during direction switching?

The SN74ABT646PW avoids bus contention by enforcing strict directional control: only one bus (A or B) may drive the other at any time, governed jointly by DIR and OE states. The function table confirms mutually exclusive output enables - e.g., when DIR = L and OE = L, only B→A is active; A outputs remain high-Z. No internal arbitration logic is needed.

Are the NC pins on the SN74ABT646PW required to be grounded or left floating?

Pins 10 and 12 of the SN74ABT646PW are marked NC (No internal connection) and must be left unconnected - neither grounded nor tied to VCC. TI's datasheet explicitly prohibits routing traces to these pins, as they have no internal bond wires or circuitry. Doing so risks mechanical stress or unintended coupling in high-frequency layouts.

SN74ABT646PW Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: 74ABT

Package/Case:: 24-TSSOP (0.173", 4.40mm Width)

Packaging:: Bulk

Product Status:: Active

Logic Type:: Transceiver, Non-Inverting

Number of Elements:: 1

Number of Bits per Element:: 8

Input Type:: -

Output Type:: 3-State

Current - Output High, Low:: 32mA, 64mA

Voltage - Supply:: 4.5V ~ 5.5V

Operating Temperature:: -40°C ~ 85°C (TA)

Grade:: -

Qualification:: -

Mounting Type:: Surface Mount

Supplier Device Package:: 24-TSSOP

SN74ABT646PW FAQ

1.How can I place an order for SN74ABT646PW through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74ABT646PW on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for SN74ABT646PW reliable?

The price and inventory of SN74ABT646PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT646PW is usually 5 days.

3.What payment methods are accepted for SN74ABT646PW?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ABT646PW transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74ABT646PW?

SN74ABT646PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74ABT646PW order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for SN74ABT646PW?

For technical support, including SN74ABT646PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT646PW requirements.

6.How does Aetrix verify that SN74ABT646PW is sourced from the original manufacturer or authorized distributors?

All SN74ABT646PW products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that SN74ABT646PW meets industry standards.

7.What is the process for return or replacement of SN74ABT646PW?

All SN74ABT646PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT646PW, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The SN74ABT646PW part is unused and in its original packaging.

Return procedure for SN74ABT646PW:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

Tech Hub

2026-09-03 Logic Level Shifter: How to Connect 3.3V and 5V Logic Safely

A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.

2026-09-03 74HC595 vs TPIC6B595: Output Drive, Pinout, Current, and Load Selection

The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…

2026-09-01 74HC595 Pinout, Timing, Output Current, and Applications

The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…

2026-09-01 Latch vs Flip-Flop: Timing, Differences and Design Choices

A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…

2026-08-30 D Latch Circuit: Truth Table, Timing, ICs and Applications

A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …

2026-08-28 SR Latch Explained: NOR and NAND Circuits, Truth Tables, and Applications

An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…

2026-08-27 Latch Circuit: SR and D Latches, Truth Tables, Timing, and Applications

Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…

2026-08-21 What Is an LED Driver? Types, Circuits, Dimming, and Selection

An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…

2026-08-18 Operational Amplifier (Op Amp): Basics, Configurations, Feedback and Applications

Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…

2026-08-14 Jumper Cables: How to Use, Connect and Choose Them Safely

Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…