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Texas Instruments SN74AS641DWRG4
- Part No.:
- SN74AS641DWRG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74AS641DWRG4.pdf
- Description:
- IC TXRX INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,527
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Product details
Overview
SN74AS641DWRG4 from Texas Instruments is an octal bidirectional bus transceiver in a 20-pin SOIC (DW) package, designed for asynchronous two-way data transfer between A and B buses. It features true logic, 64 mA low-level output drive, 5 V supply operation, and 0°C to 70°C temperature range-used in industrial backplane and legacy bus interface systems.
For engineers reviewing the SN74AS641DWRG4 datasheet, SN74AS641DWRG4 pinout, SN74AS641DWRG4 application, or SN74AS641DWRG4 equivalent, key selection criteria include direction-control (DIR) and output-enable (OE) timing, 3-state isolation capability, high-current drive for TTL-compatible loads, and compatibility with 5 V bus architectures requiring robust signal integrity.
Technical Context
The SN74AS641DWRG4 implements dual 8-bit bidirectional data paths controlled by DIR (determines A→B or B→A flow) and OE (enables/disables all outputs to high-impedance). Its TTL-compatible inputs accept standard 0.8 V/2.0 V thresholds, and outputs drive up to 64 mA at VOL ≤ 0.55 V under 4.5–5.5 V VCC.
Propagation delays are tightly specified: tPLH/tPHL from A/B to opposite bus range 1–21 ns (VCC = 4.5–5.5 V, CL = 50 pF), and enable/disable times (tPLZ/tPZH) are ≤9 ns. The device operates only in the commercial temperature range and requires no external biasing or termination.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V TTL/CMOS bus rails without regulation overhead |
| IOL Low-Level Output Current | 64 mA - drives heavy capacitive loads or multiple TTL inputs without external buffers |
| VOL Output Voltage (IOL = 64 mA) | 0.35 V (min) to 0.55 V (max) - ensures solid logic-low margin under full load |
| tPHL / tPLH Propagation Delay | 1 ns (min) to 21 ns (max) - supports >20 MHz bus toggle rates in point-to-point configurations |
| Operating Temperature Range | 0°C to 70°C - validated for commercial-grade embedded control and instrumentation applications |
| Input Voltage Thresholds | VIL = 0.8 V, VIH = 2.0 V - matches standard TTL logic families for seamless interoperability |
| ICC Supply Current (Outputs Low) | 84 mA (min) to 136 mA (max) - informs power budgeting for multi-transceiver bus segments |
Pinout & Package
SN74AS641DWRG4 uses a 20-pin SOIC (DW) package, 7.5 mm wide, 12.83 mm long, 2.65 mm max height, with 1.27 mm pitch and RoHS-compliant NiPdAu lead finish (MSL Level-1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | DIR (Direction Control) | Active-high logic input: DIR = L routes B→A; DIR = H routes A→B |
| 2, 18 | OE (Output Enable) | Active-low enable: OE = L activates transceiver; OE = H places all I/Os in high-Z state |
| 3–10 | A1–A8 | Port A bidirectional data lines - connect to local bus or controller side |
| 11–18 | B1–B8 | Port B bidirectional data lines - connect to remote bus or peripheral side |
| 9 | GND | Ground reference for all logic and output stages |
| 20 | VCC | +5 V supply - must be decoupled locally per high-speed TTL practice |
Key Features
| Feature | Design Value |
|---|---|
| True Logic Configuration | No inversion between A and B ports - preserves data polarity across bus translation |
| 64 mA Output Sink Capability | Supports direct drive of up to 16 standard TTL loads (per pin) without fanout buffers |
| Sub-10 ns Enable/Disable Timing | tPLZ/tPZH ≤ 9 ns ensures minimal bus contention during direction switching |
| 3-State Isolation with OE Control | Full high-impedance isolation on both ports when OE = H - prevents bus conflicts in multi-master systems |
| TTL-Compatible Input Thresholds | VIL = 0.8 V / VIH = 2.0 V guarantees reliable interfacing with legacy 5 V logic families |
Applications
| Industrial Backplane Interface | Legacy System Bus Extension |
|---|---|
Use Scenario: Connecting microcontroller subsystems to distributed I/O modules over a shared 8-bit parallel bus in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional data bridge enabling CPU-initiated reads/writes to remote register banks while maintaining electrical isolation between segments. Use Value: 64 mA drive strength sustains signal integrity across 15 cm PCB traces loaded with 12 TTL inputs; DIR/OE sequencing eliminates need for external bus arbitration logic. | Use Scenario: Extending a vintage 8086-based computer bus to add new peripheral cards without modifying motherboard layout. IC Role / Device Role / Timing Role: Level-shifting and direction-controlled repeater that mirrors original bus timing behavior with sub-21 ns propagation delay. Use Value: True logic and TTL-compatible thresholds ensure bit-for-bit data fidelity; 3-state isolation prevents conflicts when multiple expansion slots share the same address/data lines. |
| Test Equipment Data Acquisition | Automated Test Fixture Control |
Use Scenario: Interfacing FPGA-based pattern generators to DUTs with mismatched bus voltage domains or timing requirements. IC Role / Device Role / Timing Role: Synchronized bidirectional data conduit controlled via FPGA GPIOs for real-time stimulus/response capture. Use Value: 1 ns minimum tPHL enables precise setup/hold timing relative to FPGA clock edges; OE-controlled isolation prevents backfeeding during test mode transitions. | Use Scenario: Managing parallel control signals (e.g., START, BUSY, ERROR) between a PC-based test sequencer and custom hardware under test. IC Role / Device Role / Timing Role: Robust signal translator handling mixed-direction handshaking lines with simultaneous read/write capability. Use Value: 64 mA sink current reliably drives optocoupler LEDs and relay drivers; DIR pin allows dynamic reversal of control vs. status line direction without firmware reconfiguration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bidirectional bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS641ADWR | Lower IOL (24 mA), slower timing (tPHL up to 18 ns), ALS family propagation characteristics | Suitable for lower-speed, lower-power legacy systems where 64 mA drive is unnecessary | Select when power consumption and cost are prioritized over speed and drive strength |
| SN74AS861DWR | Same AS family, but includes separate A→B and B→A enable controls (no DIR pin); higher ICC | Used where independent unidirectional control is preferred over single-direction arbitration | Choose when system architecture requires asymmetric enable timing or avoids DIR pin dependency |
Compared with SN74ALS641ADWR, SN74AS641DWRG4 delivers 2.7× higher output current and ~2× faster propagation, making it optimal for high-speed bus loading; versus SN74AS861DWR, it simplifies control logic with single DIR pin but lacks independent path enables-favoring compact, symmetric bus designs.
Availability
SN74AS641DWRG4 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus extensions, test equipment data acquisition, automated test fixture control, and embedded controller interconnects requiring stable component supply and long-term obsolescence management.
Supply support for SN74AS641DWRG4 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 90 years of innovation in industrial, automotive, and communications markets.
The SN74AS641DWRG4 belongs to TI's 74AS advanced Schottky logic family, engineered for high-speed, high-drive 5 V TTL-compatible bus interfacing in mission-critical industrial and test systems.
FAQ
What is the maximum recommended supply voltage for SN74AS641DWRG4?
The absolute maximum supply voltage for SN74AS641DWRG4 is 7 V, but the recommended operating range is strictly 4.5 V to 5.5 V. Operation outside this range may cause permanent damage or unpredictable behavior. The SN74AS641DWRG4 is optimized for 5 V TTL systems, and exceeding 5.5 V voids guaranteed performance specs including VOL, tPLH, and ICC.
Does SN74AS641DWRG4 support hot insertion or live bus swapping?
No, SN74AS641DWRG4 does not support hot insertion. Its absolute maximum ratings specify no input voltage beyond 7 V, and the device lacks bus-hold, power-up 3-state, or Ioff protection. Applying signals before VCC stabilization risks latch-up or excessive current. For live-swap applications, external protection circuitry or purpose-built hot-swap transceivers are required alongside SN74AS641DWRG4.
How does the DIR pin function in SN74AS641DWRG4?
The DIR pin on SN74AS641DWRG4 is a synchronous direction-control input: when DIR = LOW, data flows from Port B to Port A; when DIR = HIGH, data flows from Port A to Port B. This control is level-sensitive and active during OE = LOW. The SN74AS641DWRG4 does not sample DIR on clock edges-it responds combinatorially, so DIR must be stable before data transitions to avoid metastability or bus glitches.
Can SN74AS641DWRG4 drive standard TTL loads directly?
Yes, SN74AS641DWRG4 can directly drive standard TTL loads: its 64 mA IOL rating exceeds the 16 mA per input required for 16 standard TTL unit loads (UL), and its VOL ≤ 0.55 V at full load maintains >0.4 V noise margin. The SN74AS641DWRG4 also meets TTL VIH/VIL thresholds, ensuring reliable recognition of logic levels from upstream TTL sources without level shifters.
Is SN74AS641DWRG4 pin-compatible with SN74ALS641A variants?
Yes, SN74AS641DWRG4 is pin-compatible with SN74ALS641A and SN74ALS642A in the same DW (SOIC-20) package, sharing identical pinout, footprint, and terminal functions. However, SN74AS641DWRG4 differs electrically: it offers higher drive (64 mA vs. 24 mA), faster timing (21 ns max vs. 30 ns), and higher ICC. Board-level substitution is mechanically feasible but requires validation of timing margins and power delivery for the AS-family's increased current demand.
SN74AS641DWRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AS
- Package/Case:
- 20-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Non-Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- Open Collector
- Current - Output High, Low:
- -, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74AS641DWRG4 FAQ
1.How can I place an order for SN74AS641DWRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AS641DWRG4 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 SN74AS641DWRG4 reliable?
The price and inventory of SN74AS641DWRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AS641DWRG4 is usually 5 days.
3.What payment methods are accepted for SN74AS641DWRG4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AS641DWRG4 transactions.
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4.How is shipping managed for SN74AS641DWRG4?
SN74AS641DWRG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AS641DWRG4 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 SN74AS641DWRG4?
For technical support, including SN74AS641DWRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AS641DWRG4 requirements.
6.How does Aetrix verify that SN74AS641DWRG4 is sourced from the original manufacturer or authorized distributors?
All SN74AS641DWRG4 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 SN74AS641DWRG4 meets industry standards.
7.What is the process for return or replacement of SN74AS641DWRG4?
All SN74AS641DWRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74AS641DWRG4, 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 SN74AS641DWRG4 part is unused and in its original packaging.
Return procedure for SN74AS641DWRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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