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Texas Instruments 74ACT11478DW
- Part No.:
- 74ACT11478DW
- Manufacturer:
- Texas Instruments
- Package:
- 28-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
74ACT11478DW.pdf
- Description:
- IC TXRX NON-INVERT 5.5V 28SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:893
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Product details
Overview
74ACT11478DW from Texas Instruments is an 8-bit dual-rank synchronizer IC designed for asynchronous data synchronization between clock domains, featuring TTL-compatible inputs, 3-state outputs, ±24 mA drive strength, 75 MHz max clock frequency, and operation from −40°C to 85°C. It resolves metastability in cross-clock-domain transfers in industrial control backplanes and FPGA-to-ASIC interface bridges.
For engineers reviewing the 74ACT11478DW datasheet, 74ACT11478DW pinout, 74ACT11478DW application, or 74ACT11478DW equivalent, key selection criteria include dual-stage metastability suppression, flow-through pinout for PCB routing efficiency, OE-controlled bus driving capability, and EPIC-process reliability at 5 V supply.
Technical Context
The 74ACT11478DW implements two cascaded 8-bit D-type flip-flop ranks with shared clock and output-enable control, where data requires two clock cycles to propagate from D to Q - a deliberate architectural choice to exponentially reduce second-stage metastability probability. Its flow-through pinout places inputs on one side and outputs on the opposite, minimizing trace crossovers.
Center-aligned VCC and GND pins (pins 14 and 15) suppress high-speed switching noise, while EPIC 1-µm CMOS process ensures 500-mA latch-up immunity at 125°C. Inputs accept TTL voltage levels (VIH = 2 V min, VIL = 0.8 V max), enabling direct interfacing with legacy 74LS logic without level shifters.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Function | 8-bit dual-rank synchronizer with 2-cycle latency for metastability mitigation |
| Supply Voltage | 4.5 V to 5.5 V - compatible with standard 5 V digital systems |
| Max Clock Frequency | 75 MHz - supports high-speed inter-domain handshaking in real-time controllers |
| Output Drive | ±24 mA - directly drives 50 Ω transmission lines or 10 LSTTL loads |
| Propagation Delay | tPLH/tPHL ≤ 11.6 ns at 5.5 V - enables sub-12 ns timing closure in synchronous paths |
| Operating Temperature | −40°C to +85°C - qualified for industrial-grade embedded systems |
| Input Compatibility | TTL-voltage compatible (VIH ≥ 2 V, VIL ≤ 0.8 V) - interoperable with 74LS/ALS families |
Pinout & Package
74ACT11478DW uses a 24-pin SOIC (DW) package with 300-mil body width and 1.27 mm pitch. Pin layout follows flow-through architecture: inputs (1D–8D, CLK, OE) on left side (pins 1–13), outputs (1Q–8Q) on right side (pins 16–23), with center-placed VCC (pin 14) and GND (pin 15) for noise reduction.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1D–8D (pins 1–8) | Data inputs | Asynchronous input signals synchronized to local clock domain |
| CLK (pin 9) | Clock input | Rising-edge-triggered master clock for both synchronizer ranks |
| OE (pin 10) | Output enable | Active-low control for 3-state output bus driving |
| VCC (pin 14) | Power supply | 5 V supply with center placement to minimize simultaneous switching noise |
| GND (pin 15) | Ground reference | Common return path aligned with VCC for low-inductance decoupling |
| 1Q–8Q (pins 16–23) | Synchronized outputs | Metastability-hardened outputs valid after two clock cycles |
Key Features
| Feature | Design Value |
|---|---|
| Dual-rank metastability suppression | Reduces probability of output failure under setup/hold violation by >10⁴× vs single flip-flop |
| Flow-through pinout | Enables straight-layer PCB routing with zero layer jumps between input and output banks |
| Center VCC/GND configuration | Lowers power-supply impedance and reduces ground bounce in high-frequency switching |
| TTL-compatible inputs | Eliminates need for external level translators when interfacing with 74LS/ALS logic families |
| 3-state bus-driving outputs | Allows direct connection to shared data buses without external buffers or isolation logic |
Applications
| Industrial PLC Backplane Sync | FPGA-to-Microcontroller Interface |
|---|---|
|
Use Scenario: Synchronizing sensor data streams from multiple I/O modules running on independent clocks into a central PLC CPU bus. IC Role / Device Role / Timing Role: Dual-rank synchronizer converting asynchronous fieldbus data to CPU clock domain with guaranteed metastability recovery. Use Value: Prevents spurious read errors during clock domain crossing, eliminating system resets caused by metastable latch-up in legacy 5 V control systems. |
Use Scenario: Bridging AXI or APB bus signals between Xilinx Artix FPGA fabric and ARM Cortex-M7 microcontroller operating at different frequencies. IC Role / Device Role / Timing Role: Hardened synchronization element for handshake signals (e.g., VALID, READY) across clock boundaries. Use Value: Enables reliable communication without custom RTL synchronizer chains, reducing FPGA resource usage and verification effort. |
| Legacy System Bus Expansion | Test Equipment Digital Pattern Generator |
|
Use Scenario: Adding new peripheral cards to a 1980s-era VMEbus system where expansion slots run on non-synchronized clocks. IC Role / Device Role / Timing Role: Data domain translator ensuring glitch-free insertion of new modules into existing 5 V TTL backplane. Use Value: Maintains signal integrity and timing compliance without redesigning motherboard clock distribution or adding complex PLLs. |
Use Scenario: Generating deterministic stimulus patterns in automated test equipment where pattern memory runs on a master clock distinct from DUT sampling clock. IC Role / Device Role / Timing Role: Synchronizing address and control bits from pattern RAM to DUT interface clock domain. Use Value: Guarantees zero-cycle uncertainty in pattern edge alignment, critical for jitter-sensitive parametric testing of high-speed interfaces. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual-rank synchronization applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74AC11478DW | AC-family: lower drive (±24 mA same), but higher ICC (max 100 µA vs 80 µA), no guaranteed latch-up immunity spec | Less robust in noisy industrial environments; not rated for 500-mA latch-up at 125°C | Select only if cost sensitivity outweighs reliability requirements in benign lab environments |
| SN74LVC1G175DBVR | Single-bit, 3.3 V only, no OE, no flow-through pinout, 175 ps typical tpd | Requires eight discrete devices plus external logic for 8-bit sync; incompatible voltage domain | Use only for low-pin-count, 3.3 V designs where board space permits replication and level translation |
Compared with 74ACT11478DW, the 74AC11478DW trades latch-up immunity for marginal speed gain, while SN74LVC1G175DBVR forces system-level redesign due to voltage and bit-width mismatch - making 74ACT11478DW the sole monolithic, 5 V, 8-bit, OE-enabled solution with certified industrial robustness.
Availability
74ACT11478DW is available at Aetrix Electronics and suitable for industrial PLC backplane synchronization, FPGA-to-microcontroller bridging, and legacy VMEbus expansion requiring stable component supply and long-term obsolescence management.
Supply support for 74ACT11478DW 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 founded in 1930, delivering analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The 74ACT11478DW belongs to TI's ACT (Advanced CMOS TTL-compatible) logic family, engineered specifically for high-reliability, noise-immune data synchronization in mixed-voltage industrial systems.
FAQ
What is the primary function of the 74ACT11478DW?
The 74ACT11478DW is an 8-bit dual-rank synchronizer IC that resolves metastability when transferring data between asynchronous clock domains. It uses two cascaded flip-flop stages so that input data appears at the output only after two clock cycles - a design that exponentially reduces the probability of metastable failure. This makes the 74ACT11478DW essential in systems like industrial PLCs and FPGA interfaces where setup/hold violations are unavoidable.
Does the 74ACT11478DW support 3.3 V operation?
No, the 74ACT11478DW is specified only for 4.5 V to 5.5 V supply operation and is not rated for 3.3 V use. Its TTL-compatible inputs (VIH ≥ 2 V, VIL ≤ 0.8 V) and EPIC CMOS process are optimized for 5 V industrial systems. Attempting 3.3 V operation risks undefined logic states, increased propagation delay, and potential functional failure - always operate the 74ACT11478DW within its published 4.5–5.5 V range.
How does the flow-through pinout of the 74ACT11478DW benefit PCB layout?
The flow-through pinout of the 74ACT11478DW places all inputs (1D–8D, CLK, OE) on the left side (pins 1–10) and all outputs (1Q–8Q) on the right side (pins 16–23), with VCC and GND centered (pins 14–15). This allows straight, layer-minimized routing - input traces enter from the left, cross the chip horizontally, and exit cleanly to the right - eliminating vias, crossovers, and stubs that degrade signal integrity in high-speed sync paths using the 74ACT11478DW.
Can the 74ACT11478DW replace a generic 74ACT574 octal latch?
No - the 74ACT11478DW is not a functional replacement for the 74ACT574. While both are 8-bit 5 V logic devices, the 74ACT574 is a transparent latch with single-stage storage and no metastability hardening. The 74ACT11478DW has dual-rank synchronization, mandatory 2-cycle latency, and dedicated OE control for bus driving - features absent in the 74ACT574. Substituting them would break timing guarantees and introduce unrecoverable metastability in async interfaces.
What is the significance of the center-placed VCC and GND pins on the 74ACT11478DW?
The center-placed VCC (pin 14) and GND (pin 15) on the 74ACT11478DW minimize simultaneous switching noise by shortening the current loop path for high-frequency transients. This layout reduces ground bounce and supply droop during fast output transitions - a critical feature for maintaining signal fidelity in systems using the 74ACT11478DW for high-reliability synchronization. It also simplifies decoupling capacitor placement directly between those adjacent pins.
74ACT11478DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 28-SOIC (0.295", 7.50mm Width)
- Packaging:
- Bulk
- 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:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 28-SOIC
74ACT11478DW FAQ
1.How can I place an order for 74ACT11478DW through Aetrix?
Please submit a Request for Quotation (RFQ) for 74ACT11478DW 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 74ACT11478DW reliable?
The price and inventory of 74ACT11478DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 74ACT11478DW is usually 5 days.
3.What payment methods are accepted for 74ACT11478DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 74ACT11478DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 74ACT11478DW?
74ACT11478DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 74ACT11478DW 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 74ACT11478DW?
For technical support, including 74ACT11478DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 74ACT11478DW requirements.
6.How does Aetrix verify that 74ACT11478DW is sourced from the original manufacturer or authorized distributors?
All 74ACT11478DW 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 74ACT11478DW meets industry standards.
7.What is the process for return or replacement of 74ACT11478DW?
All 74ACT11478DW units undergo pre-shipment inspection (PSI). If there is an issue with 74ACT11478DW, 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 74ACT11478DW part is unused and in its original packaging.
Return procedure for 74ACT11478DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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