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Texas Instruments SN74LVTH646DWG4
- Part No.:
- SN74LVTH646DWG4
- Manufacturer:
- Texas Instruments
- Package:
- 24-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74LVTH646DWG4.pdf
- Description:
- IC TXRX NON-INVERT 3.6V 24SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:3,771
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Product details
Overview
SN74LVTH646DWG4 from Texas Instruments is a 3.3-V octal bus transceiver with registers, dual-clock control (CLKAB/CLKBA), direction control (DIR), and output enable (OE), supporting mixed-mode 5-V/3.3-V interfacing in backplane and motherboard data paths. It features bus-hold on all A/B data inputs, Ioff for hot insertion, and operates down to 2.7 V.
For engineers reviewing the SN74LVTH646DWG4 datasheet, SN74LVTH646DWG4 pinout, SN74LVTH646DWG4 application, or SN74LVTH646DWG4 equivalent, key selection criteria include its 24-pin SOIC-DW package, 150-MHz clock frequency, 64-mA sink capability, bus-hold functionality eliminating external resistors, and support for isolated register storage of A- and B-bus data.
Technical Context
The SN74LVTH646DWG4 integrates eight bidirectional data channels with independent D-type flip-flop registers per bus, enabling simultaneous or selective latching of A- or B-side data on low-to-high clock transitions. Its dual-clock architecture (CLKAB for A→B, CLKBA for B→A) allows asynchronous capture from either bus into dedicated storage.
Control logic combines OE (global output disable), DIR (transmission direction), and SAB/SBA (select between real-time or stored data), permitting four distinct operational modes: real-time transfer, stored-data transfer, isolation with hold, and concurrent A/B register loading. Bus-hold circuitry actively maintains valid logic levels on floating A/B inputs without external components.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Operating Range | 2.7 V to 3.6 V - supports unregulated battery operation and stable 3.3-V rail tolerance. |
| Max Clock Frequency | 150 MHz - enables high-speed synchronous bus management in memory interfaces and FPGA interconnects. |
| IOL / IOH | 64 mA / −32 mA - drives standard TTL loads directly without buffering in mixed-voltage systems. |
| Bus-Hold Current | ±500 µA at VCC = 3.6 V - actively retains logic state on unused A/B inputs, eliminating pullup/pulldown resistors. |
| tPLH / tPHL (A↔B) | 1.3–4.1 ns at VCC = 2.7 V - ensures sub-5-ns transparent path delay for real-time data routing. |
| Ioff Leakage | ±100 µA at VCC = 0 V - prevents backflow current during hot insertion or partial power-down. |
| Input Voltage Tolerance | Up to 5.5 V - accepts 5-V TTL signals while powered from 3.3-V VCC, enabling legacy system interfacing. |
Pinout & Package
SN74LVTH646DWG4 is housed in a 24-pin SOIC (DW) package, 7.5 mm × 15.4 mm body, 1.27 mm pitch, with gull-wing leads and RoHS-compliant NiPdAu finish. Pin 1 index located at top-left corner with beveled edge marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4–10, 14–20 | A1–A8, B1–B8 Data I/O | Bidirectional data terminals with bus-hold; each functions as input or output depending on DIR/OE state. |
| 3 | DIR | Direction control: low enables B→A transfer; high enables A→B transfer when OE is low. |
| 11 | OE | Output enable: low activates transceiver outputs; high forces all outputs to high-impedance, retaining register contents. |
| 12, 13 | CLKAB, CLKBA | Edge-triggered clocks: CLKAB latches A-bus data into B-register; CLKBA latches B-bus into A-register. |
| 21, 22 | SAB, SBA | Select controls: determine whether transceiver outputs drive real-time or registered A/B data. |
| 23, 24 | GND, VCC | Power terminals: VCC must be 2.7–3.6 V; GND reference for all I/O and internal logic. |
Key Features
| Feature | Design Value |
|---|---|
| Mixed-mode voltage interface | Accepts 5-V TTL inputs and drives 5-V loads while operating from 3.3-V VCC - eliminates level-shifters in hybrid systems. |
| Hot-insertion support | Ioff and power-up 3-state prevent backdrive and bus contention during live board replacement in telecom and server backplanes. |
| Integrated bus-hold | Active termination on all 16 A/B data lines holds floating inputs at valid logic levels - removes need for 16 external resistors. |
| Dual-register architecture | Independent A- and B-bus registers allow concurrent storage, enabling time-stamped data capture and glitch-free switching. |
| Low ground bounce | VOLP < 0.8 V at VCC = 3.3 V - reduces noise coupling in dense PCB layouts with multiple switching outputs. |
Applications
| Backplane Data Routing | FPGA-to-ASIC Interface |
|---|---|
|
Use Scenario: High-speed parallel data exchange between line cards in modular telecom chassis using shared backplane buses. IC Role / Device Role / Timing Role: Bidirectional bus transceiver with register staging, synchronizing data transfers between asynchronous clock domains via CLKAB/CLKBA. Use Value: Enables deterministic latency through register capture and eliminates metastability risk by decoupling source and destination timing. |
Use Scenario: Interfacing Xilinx Kintex FPGA I/O banks (3.3-V tolerant) to legacy ASICs requiring 5-V TTL signaling. IC Role / Device Role / Timing Role: Level-translating transceiver with bus-hold, providing robust signal integrity across voltage domains without external biasing. Use Value: Reduces BOM count by replacing discrete level shifters and pull resistors while maintaining 150-MHz throughput. |
| Industrial PLC I/O Module | Test Equipment Bus Controller |
|
Use Scenario: Isolating and buffering sensor/actuator data between microcontroller subsystems and field I/O connectors subject to ESD and cable noise. IC Role / Device Role / Timing Role: Hot-pluggable bus interface with Ioff protection and latch-up immunity (>500 mA), managing transient fault conditions. Use Value: Prevents damage during live module swaps and sustains operation under brownout (down to 2.7 V) in factory environments. |
Use Scenario: Controlling multi-channel digital stimulus/response in automated test equipment where precise data capture timing and bus arbitration are critical. IC Role / Device Role / Timing Role: Register-based bus manager capturing real-time A/B data on clock edges, then selectively forwarding stored values under SAB/SBA control. Use Value: Supports deterministic test vector replay and synchronized sampling across 16-bit wide data paths with sub-5-ns skew. |
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 |
|---|---|---|---|
| SN74LVC16245ADGGR | 16-bit non-latching transceiver, no internal registers or dual-clock control; lower drive (24 mA), no bus-hold. | Lacks register storage and real-time/stored multiplexing - suitable only for simple level-shifted pass-through, not time-critical capture. | Choose when cost and pin count are prioritized over timing control and data staging capability. |
| SN74ALVCH162244DGGR | 16-bit buffer (unidirectional), no transceiver function, no clock inputs, includes bus-hold but no DIR/OE register coordination. | Cannot perform bidirectional transfer or isolate A/B buses - limited to fixed-direction signal conditioning in memory buffers. | Use only for static, single-direction fanout expansion where bidirectional flow and clocked capture are unnecessary. |
Compared with SN74LVC16245ADGGR and SN74ALVCH162244DGGR, the SN74LVTH646DWG4 uniquely delivers synchronized dual-bus register capture, real-time/stored data selection, and mixed-voltage robustness - making it irreplaceable in applications requiring deterministic timing, hot-swap resilience, and legacy interface compatibility.
Availability
SN74LVTH646DWG4 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, telecom backplane routing, and FPGA-to-ASIC interface designs requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for SN74LVTH646DWG4 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 expertise in high-reliability interface ICs for industrial and communications infrastructure.
The SN74LVTH646DWG4 belongs to TI's LVTH logic family, engineered for mixed-voltage system integration - specifically targeting backplane, motherboard, and modular equipment designs needing robust 3.3-V operation with 5-V signal compatibility.
FAQ
What is the maximum clock frequency supported by the SN74LVTH646DWG4?
The SN74LVTH646DWG4 supports a maximum clock frequency of 150 MHz across its recommended operating range (VCC = 2.7 V to 3.6 V). This rating applies to both CLKAB and CLKBA inputs and is verified under load conditions with CL = 50 pF. At 2.7 V, timing margins remain sufficient for reliable register capture without derating.
Does the SN74LVTH646DWG4 require external pullup or pulldown resistors on its A/B data lines?
No, the SN74LVTH646DWG4 does not require external pullup or pulldown resistors on its A1–A8 or B1–B8 data lines. It incorporates active bus-hold circuitry that maintains valid logic states on floating inputs, with ±500 µA dynamic hold current at VCC = 3.6 V. Using external resistors with this feature is explicitly discouraged in the datasheet.
Can the SN74LVTH646DWG4 operate safely with a 5-V input signal while powered from a 3.3-V supply?
Yes, the SN74LVTH646DWG4 is explicitly designed for mixed-mode operation: it accepts 5-V TTL-level inputs (VI up to 5.5 V) while powered from a 3.3-V VCC supply. This capability is confirmed in the Absolute Maximum Ratings and Recommended Operating Conditions tables, enabling direct interfacing with legacy 5-V logic without external level shifters.
What package type and lead finish does the SN74LVTH646DWG4 use?
The SN74LVTH646DWG4 uses a 24-pin SOIC (DW) package with dimensions 7.5 mm × 15.4 mm, 1.27 mm lead pitch, and RoHS-compliant NiPdAu (NIPDAU) lead finish. It is rated MSL Level-1 with unlimited floor life and qualified for reflow at 260°C peak temperature, per JEDEC J-STD-020.
How does the SN74LVTH646DWG4 support hot insertion in live systems?
The SN74LVTH646DWG4 supports hot insertion via two integrated features: Ioff circuitry disables outputs when VCC = 0 V, preventing damaging back-current flow; and power-up 3-state ensures outputs remain high-impedance during power ramp-up/down. Both mechanisms are validated per JESD78 and JESD22 standards, making SN74LVTH646DWG4 suitable for telecom line cards and server backplanes.
SN74LVTH646DWG4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LVTH
- Package/Case:
- 24-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- Product Status:
- Discontinued at Digi-Key
- 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:
- 2.7V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 24-SOIC
SN74LVTH646DWG4 FAQ
1.How can I place an order for SN74LVTH646DWG4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LVTH646DWG4 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 SN74LVTH646DWG4 reliable?
The price and inventory of SN74LVTH646DWG4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LVTH646DWG4 is usually 5 days.
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SN74LVTH646DWG4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LVTH646DWG4 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 SN74LVTH646DWG4?
For technical support, including SN74LVTH646DWG4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LVTH646DWG4 requirements.
6.How does Aetrix verify that SN74LVTH646DWG4 is sourced from the original manufacturer or authorized distributors?
All SN74LVTH646DWG4 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 SN74LVTH646DWG4 meets industry standards.
7.What is the process for return or replacement of SN74LVTH646DWG4?
All SN74LVTH646DWG4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LVTH646DWG4, 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 SN74LVTH646DWG4 part is unused and in its original packaging.
Return procedure for SN74LVTH646DWG4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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