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Texas Instruments SN74ABT640DBR
- Part No.:
- SN74ABT640DBR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SSOP (0.209", 5.30mm Width)
- Datasheet:
-
SN74ABT640DBR.pdf
- Description:
- IC TXRX INVERT 5.5V 20SSOP
- Quantity:
- Payment:
- Shipping:
Inventory:3,783
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Product details
Overview
SN74ABT640 from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in TTL-level systems. It supports inverted data transmission (A↔B), features high-drive capability (–32 mA IOH / 64 mA IOL), operates from –40°C to 85°C, and uses a 5-V supply. It is commonly deployed in industrial backplane interfaces and legacy system bus isolation.
For engineers reviewing the SN74ABT640 datasheet, SN74ABT640 pinout, SN74ABT640 application, or SN74ABT640 equivalent, key selection considerations include direction-control logic behavior, 3-state enable timing (tPZL/tPHZ), output drive strength under load, and SSOP-20 thermal performance (θJA = 115°C/W).
Technical Context
The SN74ABT640 implements dual-directional, inverting bus transceivers using EPIC-IIB BiCMOS technology to reduce power dissipation while maintaining TTL-compatible voltage thresholds (VIH = 2 V, VIL = 0.8 V). Its DIR input selects data flow direction (A→B or B→A), and OE enables/disables all outputs simultaneously into high-impedance state.
It delivers fast switching with tPLH/tPHL ≤ 4.9 ns (VCC = 5 V, CL = 50 pF), supports robust ESD protection (>2000 V HBM), and meets JEDEC JESD-17 latch-up immunity (>500 mA). The device requires OE tied to VCC via pullup during power sequencing to ensure defined startup state.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - Ensures compatibility with standard 5-V TTL and CMOS logic rails. |
| Operating Temperature | –40°C to 85°C - Qualified for industrial-grade embedded control and communications equipment. |
| Output Drive | –32 mA IOH / 64 mA IOL - Sustains signal integrity driving multiple TTL loads or unterminated traces. |
| Propagation Delay | tPLH/tPHL ≤ 4.9 ns - Enables reliable operation in sub-100-MHz bus timing budgets. |
| 3-State Enable/Disable | tPZL ≤ 7.3 ns, tPHZ ≤ 6.8 ns - Guarantees clean bus isolation without glitches during direction or enable transitions. |
| Input Clamp Current | –18 mA IIK - Protects inputs against transient overvoltage events up to –1.2 V. |
| Thermal Resistance | θJA = 115°C/W (DB package) - Defines maximum power dissipation limit (≈435 mW at ΔT = 50°C) in still-air PCB layout. |
Pinout & Package
SN74ABT640DBR is housed in a 20-pin Shrink Small-Outline Package (SSOP-DB), 0.209-inch body width, 0.65-mm lead pitch, RoHS-compliant NIPDAU finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | DIR | Direction-control input: Low = B→A data transfer; High = A→B data transfer. |
| 2–9 | A1–A8 | Input/output port A - Bidirectional data lines connected to primary bus segment. |
| 10 | GND | Ground reference for all internal circuitry and I/O signaling. |
| 11 | VCC | Positive supply rail (4.5–5.5 V); decoupling capacitor required near pin. |
| 12–19 | B1–B8 | Input/output port B - Bidirectional data lines connected to secondary bus segment. |
| 20 | OE | Output-enable input: Low = outputs active; High = all outputs in high-impedance state. |
Key Features
| Feature | Design Value |
|---|---|
| EPIC-IIB BiCMOS process | Reduces dynamic power vs. pure bipolar while retaining TTL drive strength and speed. |
| Inverting transceiver architecture | Ensures signal polarity consistency across bus segments without external inversion logic. |
| High-impedance isolation on OE high | Prevents bus contention during hot-swap, reset, or standby modes without external switches. |
| Robust ESD immunity | Exceeds 2000 V HBM and 200 V machine model - reduces need for external TVS in moderate-noise environments. |
| Latch-up immunity | Rated >500 mA per JEDEC JESD-17 - ensures survivability during transient overcurrent events. |
Applications
| Industrial Backplane Interface | Legacy System Bus Isolation |
|---|---|
|
Use Scenario: Interfacing microcontroller local bus to extended ISA or VME-style backplane with multiple slot peripherals. IC Role / Device Role / Timing Role: Bidirectional level-shifting and bus loading isolation transceiver enabling synchronous read/write cycles between master and slave cards. Use Value: Eliminates need for discrete buffers and direction logic; 64-mA sink current drives long parallel traces without signal degradation. |
Use Scenario: Replacing failed transceivers in aging test equipment or programmable logic controllers with obsolete bus architectures. IC Role / Device Role / Timing Role: Pin-compatible functional replacement for SN74LS640/SN74ALS640 in repair and sustainment programs. Use Value: Maintains identical timing (tPLH ≤ 4.9 ns) and DC specs while improving noise margin and ESD resilience. |
| Modular I/O Expansion Chassis | TTL-Level Data Multiplexing |
|
Use Scenario: Central controller managing multiple isolated I/O modules via shared parallel bus with hot-plug capability. IC Role / Device Role / Timing Role: Direction-controlled bus gate that isolates inactive modules and prevents backfeeding during insertion/removal. Use Value: OE-driven high-Z state ensures zero current leakage between modules; DIR toggling enables full-duplex diagnostics without bus arbitration. |
Use Scenario: Sharing a single 8-bit data path among multiple ADCs, DACs, or memory banks in compact instrumentation. IC Role / Device Role / Timing Role: Time-multiplexed bidirectional data conduit controlled by FPGA or microcontroller GPIO. Use Value: Inverting logic simplifies address/data handshaking; 3-state outputs allow seamless arbitration between concurrent masters. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal 3-state bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT245DBR | Non-inverting transceiver; identical pinout, drive strength, and timing; same DB package. | Used where signal polarity preservation is required (e.g., memory data bus extension). | Select SN74ABT245DBR when A→B/B→A data must retain original logic polarity; no PCB change needed. |
| SN74LVC245APWR | 3.3-V only (1.65–3.6 V), lower drive (–24/+24 mA), smaller TSSOP-20 package (4.4 × 3.0 mm). | Suitable for mixed-voltage systems with level translation; not 5-V tolerant on I/O pins. | Choose SN74LVC245APWR only if migrating to 3.3-V logic domains; requires voltage translation for 5-V bus interfacing. |
Compared with SN74ABT640DBR, SN74ABT245DBR offers identical form-factor and drive but non-inverting functionality-ideal for polarity-critical paths-while SN74LVC245APWR enables space-constrained, low-voltage designs but sacrifices 5-V interoperability and output strength.
Availability
SN74ABT640DBR is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system bus isolation, and modular I/O expansion chassis requiring stable component supply and long-term lifecycle support.
Supply support for SN74ABT640DBR 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 delivering analog, embedded processing, and logic solutions with emphasis on reliability, longevity, and industrial-grade qualification.
The ABT logic family-including SN74ABT640-is engineered for high-speed, high-drive 5-V TTL-compatible bus interfacing in mission-critical industrial, telecom, and computing infrastructure.
FAQ
What is the function of the DIR pin on the SN74ABT640DBR?
The DIR (direction-control) pin on the SN74ABT640DBR determines data flow direction: when DIR = Low, data transfers from B bus to A bus; when DIR = High, data flows from A bus to B bus. This bidirectional control allows flexible bus arbitration without external logic, and the pin accepts standard TTL input levels (VIH ≥ 2 V, VIL ≤ 0.8 V) across the full operating temperature range.
Can SN74ABT640DBR operate with a 3.3-V supply?
No, SN74ABT640DBR is specified only for 4.5 V to 5.5 V supply operation and is not rated for 3.3-V use. Applying 3.3 V may result in marginal or non-functional behavior due to insufficient voltage headroom for internal BiCMOS circuitry. For 3.3-V systems, consider SN74LVC245APWR-but note it lacks 5-V tolerance and inverting functionality.
How should OE be handled during power-up for SN74ABT640DBR?
To guarantee high-impedance outputs at power-up or power-down, OE must be held High (disabled) via a pullup resistor to VCC. TI recommends a minimum resistor value based on the driver's current-sinking capability; typical values range from 4.7 kΩ to 10 kΩ. Leaving OE floating risks undefined output states and potential bus contention.
What is the maximum output current rating for SN74ABT640DBR?
The SN74ABT640DBR supports up to 64 mA sink current (IOL) per output and –32 mA source current (IOH) per output under recommended operating conditions. Absolute maximum ratings allow brief peaks up to 128 mA (IOL), but sustained operation above 64 mA risks thermal overload in the DB package (θJA = 115°C/W), especially with multiple outputs active.
Is SN74ABT640DBR pin-compatible with SN74LS640?
Yes, SN74ABT640DBR shares identical pinout, terminal functions, and logic behavior with SN74LS640, making it a direct drop-in upgrade. It improves upon the LS version with higher drive strength (64 mA vs. 24 mA), faster propagation (≤4.9 ns vs. ~15 ns), lower ground bounce (VOLP < 1 V), and enhanced ESD/latch-up robustness-without requiring PCB or firmware changes.
SN74ABT640DBR 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:
- 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:
- 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
SN74ABT640DBR FAQ
1.How can I place an order for SN74ABT640DBR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT640DBR 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 SN74ABT640DBR reliable?
The price and inventory of SN74ABT640DBR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT640DBR is usually 5 days.
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SN74ABT640DBR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT640DBR 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 SN74ABT640DBR?
For technical support, including SN74ABT640DBR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT640DBR requirements.
6.How does Aetrix verify that SN74ABT640DBR is sourced from the original manufacturer or authorized distributors?
All SN74ABT640DBR 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 SN74ABT640DBR meets industry standards.
7.What is the process for return or replacement of SN74ABT640DBR?
All SN74ABT640DBR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT640DBR, 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 SN74ABT640DBR part is unused and in its original packaging.
Return procedure for SN74ABT640DBR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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