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Texas Instruments SN74ALS623ADWRG4
- Part No.:
- SN74ALS623ADWRG4
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ALS623ADWRG4.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,850
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Product details
Overview
SN74ALS623ADWRG4 from Texas Instruments is an octal bus transceiver with true (non-inverting) 3-state outputs, designed for asynchronous bidirectional data transfer between two 8-bit buses (A↔B). It features dual output-enable inputs (OEAB and OEBA), local bus-latch capability via simultaneous enable, and operates at 4.5–5.5 V over 0°C to 70°C. It is used in legacy industrial control backplanes and TTL-compatible system interconnects.
For engineers reviewing the SN74ALS623ADWRG4 datasheet, SN74ALS623ADWRG4 pinout, SN74ALS623ADWRG4 application, or SN74ALS623ADWRG4 equivalent, this page delivers verified functional identity, SOIC-20 package mapping, timing parameters (e.g., tPLH ≤13 ns), latch behavior under dual-OE, and validated alternatives for bus isolation and level translation in 5-V TTL systems.
Technical Context
The SN74ALS623ADWRG4 implements a dual-directional 8-bit transceiver architecture with independent A→B and B→A paths controlled by OEAB and OEBA. Its 3-state outputs support high-impedance isolation, and simultaneous assertion of both enables allows data latching by reinforcing bus states - a feature confirmed in the function table and logic diagram.
It belongs to the ALS (Advanced Low-Power Schottky) family, delivering TTL-compatible voltage thresholds (VIH = 2 V, VIL = 0.8 V), 24 mA low-level drive (IOL), and propagation delays as low as 2 ns (tPLH/tPHL min) under CL = 50 pF. No internal pull-ups, open-collector, or CMOS-level compatibility is specified - it is strictly a bipolar TTL-family device.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Type | True (non-inverting) 3-state octal transceiver - preserves signal polarity during A↔B transfer. |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5-V TTL rails; absolute max 7 V. |
| Propagation Delay | tPLH/tPHL ≤13 ns (A↔B), tPZH/tPLZ ≤22 ns (enable-to-output) - ensures tight timing in synchronous backplane designs. |
| Output Drive | IOL = 24 mA (min), IOH = –15 mA - sufficient to drive 10 LS-TTL loads or terminate short stubs on parallel buses. |
| Operating Temperature | 0°C to 70°C - rated for commercial/industrial ambient environments, not extended or automotive grade. |
| Input Thresholds | VIH = 2.0 V (min), VIL = 0.8 V (max) - matches standard TTL logic levels; no CMOS or LVTTL compatibility. |
| Package | SOIC-20 (DW), 7.5 mm × 12.8 mm, 1.27 mm pitch - surface-mount compatible with IPC-7351 land pattern DW0020A. |
Pinout & Package
SN74ALS623ADWRG4 is housed in a 20-pin SOIC (DW) package per JEDEC MS-013, with 1.27 mm lead pitch and maximum height of 2.65 mm. Pin 1 is marked by a beveled corner or notch on the top surface.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OEAB) | A-to-B Output Enable | Active-low control: enables A→B data flow when low; disables outputs to high-Z when high. |
| 2–9 (A1–A8) | Bus A I/O Ports | 8-bit bidirectional data terminals connected to source bus; driven/latched based on OEAB/OEBA state. |
| 10 (GND) | Ground Reference | Power return path for all internal logic and output stages; must be low-inductance connection. |
| 11–18 (B1–B8) | Bus B I/O Ports | 8-bit bidirectional data terminals connected to destination bus; mirror A-side behavior under control logic. |
| 19 (OEBA) | B-to-A Output Enable | Active-low control: enables B→A data flow when low; isolates B bus when high. |
| 20 (VCC) | Positive Supply | 5-V nominal supply input; bypassing with 0.1 µF ceramic capacitor near pin required for noise immunity. |
Key Features
| Feature | Design Value |
|---|---|
| Local Bus-Latch Capability | Simultaneous low assertion of OEAB and OEBA holds both A and B buses in their last valid states without external latches. |
| Dual Independent Direction Control | Separate OEAB and OEBA pins allow asymmetric bus control - e.g., A→B active while B→A isolated - enabling half-duplex arbitration. |
| TTL-Compatible Interface | Meets standard TTL VIH/VIL, VOH/VOL, and fanout specs - interoperable with 74LS, 74S, and other ALS devices without level shifters. |
| High-Noise Immunity Inputs | Input clamp diodes and guaranteed VIK = –1.2 V support robust operation in electrically noisy industrial backplanes. |
| Low Propagation Skew | Max tPHL–tPLH skew ≤1 ns across all 8 channels - critical for maintaining data validity in parallel bus transfers. |
Applications
| Industrial Backplane Interconnect | Legacy System Bus Isolation |
|---|---|
|
Use Scenario: Connecting CPU and peripheral modules across a 200-mm PCB backplane in programmable logic controllers. IC Role / Device Role / Timing Role: Bidirectional data shuttle between address/data buses, with OEAB/OEBA synchronized to bus grant signals. Use Value: Eliminates need for discrete direction-control logic and external latches; supports hot-swap-safe isolation via OE deassertion. |
Use Scenario: Isolating memory-mapped I/O sections during firmware updates in avionics maintenance interfaces. IC Role / Device Role / Timing Role: 3-state buffer enforcing strict bus segmentation; OEBA held high while OEAB toggled for write cycles only. Use Value: Prevents spurious writes to protected registers by guaranteeing high-Z during reset or configuration mode. |
| Parallel Test Equipment Interface | TTL-Level Protocol Bridge |
|
Use Scenario: Adapting 8-bit DUT (device under test) signals to automated test equipment with separate stimulus/response channels. IC Role / Device Role / Timing Role: Transceiver configured for A→B (stimulus) and B→A (response) on alternating clock phases using dual-OE timing. Use Value: Enables full-duplex test vector injection and capture within single-cycle timing budgets (≤13 ns delay). |
Use Scenario: Bridging legacy 5-V TTL UART handshaking lines (RTS/CTS/DSR) between microcontroller and modem ICs. IC Role / Device Role / Timing Role: Level-consistent signal repeater preserving edge integrity; no voltage translation needed. Use Value: Maintains <1 ns inter-channel skew across all control lines - essential for reliable hardware flow control timing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ALS623AN | Same logic, identical electrical specs, but in 20-pin PDIP (N) package - through-hole, 300-mil width, no reflow requirements. | Suitable for prototyping, repair, or legacy wave-soldered assemblies where SOIC placement is impractical. | Select SN74ALS623AN when manual assembly, socketing, or thermal mass tolerance is prioritized over board space. |
| SN74AS623 | Faster switching (tPLH/tPHL ≤9 ns), higher IOL = 64 mA, but increased ICC (up to 189 mA) and tighter VCC stability requirement (4.75–5.25 V for max IOL). | Better for high-speed backplanes (>10 MHz) or driving heavier capacitive loads, but requires improved power delivery and decoupling. | Choose SN74AS623 only if timing margin is insufficient with SN74ALS623ADWRG4 and board layout supports its higher current demand. |
Compared with SN74ALS623AN and SN74AS623, the SN74ALS623ADWRG4 offers optimal balance of speed, power, and SOIC manufacturability for cost-sensitive industrial control boards requiring proven 5-V TTL interoperability without redesign.
Availability
SN74ALS623ADWRG4 is available at Aetrix Electronics and suitable for industrial automation backplanes, legacy test equipment interfaces, and 5-V TTL system upgrades requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS623ADWRG4 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 with broad industrial and automotive reach.
The SN74ALS623ADWRG4 belongs to TI's legacy 74ALS logic family, engineered for reliability and interoperability in fixed-function 5-V TTL systems - particularly in industrial control, instrumentation, and military-grade backplane architectures.
FAQ
What is the function of OEAB and OEBA on the SN74ALS623ADWRG4?
The SN74ALS623ADWRG4 uses OEAB (pin 1) to enable data flow from bus A to bus B, and OEBA (pin 19) to enable data flow from bus B to bus A. Both are active-low inputs. When either is high, its respective direction is placed in high-impedance state. Simultaneously asserting both low enables local bus-latch behavior, holding prior data on both buses.
Does the SN74ALS623ADWRG4 support mixed-voltage operation (e.g., 3.3 V logic interfacing)?
No. The SN74ALS623ADWRG4 is strictly a 5-V TTL device with VIH = 2.0 V minimum and VIL = 0.8 V maximum. It does not tolerate or interface reliably with 3.3-V logic families. Direct connection to 3.3-V systems risks undriven inputs or excessive current and requires level-shifting circuitry.
What is the maximum capacitive load the SN74ALS623ADWRG4 can drive while maintaining specified timing?
The SN74ALS623ADWRG4 switching characteristics (tPLH, tPHL, etc.) are characterized at CL = 50 pF. Driving loads significantly above this - such as >100 pF due to long traces or multiple TTL inputs - increases propagation delay and may violate setup/hold timing. For >50 pF, derating or buffering is recommended.
Is the SN74ALS623ADWRG4 RoHS compliant and lead-free?
Yes. Per TI's packaging addendum, SN74ALS623ADWRG4 carries NIPDAU (nickel-palladium-gold) lead finish and is RoHS-compliant (marked "Yes" in material status). It meets JEDEC Level-1 moisture sensitivity and supports standard Pb-free reflow profiles up to 260°C peak.
Can the SN74ALS623ADWRG4 replace the SN74ALS620A in an existing design?
No - they differ in logic polarity: SN74ALS623ADWRG4 is true (non-inverting), while SN74ALS620A is inverting. Swapping them without inverting the data path or adjusting control logic will invert all transferred data. Functional replacement requires verification of signal polarity requirements and potential PCB modification.
SN74ALS623ADWRG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- 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:
- 4.5V ~ 5.5V
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74ALS623ADWRG4 FAQ
1.How can I place an order for SN74ALS623ADWRG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS623ADWRG4 on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
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The price and inventory of SN74ALS623ADWRG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS623ADWRG4 is usually 5 days.
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5.How can I obtain technical support or documentation for SN74ALS623ADWRG4?
For technical support, including SN74ALS623ADWRG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS623ADWRG4 requirements.
6.How does Aetrix verify that SN74ALS623ADWRG4 is sourced from the original manufacturer or authorized distributors?
All SN74ALS623ADWRG4 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 SN74ALS623ADWRG4 meets industry standards.
7.What is the process for return or replacement of SN74ALS623ADWRG4?
All SN74ALS623ADWRG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS623ADWRG4, 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 SN74ALS623ADWRG4 part is unused and in its original packaging.
Return procedure for SN74ALS623ADWRG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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