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Texas Instruments SN74ACT574NSR
- Part No.:
- SN74ACT574NSR
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74ACT574NSR.pdf
- Description:
- IC FF D-TYPE SNGL 8BIT 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,603
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Product details
Overview
SN74ACT574NSR from Texas Instruments is an octal D-type edge-triggered flip-flop with 3-state outputs, designed for bus-oriented digital systems. It operates at 4.5–5.5 V, supports TTL-compatible inputs, delivers ≤9 ns propagation delay at 5 V, and features active-low output enable for bidirectional bus control in industrial I/O and register applications.
For engineers reviewing the SN74ACT574NSR datasheet, SN74ACT574NSR pinout, SN74ACT574NSR application, or SN74ACT574NSR equivalent, this page provides verified functional role, timing behavior under 5 V operation, 3-state drive capability for capacitive bus loads, thermal resistance (RθJA = 106.2 °C/W), and validated SOP-20 package compatibility - all critical for register buffer selection and bus interface design.
Technical Context
The SN74ACT574NSR implements eight independent D-type flip-flops synchronized to the rising edge of CLK, with simultaneous latching of all eight data inputs (D1–D8) into Q1–Q8 outputs. Its 3-state outputs are controlled by a common active-low OE input, enabling high-impedance bus release without affecting internal state retention.
It uses ACT (Advanced CMOS TTL-compatible) logic family technology, ensuring 5 V supply operation, input tolerance up to 5.5 V, and robust noise immunity. The device meets JEDEC JESD78 Class II latch-up immunity and supports –40°C to +85°C industrial temperature range with guaranteed timing across voltage and temperature.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 4.5 V to 5.5 V - Ensures stable operation across standard 5 V rail tolerances and brown-out resilience. |
| tpd (max) | 12 ns at 5 V - Enables reliable 85 MHz clock operation in synchronous register pipelines. |
| IOH/IOL | –24 mA / 24 mA - Drives standard TTL loads and moderate-capacitance buses without external buffers. |
| tsu/th | 2.5 ns setup / 1 ns hold - Tight timing margins simplify high-speed PCB layout and reduce skew sensitivity. |
| RθJA | 106.2 °C/W (NS package) - Defines thermal derating for continuous 8-bit bus driving at ambient up to 85°C. |
| ESD Rating | ±2000 V HBM - Meets industrial handling requirements without additional protection circuitry. |
| Input Compatibility | TTL-voltage compatible - Interfaces directly with legacy 74LS/74F logic without level shifters. |
Pinout & Package
SOP-20 (NS) package: 12.6 mm × 7.8 mm body size, 12.6 mm × 5.3 mm footprint, 1.75 mm max height, gull-wing leads, RoHS-compliant NiPdAu finish, MSL Level-1.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OE) | Active-low output enable | Asserts high-impedance on all Q outputs simultaneously; does not affect internal flip-flop state. |
| 2–9 (D1–D8) | Data inputs | Sampled on rising CLK edge; TTL-compatible voltage thresholds ensure interoperability with legacy logic. |
| 10 (GND) | Ground reference | Common return for logic and output drive; requires low-inductance connection to minimize ground bounce. |
| 11 (CLK) | Clock input | Rising-edge triggered; 3 ns minimum pulse width ensures reliable capture across temperature and voltage. |
| 12–19 (Q8–Q1) | 3-state outputs | Output order reversed (Q8 first) to match standard bus bit ordering; each drives ±24 mA. |
| 20 (VCC) | Positive supply | Must be bypassed with 0.1 µF ceramic capacitor placed within 3 mm of pin to suppress switching noise. |
Key Features
| Feature | Design Value |
|---|---|
| Octal D-type flip-flop with 3-state outputs | Enables single-chip implementation of 8-bit latch/buffer registers with bus contention avoidance. |
| 4.5–5.5 V operation with 5.5 V-tolerant inputs | Eliminates need for input level translation when interfacing with mixed-voltage systems or legacy 5 V peripherals. |
| ≤9 ns tpd at 5 V | Supports >85 MHz system clocks in register-to-register paths, reducing pipeline latency in control logic. |
| High-impedance output disable (OE) | Allows safe sharing of data buses among multiple SN74ACT574NSR devices without external bus arbitration. |
| Industrial temperature range (–40°C to +85°C) | Validated for use in programmable logic controllers, motor drives, and factory automation equipment. |
Applications
| Industrial PLC I/O Expansion | Legacy Bus Interface Adapter |
|---|---|
|
Use Scenario: Adding parallel digital I/O capability to a microcontroller-based PLC rack via ISA or STD bus. IC Role / Device Role / Timing Role: Acts as an 8-bit input latch and output buffer, synchronizing field signals to the controller's clock domain. Use Value: Eliminates need for discrete latches and tristate drivers; 24 mA drive strength handles relay coil loads directly. |
Use Scenario: Bridging modern FPGA-based controllers to legacy 8-bit peripheral cards using TTL-level parallel buses. IC Role / Device Role / Timing Role: Provides registered, 3-state bus transceivers that isolate and time-align data between mismatched clock domains. Use Value: 9 ns propagation delay and 2.5 ns setup time ensure clean sampling of asynchronous bus reads/writes. |
| Microcontroller Parallel Port Extension | Digital Test Equipment Data Capture |
|
Use Scenario: Expanding GPIO count on an ARM Cortex-M4 MCU for sensor array readout and actuator control. IC Role / Device Role / Timing Role: Functions as a buffered, clocked input register - capturing 8-bit sensor status on rising CLK edges. Use Value: TTL-compatible inputs accept direct connection to open-collector sensors; OE allows dynamic bus release during idle cycles. |
Use Scenario: Capturing parallel waveform data from analog-to-digital converters in automated test fixtures. IC Role / Device Role / Timing Role: Serves as a high-speed acquisition latch, freezing ADC output bits at precise trigger points. Use Value: 12 ns max tpd guarantees sub-100 MHz sampling fidelity; 85 MHz fmax supports multi-channel synchronized capture. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal D-type latch applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74ACT573NSR | Octal transparent latch (enable-controlled, not edge-triggered); identical VCC, speed, and package. | Latches data while LE is high; unsuitable for synchronous clock-domain crossing where edge-triggering is required. | Select SN74ACT574NSR when clock-synchronized sampling is mandatory; choose SN74ACT573NSR for gated-data capture. |
| 74LVC574APW | 3.3 V–5.5 V supply range; lower drive (±24 mA), same 20-pin TSSOP but thinner (1.2 mm height). | Designed for mixed-voltage 3.3 V/5 V systems; lacks 5.5 V input tolerance and has higher RθJA (126.2 °C/W). | Use 74LVC574APW only if 3.3 V core logic coexists; SN74ACT574NSR remains preferred for pure 5 V industrial environments. |
Compared with SN74ACT574NSR, SN74ACT573NSR trades edge-triggering for transparency-critical for real-time gating-but sacrifices synchronous timing control. 74LVC574APW offers voltage flexibility at the cost of reduced ruggedness and thermal performance in 5 V-only systems.
Availability
SN74ACT574NSR is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy bus interface adapters, microcontroller parallel port extension, digital test equipment data capture, and embedded register buffer applications requiring stable component supply and long-term manufacturability.
Supply support for SN74ACT574NSR 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 over 90 years of innovation in industrial, automotive, and communications markets.
The SN74ACT574NSR belongs to TI's 74ACT advanced CMOS logic family, engineered for high-speed, 5 V TTL-compatible digital interfacing in industrial control, instrumentation, and legacy system upgrades.
FAQ
What is the maximum clock frequency supported by the SN74ACT574NSR?
The SN74ACT574NSR supports a maximum clock frequency of 85 MHz under recommended operating conditions (VCC = 5 V, TA = –40°C to +85°C). This is derived from its guaranteed maximum propagation delay (tpd) of 12 ns and minimum clock pulse width (tw) of 4 ns, ensuring reliable edge-triggered operation in synchronous digital systems. The SN74ACT574NSR datasheet specifies fmax = 85 MHz in Section 4.7.
Does the SN74ACT574NSR require external pull-up resistors on the OE pin?
Yes - to ensure the outputs remain in high-impedance state during power-up or power-down, the OE pin of the SN74ACT574NSR should be tied to VCC through a pull-up resistor. TI recommends a value determined by the current-sinking capability of the driver, typically 1–10 kΩ. This prevents bus contention before system initialization completes. The SN74ACT574NSR functional description explicitly states this requirement in Section 6.1.
Can the SN74ACT574NSR drive standard TTL loads directly?
Yes - the SN74ACT574NSR can drive standard TTL loads directly. Its output drive capability is specified as IOH = –24 mA and IOL = 24 mA at VCC = 4.5 V, exceeding the –0.4 mA / 1.6 mA requirements of standard TTL inputs. Additionally, its TTL-compatible input thresholds (VIH = 2 V, VIL = 0.8 V) allow seamless interconnection with 74LS and 74F logic families without level-shifting circuitry. This is confirmed in Sections 1 and 4.3 of the SN74ACT574NSR datasheet.
What is the thermal resistance (RθJA) of the SN74ACT574NSR in its SOP-20 package?
The junction-to-ambient thermal resistance (RθJA) of the SN74ACT574NSR in the SOP-20 (NS) package is 106.2 °C/W, as specified in Section 4.4 of the official datasheet. This value assumes standard JEDEC 2S2P board conditions and is critical for calculating allowable power dissipation (e.g., ~350 mW at 85°C ambient) when driving heavy capacitive loads or operating continuously at full speed. The SN74ACT574NSR thermal metric is validated per JEDEC JESD51 standards.
Is the SN74ACT574NSR pin-compatible with other 74ACT574 variants like SN74ACT574DBR or SN74ACT574DWR?
No - the SN74ACT574NSR is not pin-compatible with SN74ACT574DBR (SSOP-20) or SN74ACT574DWR (SOIC-20), despite sharing identical logic functionality and pin numbering. Each variant uses a different physical package (SOP vs. SSOP vs. SOIC) with distinct lead pitch (0.65 mm for NS/DB, 1.27 mm for DW), body dimensions, and thermal characteristics. PCB layout must be tailored to the specific package; mechanical drawings for SN74ACT574NSR confirm 12.6 mm × 7.8 mm outline and 0.65 mm pitch per JEDEC MO-153.
SN74ACT574NSR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74ACT
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- Function:
- Standard
- Type:
- D-Type
- Output Type:
- Tri-State, Non-Inverted
- Number of Elements:
- 1
- Number of Bits per Element:
- 8
- Clock Frequency:
- 110 MHz
- Max Propagation Delay @ V, Max CL:
- 11ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 4 µA
- Input Capacitance:
- 4.5 pF
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SO
SN74ACT574NSR FAQ
1.How can I place an order for SN74ACT574NSR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74ACT574NSR 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 SN74ACT574NSR reliable?
The price and inventory of SN74ACT574NSR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74ACT574NSR is usually 5 days.
3.What payment methods are accepted for SN74ACT574NSR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74ACT574NSR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74ACT574NSR?
SN74ACT574NSR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74ACT574NSR 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 SN74ACT574NSR?
For technical support, including SN74ACT574NSR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74ACT574NSR requirements.
6.How does Aetrix verify that SN74ACT574NSR is sourced from the original manufacturer or authorized distributors?
All SN74ACT574NSR 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 SN74ACT574NSR meets industry standards.
7.What is the process for return or replacement of SN74ACT574NSR?
All SN74ACT574NSR units undergo pre-shipment inspection (PSI). If there is an issue with SN74ACT574NSR, 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 SN74ACT574NSR part is unused and in its original packaging.
Return procedure for SN74ACT574NSR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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