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Texas Instruments SN74ALS623AN3
- Part No.:
- SN74ALS623AN3
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ALS623AN3.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:660
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Product details
Overview
SN74ALS623AN3 from Texas Instruments is an octal bus transceiver with true logic output, 3-state bidirectional operation, and dual output-enable control (OEAB/OEBA) for asynchronous A↔B data flow in TTL-compatible 5 V systems. It supports local bus-latch functionality via simultaneous enable and operates across 0°C to 70°C.
For engineers reviewing the SN74ALS623AN3 datasheet, SN74ALS623AN3 pinout, SN74ALS623AN3 application, or SN74ALS623AN3 equivalent, this device is selected for legacy industrial backplane interfaces, memory-mapped I/O expansion, and bidirectional data buffering where ALS-family speed-power tradeoffs and 20-pin PDIP compatibility are critical.
Technical Context
This device implements a dual-bus transceiver architecture with independent OEAB (A-to-B enable) and OEBA (B-to-A enable) inputs, allowing isolated bidirectional data transfer or simultaneous latching of both buses when both enables are active. Its true-output logic preserves signal polarity across all eight channels.
Designed for TTL-compatible 5 V operation, it features ALS-series characteristics: typical propagation delay of 2–13 ns (A↔B), 3-state output disable times under 22 ns, and guaranteed 24 mA low-level drive at VCC = 4.5 V. It lacks open-collector or inverting variants - those are assigned to SN74ALS621A and SN74ALS620A respectively.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Type | True-output (non-inverting) octal transceiver - preserves input polarity on all A/B ports |
| Output Type | 3-state (high-impedance) outputs - enables bus sharing without contention |
| VCC Range | 4.5 V to 5.5 V - compatible with standard 5 V TTL supply rails |
| IOL / IOH | 24 mA sink / –15 mA source - sufficient for driving multiple TTL loads or short traces |
| Propagation Delay | 2–13 ns (A↔B) - supports synchronous data rates up to ~50 MHz in point-to-point configurations |
| Operating Temperature | 0°C to 70°C - rated for commercial/industrial ambient environments |
| Package | 20-pin plastic DIP (N package) - through-hole mounting, 300-mil width, RoHS-compliant NIPDAU finish |
Pinout & Package
SN74ALS623AN3 is housed in a 20-pin plastic dual in-line package (PDIP, N package), 300-mil width, with standard DIP footprint and through-hole soldering requirements. Pin 1 is marked by a notch or dot at the top-left corner of the package.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OEAB) | A-to-B Output Enable | Active-low control: enables data flow from A1–A8 to B1–B8 when low |
| 2–9 (A1–A8) | Bus A I/O Ports | Bidirectional data lines connected to A-side bus; high-impedance when OEAB and OEBA both high |
| 10 (GND) | Ground Reference | Primary power return path for logic and I/O circuits |
| 11 (VCC) | Supply Voltage | +5 V DC supply input (4.5–5.5 V range); decoupling capacitor required near pin |
| 12–19 (B1–B8) | Bus B I/O Ports | Bidirectional data lines connected to B-side bus; high-impedance when OEAB and OEBA both high |
| 20 (OEBA) | B-to-A Output Enable | Active-low control: enables data flow from B1–B8 to A1–A8 when low |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent output enables (OEAB/OEBA) | Enables selective unidirectional flow, full isolation, or simultaneous bus latching without external logic |
| True (non-inverting) logic | Eliminates need for external inverters in polarity-sensitive bus architectures |
| ALS-family speed-power balance | Delivers 2–13 ns propagation delay with lower ICC than AS-series while maintaining TTL compatibility |
| Local bus-latch capability | When OEAB and OEBA are both low, both A and B buses retain last state - useful for temporary data hold |
| 20-pin PDIP (N) packaging | Supports legacy prototyping, socket-based testing, and repair-friendly through-hole assembly |
Applications
| Industrial Backplane Interface | Legacy Memory-Mapped I/O Expansion |
|---|---|
|
Use Scenario: Bidirectional data routing between CPU bus and peripheral modules on a wired backplane with shared address/data lines. IC Role / Device Role / Timing Role: Octal transceiver managing direction-controlled data flow between master and slave slots using discrete OEAB/OEBA timing signals. Use Value: Enables deterministic half-duplex communication with sub-15 ns latency and hardware-level bus isolation during arbitration. |
Use Scenario: Expanding microcontroller GPIO count via parallel I/O peripherals (e.g., 8255-style chips) using shared address/data bus. IC Role / Device Role / Timing Role: Buffering and isolating microcontroller data bus from peripheral data bus during read/write cycles controlled by address decode logic. Use Value: Prevents bus contention during peripheral access while preserving signal integrity across 20+ cm PCB traces. |
| Test Equipment Data Capture Interface | Automated Test Fixture Bus Coupling |
|
Use Scenario: Capturing parallel digital waveforms from DUTs into logic analyzer front-ends with configurable input polarity and timing margins. IC Role / Device Role / Timing Role: Level-shifting and direction-gated interface between DUT's 5 V TTL bus and acquisition system's synchronized sampling engine. Use Value: Provides clean, glitch-free sampling windows via precise OEAB/OEBA timing control and 24 mA drive strength. |
Use Scenario: Interfacing programmable test controllers to multiple DUT boards with shared test bus infrastructure. IC Role / Device Role / Timing Role: Isolating controller bus from DUT bus during setup/teardown phases and enabling per-DUT data exchange during active test sequences. Use Value: Reduces cross-talk and ground bounce in multi-DUT fixtures via 3-state control and localized bus termination support. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS623ADW | Same ALS623 logic function and electrical specs, but in 20-pin SOIC (DW) package - surface-mount, 7.5 mm × 12.8 mm footprint | Required for automated SMT assembly; not suitable for through-hole sockets or manual rework | Select SN74ALS623ADW when board space is constrained and reflow capability exists. |
| SN74AS623N | Faster propagation (1–9 ns vs. 2–13 ns), higher drive (64 mA IOL), but increased ICC (up to 189 mA) and tighter VCC tolerance (4.75–5.25 V) | Better suited for high-speed timing-critical paths; requires stricter power regulation and thermal management | Choose SN74AS623N only when ALS speed is insufficient and system can accommodate higher power and noise. |
Compared with SN74ALS623ADW, SN74ALS623AN3 offers socket compatibility and thermal robustness in legacy systems; versus SN74AS623N, it trades speed for lower power and broader supply tolerance - making it optimal for cost-sensitive, thermally constrained, or field-serviceable designs.
Availability
SN74ALS623AN3 is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy memory-mapped I/O expansion, and automated test fixture bus coupling requiring stable component supply across long-lifecycle programs.
Supply support for SN74ALS623AN3 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
SN74ALS623AN3 belongs to TI's legacy 74ALS logic family, designed specifically for reliable, low-power bidirectional bus interfacing in commercial-temperature 5 V TTL systems where pin compatibility and long-term availability are essential.
FAQ
What is the logic configuration of SN74ALS623AN3?
SN74ALS623AN3 implements true (non-inverting) logic with 3-state outputs. Unlike SN74ALS620A (inverting) or SN74ALS621A (open-collector), SN74ALS623AN3 passes A→B and B→A data without polarity inversion, and its outputs enter high-impedance state when both OEAB and OEBA are high.
Does SN74ALS623AN3 support bus-latching functionality?
Yes - SN74ALS623AN3 supports local bus-latch behavior. When both OEAB and OEBA are asserted low simultaneously, the transceiver enters a mode where each output reinforces its input, allowing both A and B buses to retain their last valid states even after upstream drivers go high-Z - a feature confirmed in the functional description and timing diagrams of the SDAS226A datasheet.
What are the absolute maximum ratings for SN74ALS623AN3?
SN74ALS623AN3 has an absolute maximum supply voltage of 7 V, input voltage limit of 7 V on all pins, and I/O port voltage limit of 5.5 V. The operating temperature range is 0°C to 70°C, and storage temperature spans –65°C to 150°C. Exceeding these values may cause permanent damage, per TI's SDAS226A datasheet Section 4.
Can SN74ALS623AN3 be used interchangeably with SN74ALS623ADW?
No - SN74ALS623AN3 and SN74ALS623ADW share identical logic function and electrical specifications but differ in package: N is 20-pin PDIP (through-hole), DW is 20-pin SOIC (surface-mount). They are not physically interchangeable; PCB layout, assembly process, and thermal profile must match the chosen package.
What is the recommended operating condition for VCC on SN74ALS623AN3?
The recommended VCC range for SN74ALS623AN3 is 4.5 V to 5.5 V, with nominal operation at 5 V. This ensures compliance with VIH ≥ 2 V, VIL ≤ 0.8 V, and specified IOL/IOH performance. Operation outside this range may result in undefined logic states or degraded timing, as defined in the SDAS226A "Recommended Operating Conditions" table.
SN74ALS623AN3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- 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:
- 15mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74ALS623AN3 FAQ
1.How can I place an order for SN74ALS623AN3 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS623AN3 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 SN74ALS623AN3 reliable?
The price and inventory of SN74ALS623AN3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS623AN3 is usually 5 days.
3.What payment methods are accepted for SN74ALS623AN3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS623AN3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS623AN3?
SN74ALS623AN3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS623AN3 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 SN74ALS623AN3?
For technical support, including SN74ALS623AN3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS623AN3 requirements.
6.How does Aetrix verify that SN74ALS623AN3 is sourced from the original manufacturer or authorized distributors?
All SN74ALS623AN3 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 SN74ALS623AN3 meets industry standards.
7.What is the process for return or replacement of SN74ALS623AN3?
All SN74ALS623AN3 units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS623AN3, 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 SN74ALS623AN3 part is unused and in its original packaging.
Return procedure for SN74ALS623AN3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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