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Texas Instruments SN74ABT646DWR
- Part No.:
- SN74ABT646DWR
- Manufacturer:
- Texas Instruments
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74ABT646DWR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:4,421
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Product details
Overview
SN74ABT646DWR from Texas Instruments is an octal bus transceiver with dual D-type registers, direction control, and output-enable logic for bidirectional data flow between A and B buses. It supports 5-V operation, delivers ±32-mA high-drive outputs, features Ioff partial-power-down protection, and operates up to 125 MHz clock frequency in industrial temperature range (−40°C to 85°C). It is used in high-speed backplane and board-level bus isolation applications requiring register-controlled data staging.
For engineers reviewing the SN74ABT646DWR datasheet, SN74ABT646DWR pinout, SN74ABT646DWR application, or SN74ABT646DWR equivalent, key selection criteria include its dual-clock (CLKAB/CLKBA) register capture capability, real-time vs. stored-data multiplexing via SAB/SBA controls, and SOIC-24 package compatibility with legacy 5-V TTL systems.
Technical Context
The SN74ABT646DWR integrates two independent 8-bit D-type flip-flop banks synchronized to separate low-to-high clock edges (CLKAB for A→B, CLKBA for B→A), enabling asynchronous register loading from either bus. Its DIR input selects bus direction during OE-active transmission, while SAB and SBA determine whether real-time or registered data appears on the driven bus.
It implements true three-state outputs with Ioff circuitry that disables all outputs when VCC = 0 V, preventing backflow current during partial power-down. The device meets JEDEC JESD-17 latch-up immunity (>500 mA) and exceeds JESD-22 ESD ratings (2000-V HBM, 200-V MM).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Supply | 4.5 V to 5.5 V - ensures compatibility with standard 5-V TTL logic rails and noise margin compliance. |
| IOH/IOL Drive | −32 mA / +64 mA - enables direct driving of heavy capacitive loads or multiple TTL inputs without external buffers. |
| Max Clock Frequency | 125 MHz - supports high-throughput data transfer in fast synchronous bus architectures. |
| Propagation Delay | tPLH/tPHL ≤ 5.6 ns (CL = 50 pF) - guarantees sub-6-ns timing for critical setup/hold paths in 125-MHz systems. |
| Ioff Current | ±100 µA at VCC = 0 - prevents damaging reverse current flow during hot-insertion or partial system power-down. |
| Operating Temp | −40°C to +85°C - qualified for industrial-grade embedded control and communications equipment. |
| ESD Rating | 2000-V HBM, 200-V MM - provides robust handling tolerance during PCB assembly and field service. |
Pinout & Package
SN74ABT646DWR is packaged in a 24-pin SOIC (DW) body measuring 15.4 mm × 7.5 mm × 2.35 mm, with 1.27-mm lead pitch and RoHS-compliant NiPdAu lead finish (Level-1 MSL rating).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4–10, 13–20 | A1–A8, B1–B8 I/O | Bidirectional data terminals: high-impedance when OE high; driven by register or real-time bus depending on DIR/SAB/SBA state. |
| 11, 12 | NC | No internal connection - must be left unconnected per TI design guidance. |
| 3, 21, 22, 23 | DIR, OE, SAB, SBA | Control inputs: DIR sets transmit direction; OE enables/disables outputs; SAB/SBA select source (real-time or stored) for output bus. |
| 24 | VCC | Positive supply rail - requires local 0.1-µF ceramic decoupling adjacent to pin. |
| 12 | GND | Ground reference - shared return for all I/O and logic functions; must connect to low-impedance system ground plane. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent clock domains | CLKAB and CLKBA allow asynchronous registration of A- and B-bus data without cross-domain timing constraints. |
| Multiplexed output sourcing | SAB/SBA enable dynamic switching between real-time and registered data on output bus - eliminates need for external multiplexers. |
| Ioff partial-power-down support | Outputs disable safely at VCC = 0 V, allowing live insertion into powered-backplane systems without risk of backfeeding. |
| High-drive 5-V TTL-compatible outputs | −32 mA IOH / +64 mA IOL drive strength ensures signal integrity across long traces or fan-out to ≥10 standard TTL loads. |
| Robust latch-up immunity | Exceeds 500 mA per JEDEC JESD-17 - suitable for noisy industrial environments with transient coupling risks. |
Applications
| Backplane Bus Isolation | Industrial PLC I/O Module |
|---|---|
Use Scenario: Isolating CPU-side and peripheral-side data buses in modular rack-mounted systems with hot-swap capability. IC Role / Device Role / Timing Role: Bidirectional bus transceiver with register staging; DIR and OE manage direction and enable timing; CLKAB/CLKBA synchronize module data capture. Use Value: Enables deterministic data handoff between independently clocked subsystems while supporting safe hot-insertion via Ioff. | Use Scenario: Interfacing microcontroller-based logic controllers to field I/O cards with varying voltage levels and timing requirements. IC Role / Device Role / Timing Role: Level-shifting and timing-aligned bus interface; stores sensor/actuator data in registers before CPU read, reducing bus arbitration overhead. Use Value: Reduces CPU polling latency by pre-staging field data in on-chip registers, improving real-time response in deterministic control loops. |
| Test Equipment Data Capture | Legacy System Bus Extension |
Use Scenario: Capturing parallel digital waveforms from DUTs in automated test systems with precise timestamp alignment. IC Role / Device Role / Timing Role: High-speed parallel data latch and buffer; CLKAB/CLKBA align acquisition to external trigger clocks; SAB/SBA route captured vs. live data to analyzer interface. Use Value: Achieves 125-MHz sampling edge alignment and eliminates external latch ICs, shrinking PCB area and signal path skew. | Use Scenario: Extending aging 5-V TTL backplanes with new function modules while maintaining full backward compatibility. IC Role / Device Role / Timing Role: Pin-compatible bus repeater and register buffer; matches original timing specs (tSU = 3 ns, tH = 0 ns) and drive strength (64-mA IOL). Use Value: Preserves existing firmware and layout while adding register-based buffering to improve noise margin and timing margin on extended traces. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver with register applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT245DWR | Octal non-inverting transceiver without internal registers or dual-clock capability; only real-time pass-through mode. | Lacks register storage and multiplexed output sourcing - unsuitable where data staging or asynchronous capture is required. | Select when only simple bidirectional level translation is needed and clocked register functionality is unnecessary. |
| SN74LVTH16245ADGGR | 16-bit LVTTL transceiver with 3.3-V supply, lower drive (−24/+24 mA), and no Ioff or dual-clock registers. | Designed for 3.3-V systems; incompatible with 5-V bus voltages and lacks partial-power-down safety for hot-swap. | Choose only for 3.3-V mixed-signal designs where 5-V tolerance and Ioff are not required. |
Compared with SN74ABT245DWR and SN74LVTH16245ADGGR, the SN74ABT646DWR uniquely combines 5-V operation, dual-clock register capture, Ioff protection, and multiplexed output sourcing - making it the sole option among these three for applications demanding staged, isolated, and hot-pluggable bus management.
Availability
SN74ABT646DWR is available at Aetrix Electronics and suitable for industrial automation, test instrumentation, and legacy system upgrades requiring stable component supply, long-term obsolescence mitigation, and RoHS-compliant SOIC packaging.
Supply support for SN74ABT646DWR 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 connectivity solutions for industrial, automotive, and communications markets.
The SN74ABT646DWR belongs to TI's ABT logic family, designed specifically for high-speed, 5-V TTL-compatible bus management in industrial and telecom infrastructure where register-controlled data staging and robust power-down behavior are essential.
FAQ
What is the maximum clock frequency supported by SN74ABT646DWR?
The SN74ABT646DWR supports a maximum clock frequency of 125 MHz under recommended operating conditions (VCC = 5 V, TA = 25°C), as specified in the timing requirements table of the SCBS069H datasheet. This applies to both CLKAB and CLKBA inputs for register capture operations.
Does SN74ABT646DWR support partial power-down operation?
Yes, the SN74ABT646DWR includes Ioff circuitry that disables all outputs when VCC = 0 V, limiting Ioff to ±100 µA. This prevents damaging current backflow during partial-power-down scenarios such as hot-swap or staged system power sequencing.
What package type is used for SN74ABT646DWR?
SN74ABT646DWR uses a 24-pin SOIC (DW) package with dimensions 15.4 mm × 7.5 mm × 2.35 mm, 1.27-mm lead pitch, and RoHS-compliant NiPdAu lead finish. It is supplied in tape-and-reel format (2000 units per reel) with MSL Level-1 rating.
How does the SAB and SBA control logic function in SN74ABT646DWR?
In SN74ABT646DWR, SAB selects data source for bus A (real-time or stored B data), and SBA selects data source for bus B (real-time or stored A data). When SAB = L, real-time B data transfers to A; when SAB = H, stored B data transfers to A - enabling flexible multiplexed bus routing without external logic.
Is SN74ABT646DWR compatible with standard 5-V TTL logic families?
Yes, SN74ABT646DWR is fully compatible with standard 5-V TTL logic: VIH = 2 V min, VIL = 0.8 V max, VOH ≥ 2.5 V at −24 mA, VOL ≤ 0.55 V at 64 mA. Its high-drive outputs (−32/+64 mA) exceed standard TTL sink/source requirements, ensuring robust interfacing.
SN74ABT646DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ABT
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Tape & Reel (TR)
- 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-SOIC
SN74ABT646DWR FAQ
1.How can I place an order for SN74ABT646DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT646DWR 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 SN74ABT646DWR reliable?
The price and inventory of SN74ABT646DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT646DWR is usually 5 days.
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SN74ABT646DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT646DWR 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 SN74ABT646DWR?
For technical support, including SN74ABT646DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT646DWR requirements.
6.How does Aetrix verify that SN74ABT646DWR is sourced from the original manufacturer or authorized distributors?
All SN74ABT646DWR 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 SN74ABT646DWR meets industry standards.
7.What is the process for return or replacement of SN74ABT646DWR?
All SN74ABT646DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT646DWR, 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 SN74ABT646DWR part is unused and in its original packaging.
Return procedure for SN74ABT646DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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