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Texas Instruments SN74ALS620AN
- Part No.:
- SN74ALS620AN
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ALS620AN.pdf
- Description:
- IC TRANSCEIVER INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:2,102
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Product details
Overview
SN74ALS620AN from Texas Instruments is an octal bus transceiver with 3-state inverting outputs, designed for asynchronous bidirectional data transfer between A and B buses in TTL-compatible systems. It features dual output-enable inputs (OEAB/OEBA), local bus-latch capability, and operates over 0°C to 70°C at 4.5–5.5 V supply. It is used in legacy industrial control backplanes and memory-mapped I/O expansion interfaces.
For engineers reviewing the SN74ALS620AN datasheet, SN74ALS620AN pinout, SN74ALS620AN application, or SN74ALS620AN equivalent, key selection criteria include its inverting logic polarity, 24 mA low-level drive strength, 10 ns typical propagation delay (A↔B), 3-state isolation timing (tPZH/tPLZ ≤ 17 ns), and PDIP-20 package compatibility with through-hole legacy designs.
Technical Context
The SN74ALS620AN implements a dual-bus transceiver architecture with independent OEAB (A-to-B enable) and OEBA (B-to-A enable) controls, enabling flexible direction control and simultaneous bus latching when both enables are active. Its inverting output logic means An drives Bn as ¬An, and vice versa - critical for signal inversion requirements in address/data bus interfacing.
It uses Advanced Low-Power Schottky (ALS) TTL technology, delivering lower power consumption than standard LS while maintaining compatible voltage thresholds (VIL = 0.8 V, VIH = 2.0 V) and noise margins. The device supports true 3-state outputs with guaranteed high-impedance off-state leakage (IOH/IOL ≤ ±0.1 mA) and robust absolute maximum ratings (VCC ≤ 7 V, VI ≤ 7 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Function | Inverting octal bus transceiver with dual 3-state control (OEAB/OEBA) |
| Supply Voltage Range | 4.5 V to 5.5 V - ensures compatibility with 5 V TTL/ALS system rails |
| Propagation Delay (A↔B) | 2–10 ns - enables high-speed data handshaking in 20–30 MHz bus cycles |
| Output Drive (IOL) | 24 mA - sufficient to drive 10 LS-TTL loads or terminate short stubs on parallel buses |
| Operating Temperature | 0°C to 70°C - qualified for commercial-grade industrial control and instrumentation |
| Input Thresholds | VIL = 0.8 V, VIH = 2.0 V - matches standard TTL logic families for seamless integration |
| 3-State Enable Timing | tPZH/tPLZ ≤ 17 ns - ensures fast bus isolation during direction switching or arbitration |
Pinout & Package
SN74ALS620AN is supplied in a 20-pin plastic DIP (PDIP-N) package with 300-mil width, 2.54 mm pitch, and through-hole mounting. Pin 1 is located at the left end of the top row (notch-up orientation).
| 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 Data Inputs/Outputs | 8-bit bidirectional port; driven by B bus when OEBA low, drive B bus when OEAB low (inverted) |
| 10 (GND) | Ground Reference | Power return path for all internal logic and I/O circuits |
| 11 (VCC) | Positive Supply | 5 V nominal supply input; must be decoupled locally per TTL design practice |
| 12–19 (B1–B8) | Bus B Data Inputs/Outputs | 8-bit bidirectional port; driven by A bus when OEAB low, drive A bus when OEBA low (inverted) |
| 20 (OEBA) | B-to-A Output Enable | Active-low control: enables B→A data flow when low; disables outputs to high-Z when high |
Key Features
| Feature | Design Value |
|---|---|
| Inverting transceiver logic | Ensures signal polarity inversion across buses - required for certain address decoding and parity generation schemes |
| Dual independent output enables | Enables simultaneous A↔B bidirectional transfer or isolated bus latching without external logic |
| Local bus-latch capability | When OEAB and OEBA are both low, A and B buses retain last state - eliminates need for external latch ICs |
| ALS TTL compatibility | Matches LS-TTL voltage levels and drive strength while reducing power by ~30% vs. standard LS |
| 300-mil PDIP package | Supports legacy prototyping, socket-based test fixtures, and repair-friendly through-hole assembly |
Applications
| Industrial Backplane Interface | Legacy Memory-Mapped I/O Expansion |
|---|---|
|
Use Scenario: Interfacing microprocessor address/data buses to multiple peripheral cards in a 19-inch rack-mounted controller. IC Role / Device Role / Timing Role: Bidirectional level-shifting and bus isolation transceiver between CPU bus and card-local buses. Use Value: Inverting logic enables direct connection to peripherals requiring complemented address strobes; 24 mA drive sustains signal integrity across 15 cm backplane traces. |
Use Scenario: Adding parallel I/O ports to an 8086-based embedded system using ISA-style expansion slots. IC Role / Device Role / Timing Role: Direction-controlled data path between CPU data bus and peripheral register banks. Use Value: Dual OE inputs allow precise timing control of read/write handshaking; tPHL/tPLH ≤ 10 ns meets 8086's 200 ns minimum bus cycle requirement. |
| Programmable Logic Controller (PLC) I/O Module | TTL-Based Test Equipment Bus Coupling |
|
Use Scenario: Isolating and buffering digital I/O signals between PLC CPU and field I/O terminal blocks. IC Role / Device Role / Timing Role: Fault-tolerant bus interface with high-Z isolation during module hot-swap or fault conditions. Use Value: Guaranteed 3-state leakage < ±0.1 mA prevents bus contention during module insertion/removal; 0–70°C rating matches industrial ambient. |
Use Scenario: Coupling pattern generator and logic analyzer channels in benchtop automated test equipment. IC Role / Device Role / Timing Role: Synchronized bidirectional data routing between stimulus and capture subsystems. Use Value: Simultaneous OEAB/OEBA assertion latches bus states for deterministic signal capture; PDIP-20 allows manual probe access to all pins. |
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 | True (non-inverting) logic output; otherwise identical pinout, timing, and drive specs | Used where bus signal polarity must be preserved (e.g., direct data forwarding without inversion) | Select SN74ALS623AN when inverting logic is not required; verify downstream logic accepts non-inverted data paths |
| SN74AS623N | Faster propagation (1–9 ns vs. 2–10 ns); higher IOL (64 mA); AS-series, not ALS - higher power, tighter noise margins | Suitable for high-speed backplanes (>25 MHz) or heavy capacitive loads requiring stronger drive | Choose SN74AS623N only if speed or drive gain justifies increased power and reduced noise immunity; not drop-in due to different ICC and VIH/VIL |
Compared with SN74ALS620AN, SN74ALS623AN provides identical timing and packaging but preserves signal polarity, while SN74AS623N delivers significantly faster switching at the cost of higher supply current and stricter layout requirements for noise control.
Availability
SN74ALS620AN is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy memory-mapped I/O expansion, and programmable logic controller (PLC) I/O modules requiring stable component supply and long-term obsolescence management.
Supply support for SN74ALS620AN 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.
The SN74ALS620AN belongs to TI's legacy Advanced Low-Power Schottky (ALS) TTL logic family, engineered for reliable, low-power bidirectional bus interfacing in commercial-temperature industrial control systems.
FAQ
What logic polarity does the SN74ALS620AN implement?
The SN74ALS620AN implements inverting logic: when enabled, it drives the B bus with the logical complement of the A bus (¬An → Bn), and vice versa. This is confirmed in the device description and function table of the SDAS226A datasheet. The SN74ALS620AN's inverting behavior distinguishes it from the true-logic SN74ALS623AN and SN74AS623N variants.
What is the maximum recommended operating supply voltage for the SN74ALS620AN?
The SN74ALS620AN has a recommended operating supply voltage range of 4.5 V to 5.5 V, with an absolute maximum rating of 7 V. Operation outside the recommended range may cause unreliable switching or accelerated aging. The SN74ALS620AN is specified for full functionality only within 4.5–5.5 V at 0°C to 70°C ambient.
Does the SN74ALS620AN support simultaneous bidirectional data transfer?
No - the SN74ALS620AN does not support true simultaneous bidirectional transfer. Its dual OE inputs (OEAB and OEBA) allow either A→B or B→A transfer, or bus latching when both are active, but data flows in one direction at a time. The function table confirms that L/L enables B→A, H/L enables A→B, and L/H enables concurrent B→A + A→B - which results in complementary bus states, not independent full-duplex operation.
What package type is used for the SN74ALS620AN?
The SN74ALS620AN uses a 20-pin plastic dual in-line package (PDIP-N) with 300-mil width and 0.100″ lead pitch. This through-hole package is documented in TI's Package Option Addendum and matches the "N" suffix designation. It is distinct from the SOIC (DW) variant SN74ALS620ADW and is intended for socketed or hand-soldered legacy designs.
How does the SN74ALS620AN achieve bus-latch functionality?
The SN74ALS620AN achieves local bus-latch functionality when both OEAB and OEBA are asserted low: in this mode, each output reinforces its corresponding input, and - provided all other drivers on the A and B buses are in high-impedance state - both 8-bit buses retain their last logic states. This behavior is explicitly described in the device description section of the SDAS226A datasheet and requires no external latching components.
SN74ALS620AN 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, 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
SN74ALS620AN FAQ
1.How can I place an order for SN74ALS620AN through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS620AN 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 SN74ALS620AN reliable?
The price and inventory of SN74ALS620AN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS620AN is usually 5 days.
3.What payment methods are accepted for SN74ALS620AN?
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Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS620AN?
SN74ALS620AN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS620AN 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 SN74ALS620AN?
For technical support, including SN74ALS620AN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS620AN requirements.
6.How does Aetrix verify that SN74ALS620AN is sourced from the original manufacturer or authorized distributors?
All SN74ALS620AN 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 SN74ALS620AN meets industry standards.
7.What is the process for return or replacement of SN74ALS620AN?
All SN74ALS620AN units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS620AN, 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 SN74ALS620AN part is unused and in its original packaging.
Return procedure for SN74ALS620AN:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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