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onsemi 74ABT646CMTCX
- Part No.:
- 74ABT646CMTCX
- Manufacturer:
- onsemi
- Package:
- 24-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
74ABT646CMTCX.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 24TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:2,582
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Product details
Overview
74ABT646CMTCX from Fairchild Semiconductor is an octal transceiver and register IC with 3-STATE outputs, designed for bidirectional data bus multiplexing between A and B buses in high-speed TTL-compatible systems. It features independent A/B registers, real-time transparent mode, stored-mode transfer, and direction-controlled data flow under OE-active-low enable. Used in backplane interfaces and memory-mapped I/O expansion where bus isolation and registered data staging are required.
For engineers reviewing the 74ABT646CMTCX datasheet, pinout, applications, or equivalent options, key selection criteria include guaranteed skew (≤2.5 ns), 64 mA sink capability per output, simultaneous switching noise control, nondestructive hot insertion support, and TSSOP-24 packaging compatible with dense PCB layouts.
Technical Context
The 74ABT646CMTCX integrates dual 8-bit D-type flip-flop registers (A and B), clocked by CPAB/CPBA, with multiplexed select logic (SAB/SBA) enabling real-time or registered data routing. Its DIR input determines bus direction during active transceiver mode, while OE controls 3-STATE output enable/disable.
It operates across −40°C to +85°C with VCC = 4.5–5.5 V, supports 200 MHz maximum clock frequency (CL = 50 pF), and guarantees propagation delays as low as 1.5 ns (tPLH/tPHL) and output disable time ≤6.0 ns. All timing specs are validated for both 50 pF and 250 pF loads.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | +4.5 V to +5.5 V - Ensures compatibility with 5 V TTL and mixed-voltage system rails. |
| Max Clock Frequency | 200 MHz - Supports high-throughput data transfer in fast bus architectures. |
| Output Sink Current | 64 mA per pin - Drives heavy capacitive loads or multiple TTL inputs without external buffers. |
| Propagation Delay | 1.5–5.6 ns (CL = 50 pF) - Enables sub-5 ns timing margins in synchronous bus designs. |
| Pin-to-Pin Skew | ≤2.5 ns (HL transitions) - Guarantees deterministic setup/hold timing across all 8 bits. |
| Hot Insertion | Nondestructive - Allows safe live insertion into powered-backplane systems without latchup risk. |
| Operating Temperature | −40°C to +85°C - Qualified for industrial-grade embedded and communications equipment. |
Pinout & Package
74ABT646CMTCX is housed in a 24-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, 4.4 mm wide, with 0.65 mm lead pitch - optimized for high-density PCB layouts and automated assembly.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| A0–A7 | Data Register A Inputs / 3-STATE Outputs | Bidirectional I/O port for A-side bus; latched on CPAB rising edge or routed transparently when enabled. |
| B0–B7 | Data Register B Inputs / 3-STATE Outputs | Bidirectional I/O port for B-side bus; latched on CPBA rising edge or routed transparently when enabled. |
| CPAB | Register Clock Input (A → B) | Rising-edge-triggered clock for loading A-bus data into A register or transferring to B bus. |
| CPBA | Register Clock Input (B → A) | Rising-edge-triggered clock for loading B-bus data into B register or transferring to A bus. |
| SAB | Select Input (A → B path) | Controls multiplexing of A-register or real-time A-bus data onto B outputs. |
| SBA | Select Input (B → A path) | Controls multiplexing of B-register or real-time B-bus data onto A outputs. |
| OE | Output Enable (Active LOW) | Global 3-STATE control: HIGH disables all A/B outputs; LOW enables transceiver/register operation. |
| DIR | Direction Control Input | Determines primary data flow direction: HIGH = A→B; LOW = B→A during transceiver mode. |
Key Features
| Feature | Design Value |
|---|---|
| Independent A/B registers | Enables concurrent storage and routing of two separate 8-bit data streams without interference. |
| Multiplexed real-time + stored data | Per-pin SAB/SBA control allows dynamic mixing of live bus signals and registered values on same output. |
| Guaranteed output skew | ≤2.5 ns max pin-to-pin skew ensures timing-critical parallel bus integrity across full temperature range. |
| 64 mA sink / 32 mA source drive | Eliminates need for external bus drivers in standard TTL fanout scenarios. |
| Nondestructive hot insertion | Prevents latchup or damage during live board replacement in telecom or server backplanes. |
Applications
| Backplane Data Multiplexing | Memory-Mapped I/O Expansion |
|---|---|
Use Scenario: Bidirectional data routing between CPU and peripheral modules across a shared backplane bus with isolation requirements. IC Role / Device Role / Timing Role: 74ABT646CMTCX acts as a registered transceiver, buffering and synchronizing data transfers while providing bus contention prevention via 3-STATE control. Use Value: Enables deterministic timing with <5.6 ns propagation delay and <2.5 ns skew, ensuring reliable handshaking at 200 MHz clock rates. |
Use Scenario: Extending microcontroller GPIOs to drive multiple peripherals (ADCs, DACs, sensors) over a shared 8-bit data bus. IC Role / Device Role / Timing Role: 74ABT646CMTCX serves as a direction-controlled bus interface with internal register staging, decoupling slow peripheral access from CPU timing. Use Value: Provides 64 mA per output to directly drive multiple TTL loads, reducing component count and layout complexity. |
| Industrial PLC I/O Module | Legacy Bus Interface Bridge |
Use Scenario: Isolating and conditioning digital I/O signals between field devices and controller logic in harsh industrial environments. IC Role / Device Role / Timing Role: 74ABT646CMTCX functions as a ruggedized bus transceiver with latchup protection and −40°C to +85°C operation. Use Value: Guaranteed simultaneous switching noise immunity and hot-insertion capability ensure reliability during field maintenance. |
Use Scenario: Bridging legacy ISA or VME bus segments with modern controllers requiring registered handshake and voltage-level translation. IC Role / Device Role / Timing Role: 74ABT646CMTCX provides registered data capture and direction-flexible transfer between mismatched subsystems. Use Value: Independent A/B registers allow asynchronous staging of data from legacy bus cycles before forwarding to high-speed host interface. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal transceiver and register applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ABT646DBR | TSSOP-24 package, identical AC/DC specs, TI-specified 200 MHz max fCLK, same pinout. | Same functional behavior and timing; qualified for automotive AEC-Q100 Grade 2 (−40°C to +105°C). | Preferred for automotive or extended-temp designs requiring AEC-Q100 compliance. |
| 74FCT646CTSO24 | SOIC-24 package, lower ICCZ (20 µA vs. 50 µA), slightly higher VOL (0.6 V @ 64 mA), same 200 MHz rating. | Higher noise margin but larger footprint; lacks nondestructive hot insertion guarantee. | Selected when SOIC mounting is preferred and hot-swap is not required. |
Compared with SN74ABT646DBR and 74FCT646CTSO24, the 74ABT646CMTCX offers identical TSSOP-24 pin compatibility and industrial temperature range, but uniquely guarantees nondestructive hot insertion - critical for modular backplane systems requiring field-replaceable units.
Availability
74ABT646CMTCX is available at Aetrix Electronics and suitable for industrial PLC I/O modules, telecom backplane interfaces, memory-mapped microcontroller expansions, and legacy bus bridge designs requiring stable component supply and long-term lifecycle support.
Supply support for 74ABT646CMTCX 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
Fairchild Semiconductor was a leading designer of high-performance analog and logic ICs, acquired by ON Semiconductor in 2016; its ABT logic family remains widely deployed in industrial and communications infrastructure.
The 74ABT646CMTCX belongs to Fairchild's Advanced BiCMOS Transceiver (ABT) product line, engineered for high-speed, low-skew, hot-pluggable bus interfacing in mission-critical industrial and telecom systems.
FAQ
What is the operating voltage range for the 74ABT646CMTCX?
The 74ABT646CMTCX operates over a supply voltage range of +4.5 V to +5.5 V, fully compatible with standard 5 V TTL logic systems. This range ensures robust noise immunity and interoperability with legacy and mixed-signal components without level-shifting circuitry.
Does the 74ABT646CMTCX support hot insertion without damage?
Yes, the 74ABT646CMTCX is explicitly specified for nondestructive hot insertion, verified by guaranteed latchup protection (±500 mA) and controlled power-up/down bus loading. This makes it suitable for live backplane upgrades in telecom and server applications where system uptime is critical.
What is the maximum clock frequency supported by the 74ABT646CMTCX?
The 74ABT646CMTCX supports a maximum clock frequency of 200 MHz under standard conditions (VCC = 5.0 V, TA = +25°C, CL = 50 pF). At full industrial temperature range (−40°C to +85°C), this rating is maintained with VCC = 4.5–5.5 V, enabling reliable high-speed bus operation.
How many pins does the 74ABT646CMTCX have, and what is its package type?
The 74ABT646CMTCX uses a 24-lead Thin Shrink Small Outline Package (TSSOP), JEDEC MO-153 compliant, with 4.4 mm body width and 0.65 mm lead pitch. This compact, surface-mount package supports high-density PCB layouts and automated reflow assembly.
What are the key timing parameters for the 74ABT646CMTCX output enable/disable function?
The 74ABT646CMTCX guarantees tPZH (enable time) ≤6.3 ns and tPHZ (disable time) ≤6.0 ns under industrial conditions (VCC = 4.5–5.5 V, CL = 50 pF). These tight 3-STATE timing specs ensure minimal bus turnaround latency in bidirectional communication protocols.
74ABT646CMTCX Specifications
- Product attributes
- Attribute value
- Manufacturer:
- onsemi
- 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
74ABT646CMTCX FAQ
1.How can I place an order for 74ABT646CMTCX through Aetrix?
Please submit a Request for Quotation (RFQ) for 74ABT646CMTCX 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 74ABT646CMTCX reliable?
The price and inventory of 74ABT646CMTCX are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ABT646CMTCX is usually 5 days.
3.What payment methods are accepted for 74ABT646CMTCX?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ABT646CMTCX transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74ABT646CMTCX?
74ABT646CMTCX orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74ABT646CMTCX 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 74ABT646CMTCX?
For technical support, including 74ABT646CMTCX datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ABT646CMTCX requirements.
6.How does Aetrix verify that 74ABT646CMTCX is sourced from the original manufacturer or authorized distributors?
All 74ABT646CMTCX 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 74ABT646CMTCX meets industry standards.
7.What is the process for return or replacement of 74ABT646CMTCX?
All 74ABT646CMTCX units undergo pre-shipment inspection (PSI). If there is an issue with 74ABT646CMTCX, 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 74ABT646CMTCX part is unused and in its original packaging.
Return procedure for 74ABT646CMTCX:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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