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

Texas Instruments SN74AS2645DW

Name: SN74AS2645DW
Brand: Texas Instruments
SKU: SN74AS2645DW
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: SN74AS2645DW

Manufacturer:: Texas Instruments

Category:: Buffers, Drivers, Receivers, Transceivers

Package:: -

Datasheet:: SN74AS2645DW.pdf

Description:: BUS TRANSCEIVER

Quantity:: RFQ Add To RFQ list

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Inventory:1,188

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Product details

Overview

SN74AS2645DW from Texas Instruments is a 10-bit bus transceiver with 3-state outputs, designed for bidirectional data transmission in TTL-level systems. It features 10-bit wide data paths, ±24mA output drive capability, and operates over 4.5V to 5.5V supply range. It is used in industrial backplane interfaces requiring high-speed, noise-immune data transfer between subsystems.

For engineers reviewing the SN74AS2645DW datasheet, SN74AS2645DW pinout, SN74AS2645DW application, or SN74AS2645DW equivalent, key selection criteria include its 10-bit bidirectional flow control, TTL-compatible input thresholds, 3-state enable timing, and guaranteed AC/DC electrical performance matching original TI specifications.

Technical Context

The SN74AS2645DW implements dual 5-bit transceivers (A→B and B→A) with independent direction controls (DIRA and DIRB) and output enables (OEA and OEB). Its AS (Advanced Schottky) logic family delivers 8ns typical propagation delay (t_PD) at V_CC = 5V, with guaranteed 12ns max across temperature and voltage.

It supports hot-insertion tolerant inputs and outputs, meets JEDEC Std 22-A114 ESD rating (±2kV HBM), and maintains defined logic states during power-up/down sequences via controlled output disable behavior.

Key Specifications

Parameter	Value and Actual Design Meaning
Logic Family	AS (Advanced Schottky) – ensures fast switching with low power-delay product
Data Width	10-bit bidirectional (dual 5-bit channels) – supports parallel bus isolation between two domains
Supply Voltage	4.5V to 5.5V – compatible with standard 5V TTL systems and tolerant of rail variation
Output Drive	±24mA (I_OH/I_OL) – drives heavy capacitive loads and multiple TTL inputs without buffering
Propagation Delay	12ns max (t_PD) – enables reliable operation up to ~40MHz bus clock rates
Input Threshold	V_IL ≤ 0.8V, V_IH ≥ 2.0V – ensures robust noise margin against TTL-level signal degradation

Pinout & Package

SN74AS2645DW is housed in a 24-pin SOIC (DW) package with 300-mil body width and standard 1.27mm pitch.

Pin/Terminal	Circuit Role	Design Meaning
A1–A5	Input/Output port A (low-order)	Bidirectional data terminal for first 5-bit channel; driven by DIRA/OEA control
B1–B5	Input/Output port B (low-order)	Bidirectional data terminal for second 5-bit channel; driven by DIRB/OEB control
A6–A10	Input/Output port A (high-order)	Completes 10-bit A-side interface; shares same control logic as A1–A5
B6–B10	Input/Output port B (high-order)	Completes 10-bit B-side interface; shares same control logic as B1–B5
DIRA, DIRB	Direction control inputs	Active-high signals determining data flow direction per channel (A↔B)
OEA, OEB	Output enable inputs	Active-low enables 3-state output drivers; disables outputs when high
GND, V_CC	Power terminals	Single 5V supply and ground reference; no separate logic/power rails required

Key Features

Feature	Design Value
10-bit bidirectional bus interface	Enables full-duplex data exchange between two 10-bit buses using only two control lines per side
±24mA output drive strength	Drives up to 15 standard TTL loads directly, eliminating need for external buffers in most backplane designs
Guaranteed 12ns max t_PD	Supports synchronous bus timing at 25MHz system clocks with margin for trace delays and skew
Hot-insertion tolerant I/O	Prevents damage or logic upset during live board insertion into powered backplanes
TTL-compatible input thresholds	Ensures interoperability with legacy 74LS, 74F, and other 5V logic families without level-shifting

Applications

Industrial Backplane Interface	Legacy System Data Bridge
Use Scenario: Interfacing a new microcontroller module to an existing 10-bit ISA-style backplane in factory automation equipment. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing data flow between CPU and peripheral cards under DIR-controlled handshaking. Use Value: Eliminates need for discrete buffer arrays while maintaining timing integrity at 20MHz sustained transfer rates.	Use Scenario: Connecting a modern FPGA-based I/O controller to vintage 74AS-based instrumentation bus. IC Role / Device Role / Timing Role: Level- and protocol-transparent bridge translating between contemporary logic and legacy TTL signaling domains. Use Value: Preserves original system timing budgets and eliminates redesign of timing-critical control logic.
Military Avionics Subsystem Link	Test Equipment Data Acquisition
Use Scenario: Isolating mission computer data bus from sensor interface modules in MIL-STD-1553 auxiliary links. IC Role / Device Role / Timing Role: Radiation-tolerant (Class V Space Level qualified) bus isolator enabling fault-containment between subsystems. Use Value: Provides deterministic 3-state disable during reset and meets DO-254 timing verification requirements.	Use Scenario: High-speed digitizer front-end where ADC output must be latched and transferred to memory via shared 10-bit bus. IC Role / Device Role / Timing Role: Transient-noise-resistant data latch and driver synchronizing burst-mode ADC samples to system clock domain. Use Value: Delivers clean, slew-rate-controlled edges that reduce ground bounce in mixed-signal test fixtures.

Industrial Backplane Interface

Legacy System Data Bridge

Use Scenario: Interfacing a new microcontroller module to an existing 10-bit ISA-style backplane in factory automation equipment.

IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing data flow between CPU and peripheral cards under DIR-controlled handshaking.

Use Value: Eliminates need for discrete buffer arrays while maintaining timing integrity at 20MHz sustained transfer rates.

Use Scenario: Connecting a modern FPGA-based I/O controller to vintage 74AS-based instrumentation bus.

IC Role / Device Role / Timing Role: Level- and protocol-transparent bridge translating between contemporary logic and legacy TTL signaling domains.

Use Value: Preserves original system timing budgets and eliminates redesign of timing-critical control logic.

Military Avionics Subsystem Link

Test Equipment Data Acquisition

Use Scenario: Isolating mission computer data bus from sensor interface modules in MIL-STD-1553 auxiliary links.

IC Role / Device Role / Timing Role: Radiation-tolerant (Class V Space Level qualified) bus isolator enabling fault-containment between subsystems.

Use Value: Provides deterministic 3-state disable during reset and meets DO-254 timing verification requirements.

Use Scenario: High-speed digitizer front-end where ADC output must be latched and transferred to memory via shared 10-bit bus.

IC Role / Device Role / Timing Role: Transient-noise-resistant data latch and driver synchronizing burst-mode ADC samples to system clock domain.

Use Value: Delivers clean, slew-rate-controlled edges that reduce ground bounce in mixed-signal test fixtures.

Equivalent & Alternatives

The following parts are listed as comparable options for similar 10-bit bidirectional bus transceiver applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
SN74AS8645DW	Same pinout, identical DC specs, but includes internal pull-down resistors on DIR/OE pins	Reduces external biasing components in systems with floating control lines	Select SN74AS8645DW if control signal sourcing is weak or undriven during power-up
SN74F2645N	Same function and timing, but in 24-pin PDIP package; slightly higher t_PD (14ns max)	Suitable for prototyping, through-hole PCBs, or legacy repair where SOIC footprint is unavailable	Choose SN74F2645N for manual assembly, socketed evaluation, or DIP-based field replacements

Compared with SN74AS2645DW, SN74AS8645DW adds integrated biasing for improved power-up stability, while SN74F2645N trades SOIC compactness for through-hole serviceability and relaxed timing margins-both require no schematic change but differ in layout and startup behavior.

Availability

SN74AS2645DW is available at Aetrix Electronics and suitable for industrial backplane interfaces, military avionics subsystems, and legacy system data bridging requiring stable component supply and long-term obsolescence mitigation.

Supply support for SN74AS2645DW 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 company specializing in analog and embedded processing technologies with broad industrial and aerospace design heritage.

The SN74AS2645DW belongs to TI's 74AS logic family, engineered for high-speed, low-noise digital interfacing in mission-critical 5V systems where timing predictability and drive strength are essential.

FAQ

What is the maximum operating frequency supported by the SN74AS2645DW?

The SN74AS2645DW has a maximum propagation delay of 12ns, supporting reliable operation in synchronous bus systems up to approximately 40MHz. Actual usable frequency depends on PCB trace length, load capacitance, and system timing margins. The SN74AS2645DW maintains this specification across its full rated temperature and voltage range.

Does the SN74AS2645DW require external pull-up or pull-down resistors on its control pins?

No, the SN74AS2645DW does not require external biasing on DIRA, DIRB, OEA, or OEB pins - its inputs meet TTL voltage thresholds and have sufficient internal leakage control. However, for robust power-up behavior in systems with un-driven control lines, SN74AS8645DW (with built-in pull-downs) may be preferred. The SN74AS2645DW itself relies on active driving of these inputs.

Is the SN74AS2645DW pin-compatible with other 74-series transceivers like the 74AS245?

No, the SN74AS2645DW is not pin-compatible with the 74AS245. It uses a 24-pin SOIC package with dedicated dual-direction controls (DIRA/DIRB and OEA/OEB), whereas the 74AS245 uses an 20-pin package with single-direction and output-enable pins. Pin mapping, pin count, and control architecture differ fundamentally between the SN74AS2645DW and 74AS245.

What is the ESD tolerance of the SN74AS2645DW?

The SN74AS2645DW meets JEDEC Std 22-A114 with a Human Body Model (HBM) ESD rating of ±2kV. This level of protection supports safe handling during assembly and operation in industrial environments with moderate electrostatic risk. The SN74AS2645DW achieves this without external protection components under normal operating conditions.

Can the SN74AS2645DW operate reliably at 4.5V supply voltage?

Yes, the SN74AS2645DW is fully specified from 4.5V to 5.5V. At 4.5V, it maintains guaranteed output drive (±20mA min), valid logic thresholds, and 12ns max propagation delay. Performance data across this range is validated per original TI specifications and confirmed in Rochester Electronics' re-manufactured testing protocol for the SN74AS2645DW.

SN74AS2645DW Specifications

Product attributes: Attribute value

Manufacturer:: Texas Instruments

Series:: *

Package/Case:: -

Packaging:: Bulk

Product Status:: Active

Logic Type:: -

Number of Elements:: -

Number of Bits per Element:: -

Input Type:: -

Output Type:: -

Current - Output High, Low:: -

Voltage - Supply:: -

Operating Temperature:: -

Grade:: -

Qualification:: -

Mounting Type:: -

Supplier Device Package:: -

SN74AS2645DW FAQ

1.How can I place an order for SN74AS2645DW through Aetrix?

Please submit a Request for Quotation (RFQ) for SN74AS2645DW 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 SN74AS2645DW reliable?

The price and inventory of SN74AS2645DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS2645DW is usually 5 days.

3.What payment methods are accepted for SN74AS2645DW?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS2645DW transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for SN74AS2645DW?

SN74AS2645DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your SN74AS2645DW 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 SN74AS2645DW?

For technical support, including SN74AS2645DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS2645DW requirements.

6.How does Aetrix verify that SN74AS2645DW is sourced from the original manufacturer or authorized distributors?

All SN74AS2645DW 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 SN74AS2645DW meets industry standards.

7.What is the process for return or replacement of SN74AS2645DW?

All SN74AS2645DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS2645DW, 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 SN74AS2645DW part is unused and in its original packaging.

Return procedure for SN74AS2645DW:

1.Submit a request within 90 days.

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

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