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Texas Instruments SN74ABT640N
- Part No.:
- SN74ABT640N
- Manufacturer:
- Texas Instruments
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74ABT640N.pdf
- Description:
- IC TXRX INVERT 5.5V 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:1,482
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Product details
Overview
SN74ABT640N from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses. It features inverted data transmission, ±32-mA high-drive outputs (IOH/IOL), 5-V supply operation, and operates from –40°C to 85°C. Used in legacy industrial control backplanes and board-level bus isolation.
For engineers reviewing the SN74ABT640N datasheet, SN74ABT640N pinout, SN74ABT640N application, or SN74ABT640N equivalent, this page delivers verified electrical specs, DIR/OE logic behavior, thermal resistance (67°C/W), and direct alternatives for bus interface redesigns requiring TTL-compatible drive strength and 3-state isolation.
Technical Context
The SN74ABT640N implements a dual-directional 8-bit transceiver with active-low output enable (OE) and direction-control (DIR) inputs. Its EPIC-IIB BiCMOS process enables high-current drive (–32 mA IOH, 64 mA IOL) while maintaining low ground bounce (<1 V VOLP) at 5 V.
Operation is defined by the function table: OE = L enables bidirectional transfer (DIR = L routes B→A; DIR = H routes A→B); OE = H forces all outputs into high-impedance. Input thresholds are TTL-compatible (VIL = 0.8 V, VIH = 2 V), and unused inputs must be tied high or low per JEDEC recommendations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures compatibility with standard 5-V TTL and CMOS systems without level-shifting. |
| IOH / IOL | –32 mA / 64 mA - Delivers robust drive capability for heavy capacitive loads on legacy backplane buses. |
| tPLH / tPHL | 1 ns to 4.9 ns - Supports reliable data rates up to ~100 MHz in short-trace, low-capacitance configurations. |
| θJA | 67°C/W (PDIP-N package) - Enables stable operation at full drive current without forced airflow in industrial enclosures. |
| VOL / VOH | 0.55 V @ 64 mA / 2.0 V @ –32 mA - Guarantees noise margins >0.4 V under worst-case loading per TTL standards. |
| VIK | –1.2 V - Provides negative input clamp protection exceeding MIL-STD-883 requirements. |
| ESD Rating | >2000 V HBM - Meets industrial handling requirements without additional external protection. |
Pinout & Package
SN74ABT640N uses a 20-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width and through-hole mounting. Thermal resistance θJA = 67°C/W supports continuous operation at full output drive in ambient temperatures up to 85°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (DIR) | Direction control input | Low = B-bus data routed to A-bus; High = A-bus data routed to B-bus; TTL-compatible threshold. |
| 2–9 (A1–A8) | A-side data I/O | Inverted data path: A1 connects to B1 with polarity inversion; all pins support 64-mA sink capability. |
| 10 (GND) | Ground reference | Primary return path for all output currents; requires low-impedance PCB plane connection. |
| 11 (VCC) | Power supply | 5-V nominal supply; bypass capacitor (0.1 µF) required within 10 mm of pin for stable switching. |
| 12 (OE) | Output enable input | Active-low; tie to VCC via pullup resistor at power-up to ensure high-Z state during sequencing. |
| 13–20 (B1–B8) | B-side data I/O | Inverted mirror of A-side; identical drive strength and voltage thresholds as A pins. |
Key Features
| Feature | Design Value |
|---|---|
| Inverted bidirectional data path | Ensures signal integrity across mismatched bus impedances by reducing simultaneous switching noise. |
| High-drive BiCMOS outputs | –32 mA source / 64 mA sink eliminates need for external buffer stages in 5-V backplane interfaces. |
| Low ground bounce (VOLP < 1 V) | Maintains valid logic levels during fast edge transitions, critical for multi-drop bus reliability. |
| TTL-compatible input thresholds | VIH = 2 V / VIL = 0.8 V allows direct interfacing with legacy 74LS/74F logic without level translation. |
| Latch-up immunity >500 mA | Complies with JEDEC JESD-17, enabling safe operation in electrically noisy industrial environments. |
Applications
| Industrial Backplane Interface | Legacy System Bus Isolation |
|---|---|
|
Use Scenario: Isolating CPU and peripheral modules on a 5-V ISA-style backplane with shared address/data lines. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing A-bus (CPU side) and B-bus (peripheral side) with direction controlled by system address decoder. Use Value: Eliminates contention during DMA cycles using OE-controlled 3-state isolation and provides 64-mA drive for 10+ load capacitance. |
Use Scenario: Replacing failed 74LS245 units in aging test equipment where PCB layout cannot be modified. IC Role / Device Role / Timing Role: Pin-compatible octal transceiver delivering higher drive strength and lower propagation delay than LS-family equivalents. Use Value: Restores signal integrity on long traces without changing routing; operates over full industrial temperature range (–40°C to 85°C). |
| Microcontroller Expansion Bus | Programmable Logic Interface |
|
Use Scenario: Extending GPIO count of an 8-bit MCU to drive parallel LCD, keypad, or sensor arrays. IC Role / Device Role / Timing Role: Data bridge between MCU port and external peripherals, with DIR set statically and OE toggled per transaction. Use Value: Enables software-configurable read/write direction without external logic; high sink current drives LED segments directly. |
Use Scenario: Interfacing CPLD/FPGA I/O banks to 5-V legacy logic in hybrid digital systems. IC Role / Device Role / Timing Role: Level-adapting transceiver providing robust 5-V signaling to FPGA I/Os configured for 5-V tolerant mode. Use Value: Prevents damage from bus contention during configuration; ESD rating exceeds 2000 V HBM for handling safety. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT245N | Non-inverting data path; identical drive strength, timing, and package. | Required when bus protocol mandates non-inverted data flow (e.g., memory-mapped peripherals). | Select SN74ABT245N only if signal polarity matching is mandatory; otherwise SN74ABT640N provides inherent noise reduction via inversion. |
| SN74LVC245APWR | 3.3-V only operation; 24-mA drive; smaller TSSOP-20 package; no 5-V tolerance. | Suitable for modern low-voltage designs but incompatible with 5-V buses without level shifters. | Choose SN74LVC245APWR for new 3.3-V systems prioritizing size/power; retain SN74ABT640N for 5-V legacy integration. |
Compared with SN74ABT245N, SN74ABT640N provides signal inversion that reduces simultaneous switching noise on shared buses; versus SN74LVC245APWR, it maintains full 5-V compatibility and higher drive strength at the cost of larger PDIP footprint and higher static current.
Availability
SN74ABT640N is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy system upgrades, and microcontroller expansion buses requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for SN74ABT640N 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 industry-standard logic families.
The SN74ABT640N belongs to TI's ABT-series advanced bi-directional transceivers, engineered for high-noise-immunity 5-V bus interfacing in industrial, computing, and communications infrastructure.
FAQ
What is the operating temperature range for SN74ABT640N?
The SN74ABT640N is characterized for operation from –40°C to +85°C, making it suitable for industrial environments where ambient conditions exceed commercial-grade limits. This range is confirmed in the recommended operating conditions table of the SCBS104C datasheet and applies specifically to the N-package variant. The SN74ABT640N does not support the extended military range (–55°C to 125°C) reserved for the SN54ABT640 variant.
Does SN74ABT640N support 3.3-V operation?
No, SN74ABT640N is specified only for 4.5 V to 5.5 V supply operation. Its input thresholds, output drive strength, and internal BiCMOS structure are optimized for 5-V TTL compatibility. Attempting to operate SN74ABT640N at 3.3 V may result in undefined logic states, insufficient output swing, or excessive ICC. For 3.3-V systems, consider SN74LVC245A instead.
How should OE and DIR be handled during power-up for SN74ABT640N?
To guarantee high-impedance outputs at power-up, OE must be held high (inactive) via a pullup resistor to VCC; the minimum value depends on the driver's sink capability but is typically ≥4.7 kΩ. DIR may be left floating only if externally controlled-however, TI recommends tying unused control inputs to VCC or GND to prevent metastability. The SN74ABT640N datasheet explicitly states that OE should be pulled up to avoid bus contention during supply ramp.
What is the maximum capacitive load SN74ABT640N can drive reliably?
SN74ABT640N switching characteristics are specified with CL = 50 pF, and propagation delays remain within datasheet limits up to this load. While its 64-mA IOL supports heavier loads, signal integrity degrades beyond ~75 pF due to increased rise/fall times and ground bounce. For loads exceeding 50 pF, verify timing margins using the tPLH/tPHL max values (4.9 ns) and account for trace capacitance in layout. The SN74ABT640N is not rated for transmission line driving.
Is SN74ABT640N pin-compatible with SN74LS245N?
Yes, SN74ABT640N shares identical 20-pin PDIP (N) footprint, pin numbering, and basic functional mapping (DIR, OE, A/B ports) with SN74LS245N. However, SN74ABT640N provides inverted data transfer versus non-inverting in the LS245, and delivers significantly higher drive strength (64 mA vs. 24 mA). No PCB changes are needed for drop-in replacement, but firmware or logic must accommodate polarity inversion.
SN74ABT640N Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ABT
- 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:
- 32mA, 64mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74ABT640N FAQ
1.How can I place an order for SN74ABT640N through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT640N 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 SN74ABT640N reliable?
The price and inventory of SN74ABT640N are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT640N is usually 5 days.
3.What payment methods are accepted for SN74ABT640N?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ABT640N transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ABT640N?
SN74ABT640N orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT640N 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 SN74ABT640N?
For technical support, including SN74ABT640N datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT640N requirements.
6.How does Aetrix verify that SN74ABT640N is sourced from the original manufacturer or authorized distributors?
All SN74ABT640N 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 SN74ABT640N meets industry standards.
7.What is the process for return or replacement of SN74ABT640N?
All SN74ABT640N units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT640N, 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 SN74ABT640N part is unused and in its original packaging.
Return procedure for SN74ABT640N:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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