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Texas Instruments SN74ABT646ANSR
- Part No.:
- SN74ABT646ANSR
- Manufacturer:
- Texas Instruments
- Package:
- 24-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ABT646ANSR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 24SO
- Quantity:
- Payment:
- Shipping:
Inventory:4,400
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Product details
Overview
SN74ABT646ANSR from Texas Instruments is a 16-bit bus transceiver with dual D-type flip-flop registers, direction control (DIR), output enable (OE), and multiplexed clocking (CLKAB/CLKBA) for bidirectional data routing between A and B buses. It delivers high-drive outputs (−32 mA IOH, 64 mA IOL), supports partial-power-down via Ioff, and operates from −40°C to 85°C at 4.5–5.5 V. It enables real-time or registered data transfer in industrial backplane and memory interface applications.
For engineers reviewing the SN74ABT646ANSR datasheet, SN74ABT646ANSR pinout, SN74ABT646ANSR application, or SN74ABT646ANSR equivalent, key selection factors include its 125 MHz clock frequency, 24-pin SOP (NS) package, Ioff-enabled power-down isolation, bus-hold capability during power sequencing, and compatibility with TTL-level control inputs.
Technical Context
This device integrates two independent 8-bit register banks with separate clock inputs (CLKAB for A→B storage, CLKBA for B→A storage), enabling synchronous capture of data from either bus. Its DIR input selects bus direction during transceiver mode, while OE disables all outputs without affecting input functionality.
The SAB/SBA select controls allow mixing of transparent (real-time) and registered data paths - for example, driving stored B-bus data onto A-bus while accepting live A-bus inputs. All control inputs (DIR, OE, SAB, SBA, CLKAB, CLKBA) are TTL-compatible and fully specified for operation across the full supply range (4.5–5.5 V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures robust operation under noisy industrial rail conditions and compatibility with standard 5-V logic systems. |
| Max Clock Frequency | 125 MHz - supports high-speed synchronous bus arbitration in data acquisition and communications subsystems. |
| Output Drive | −32 mA IOH / 64 mA IOL - provides strong fanout capability for driving multiple TTL loads or long PCB traces without external buffers. |
| Ioff Support | Yes - prevents backflow current during partial power-down, enabling safe hot-swap and power-gating in modular systems. |
| Operating Temperature | −40°C to +85°C - qualified for extended-temperature industrial environments including factory automation and transportation electronics. |
| Propagation Delay | 1.5 ns to 5.6 ns - guarantees tight timing margins for setup/hold compliance in 100+ MHz synchronous designs. |
| ESD Rating | 2000-V HBM - meets industrial-grade ESD immunity requirements without additional protection circuitry. |
Pinout & Package
The SN74ABT646ANSR is housed in a 24-pin SOP (Small Outline Package) per JEDEC MS-012, with 0.65 mm lead pitch and body dimensions of 7.9 mm × 4.5 mm × 1.75 mm max height. Pin 1 is located at the top-left corner with a molded index notch.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | A1–A8 Data Inputs/Outputs | Bi-directional A-bus terminals; function as inputs when DIR = HIGH and OE = LOW, outputs otherwise. |
| 9, 10, 11, 12, 13, 14, 15, 16 | B1–B8 Data Inputs/Outputs | Bi-directional B-bus terminals; function as inputs when DIR = LOW and OE = LOW, outputs otherwise. |
| 17 | GND | Ground reference for all internal logic and I/O circuits. |
| 18 | VCC | Primary 5-V supply connection; decoupling capacitor required within 1 cm. |
| 19 | CLKAB | Clock input triggering storage of A-bus data into internal register for later B-bus output. |
| 20 | CLKBA | Clock input triggering storage of B-bus data into internal register for later A-bus output. |
| 21 | DIR | Direction control: HIGH enables A→B data flow; LOW enables B→A data flow during transceiver mode. |
| 22 | SBA | Select-B-A: when LOW, routes stored B-bus data to A-bus; when HIGH, enables real-time B→A transfer. |
| 23 | SAB | Select-A-B: when LOW, routes stored A-bus data to B-bus; when HIGH, enables real-time A→B transfer. |
| 24 | OE | Output Enable: LOW activates transceiver outputs; HIGH forces all A/B outputs into high-impedance state. |
Key Features
| Feature | Design Value |
|---|---|
| Dual 8-bit register banks | Enables independent, clock-synchronized capture of A- and B-bus data for deterministic latency and glitch-free handshaking. |
| Real-time + registered multiplexing | Allows concurrent use of live and latched data streams - e.g., forwarding real-time sensor inputs while outputting buffered command responses. |
| Ioff partial-power-down | Disables outputs and blocks reverse current when VCC = 0 V, supporting safe insertion/removal in powered-backplane systems. |
| TTL-compatible control inputs | Accepts standard 0.8 V / 2.0 V logic thresholds without level-shifting, simplifying integration with legacy microcontrollers and FPGAs. |
| High noise immunity | 100 mV input hysteresis and ground-bounce <1 V reduce susceptibility to switching noise in dense PCB layouts. |
Applications
| Industrial Backplane Interface | Memory-Mapped Peripheral Bridge |
|---|---|
Use Scenario: Connecting isolated controller and I/O module cards across a shared 16-bit parallel backplane with strict timing and hot-swap requirements. IC Role / Device Role / Timing Role: Bidirectional bus transceiver with registered data path; synchronizes asynchronous card-to-card transfers using CLKAB/CLKBA edges. Use Value: Eliminates metastability risk via synchronous register staging and supports safe card insertion via Ioff isolation during partial power-down. | Use Scenario: Interfacing an FPGA's memory-mapped peripheral bus to external SRAM or flash with address/data multiplexing constraints. IC Role / Device Role / Timing Role: Direction-controlled transceiver buffering address/data lines; DIR and OE coordinate read/write cycles with FPGA control logic. Use Value: High-drive outputs ensure signal integrity over 10+ cm traces; 125 MHz clock support matches FPGA system clock domains. |
| Programmable Logic I/O Expansion | Legacy Microcontroller Bus Extension |
Use Scenario: Expanding GPIO count of a CPLD by connecting its local bus to a remote I/O bank via ribbon cable or flex PCB. IC Role / Device Role / Timing Role: Registered transceiver providing setup/hold margin for slow CPLD clocks; SAB/SBA selects between immediate or delayed I/O updates. Use Value: 3 ns setup time and 0 ns hold time at 5 V simplify timing closure; low ground bounce (<1 V) prevents logic errors on shared ground planes. | Use Scenario: Adding external peripherals (ADCs, DACs, displays) to an 8051-based system where the microcontroller lacks sufficient native I/O pins. IC Role / Device Role / Timing Role: Level-translating and buffering interface between 5-V microcontroller bus and mixed-voltage peripherals. Use Value: TTL-compatible inputs eliminate need for external level shifters; Ioff protects microcontroller ports during peripheral power sequencing. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT245DBR | Octal (8-bit), no internal registers; only real-time transceiver mode; lacks CLKAB/CLKBA, SAB/SBA, and DIR-controlled registered transfer. | Best suited for simple unidirectional or bidirectional data pass-through without storage or clocked arbitration. | Select when registered functionality is unnecessary and board space or cost optimization is prioritized over synchronous bus management. |
| SN74LVC16245ADGGR | 16-bit, no internal registers; 3.3-V only (1.65–3.6 V); lower drive (−24 mA / 24 mA); no Ioff or ground-bounce spec. | Designed for modern low-voltage digital systems; incompatible with 5-V buses without level translation. | Choose for 3.3-V FPGA or ASIC interfaces requiring compact 48-pin TSSOP; not drop-in replaceable for 5-V SN74ABT646ANSR designs. |
Compared with SN74ABT245DBR and SN74LVC16245ADGGR, the SN74ABT646ANSR uniquely combines 16-bit width, dual-clock register staging, and 5-V robustness - making it irreplaceable in applications demanding synchronized, glitch-free, hot-pluggable bus arbitration.
Availability
SN74ABT646ANSR is available at Aetrix Electronics and suitable for industrial backplane interfaces, memory-mapped peripheral bridges, and programmable logic I/O expansion requiring stable component supply, long-term lifecycle support, and guaranteed traceable sourcing.
Supply support for SN74ABT646ANSR 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 for industrial, automotive, and communications markets.
The ABT logic family, including SN74ABT646ANSR, was engineered for high-speed, noise-immune 5-V bus interfacing in mission-critical industrial control and instrumentation systems.
FAQ
What is the maximum operating frequency of the SN74ABT646ANSR?
The SN74ABT646ANSR supports a maximum clock frequency of 125 MHz under recommended operating conditions (VCC = 5 V, TA = 25°C). This applies to both CLKAB and CLKBA inputs and is validated across the full industrial temperature range (−40°C to +85°C) with appropriate load capacitance (CL = 50 pF).
Does the SN74ABT646ANSR support partial power-down?
Yes, the SN74ABT646ANSR features Ioff circuitry that disables outputs and blocks damaging current backflow when VCC = 0 V. This allows safe partial-power-down operation in modular systems - for example, powering down a peripheral card while the backplane remains active - without risking latch-up or damage to adjacent components.
What package type is used for the SN74ABT646ANSR?
The SN74ABT646ANSR uses a 24-pin SOP (Small Outline Package) with JEDEC MO-153 compliance, marked as "NS" in TI documentation. It has a 0.65 mm lead pitch, body size of 7.9 mm × 4.5 mm, and maximum height of 1.75 mm - optimized for automated assembly and high-density PCB layouts.
How does the DIR pin control data flow in the SN74ABT646ANSR?
The DIR pin determines bus direction during transceiver mode (OE = LOW): when DIR = HIGH, data flows from A-bus to B-bus; when DIR = LOW, data flows from B-bus to A-bus. DIR has no effect in isolation mode (OE = HIGH), where both buses remain in high-impedance state regardless of DIR state.
Can the SN74ABT646ANSR operate with mixed voltage interfaces?
No, the SN74ABT646ANSR is a 5-V-only device with recommended supply range 4.5–5.5 V and TTL-compatible input thresholds. It does not support level translation or mixed-voltage operation. For interfacing with 3.3-V or lower systems, external level shifters or a compatible LVC-family part like SN74LVC16245ADGGR must be used instead of the SN74ABT646ANSR.
SN74ABT646ANSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ABT
- Package/Case:
- 24-SOIC (0.209", 5.30mm 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-SO
SN74ABT646ANSR FAQ
1.How can I place an order for SN74ABT646ANSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT646ANSR 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 SN74ABT646ANSR reliable?
The price and inventory of SN74ABT646ANSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT646ANSR is usually 5 days.
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4.How is shipping managed for SN74ABT646ANSR?
SN74ABT646ANSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT646ANSR 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 SN74ABT646ANSR?
For technical support, including SN74ABT646ANSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT646ANSR requirements.
6.How does Aetrix verify that SN74ABT646ANSR is sourced from the original manufacturer or authorized distributors?
All SN74ABT646ANSR 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 SN74ABT646ANSR meets industry standards.
7.What is the process for return or replacement of SN74ABT646ANSR?
All SN74ABT646ANSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT646ANSR, 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 SN74ABT646ANSR part is unused and in its original packaging.
Return procedure for SN74ABT646ANSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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