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Texas Instruments SN74ALS620ANS
- Part No.:
- SN74ALS620ANS
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ALS620ANS.pdf
- Description:
- BUS XCVR SINGLE 8-CH 3-ST 20-PIN
- Quantity:
- Payment:
- Shipping:
Inventory:3,757
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Product details
Overview
SN74ALS620ANS 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 controls (OEAB/OEBA), local bus-latch capability, and operates over 0°C to 70°C at 4.5–5.5 V supply. Its key use case is isolated bus communication in legacy industrial control backplanes.
For engineers reviewing the SN74ALS620ANS datasheet, SN74ALS620ANS pinout, SN74ALS620ANS application, or SN74ALS620ANS equivalent, this page delivers verified electrical specs, true/inverting logic behavior, timing parameters under 50 pF load, package-confirmed pin mapping, and validated alternatives for bus isolation and latch-mode operation.
Technical Context
The SN74ALS620ANS implements a dual-enable 8-bit bidirectional transceiver architecture where simultaneous assertion of OEAB and OEBA enables local bus-latch functionality-holding both A and B bus states when all external drivers are high-impedance. Its inverting logic path ensures complementary data transmission between buses.
It uses ALS (Advanced Low-Power Schottky) TTL technology, delivering 24 mA low-level output drive, 15 mA high-level sink, and propagation delays as low as 2 ns (tPLH/tPHL) with 50 pF load. Input thresholds meet standard TTL levels (VIH = 2 V, VIL = 0.8 V), and absolute max ratings include 7 V supply and 5.5 V I/O voltage tolerance.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Type | Inverting octal bus transceiver with 3-state outputs |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V TTL systems |
| Output Drive | IOL = 24 mA (min), IOH = –15 mA - sufficient for driving multiple TTL loads |
| Propagation Delay | tPLH/tPHL ≤ 10 ns (A↔B) at VCC = 4.5–5.5 V, CL = 50 pF - supports >50 MHz bus toggle rates |
| Operating Temperature | 0°C to 70°C - rated for commercial/industrial ambient environments |
| Input Thresholds | VIH = 2 V (min), VIL = 0.8 V (max) - fully compatible with standard TTL logic families |
| Enable Architecture | Dual independent enables (OEAB, OEBA) - enables bidirectional flow control and bus isolation |
Pinout & Package
SN74ALS620ANS is supplied in a 20-pin plastic DIP (N package), 300-mil width, with standard through-hole mounting and JEDEC MS-001 compliant footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OEAB | Output-enable for A-to-B direction; active-low control |
| 2–9 | A1–A8 | Input/output port A (inverting transceiver path) |
| 10 | GND | Ground reference for power and signal integrity |
| 11–18 | B1–B8 | Input/output port B (inverting transceiver path) |
| 19 | OEBA | Output-enable for B-to-A direction; active-low control |
| 20 | VCC | +5 V supply input; decoupling required per TTL design practice |
Key Features
| Feature | Design Value |
|---|---|
| Local Bus-Latch Capability | Simultaneous OEAB + OEBA assertion holds last A/B bus states without external latches |
| Inverting Logic Path | Ensures complementary data transfer - critical for differential bus arbitration schemes |
| ALS TTL Compatibility | Meets standard TTL VIH/VIL, drives 10+ LS-TTL loads, and interfaces directly with 74LS/74F families |
| Dual Independent Enables | Enables asymmetric bus control - e.g., A→B only while B remains isolated |
| High Noise Immunity | Input hysteresis and 0.4 V noise margin (VIH–VIL) reduce susceptibility to ground bounce in dense backplanes |
Applications
| Industrial Backplane Interface | Legacy System Bus Isolation |
|---|---|
|
Use Scenario: Connecting CPU address/data buses to peripheral expansion slots in programmable logic controllers (PLCs). IC Role / Device Role / Timing Role: Bidirectional bus transceiver enabling read/write cycles between master and slave modules with cycle-synchronized enable control. Use Value: Eliminates need for discrete direction-control logic and reduces PCB routing complexity via single-package A↔B handshaking. |
Use Scenario: Isolating memory-mapped I/O regions during firmware updates in embedded instrumentation systems. IC Role / Device Role / Timing Role: High-impedance bus gate controlled by system supervisor logic to prevent spurious writes during reconfiguration. Use Value: Prevents bus contention during hot-swap events using fast disable timing (tPZL ≤ 25 ns) and guaranteed high-Z state. |
| Asynchronous Data Bridge | TTL-Level Protocol Converter |
|
Use Scenario: Bridging two independent 8-bit data paths operating at different clock domains in test equipment. IC Role / Device Role / Timing Role: Level-shifting and direction-controlled buffer with no internal clock - supports fully asynchronous handshaking. Use Value: Enables deterministic latency (≤10 ns propagation) and eliminates metastability risk inherent in clock-domain crossing circuits. |
Use Scenario: Converting parallel status signals from industrial sensors (TTL output) to microcontroller GPIO inputs with polarity inversion. IC Role / Device Role / Timing Role: Inverting transceiver providing signal conditioning, drive strength boost, and noise filtering via Schottky-clamped inputs. Use Value: Compensates for long trace losses and improves noise margin by reinforcing signal edges with 24 mA sink capability. |
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 path; identical pinout, timing, and drive specs | Used where bus data must retain polarity across transceiver - e.g., direct memory-mapped I/O mirroring | Select when system logic requires non-inverted data flow; drop-in replacement except for logic polarity |
| SN74AS623N | Faster propagation (1–9 ns vs. 2–13 ns); higher IOL (64 mA); AS-family speed grade | Suitable for high-speed backplanes (>20 MHz sustained toggle) where ALS timing margins are insufficient | Choose for performance-critical upgrades; verify layout for reduced noise immunity and increased ICC (up to 189 mA) |
Compared with SN74ALS620ANS, SN74ALS623AN provides identical timing and packaging but preserves data polarity, while SN74AS623N delivers significantly faster switching at the cost of higher power and lower noise margin - making each suitable for distinct trade-offs in legacy system maintenance or performance enhancement.
Availability
SN74ALS620ANS is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus isolation, asynchronous data bridging, and TTL-level protocol conversion requiring stable component supply and long-term obsolescence support.
Supply support for SN74ALS620ANS 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 qualification.
The SN74ALS620ANS belongs to TI's legacy 74ALS logic family, engineered for robustness in commercial/industrial environments where reliability, TTL compatibility, and bus-latch functionality are prioritized over ultra-high speed.
FAQ
What is the logic function of SN74ALS620ANS?
The SN74ALS620ANS is an inverting octal bus transceiver: data transmitted from A to B or B to A appears complemented at the destination port. This behavior is fixed and cannot be configured. The device uses dual active-low output-enable inputs (OEAB and OEBA) to control direction and isolation, and its inverting nature is intrinsic to the SN74ALS620A silicon design per TI's SDAS226A datasheet.
Does SN74ALS620ANS support bus-latch operation?
Yes, SN74ALS620ANS supports local bus-latch functionality. When both OEAB and OEBA are asserted low simultaneously, and all other drivers on the A and B buses are in high-impedance state, the transceiver reinforces its own inputs - holding the last valid logic states on both 8-bit buses. This eliminates the need for external latches in applications like CPU-peripheral handshaking or diagnostic mode retention.
What package types are available for SN74ALS620ANS?
SN74ALS620ANS specifically denotes the 20-pin plastic DIP (N package), 300-mil width, with through-hole mounting. TI also offers SN74ALS620ADW in SOIC (DW) and SN74ALS620ANSR in SOP (NS), but the "NS" suffix in SN74ALS620ANS confirms the N-package variant per TI's packaging addendum. Pin 1 location and mechanical dimensions match JEDEC MS-001 standards.
What are the absolute maximum ratings for SN74ALS620ANS?
Per the SDAS226A datasheet, SN74ALS620ANS has an absolute maximum supply voltage of 7 V, input voltage limit of 7 V on control pins and 5.5 V on I/O ports, and operating temperature range of 0°C to 70°C. Storage temperature is rated from –65°C to 150°C. Exceeding any of these values may cause permanent damage, and functional operation is only assured within the recommended conditions (4.5–5.5 V, 0–70°C).
How does SN74ALS620ANS differ from SN74ALS621A?
SN74ALS620ANS uses 3-state outputs with inverting logic, while SN74ALS621A employs open-collector outputs with true (non-inverting) logic. Their pinouts are identical, but SN74ALS621A requires external pull-up resistors and cannot drive low-impedance loads directly. SN74ALS620ANS is suited for bidirectional bus sharing; SN74ALS621A is intended for wired-OR applications like interrupt aggregation or shared acknowledge lines.
SN74ALS620ANS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ALS
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- 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:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74ALS620ANS FAQ
1.How can I place an order for SN74ALS620ANS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ALS620ANS 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 SN74ALS620ANS reliable?
The price and inventory of SN74ALS620ANS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ALS620ANS is usually 5 days.
3.What payment methods are accepted for SN74ALS620ANS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ALS620ANS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ALS620ANS?
SN74ALS620ANS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ALS620ANS 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 SN74ALS620ANS?
For technical support, including SN74ALS620ANS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ALS620ANS requirements.
6.How does Aetrix verify that SN74ALS620ANS is sourced from the original manufacturer or authorized distributors?
All SN74ALS620ANS 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 SN74ALS620ANS meets industry standards.
7.What is the process for return or replacement of SN74ALS620ANS?
All SN74ALS620ANS units undergo pre-shipment inspection (PSI). If there is an issue with SN74ALS620ANS, 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 SN74ALS620ANS part is unused and in its original packaging.
Return procedure for SN74ALS620ANS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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