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Texas Instruments SN74ABT640NSR
- Part No.:
- SN74ABT640NSR
- Manufacturer:
- Texas Instruments
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ABT640NSR.pdf
- Description:
- IC TXRX INVERT 5.5V 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,383
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Product details
Overview
SN74ABT640NSR from Texas Instruments is an octal bus transceiver with 3-state outputs, designed for asynchronous bidirectional data transfer between A and B buses in 5-V TTL-compatible systems. It features high-drive capability (–32 mA IOH / 64 mA IOL), low ground bounce (<1 V VOLP), and operates across –40°C to 85°C. Used in backplane interface logic and legacy industrial control bus isolation.
For engineers reviewing the SN74ABT640NSR datasheet, SN74ABT640NSR pinout, SN74ABT640NSR application, or SN74ABT640NSR equivalent, key selection criteria include direction-control (DIR) and output-enable (OE) logic behavior, 20-pin SOP (NS) package thermal performance (θJA = 105°C/W per TI characterization), and compatibility with 5-V CMOS/TTL bus loading requirements.
Technical Context
The SN74ABT640NSR implements dual 8-bit bidirectional data paths controlled by DIR (data flow direction) and OE (output enable/disable). Its EPIC-IIB BiCMOS process enables fast switching (tPLH/tPHL ≤ 4.9 ns at 5 V, CL = 50 pF) while maintaining low static current (ICC ≤ 30 mA active, ≤ 250 µA disabled).
It supports true 3-state isolation with IOFF ≤ ±100 µA when VCC = 0 V, and meets MIL-STD-883 ESD ratings (>2000 V HBM, >200 V MM). Input hysteresis (VHYST = 100 mV) ensures noise immunity on control lines.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures robust operation under 5-V rail tolerance and brownout conditions. |
| IOL / IOH | 64 mA / –32 mA - Drives heavy capacitive loads (e.g., long PCB traces or multiple TTL inputs) without signal degradation. |
| tPLH / tPHL | 1 ns (min) to 4.9 ns (max) at 5 V - Enables reliable timing in 100+ MHz bus systems with 50-pF load. |
| VOL / VOH | 0.55 V (at 64 mA) / 2.0 V (at –32 mA) - Guarantees TTL-compatible logic thresholds under full drive. |
| VIH / VIL | 2.0 V / 0.8 V - Matches standard TTL input thresholds for seamless interfacing with legacy logic families. |
| θJA (NS package) | 105°C/W - Derived from TI's SOP-20 (NS) thermal model; informs heatsink/no-airflow derating in enclosed enclosures. |
| ESD Rating | >2000 V HBM - Reduces risk of handling damage during manual assembly or field service. |
Pinout & Package
SOP-20 (NS) package: 12.8 mm × 7.5 mm body, 1.27 mm pitch, gull-wing leads, RoHS-compliant NiPdAu finish, MSL Level-1 (260°C reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | DIR | Direction control: Low = B→A, High = A→B; must be stable before data valid to avoid bus contention. |
| 2–9 | A1–A8 | Input/output port A - Bidirectional data pins tied to local bus; high-impedance when OE = High. |
| 10 | GND | Ground reference - Shared return path for all signals; requires low-inductance connection to minimize ground bounce. |
| 11 | VCC | 5-V supply - Decoupling capacitor (0.1 µF ceramic) required within 5 mm for stable switching performance. |
| 12 | OE | Output enable: Low = active, High = 3-state; tie to VCC via pullup resistor (≥10 kΩ) for power-up isolation. |
| 13–20 | B1–B8 | Input/output port B - Mirrored bidirectional port for remote bus; electrically identical to A-side. |
Key Features
| Feature | Design Value |
|---|---|
| Inverting transceiver architecture | Transfers inverted data between A and B buses - simplifies parity generation and differential signaling interfaces. |
| High-drive BiCMOS outputs | –32 mA source / +64 mA sink capability - eliminates need for external buffer stages in high-fanout backplane designs. |
| Low ground bounce (VOLP < 1 V) | Minimizes simultaneous switching noise - critical for mixed-signal systems where analog sections share ground plane. |
| Wide temperature range (–40°C to 85°C) | Validated for industrial ambient operation - supports deployment in uncontrolled cabinet environments without forced cooling. |
| 3-state isolation with IOFF ≤ ±100 µA | Enables hot-swap capability and safe bus sharing among multiple masters - prevents leakage-induced logic faults during power sequencing. |
Applications
| Industrial Backplane Interface | Legacy System Bus Isolation |
|---|---|
|
Use Scenario: Interfacing a microcontroller-based control module to a legacy 8-bit ISA-style backplane carrying sensor and actuator data. IC Role / Device Role / Timing Role: Bidirectional bus transceiver managing data flow between local CPU bus (A-side) and shared backplane (B-side), synchronized by DIR/OE handshaking. Use Value: Eliminates level-shifting and buffering components while supporting 64-mA drive needed for 20+ daisy-chained peripheral slots. |
Use Scenario: Isolating two independent 5-V TTL subsystems during firmware update to prevent bus contention or corruption. IC Role / Device Role / Timing Role: 3-state gate enabling/disabling communication paths; OE driven by system supervisor IC to enforce atomic bus access windows. Use Value: Prevents metastability and latch-up during partial power-down sequences, verified per JEDEC JESD-17 (latch-up >500 mA). |
| Test Equipment Data Capture | Programmable Logic Interface |
|
Use Scenario: Capturing parallel digital waveforms from DUTs using a logic analyzer with limited channel count, requiring multiplexed bus sampling. IC Role / Device Role / Timing Role: Direction-controlled data funnel routing selected 8-bit segments from multiple DUT buses into a single acquisition path. Use Value: Leverages DIR-driven inversion to encode bus ID in data stream, reducing need for additional address decoding logic. |
Use Scenario: Connecting FPGA I/O banks to fixed-function ASICs with mismatched drive strength or timing margins. IC Role / Device Role / Timing Role: Signal conditioning layer providing deterministic propagation delay (tPLH/tPHL = 1–4.9 ns) and noise-immune inputs (100-mV hysteresis). Use Value: Compensates for FPGA output skew and ensures setup/hold compliance on ASIC inputs without custom timing constraints. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT245NSR | Non-inverting architecture; identical drive strength, timing, and package. | Requires inverted control logic for DIR function; unsuitable where data polarity must be preserved end-to-end. | Select SN74ABT245NSR only when system-level data inversion is acceptable or compensated elsewhere. |
| SN74LVC8T245PW | 3.3-V only operation; lower drive (–24/+24 mA); 1.65–3.6-V VCC range. | Not compatible with 5-V TTL buses; requires level translation if interfacing to legacy 5-V peripherals. | Choose SN74LVC8T245PW only in new 3.3-V-only designs with no 5-V interface requirements. |
Compared with SN74ABT640NSR, SN74ABT245NSR offers identical 5-V performance but lacks data inversion, while SN74LVC8T245PW reduces power and voltage headroom at the cost of 5-V interoperability - making SN74ABT640NSR the sole choice for legacy 5-V bus bridging with polarity control.
Availability
SN74ABT640NSR is available at Aetrix Electronics and suitable for industrial backplane interface, legacy system bus isolation, and programmable logic interface applications requiring stable component supply and long-term lifecycle support.
Supply support for SN74ABT640NSR 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 over 50 years of innovation in industrial and automotive electronics.
The ABT logic family, including SN74ABT640NSR, was engineered for high-speed, high-drive 5-V TTL-compatible bus interfacing in mission-critical industrial and telecom infrastructure equipment.
FAQ
What is the maximum operating temperature range for SN74ABT640NSR?
The SN74ABT640NSR is characterized for operation from –40°C to +85°C ambient temperature. This industrial-grade rating is validated per TI's recommended operating conditions and supports deployment in unventilated control cabinets, factory-floor PLC modules, and outdoor telecom enclosures without active thermal management.
Does SN74ABT640NSR support hot-swap or live insertion?
Yes, SN74ABT640NSR supports hot-swap operation due to its IOFF specification (±100 µA at VCC = 0 V) and robust ESD protection (>2000 V HBM). When VCC is absent, all I/Os remain high-impedance and non-disruptive to the powered bus - a key requirement for modular backplane systems using SN74ABT640NSR.
What is the correct power-up sequence for SN74ABT640NSR to ensure 3-state isolation?
To guarantee high-impedance outputs at power-up, OE must be held high until VCC stabilizes. TI recommends tying OE to VCC through a pullup resistor ≥10 kΩ. This ensures the device enters isolation mode before any A/B bus signals become active, preventing bus contention during power ramp - a behavior confirmed in the SN74ABT640NSR function table and application guidance.
Can SN74ABT640NSR drive a 50-pF load at 100 MHz?
While SN74ABT640NSR switching specs (tPLH/tPHL ≤ 4.9 ns) are tested at CL = 50 pF and 5 V, sustained 100-MHz toggling requires verifying total dynamic current (ICC ≈ 30 mA max) and thermal dissipation in the NS package (θJA = 105°C/W). At 100 MHz with 50-pF load, average power exceeds 150 mW - feasible in still-air environments but may require airflow or derating above 70°C ambient.
Is SN74ABT640NSR pin-compatible with other 20-pin bus transceivers like SN74LS245?
No, SN74ABT640NSR is not pin-compatible with SN74LS245. Although both are 20-pin octal transceivers, SN74ABT640NSR places DIR on Pin 1 and OE on Pin 12, whereas SN74LS245 uses Pin 1 for OE and Pin 19 for DIR. Physical layout, drive strength, and timing differ significantly - direct replacement would require PCB redesign and logic-level validation.
SN74ABT640NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ABT
- Package/Case:
- 20-SOIC (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-SO
SN74ABT640NSR FAQ
1.How can I place an order for SN74ABT640NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT640NSR 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 SN74ABT640NSR reliable?
The price and inventory of SN74ABT640NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT640NSR is usually 5 days.
3.What payment methods are accepted for SN74ABT640NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ABT640NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ABT640NSR?
SN74ABT640NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT640NSR 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 SN74ABT640NSR?
For technical support, including SN74ABT640NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT640NSR requirements.
6.How does Aetrix verify that SN74ABT640NSR is sourced from the original manufacturer or authorized distributors?
All SN74ABT640NSR 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 SN74ABT640NSR meets industry standards.
7.What is the process for return or replacement of SN74ABT640NSR?
All SN74ABT640NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT640NSR, 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 SN74ABT640NSR part is unused and in its original packaging.
Return procedure for SN74ABT640NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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