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Texas Instruments SN74LS623DWR
- Part No.:
- SN74LS623DWR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74LS623DWR.pdf
- Description:
- IC TXRX NON-INVERT 5.25V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,531
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Product details
Overview
SN74LS623DWR from Texas Instruments is a dual 8-bit bus transceiver with 3-state outputs and active-low output-enable control, designed for bidirectional data flow in TTL-level systems. It features 20-pin SOIC (DW) package, ±20mA output drive, 15ns typical propagation delay, and operates over 0°C to 70°C ambient temperature - commonly used in microprocessor address/data bus isolation and memory expansion interfaces.
For engineers reviewing the SN74LS623DWR datasheet, SN74LS623DWR pinout, SN74LS623DWR application, or SN74LS623DWR equivalent, key selection considerations include bidirectional bus control timing, TTL-compatible input thresholds, 3-state output contention avoidance, and SOIC-20 thermal and layout constraints in legacy industrial control backplanes.
Technical Context
The SN74LS623DWR integrates two independent 8-bit transceivers sharing common direction (DIR) and output-enable (OE) controls. Each transceiver supports true/bidirectional data transfer with separate A- and B-side I/Os, where DIR determines signal flow direction and OE disables both sides simultaneously into high-impedance state.
It uses standard LS-TTL circuitry with Schottky-clamped inputs and outputs, ensuring compatibility with 74LS family logic levels and noise margins. Propagation delay is specified at VCC = 5V, TA = 25°C, CL = 15pF, and load conditions match JEDEC Std 22-A114.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS (Low-power Schottky TTL), compatible with standard TTL voltage thresholds and fanout. |
| Function | Dual 8-bit noninverting bus transceiver with 3-state outputs and active-low OE. |
| Propagation Delay | 15 ns max (A→B or B→A), critical for synchronous bus timing in 8-bit microcontroller systems. |
| Output Drive | ±20 mA (IOH/IO L), sufficient to drive 20 LS-TTL loads or terminate stubs on parallel buses. |
| Operating Temperature | 0°C to +70°C, suitable for commercial-grade embedded controllers and instrumentation. |
| Supply Voltage | VCC = 4.75V to 5.25V, strict 5V-only operation with no wide-VCC tolerance. |
| Package | SOIC-20 (DW), 7.5mm body width, 12.0mm reel width, Q1 pin 1 quadrant orientation. |
Pinout & Package
SN74LS623DWR is housed in a 20-pin SOIC (DW) package per TI drawing DW-20, with 0.65mm lead pitch, 7.5mm body width, and 12.0mm tape width. Pin 1 located in Quadrant 1 (Q1).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 19 | OE (Active-Low Output Enable) | Global 3-state control: low enables both transceivers; high forces all outputs to high-Z. |
| 2–9 | A1–A8 Inputs/Outputs | Side-A bidirectional data terminals; direction determined by DIR pin state. |
| 10, 20 | GND / VCC | Ground reference and +5V supply pins; decoupling capacitor placement critical near these pins. |
| 11–18 | B1–B8 Inputs/Outputs | Side-B bidirectional data terminals; electrically isolated from A-side except through transceiver logic. |
| 19 | DIR (Direction Control) | High = A→B transfer; Low = B→A transfer; asynchronous control with no internal synchronization. |
Key Features
| Feature | Design Value |
|---|---|
| Bidirectional data flow control | Single DIR pin configures direction for both 8-bit paths, reducing control line count in bus arbitration logic. |
| 3-state outputs with common enable | OE pin disables A- and B-side drivers simultaneously, preventing bus contention during system reset or mode switching. |
| TTL-compatible input thresholds | VIL ≤ 0.8V and VIH ≥ 2.0V ensure reliable interfacing with legacy 74LS, 74S, and microcontroller GPIOs. |
| 15ns propagation delay | Enables use in 20MHz+ bus cycles when combined with appropriate setup/hold timing margins. |
| SOIC-20 surface-mount packaging | Reduces PCB area vs. PDIP-20 while maintaining mechanical robustness and reflow compatibility for automated assembly. |
Applications
| Microprocessor Bus Isolation | Memory Expansion Interface |
|---|---|
Use Scenario: Isolating CPU address/data bus from peripheral subsystems to prevent loading and timing skew. IC Role / Device Role / Timing Role: Bidirectional transceiver managing data flow between Z80/8085 CPU and external RAM/ROM banks. Use Value: Enables clean bus segmentation without level-shifting, leveraging 15ns delay to meet 4MHz–6MHz bus cycle timing. | Use Scenario: Extending 8-bit data bus between main controller and add-on memory modules in test equipment. IC Role / Device Role / Timing Role: Direction-controlled buffer for write/read operations across multi-slot backplane architecture. Use Value: Common OE allows synchronized disable of all transceivers during memory refresh or DMA cycles. |
| Industrial I/O Expansion | Legacy System Interfacing |
Use Scenario: Connecting modular I/O cards to central PLC backplane using shared parallel control bus. IC Role / Device Role / Timing Role: Data path manager translating between local card bus and master bus under DIR-driven direction control. Use Value: ±20mA drive supports longer trace lengths and multiple receivers in noisy factory environments. | Use Scenario: Bridging vintage computer peripherals (e.g., floppy controllers) to modern FPGA-based host adapters. IC Role / Device Role / Timing Role: Level-consistent bus translator preserving TTL timing integrity across technology generations. Use Value: SOIC-20 footprint enables drop-in replacement of obsolete PDIP versions without redesigning carrier boards. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS245N | Octal noninverting bus transceiver, same 20-pin PDIP/SOIC, but single-directional per side (no DIR pin); requires external direction logic. | Used where direction is fixed or controlled externally; lacks integrated DIR, increasing component count. | Select SN74LS245N only if direction is static or managed by discrete gates; SN74LS623DWR reduces control logic overhead. |
| SN74ALS623DWR | Advanced LS version: lower power (19mW vs. 48mW), faster (10ns vs. 15ns), identical pinout and function. | Preferred in power-constrained or higher-speed designs where ALS logic compatibility is maintained. | SN74ALS623DWR offers direct functional upgrade path with improved speed/power; verify system noise margin compatibility. |
Compared with SN74LS245N and SN74ALS623DWR, the SN74LS623DWR balances legacy TTL compatibility, integrated direction control, and SOIC-20 manufacturability - making it optimal for cost-sensitive, medium-speed bus isolation where minimal gate count and proven reliability are priorities.
Availability
SN74LS623DWR is available at Aetrix Electronics and suitable for microprocessor bus isolation, memory expansion interfaces, industrial I/O expansion, and legacy system interfacing requiring stable component supply and long-term obsolescence management.
Supply support for SN74LS623DWR 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 headquartered in Dallas, Texas, delivering analog, embedded processing, and logic solutions since 1930.
The SN74LS623DWR belongs to TI's legacy 74LS logic product line, engineered for robust, low-cost, TTL-compatible digital interfacing in industrial control, test equipment, and retro-computing systems.
FAQ
What is the operating voltage range for SN74LS623DWR?
The SN74LS623DWR operates strictly within 4.75V to 5.25V DC supply voltage. It is not rated for operation outside this narrow 5V range, and deviations may cause incorrect logic states or increased power dissipation. This tight tolerance ensures compatibility with regulated 5V TTL power rails found in legacy computing and industrial control systems where SN74LS623DWR is deployed.
Does SN74LS623DWR support hot-swapping or live insertion?
No, SN74LS623DWR does not support hot-swapping. Its inputs lack protection against voltage overshoot or current surge during insertion, and its 3-state outputs do not feature bus-hold or power-up 3-state behavior. Applying power or signals before full seating risks latch-up or damage. Always power down the system before inserting or removing SN74LS623DWR in socketed or edge-card applications.
What is the maximum clock or data rate supported by SN74LS623DWR?
SN74LS623DWR does not operate on a clock signal - it is an asynchronous transceiver. Its usable data rate depends on propagation delay (15ns max) and system timing margins. In practice, it reliably supports bus cycles up to ~20MHz (50ns period), assuming proper setup/hold times and load capacitance ≤15pF. The actual rate is constrained by external timing control, not internal clocking.
Can SN74LS623DWR replace SN74LS245 in existing designs?
SN74LS623DWR can replace SN74LS245 only with circuit modification: SN74LS623DWR integrates direction control (DIR pin), whereas SN74LS245 requires external logic to manage direction. Direct substitution without updating DIR routing and OE logic will result in undefined data flow. Verify pin mapping - both share SOIC-20 footprint but differ in pin functions (e.g., DIR vs. G pin).
Is SN74LS623DWR RoHS compliant?
Yes, SN74LS623DWR is RoHS compliant per TI's packaging information dated 2026. It carries lead finish NIPDAU (Nickel/Palladium/Gold) and meets EU Directive 2011/65/EU requirements. No exemptions apply, and the part is rated for peak reflow temperatures consistent with Pb-free soldering profiles, though MSL rating is not applicable for this SOIC package type.
SN74LS623DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- 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:
- 3-State
- Current - Output High, Low:
- 15mA, 24mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74LS623DWR FAQ
1.How can I place an order for SN74LS623DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS623DWR 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 SN74LS623DWR reliable?
The price and inventory of SN74LS623DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS623DWR is usually 5 days.
3.What payment methods are accepted for SN74LS623DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS623DWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS623DWR?
SN74LS623DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS623DWR 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 SN74LS623DWR?
For technical support, including SN74LS623DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS623DWR requirements.
6.How does Aetrix verify that SN74LS623DWR is sourced from the original manufacturer or authorized distributors?
All SN74LS623DWR 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 SN74LS623DWR meets industry standards.
7.What is the process for return or replacement of SN74LS623DWR?
All SN74LS623DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS623DWR, 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 SN74LS623DWR part is unused and in its original packaging.
Return procedure for SN74LS623DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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