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Texas Instruments SN74ABT646APW
- Part No.:
- SN74ABT646APW
- Manufacturer:
- Texas Instruments
- Package:
- 24-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74ABT646APW.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:345
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Product details
Overview
SN74ABT646APW from Texas Instruments is a 16-bit bus transceiver with dual D-type registers, direction control (DIR), output enable (OE), and clocked multiplexing (CLKAB/CLKBA, SAB/SBA). It supports high-drive outputs (−32 mA IOH, 64 mA IOL), Ioff partial-power-down operation, and operates at 5 V over −40°C to 85°C. Used in bidirectional data buffering and register-controlled bus isolation in industrial backplanes and legacy computing interfaces.
For engineers reviewing the SN74ABT646APW datasheet, SN74ABT646APW pinout, SN74ABT646APW application, or SN74ABT646APW equivalent, key selection criteria include its 125 MHz clock frequency, real-time vs. registered transfer modes, TSSOP-24 package thermal resistance (88°C/W), and compatibility with 5-V TTL-level systems requiring latch-up immunity (>500 mA) and ESD protection (2000-V HBM).
Technical Context
This device integrates two independent 8-bit buses (A1–A8 and B1–B8), dual edge-triggered D-type flip-flops per channel, and combinational logic for four bus-management functions: real-time A→B/B→A transfer, storage from either bus, and simultaneous output of stored data to A and/or B. Clock inputs CLKAB and CLKBA trigger latching on low-to-high transitions.
Control logic uses DIR to select data flow direction when OE is active low, while SAB/SBA select between transparent and registered data paths. In isolation mode (OE high), registers retain stored data without bus loading. Ioff circuitry disables outputs during power-down to prevent backflow current.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5-V TTL and CMOS systems without level-shifting. |
| Max Clock Frequency | 125 MHz - enables high-speed synchronous bus interfacing in legacy PCI, ISA, or custom parallel architectures. |
| IOH / IOL Drive | −32 mA / 64 mA - provides robust noise margin and fan-out capability for driving multiple TTL loads or long traces. |
| Propagation Delay | 1.5 ns to 5.6 ns - guarantees sub-8 ns worst-case timing for setup/hold-critical synchronous designs. |
| Ioff Current | ±100 µA at VCC = 0 - prevents damaging current flow during hot-insertion or partial system power-down sequences. |
| ESD Rating | 2000-V HBM - meets industrial-grade reliability requirements for handling and board assembly environments. |
| Latch-Up Immunity | >500 mA per JEDEC JESD-17 - ensures robustness against transient-induced parasitic thyristor activation. |
Pinout & Package
TSSOP-24 package (PW), 7.8 mm × 4.4 mm × 1.2 mm max height, lead pitch 0.65 mm, exposed pad not present, RoHS-compliant NiPdAu finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4–11, 13–20, 22–24 | A1–A8, B1–B8 I/O | Bidirectional data terminals; high-impedance when OE high or direction mismatched; support real-time or registered transfer. |
| 3 | DIR | Direction control: low enables B→A transfer, high enables A→B transfer when OE is low. |
| 12 | OE | Output enable: low activates transceiver function; high places all outputs in high-Z state while preserving register contents. |
| 21 | CLKAB | Clock for latching data from B bus into A-side register on rising edge. |
| 23 | CLKBA | Clock for latching data from A bus into B-side register on rising edge. |
| 2, 22 | SAB, SBA | Select inputs: control whether output reflects real-time or stored data; SAB selects A-side source, SBA selects B-side source. |
| 24 | VCC | 5-V power supply connection; decoupling capacitor required within 1 cm for stable high-speed operation. |
| 12 | GND | Ground reference for all logic and I/O; shared return path requires low-inductance layout to minimize ground bounce (<1 V typical). |
Key Features
| Feature | Design Value |
|---|---|
| Dual 8-bit registered transceivers | Enables independent capture and synchronized release of A and B bus data-critical for protocol bridging and FIFO-like buffering. |
| Ioff partial-power-down support | Allows safe insertion/removal in live backplanes by disabling outputs when VCC = 0, eliminating risk of backdrive damage. |
| 125 MHz maximum clock rate | Supports high-throughput data movement in legacy high-speed parallel interfaces without requiring external PLLs or clock doublers. |
| High-current drive (64 mA sink) | Drives 10+ standard TTL loads directly, reducing need for external buffers in dense PCB layouts. |
| Four-mode bus management | Real-time transfer, storage, isolation, and stored-data output provide flexible data routing without external glue logic. |
Applications
| Industrial Backplane Interface | Legacy Computing Bus Bridge |
|---|---|
Use Scenario: Interfacing FPGA-based control modules to aging PLC I/O racks using parallel address/data buses. IC Role / Device Role / Timing Role: Bidirectional registered transceiver managing timing-aligned data transfers between asynchronous domains with programmable direction and clock gating. Use Value: Eliminates need for discrete latches and direction logic; 125 MHz clock tolerance accommodates jitter-prone industrial clocks. |
Use Scenario: Adapting modern microcontroller peripherals to ISA or PC/104 expansion slots requiring 16-bit data handshaking. IC Role / Device Role / Timing Role: Bus interface IC providing registered data staging, direction control, and output enable sequencing aligned to ISA STROBE and IOR/IOW signals. Use Value: Enables direct connection to 5-V ISA bus without level shifters; Ioff protects MCU during slot hot-swap events. |
| Test Equipment Data Capture | Automated Test System (ATE) Fixture |
Use Scenario: Capturing parallel digital waveforms from DUTs under test using high-speed logic analyzers with limited onboard memory depth. IC Role / Device Role / Timing Role: High-drive registered buffer capturing and holding snapshot data on CLKAB/CLKBA edges before serial upload. Use Value: 64-mA IOL drives long cables to analyzer inputs; low propagation delay (<5.6 ns) preserves signal integrity at 100+ MHz sampling rates. |
Use Scenario: Isolating and conditioning signals between ATE controller and mixed-voltage DUT boards during functional testing. IC Role / Device Role / Timing Role: Direction-controllable isolation barrier with register hold capability to synchronize test vector application and response capture. Use Value: OE-controlled high-Z state prevents bus contention during test reconfiguration; latch-up immunity ensures reliability across thousands of test cycles. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT245APW | Octal (8-bit), no internal registers; lacks CLKAB/CLKBA, SAB/SBA, and dual-register architecture. | Suitable only for simple unidirectional/bidirectional buffering-not for clocked storage or multiplexed transfer. | Select when real-time-only transfer suffices and board space allows separate latch ICs. |
| SN74LVC16245APAG | 16-bit, 3.3-V only (1.65–3.6 V), no Ioff, lower drive (−24/+24 mA), no clocked register functionality. | Requires level translation for 5-V systems; cannot replace SN74ABT646APW in registered or hot-swap contexts. | Choose only for new 3.3-V designs where cost and power efficiency outweigh legacy interface needs. |
Compared with SN74ABT245APW and SN74LVC16245APAG, the SN74ABT646APW uniquely delivers integrated clocked registration, 5-V operation with Ioff, and four-mode bus control-making it irreplaceable in applications demanding synchronized data capture, partial-power-down safety, and backward-compatible 5-V signaling.
Availability
SN74ABT646APW is available at Aetrix Electronics and suitable for industrial backplane interfaces, legacy computing bus bridges, test equipment data capture, and automated test system fixtures requiring stable component supply across extended product lifecycles.
Supply support for SN74ABT646APW 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 90 years of innovation in industrial, automotive, and communications markets.
The ABT logic family-including SN74ABT646APW-is engineered for high-speed, 5-V TTL-compatible applications requiring robust drive strength, latch-up immunity, and partial-power-down resilience in mission-critical infrastructure.
FAQ
What is the maximum operating temperature range for the SN74ABT646APW?
The SN74ABT646APW is rated for operation from −40°C to +85°C ambient temperature. This industrial-grade range ensures reliable performance in factory automation controllers, test equipment enclosures, and outdoor telecom infrastructure where thermal cycling occurs. The TSSOP-24 package's 88°C/W θJA supports this rating with appropriate PCB copper area and airflow.
Does the SN74ABT646APW support hot-swap or partial-power-down operation?
Yes, the SN74ABT646APW supports partial-power-down via its Ioff circuitry, which limits current to ±100 µA when VCC = 0 V and any input or output is biased ≤4.5 V. This feature enables safe insertion into live backplanes and prevents backdrive damage-critical for modular industrial systems where SN74ABT646APW serves as an interface buffer.
How does the SN74ABT646APW differ from standard octal transceivers like the SN74ABT245APW?
The SN74ABT646APW integrates dual 8-bit D-type registers, clock inputs (CLKAB/CLKBA), and select controls (SAB/SBA) enabling four distinct bus-management modes-including real-time transfer, storage, isolation, and stored-data output. In contrast, the SN74ABT245APW offers only basic bidirectional buffering with no clocked storage, making SN74ABT646APW essential for synchronized data capture applications.
What is the recommended power-supply decoupling for the SN74ABT646APW in high-speed operation?
TI recommends a 0.1 µF ceramic capacitor placed within 1 cm of the SN74ABT646APW VCC (pin 24) and GND (pin 12) pins, plus a bulk 4.7 µF tantalum or ceramic capacitor near the power entry point. This minimizes ground bounce (<1 V typical) and sustains 64-mA IOL drive during fast edge transitions-especially critical when multiple SN74ABT646APW devices share a rail in backplane designs.
Can the SN74ABT646APW be used in 3.3-V systems?
No-the SN74ABT646APW is specified only for 4.5 V to 5.5 V operation and is not 3.3-V tolerant. Applying 3.3 V to VCC results in undefined logic thresholds and degraded drive strength. For 3.3-V systems, TI's SN74LVC16245A or SN74ALVCH16245A are functionally similar alternatives-but neither provides the clocked register features or Ioff capability of the SN74ABT646APW.
SN74ABT646APW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ABT
- Package/Case:
- 24-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- Product Status:
- Active
- Logic Type:
- Transceiver, Non-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:
- 24-TSSOP
SN74ABT646APW FAQ
1.How can I place an order for SN74ABT646APW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT646APW 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 SN74ABT646APW reliable?
The price and inventory of SN74ABT646APW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT646APW is usually 5 days.
3.What payment methods are accepted for SN74ABT646APW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ABT646APW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ABT646APW?
SN74ABT646APW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT646APW 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 SN74ABT646APW?
For technical support, including SN74ABT646APW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT646APW requirements.
6.How does Aetrix verify that SN74ABT646APW is sourced from the original manufacturer or authorized distributors?
All SN74ABT646APW 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 SN74ABT646APW meets industry standards.
7.What is the process for return or replacement of SN74ABT646APW?
All SN74ABT646APW units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT646APW, 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 SN74ABT646APW part is unused and in its original packaging.
Return procedure for SN74ABT646APW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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