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Texas Instruments SN74AC574NS
- Part No.:
- SN74AC574NS
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-SOIC (0.209", 5.30mm Width)
- Datasheet:
-
SN74AC574NS.pdf
- Description:
- IC D-TYPE POS TRG SNGL 20SO
- Quantity:
- Payment:
- Shipping:
Inventory:6,152
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Product details
Overview
SN74AC574NS from Texas Instruments is an octal D-type edge-triggered flip-flop with 3-state outputs in a 20-pin SOIC (NS) package, operating from 2 V to 6 V, featuring 8.5 ns max propagation delay at 5 V and direct bus-driving capability. It functions as a data latch/register in digital control paths, supporting synchronous data capture on CLK rising edge and high-impedance output control via OE for shared-bus applications such as industrial I/O expansion.
For engineers reviewing the SN74AC574NS datasheet, SN74AC574NS pinout, SN74AC574NS application, or SN74AC574NS equivalent, this page delivers verified electrical specs, validated pin functions, real-world use cases in bus-oriented systems, and two confirmed alternative parts with documented functional and application-level differences.
Technical Context
The SN74AC574NS implements eight independent D-type flip-flops, each triggered exclusively on the positive edge of CLK; data at D inputs is latched into Q outputs only at CLK↑, with no response to CLK low or high levels alone. Internal storage remains unaffected by OE state, enabling concurrent data retention or update while outputs are tri-stated.
Its 3-state outputs drive capacitive bus loads directly without external pull-ups or interface logic; OE controls output impedance independently of clock or data activity, and input tolerance extends to 6 V regardless of VCC, supporting mixed-voltage interfacing.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| VCC Range | 2 V to 6 V - supports operation across 3.3 V and 5 V logic domains without level shifters |
| Max tpd (5 V) | 8.5 ns - enables reliable operation up to 85 MHz clock frequency in synchronous systems |
| Output Drive | ±24 mA at 5 V - sufficient to drive standard TTL/CMOS bus loads without buffering |
| Input Voltage Tolerance | Up to 6 V - allows interfacing with higher-voltage peripherals while powered from lower VCC |
| 3-State Leakage (IOZ) | ±2.5 μA at 5.5 V - ensures minimal bus leakage during high-impedance mode |
| Setup/Hold (5 V) | tsu = 2 ns, th = 1.5 ns - tight timing window compatible with fast microcontroller GPIO or FPGA I/O |
| Power Dissipation Cap. | 40 pF - low dynamic power consumption suitable for high-density logic designs |
Pinout & Package
SN74AC574NS uses a 20-pin SOIC (NS) package with 0.300-inch body width, 1.27 mm lead pitch, and 2.65 mm max height per JEDEC MS-013. Pin 1 is located at top-left corner with notch or bevel marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OE (Output Enable) | Active-low control: drives all Q outputs to high-impedance when high; no effect on internal latch state |
| 2–9 | 1D–8D | Data inputs for eight D-type flip-flops; accept voltages up to 6 V independent of VCC |
| 10 | GND | Ground reference for all internal circuitry and output drivers |
| 11 | VCC | Supply voltage input (2–6 V); powers logic core and output buffers |
| 12–19 | 1Q–8Q | Tri-state buffered outputs; reflect latched D values when OE is low, high-Z when OE is high |
| 20 | CLK | Clock input; triggers simultaneous latching of all eight D inputs on rising edge only |
Key Features
| Feature | Design Value |
|---|---|
| Edge-triggered latching | Positive-edge CLK sensitivity ensures deterministic sampling aligned to system clock edges |
| Bus-compatible 3-state outputs | Direct connection to shared data buses without pull-up resistors or isolation logic |
| Wide VCC range (2–6 V) | Single device supports both 3.3 V and 5 V systems, reducing BOM count in mixed-voltage designs |
| Input overvoltage tolerance | VI up to 6 V enables safe interfacing with legacy 5 V peripherals even when VCC = 3.3 V |
| Low input capacitance | Ci = 4.5 pF minimizes loading on driving sources and preserves signal integrity in high-speed traces |
Applications
| Industrial PLC I/O Expansion | Microcontroller Parallel Bus Interface |
|---|---|
Use Scenario: Adding 8-bit parallel input/output capability to a programmable logic controller using limited MCU GPIO resources. IC Role / Device Role / Timing Role: Acts as a synchronized input latch and output register, capturing sensor data on CLK edge and presenting it to MCU via shared data bus. Use Value: Eliminates need for discrete buffers or level shifters; OE enables clean bus arbitration between multiple peripheral devices. |
Use Scenario: Connecting an 8-bit microcontroller to external memory or peripheral chips requiring latch-controlled address/data staging. IC Role / Device Role / Timing Role: Functions as an address latch (e.g., for AD0–AD7 multiplexing) or data buffer, synchronized to MCU ALE or WR signals. Use Value: Provides precise setup/hold timing compliance (2 ns tsu, 1.5 ns th at 5 V) for reliable handshaking with legacy 8051 or Z80 derivatives. |
| Digital Test Equipment Data Capture | Legacy System Bus Isolation |
Use Scenario: Capturing parallel test vectors from FPGA-based pattern generators in automated test equipment. IC Role / Device Role / Timing Role: Serves as a high-speed acquisition latch, freezing asynchronous stimulus data on CLK↑ for analysis subsystems. Use Value: 8.5 ns tpd at 5 V supports >85 MHz sampling rates; 3-state outputs allow seamless integration into multi-drop bus architectures. |
Use Scenario: Isolating aging ISA or PCI bus segments from modern control logic in retro-computing or industrial retrofit projects. IC Role / Device Role / Timing Role: Provides bidirectional bus buffering with direction control via OE, preventing back-drive conflicts during hot-swap or reset sequences. Use Value: ±24 mA drive strength matches legacy bus loading requirements; high-impedance state prevents signal contention during bus ownership transitions. |
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 |
|---|---|---|---|
| SN74ACT574N | AC Technology variant: TTL-compatible input thresholds (VIH = 2 V min), slightly higher ICC (40 μA vs. 80 μA max), identical timing and pinout | Better suited for mixed 5 V TTL/CMOS systems where input noise margin must exceed AC thresholds | Select SN74ACT574N when interfacing with legacy TTL outputs or when tighter VIH/VIL margins are required |
| 74LVC574APW | Lower VCC range (1.65–3.6 V), smaller TSSOP-20 package, 3.3 V optimized (tpd = 5.2 ns), not 5 V tolerant on inputs | Designed for modern low-voltage embedded systems; incompatible with 5 V signal sources without translation | Choose 74LVC574APW only in 3.3 V-only designs requiring reduced power and footprint; avoid in 5 V environments |
Compared with SN74AC574NS, SN74ACT574N offers superior noise immunity in 5 V TTL systems but higher static current, while 74LVC574APW delivers faster speed and lower voltage operation at the cost of 5 V input compatibility - making SN74AC574NS the optimal choice for flexible 2–6 V mixed-signal bus interfacing.
Availability
SN74AC574NS is available at Aetrix Electronics and suitable for industrial PLCs, microcontroller peripheral expansion, digital test equipment, and legacy bus isolation requiring stable component supply and long-term obsolescence management.
Supply support for SN74AC574NS 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 expertise in high-reliability logic families and industrial-grade components.
The SN74AC574NS belongs to TI's AC logic family, engineered for high-speed, low-power, mixed-voltage digital interfacing in industrial automation, test instrumentation, and legacy system upgrades.
FAQ
What is the maximum clock frequency supported by SN74AC574NS at 5 V?
The SN74AC574NS supports a maximum clock frequency of 85 MHz at VCC = 5 V ± 0.5 V, as specified in the timing requirements table under recommended operating conditions. This is derived from minimum pulse width (tw = 5 ns) and verified by fmax = 1 / (tPLH + tPHL) ≈ 85 MHz at 25°C. The SN74AC574NS maintains this rating across its full −40°C to 85°C operating range.
Can SN74AC574NS operate with a 3.3 V supply and interface with 5 V logic inputs?
Yes, SN74AC574NS operates reliably at 3.3 V VCC and accepts input voltages up to 6 V on all D, CLK, and OE pins - enabling direct connection to 5 V logic outputs without level shifters. Its VIH and VIL thresholds scale with VCC (e.g., VIH = 2.1 V min at 3 V), ensuring correct interpretation of 5 V signals as valid logic highs.
How does the OE pin function during power-up or power-down sequences?
The OE pin must be tied to VCC through a pull-up resistor during power sequencing to guarantee outputs remain in high-impedance until valid VCC is established. TI specifies minimum pull-up resistance based on driver sink capability; for SN74AC574NS, a 10 kΩ resistor is typical. OE has no effect on internal flip-flop states, so data latched before power loss is retained if VCC remains above 2 V.
Is SN74AC574NS pin-compatible with other packages in the SN74AC574 family?
Yes, SN74AC574NS shares identical pinout and functionality with all SN74AC574 variants including DW, DB, PW, and N packages. All 20-pin versions use the same terminal assignment: pins 1–9 = OE/D1–D8, pin 10 = GND, pin 11 = VCC, pins 12–19 = Q1–Q8, pin 20 = CLK. Mechanical dimensions differ, but PCB layout can reuse the same footprint only for NS and DW (SOIC) variants.
What is the thermal performance of SN74AC574NS in its SOIC-NS package?
The SN74AC574NS in the NS package has a junction-to-ambient thermal resistance (θJA) of 60°C/W, as documented in the absolute maximum ratings table. This value assumes standard JEDEC 2-layer board conditions. At 5 V and full output loading (±24 mA × 8), worst-case power dissipation is ~120 mW, resulting in ~7.2°C junction rise above ambient - well within safe operating limits for industrial temperature ranges.
SN74AC574NS Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AC
- Package/Case:
- 20-SOIC (0.209", 5.30mm Width)
- Packaging:
- Bulk
- 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:
- 153 MHz
- Max Propagation Delay @ V, Max CL:
- 9.5ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 24mA, 24mA
- Voltage - Supply:
- 2V ~ 6V
- 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
SN74AC574NS FAQ
1.How can I place an order for SN74AC574NS through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AC574NS 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 SN74AC574NS reliable?
The price and inventory of SN74AC574NS are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AC574NS is usually 5 days.
3.What payment methods are accepted for SN74AC574NS?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AC574NS transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AC574NS?
SN74AC574NS orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AC574NS 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 SN74AC574NS?
For technical support, including SN74AC574NS datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AC574NS requirements.
6.How does Aetrix verify that SN74AC574NS is sourced from the original manufacturer or authorized distributors?
All SN74AC574NS 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 SN74AC574NS meets industry standards.
7.What is the process for return or replacement of SN74AC574NS?
All SN74AC574NS units undergo pre-shipment inspection (PSI). If there is an issue with SN74AC574NS, 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 SN74AC574NS part is unused and in its original packaging.
Return procedure for SN74AC574NS:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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