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Texas Instruments SN74ABT646APWR
- Part No.:
- SN74ABT646APWR
- Manufacturer:
- Texas Instruments
- Package:
- 24-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74ABT646APWR.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:4,996
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Product details
Overview
SN74ABT646APWR 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. It enables real-time or registered data transfer between A and B buses in industrial backplane and memory interface applications.
For engineers reviewing the SN74ABT646APWR datasheet, SN74ABT646APWR pinout, SN74ABT646APWR application, or SN74ABT646APWR equivalent, key selection criteria include its 125 MHz clock frequency, 4.3 ns typical tPLH/tPHL propagation delay, TSSOP-24 package thermal resistance (88°C/W), and support for isolated register storage during OE-high states.
Technical Context
The SN74ABT646APWR integrates two independent 8-bit bidirectional transceivers, each with dedicated clock inputs (CLKAB for A→B, CLKBA for B→A) and select controls (SAB/SBA) to route either real-time or registered data. Its DIR input determines bus direction during active transfer, while OE disables all outputs into high-impedance without disabling input functionality.
It implements Ioff circuitry to block current flow when VCC = 0 V, enabling safe hot-insertion in partial-power-down systems. Latch-up immunity exceeds 500 mA per JESD-17, and ESD protection meets 2000-V HBM and 200-V MM per JESD-22.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures compatibility with standard 5-V TTL logic rails and noise margin stability |
| Max Clock Frequency | 125 MHz - supports high-speed synchronous bus arbitration in backplane and processor interface designs |
| Output Drive | −32 mA IOH / 64 mA IOL - drives heavy capacitive loads (e.g., >30 pF traces or multiple TTL inputs) without signal degradation |
| Propagation Delay | 1.5–5.6 ns (tPLH/tPHL) - enables sub-8 ns round-trip latency for time-critical register-to-bus transfers |
| Ioff Current | ±100 µA at VCC = 0 - prevents backflow damage during board-level power sequencing or hot-swap events |
| Operating Temperature | −40°C to +85°C - qualified for industrial-grade embedded control and communications equipment |
| ESD Rating | 2000-V HBM, 200-V MM - withstands handling and system-level electrostatic discharge in factory and field environments |
Pinout & Package
TSSOP-24 package (PW), 7.8 mm × 4.4 mm × 1.2 mm height, lead pitch 0.65 mm, RoHS-compliant NiPdAu finish, MSL Level-1 (260°C peak reflow).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 4–11, 13–20 | A1–A8, B1–B8 I/O | Bi-directional data terminals; internally isolated by DIR/OE state; support real-time or registered transfer |
| 12 | GND | Power ground reference for all internal logic and output drivers |
| 21 | OE | Active-low output enable - places all A/B outputs in high-Z when high; input remains functional |
| 22 | SBA | Select-B-to-A - controls whether B-bus data routed to A is real-time or from CLKBA-registered storage |
| 23 | CLKBA | Low-to-high clock edge latches B-bus data into internal register for later SBA-controlled output |
| 24 | VCC | 5-V supply input - powers all logic, registers, and output drivers; requires local 0.1 µF decoupling |
| 3 | DIR | Direction control - when OE low, determines if A drives B (DIR = H) or B drives A (DIR = L) |
| 2 | SAB | Select-A-to-B - selects real-time or CLKAB-registered A-bus data for output to B bus |
| 1 | CLKAB | Low-to-high clock edge captures A-bus data into internal register for subsequent SAB-controlled output |
Key Features
| Feature | Design Value |
|---|---|
| High-Drive Outputs | Delivers −32 mA source / 64 mA sink to maintain signal integrity across long PCB traces or multi-load buses |
| Ioff Partial-Power-Down | Disables outputs at VCC = 0 V, eliminating risk of reverse current injection during power sequencing or hot-swap |
| Dual Independent Registers | Separately clocks A→B (CLKAB) and B→A (CLKBA), enabling asynchronous bidirectional buffering without external FIFOs |
| Multiplexed Transfer Modes | Combines real-time pass-through and registered storage via SAB/SBA, supporting flexible bus arbitration and glitch-free handshaking |
| Latch-Up Immunity | Exceeds 500 mA per JEDEC JESD-17 - ensures robust operation in noisy industrial power environments |
Applications
| Backplane Data Routing | Processor-to-Peripheral Interface |
|---|---|
Use Scenario: Isolating CPU address/data buses from expansion slot peripherals while maintaining timing-critical read/write cycles. IC Role / Device Role / Timing Role: Bidirectional bus transceiver with registered hold capability; synchronizes data transfer using CLKAB/CLKBA edges aligned to CPU clock domain. Use Value: Eliminates need for discrete latches and direction logic, reducing component count and interconnect skew in modular chassis designs. | Use Scenario: Interfacing an FPGA I/O bank to legacy parallel memory (e.g., SRAM or Flash) operating at 5 V. IC Role / Device Role / Timing Role: Level-shifting and drive-strengthening transceiver; DIR and OE enable precise control of memory read/write strobes and data direction. Use Value: Provides 64 mA sink capability to meet memory data bus loading requirements while supporting Ioff for safe FPGA configuration sequencing. |
| Industrial PLC I/O Module | Test Equipment Bus Controller |
Use Scenario: Managing isolated sensor/actuator data paths in programmable logic controller backplanes with mixed-voltage subsystems. IC Role / Device Role / Timing Role: Registered bus isolator; stores sensor readings on CLKBA edge and forwards them on demand via SBA under PLC scan cycle control. Use Value: Enables deterministic sampling and synchronized reporting across distributed I/O nodes without software overhead or jitter. | Use Scenario: Controlling GPIB or VXIbus-compatible instruments where precise timing and bus contention avoidance are critical. IC Role / Device Role / Timing Role: Synchronized bus arbiter; uses DIR and OE to enforce master/slave handshaking and prevent simultaneous drive conflicts. Use Value: Guarantees sub-5 ns propagation delay consistency across all 16 bits, ensuring compliant setup/hold timing for IEEE 488.2 handshakes. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar bus transceiver applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT245APWR | Octal (8-bit), no internal registers; lacks CLKAB/CLKBA, SAB/SBA, and DIR-controlled bidirectional mode | Used only for simple unidirectional or direction-switched data transfer; cannot store or multiplex registered data | Select when register functionality is unnecessary and lower pin count/cost is prioritized |
| SN74LVTH16245ADGGR | 16-bit, 3.3-V only (VCC = 2.7–3.6 V); no Ioff; lower drive (−32/32 mA); supports 3.3-V LVTTL, not 5-V ABT | Targeted for low-voltage portable or battery-powered systems; incompatible with 5-V bus domains | Select only for 3.3-V designs requiring LVTH speed/power trade-off; not drop-in compatible |
Compared with SN74ABT245APWR and SN74LVTH16245ADGGR, the SN74ABT646APWR uniquely delivers 5-V registered bidirectional transfer with Ioff and 64-mA sink, making it irreplaceable in industrial backplanes requiring clocked arbitration and hot-swap safety.
Availability
SN74ABT646APWR is available at Aetrix Electronics and suitable for industrial backplane routing, processor-peripheral interfacing, and PLC I/O modules requiring stable component supply and long-term manufacturability.
Supply support for SN74ABT646APWR 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 heritage in industry-standard interface ICs.
The SN74ABT646APWR belongs to TI's ABT logic family, engineered for high-speed 5-V TTL-compatible bus management in industrial, computing, and instrumentation systems where drive strength, noise immunity, and power sequencing robustness are critical.
FAQ
What is the maximum clock frequency supported by the SN74ABT646APWR?
The SN74ABT646APWR supports a maximum clock frequency of 125 MHz under recommended operating conditions (VCC = 5 V, TA = 25°C). This specification applies to both CLKAB and CLKBA inputs and is validated across the full industrial temperature range (−40°C to +85°C) per the SCBS069H datasheet timing tables. The device maintains this rate with guaranteed setup/hold times and propagation delays meeting 125-MHz cycle requirements.
Does the SN74ABT646APWR support partial-power-down operation?
Yes, the SN74ABT646APWR supports partial-power-down operation via its Ioff circuitry. When VCC = 0 V, Ioff limits input/output leakage current to ±100 µA, preventing damaging current backflow through powered-down sections of the system. This feature is explicitly verified per datasheet Section "Absolute Maximum Ratings" and "Electrical Characteristics", and is essential for hot-swap and power-gated subsystem designs.
What package type is used for the SN74ABT646APWR?
The SN74ABT646APWR uses a TSSOP-24 (PW) package: 7.8 mm × 4.4 mm body, 1.2 mm max height, 0.65 mm lead pitch, RoHS-compliant NiPdAu finish, and MSL Level-1 rating (unlimited floor life at ≤30°C/60% RH). This information is confirmed in TI's Package Option Addendum and mechanical drawing PW0024A.
How does the DIR pin control data flow in the SN74ABT646APWR?
The DIR pin on the SN74ABT646APWR determines bus direction only when OE is low (outputs enabled). With DIR = HIGH, data flows from A bus to B bus; with DIR = LOW, data flows from B bus to A bus. DIR has no effect on register clocking (CLKAB/CLKBA) or select logic (SAB/SBA), which remain fully functional regardless of DIR state.
Can the SN74ABT646APWR operate at 3.3 V?
No, the SN74ABT646APWR is specified exclusively for 4.5 V to 5.5 V operation. Its ABT-family architecture requires 5-V rail compliance for guaranteed VOH/VOL levels, timing performance, and drive strength. Attempting 3.3-V operation violates recommended conditions and results in undefined behavior, including failure to meet 125-MHz timing or 64-mA IOL specifications.
SN74ABT646APWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ABT
- Package/Case:
- 24-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- 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
SN74ABT646APWR FAQ
1.How can I place an order for SN74ABT646APWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ABT646APWR 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 SN74ABT646APWR reliable?
The price and inventory of SN74ABT646APWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ABT646APWR is usually 5 days.
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SN74ABT646APWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ABT646APWR 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 SN74ABT646APWR?
For technical support, including SN74ABT646APWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ABT646APWR requirements.
6.How does Aetrix verify that SN74ABT646APWR is sourced from the original manufacturer or authorized distributors?
All SN74ABT646APWR 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 SN74ABT646APWR meets industry standards.
7.What is the process for return or replacement of SN74ABT646APWR?
All SN74ABT646APWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ABT646APWR, 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 SN74ABT646APWR part is unused and in its original packaging.
Return procedure for SN74ABT646APWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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