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Texas Instruments SN74ALS623ADW
- Part No.:
- SN74ALS623ADW
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ALS623ADW.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,124
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Product details
Overview
SN74ALS623ADW from Texas Instruments is an octal bus transceiver with true logic output, 3-state outputs, and dual output-enable control (OEAB/OEBA) for bidirectional A↔B data flow in TTL-compatible 5 V systems. It operates from 0°C to 70°C, supports local bus-latch functionality via simultaneous OEAB/OEBA assertion, and delivers 24 mA low-level output drive at VCC = 4.5 V. It is used in legacy industrial backplane interfaces and synchronous bus isolation circuits.
For engineers reviewing the SN74ALS623ADW datasheet, SN74ALS623ADW pinout, SN74ALS623ADW application, or SN74ALS623ADW equivalent, this page provides verified functional identity, SOIC-20 package mapping, timing parameters (tPLH/tPHL ≤13 ns), electrical specs (VOL ≤0.4 V @ IOL=24 mA), and validated alternatives for bus interface redesign or obsolescence mitigation.
Technical Context
This device implements asynchronous bidirectional 8-bit data transfer between two independent buses using dual 3-state output enables. Its logic is non-inverting (true), and it features bus-latch capability when both OEAB and OEBA are asserted - holding prior states on both A and B buses while all external drivers are high-impedance.
It belongs to the ALS (Advanced Low-Power Schottky) family, offering lower power than standard LS logic while maintaining TTL voltage thresholds (VIH = 2 V, VIL = 0.8 V) and compatible AC performance. Propagation delays are specified under CL = 50 pF, R1/R2 = 500 Ω, and operate across full 4.5–5.5 V supply range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Type | True (non-inverting) octal bus transceiver with 3-state outputs |
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5 V TTL/ALS systems |
| Output Drive | 24 mA sink current (IOL) at VCC = 4.5 V - sufficient for driving multiple TTL loads |
| Propagation Delay | tPLH/tPHL ≤13 ns (A↔B) - enables sub-10 MHz bus operation with margin |
| Enable Timing | tPZH/tPLZ ≤22 ns (OEAB→B, OEBA→A) - supports fast bus arbitration and direction switching |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade industrial control and instrumentation |
| VOL / VOH | VOL ≤0.4 V @ IOL = 24 mA; VOH ≥2.4 V @ IOH = –15 mA - meets TTL output swing requirements |
Pinout & Package
SN74ALS623ADW is housed in a 20-pin SOIC (DW) package per JEDEC MS-013, 7.5 mm body width, 1.27 mm pitch, 2.65 mm max height, RoHS-compliant NiPdAu lead finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OEAB | Output-enable for A-to-B direction; low enables A→B data flow |
| 2–9 | A1–A8 | Input/output port A (bidirectional); connects to source bus |
| 10 | GND | Ground reference for all logic and I/O |
| 11–18 | B1–B8 | Input/output port B (bidirectional); connects to destination bus |
| 19 | OEBA | Output-enable for B-to-A direction; low enables B→A data flow |
| 20 | VCC | +5 V supply input; decoupling required near pin |
Key Features
| Feature | Design Value |
|---|---|
| Asynchronous bidirectional control | Dual independent enables (OEAB/OEBA) allow flexible, non-synchronized A↔B data routing without clock dependency |
| Local bus-latch mode | Simultaneous assertion of OEAB and OEBA holds last valid state on both A and B buses - eliminates need for external latches |
| TTL-compatible interface | Meets standard VIH (2 V), VIL (0.8 V), VOL (≤0.4 V), and VOH (≥2.4 V) - interoperable with 74LS/ALS/AS families |
| High noise immunity | Input clamp diode (VIK = –1.2 V) and controlled IIL/IIL (±0.1 mA) suppress transient coupling on shared bus lines |
| SOIC-20 thermal profile | MSL Level-1 rating enables standard reflow without dry-pack or bake preconditioning - simplifies SMT manufacturing |
Applications
| Industrial Backplane Interface | Legacy System Bus Isolation |
|---|---|
Use Scenario: Interfacing microcontroller address/data buses to modular I/O expansion slots in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional bus transceiver enabling CPU-initiated read/write cycles across isolated backplane segments. Use Value: Prevents bus contention during hot-swap events and allows selective enablement of peripheral modules without system reset. |
Use Scenario: Isolating memory-mapped peripherals (e.g., EPROM, UART) from main CPU bus in retro-computing restoration projects. IC Role / Device Role / Timing Role: Direction-controlled buffer that blocks signal leakage when peripherals are disabled or unpowered. Use Value: Eliminates signal integrity degradation from floating bus stubs and reduces standby current in powered-down subsystems. |
| Test Equipment Data Routing | Automated Test Fixture Control |
Use Scenario: Routing stimulus/response signals between DUT interface connectors and pattern generator/analyzer channels in ATE systems. IC Role / Device Role / Timing Role: Reconfigurable 8-bit path selector supporting both forward (stimulus) and reverse (response) data flow. Use Value: Enables single-hardware test head to support multiple DUT pin configurations without physical rewiring. |
Use Scenario: Controlling parallel status/control lines (e.g., START, BUSY, ERROR) between PLC and custom test fixture logic. IC Role / Device Role / Timing Role: Level-shifting and fanout buffer ensuring clean TTL-level signaling across long PCB traces. Use Value: Guarantees noise-immune handshaking with <13 ns propagation delay - critical for deterministic cycle timing in closed-loop tests. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS623AN | Same logic, same specs, but in 20-pin PDIP (N) package - through-hole mounting, no reflow requirement | Preferred for prototyping, repair, or legacy wave-solder assembly where SOIC footprint is unavailable | Select SN74ALS623AN if manual soldering, socketing, or board-level repair is required. |
| SN74AS623 | Faster propagation (tPLH/tPHL ≤9 ns), higher IOL (64 mA), but increased ICC (up to 189 mA) and tighter VIH/VIL margins | Suitable for high-speed bus extensions requiring sub-10 ns timing, but demands stricter power delivery and layout | Choose SN74AS623 only when speed is critical and thermal/power budgets permit its higher dissipation. |
Compared with SN74ALS623ADW, SN74ALS623AN offers identical functionality in through-hole form for serviceability, while SN74AS623 trades power efficiency for raw speed - making the DW variant optimal for cost-sensitive, thermally constrained commercial designs needing proven ALS reliability.
Availability
SN74ALS623ADW is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus isolation, and automated test fixture control requiring stable component supply across extended production lifecycles.
Supply support for SN74ALS623ADW 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 with over 90 years of analog and logic innovation, delivering reliable, industry-standard components for industrial, automotive, and communications infrastructure.
SN74ALS623ADW belongs to TI's legacy Advanced Low-Power Schottky (ALS) logic family, engineered for robust 5 V TTL interoperability, low static power, and deterministic timing in mission-critical industrial control and instrumentation systems.
FAQ
What is the function of OEAB and OEBA on the SN74ALS623ADW?
OEAB (pin 1) enables data transmission from port A to port B when low; OEBA (pin 19) enables transmission from port B to port A when low. Both can be asserted simultaneously to enter bus-latch mode, preserving the last valid logic states on both A and B buses. This dual-enable architecture eliminates external latch components in bidirectional bus architectures and is fully documented in the SN74ALS623ADW function table.
Does SN74ALS623ADW support 3.3 V operation?
No, SN74ALS623ADW is specified only for 4.5 V to 5.5 V operation and is not 3.3 V tolerant. Its input thresholds (VIH = 2 V, VIL = 0.8 V) and output drive characteristics are optimized for 5 V TTL/ALS systems. Applying 3.3 V supply risks undefined logic behavior and violates recommended operating conditions per the SN74ALS623ADW datasheet.
What is the maximum capacitive load SN74ALS623ADW can drive reliably?
SN74ALS623ADW is characterized for CL = 50 pF in switching specifications, with tPLH/tPHL ≤13 ns under those conditions. Driving loads >50 pF increases propagation delay nonlinearly and may cause timing violations; for heavier loads, use series termination or buffer staging. This 50 pF limit is explicitly defined in the SN74ALS623ADW switching characteristics table.
Is SN74ALS623ADW pin-compatible with SN74ALS620ADW or SN74ALS621ADW?
No - although all three share the SOIC-20 (DW) package and pin count, their logic functions differ: SN74ALS620ADW is inverting, SN74ALS621ADW has open-collector outputs, and SN74ALS623ADW is true-logic 3-state. Swapping them without circuit revision causes functional failure. Pin compatibility does not imply functional equivalence for the SN74ALS623ADW.
What is the thermal resistance (θJA) of the SN74ALS623ADW SOIC package?
The SN74ALS623ADW DW package has a typical junction-to-ambient thermal resistance (θJA) of 100°C/W under standard JEDEC JESD51-7 conditions (single-layer 1-in² copper pad). This value is derived from TI's SOIC-20 thermal characterization data and applies directly to SN74ALS623ADW in typical PCB layouts without added heatsinking.
SN74ALS623ADW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 20-SOIC (0.295", 7.50mm 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:
- 15mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74ALS623ADW FAQ
1.How can I place an order for SN74ALS623ADW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS623ADW 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 SN74ALS623ADW reliable?
The price and inventory of SN74ALS623ADW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS623ADW is usually 5 days.
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SN74ALS623ADW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS623ADW 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 SN74ALS623ADW?
For technical support, including SN74ALS623ADW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS623ADW requirements.
6.How does Aetrix verify that SN74ALS623ADW is sourced from the original manufacturer or authorized distributors?
All SN74ALS623ADW 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 SN74ALS623ADW meets industry standards.
7.What is the process for return or replacement of SN74ALS623ADW?
All SN74ALS623ADW units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS623ADW, 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 SN74ALS623ADW part is unused and in its original packaging.
Return procedure for SN74ALS623ADW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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