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Texas Instruments SN74ABT620DBR
- Part No.:
- SN74ABT620DBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74ABT620DBR.pdf
- Description:
- IC TXRX INVERT 5.5V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,849
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Product details
Overview
SN74ABT620DBR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data communication between A and B buses in 5-V TTL systems. It features inverted output logic, dual output-enable controls (OEAB/OEBA), high-drive capability (–32 mA IOH / 64 mA IOL), and operates from –40°C to 85°C. It is used in industrial backplane interfaces requiring bus isolation and data direction control.
For engineers reviewing the SN74ABT620DBR datasheet, SN74ABT620DBR pinout, SN74ABT620DBR application, or SN74ABT620DBR equivalent, key selection criteria include 3-state bus isolation timing, dual-enable storage mode, output drive strength, thermal performance in DB package (θJA = 115°C/W), and compatibility with 5-V TTL logic families.
Technical Context
The SN74ABT620DBR implements a dual-control 3-state transceiver architecture with independent OEAB (A→B enable) and OEBA (B→A enable) inputs, enabling four distinct operational modes: A-to-B, B-to-A, bidirectional pass-through, and high-impedance isolation. Its EPIC-II™ BiCMOS process delivers low ground bounce (VOLP < 1 V) and latch-up immunity (>500 mA per JESD 17).
It supports data retention via simultaneous OEAB/OEBA assertion-locking both A and B bus lines in their last state when external drivers are tri-stated. Input transition rate tolerance is 5 ns/V, and all control inputs exhibit ±1 µA leakage at 5.5 V, ensuring stable operation under marginal signal conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures robust operation across standard 5-V supply tolerances in industrial environments. |
| IOH / IOL | –32 mA / 64 mA - Drives heavy capacitive loads (e.g., long traces or multiple TTL inputs) without signal degradation. |
| tPLH / tPHL | 1 ns to 4.8 ns - Enables sub-5-ns propagation delay for high-speed bus arbitration and synchronous handshaking. |
| VIH / VIL | 2.0 V / 0.8 V - Fully compatible with standard TTL input thresholds, eliminating level-shifting requirements. |
| θJA (DB) | 115°C/W - Defines thermal derating limit for continuous operation in compact PCB layouts with limited airflow. |
| ESD Rating | >2000 V HBM - Meets MIL-STD-883 Class 3015, supporting handling in non-EPA assembly environments. |
| Operating Temp | –40°C to +85°C - Qualified for extended-temperature industrial and telecom infrastructure applications. |
Pinout & Package
SN74ABT620DBR uses a 20-pin Shrink Small-Outline (DB) package (SOIC variant), 7.5 mm × 4.4 mm body, 1.0 mm max height, with 0.65 mm lead pitch. Pin 1 is located at top-left corner (quadrant Q1) when notch faces upward.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OEAB | Active-low enable for A→B data path; asserts high-impedance on B outputs when high. |
| 2–9 | A1–A8 | Input/output port A - bidirectional data lines with inverted output logic relative to input. |
| 10 | GND | Ground reference for all internal circuitry and I/O structures. |
| 11 | VCC | 5-V power supply - must be decoupled locally (0.1 µF ceramic + 10 µF bulk) near pin 11. |
| 12 | OEBA | Active-low enable for B→A data path; isolates A outputs when high. |
| 13–20 | B1–B8 | Input/output port B - bidirectional data lines, inverted relative to A-side inputs. |
Key Features
| Feature | Design Value |
|---|---|
| Dual Output-Enable Control | Independent OEAB and OEBA pins allow selective direction control, isolation, or simultaneous bus latching without external logic. |
| Inverted Output Logic | Each output presents complemented data - simplifies interface with differential receivers or active-low control buses. |
| High-Drive Outputs | 64-mA sink capability supports driving ≥10 standard TTL loads or ≥20 LVTTL inputs on shared backplanes. |
| Low Ground Bounce | VOLP < 1 V at 5 V/25°C ensures signal integrity during simultaneous switching of all eight outputs. |
| BiCMOS Process (EPIC-II™) | Reduces static power vs. bipolar-only designs while retaining TTL-compatible speed and drive strength. |
Applications
| Industrial Backplane Interface | Legacy System Bus Extension |
|---|---|
Use Scenario: Interfacing a microcontroller-based master module to multiple peripheral cards over a 20-cm, 8-bit parallel bus with stubs. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing data flow direction and isolating card-specific address/data domains during reset or fault. Use Value: Dual OE control enables precise timing of bus release and capture; high drive strength maintains signal edge rates despite 30-pF total trace+stub capacitance. |
Use Scenario: Extending a vintage 80C88 CPU bus to add memory-mapped I/O expansion in a retro-computing chassis. IC Role / Device Role / Timing Role: Level-translating and isolating legacy TTL peripherals from CPU bus while preserving signal polarity inversion required by ISA-style protocols. Use Value: Inverted output logic matches ISA's active-low data strobe conventions; 5-V tolerance avoids need for external voltage translation. |
| Modular PLC I/O Carrier | Test Equipment Signal Routing |
Use Scenario: Hot-swap-capable I/O carrier board routing sensor data between field-side analog modules and controller-side digital bus. IC Role / Device Role / Timing Role: Isolating field-side transients from controller bus using OEBA-driven high-Z state during module insertion/removal. Use Value: Simultaneous OEAB/OEBA assertion holds bus state during hot-swap transitions, preventing metastability in downstream FIFOs or registers. |
Use Scenario: Automated test system switching DUT signals between stimulus sources and measurement instruments via programmable relay matrix. IC Role / Device Role / Timing Role: Replacing electromechanical relays with solid-state bidirectional signal routing under FPGA control. Use Value: Sub-5-ns propagation delay enables tight timing closure in 100-MHz test pattern generation; 3-state outputs prevent signal contention during reconfiguration. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT245DBR | Non-inverting output logic; identical pinout, drive strength, and timing specs. | Requires logic inversion in upstream/downstream logic if system relies on SN74ABT620DBR's inherent inversion. | Select when bidirectional data flow must preserve polarity (e.g., memory-mapped register access). |
| SN74LVC245APW | 3.3-V only operation; lower drive (–24 mA / 24 mA); different VIL/VIH thresholds (0.7×VCC / 0.3×VCC). | Not interoperable with 5-V TTL buses without level shifters; unsuitable for legacy 5-V industrial backplanes. | Select only for new 3.3-V designs where power efficiency and smaller PW package outweigh compatibility needs. |
Compared with SN74ABT620DBR, SN74ABT245DBR eliminates the need for external inverters but requires redesign of control logic sequencing, while SN74LVC245APW reduces power and size at the cost of 5-V bus incompatibility and halved drive strength-making it unsuitable for direct replacement in existing 5-V systems.
Availability
SN74ABT620DBR is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus extensions, modular PLC I/O carriers, and automated test equipment signal routing requiring stable component supply and long-term obsolescence management.
Supply support for SN74ABT620DBR 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 specializing in analog, embedded processing, and logic solutions, with decades of heritage in high-reliability industrial and automotive-grade components.
The SN74ABT620DBR belongs to TI's ABT logic family-designed specifically for high-speed, high-drive 5-V TTL bus interfacing in noise-immune industrial control and communications infrastructure.
FAQ
What is the function of OEAB and OEBA on the SN74ABT620DBR?
The SN74ABT620DBR uses OEAB (pin 1) to enable data transmission from port A to port B, and OEBA (pin 12) to enable transmission from port B to port A. Both are active-low inputs: when low, the respective path is enabled; when high, the corresponding outputs enter high-impedance state. Simultaneous assertion of both enables bus latching behavior, holding prior states on both A and B buses.
Does the SN74ABT620DBR support 3.3-V operation?
No, the SN74ABT620DBR is specified only for 4.5 V to 5.5 V operation. Its input thresholds (VIH = 2.0 V, VIL = 0.8 V), output drive strength, and internal BiCMOS structure are optimized for 5-V TTL compatibility. Operating below 4.5 V risks failure to meet timing or drive specifications, and is outside the recommended operating conditions defined in the SCBS113D datasheet.
How does the SN74ABT620DBR handle power-up and power-down sequencing?
To ensure high-impedance outputs during power transitions, OEBA (pin 12) must be tied to VCC via a pullup resistor, and OEAB (pin 1) to GND via a pulldown resistor. Minimum resistor values depend on driver current-sinking/source capability-TI recommends verifying against the specific driver's IOL/IOH ratings to avoid unintended enablement during ramp-up.
Is the SN74ABT620DBR pin-compatible with other ABT-series transceivers?
Yes, the SN74ABT620DBR shares the same 20-pin DB package footprint and pinout with SN74ABT245DBR and SN74ABT541DBR. However, functional differences exist: SN74ABT245DBR is non-inverting, and SN74ABT541DBR is octal buffer (unidirectional). Direct substitution requires verification of logic polarity and directionality requirements in the target design.
What thermal considerations apply to the SN74ABT620DBR in the DB package?
The SN74ABT620DBR in the DB package has a junction-to-ambient thermal resistance (θJA) of 115°C/W. At maximum rated output current (64 mA per pin, worst-case 8 pins active), power dissipation can exceed 500 mW. Adequate copper pour, thermal vias under the exposed pad (if present), and ambient temperature derating per TI's thermal guidelines are essential to maintain junction temperature below 125°C.
SN74ABT620DBR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ABT
- Package/Case:
- 20-SSOP (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Logic Type:
- Transceiver, Inverting
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Input Type:
- -
- Output Type:
- 3-State
- Current - Output High, Low:
- 32mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SSOP
SN74ABT620DBR FAQ
1.How can I place an order for SN74ABT620DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT620DBR 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 SN74ABT620DBR reliable?
The price and inventory of SN74ABT620DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT620DBR is usually 5 days.
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SN74ABT620DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT620DBR 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 SN74ABT620DBR?
For technical support, including SN74ABT620DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT620DBR requirements.
6.How does Aetrix verify that SN74ABT620DBR is sourced from the original manufacturer or authorized distributors?
All SN74ABT620DBR 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 SN74ABT620DBR meets industry standards.
7.What is the process for return or replacement of SN74ABT620DBR?
All SN74ABT620DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT620DBR, 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 SN74ABT620DBR part is unused and in its original packaging.
Return procedure for SN74ABT620DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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