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Texas Instruments SN74HCT574NE4
- Part No.:
- SN74HCT574NE4
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74HCT574NE4.pdf
- Description:
- IC FF D-TYPE SNGL 8BIT 20DIP
- Quantity:
- Payment:
- Shipping:
Inventory:3,086
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Product details
Overview
SN74HCT574NE4 from Texas Instruments is an octal edge-triggered D-type flip-flop with 3-state noninverting outputs, designed for bus interface and data latching in 5V digital systems. It operates from 4.5V to 5.5V, delivers ±6mA output drive, features 22ns typical propagation delay (tpd), and draws ≤80μA quiescent current. It is used in I/O port expansion and bidirectional bus buffering applications requiring TTL-compatible inputs and high-current bus driving capability.
For engineers reviewing the SN74HCT574NE4 datasheet, SN74HCT574NE4 pinout, SN74HCT574NE4 application, or SN74HCT574NE4 equivalent, this page provides verified functional identity, confirmed PDIP-20 package mapping, validated timing and drive specifications, and two technically documented alternative parts for 5V logic bus register designs.
Technical Context
The SN74HCT574NE4 implements eight independent D-type flip-flops synchronized on the low-to-high clock transition, each with individual D input and Q output. Its dual output-enable inputs (1OE and 2OE) control two groups of four outputs, enabling selective 3-state bus isolation without affecting internal latch states.
It uses HCMOS-compatible circuitry with TTL-voltage-level inputs (VIH = 2V, VIL = 0.8V), supports up to 15 LSTTL loads per output, and maintains stable operation across –40°C to +85°C ambient temperature. The device does not include internal pull-ups or level-shifting - all unused inputs must be externally tied to VCC or GND.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V–5.5V - compatible with standard 5V TTL/CMOS logic rails; no regulation required beyond bypass capacitor. |
| Propagation Delay (tpd) | 22ns typical at VCC = 5V, CL = 50pF - enables reliable operation up to 24MHz clock frequency in buffered bus systems. |
| Output Drive | ±6mA at VCC = 5V - sufficient to directly drive 15 LSTTL loads or terminate unterminated bus traces without external resistors. |
| Quiescent Current (ICC) | ≤80μA max - supports low-power system standby modes when outputs are disabled but clocks remain active. |
| Input Compatibility | TTL-voltage levels (VIH ≥ 2V, VIL ≤ 0.8V) - interoperable with legacy 74LS and microcontroller GPIO without level shifters. |
| 3-State Enable Logic | Active-low OE (1OE, 2OE) - allows independent control of two 4-bit output groups for multiplexed bus arbitration. |
| Operating Temperature | –40°C to +85°C - qualified for industrial-grade embedded control and instrumentation applications. |
Pinout & Package
SN74HCT574NE4 is packaged in a 20-pin plastic dual in-line package (PDIP-N), with 6.35mm body width, 24.33mm length, and through-hole mounting. Pin 1 is located at the left end of the top row, identified by a notch or dot marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE, 2OE | Active-low output enable | Disables respective 4-bit output group into high-impedance state; does not affect internal flip-flop state or clocking behavior. |
| CLK | Clock input | Positive-edge-triggered; data on D inputs is latched only on rising edge; asynchronous reset/set not supported. |
| D1–D8 | Data inputs | Eight independent D inputs aligned to corresponding Q outputs; TTL-compatible voltage thresholds ensure robust noise margin. |
| Q1–Q8 | 3-state outputs | Noninverting buffered outputs; each capable of sourcing/sinking ±6mA; high-Z state eliminates bus contention during data transfer. |
| VCC, GND | Power supply | Single 5V supply rail; requires local 0.1μF ceramic bypass capacitor placed adjacent to VCC pin for switching noise suppression. |
Key Features
| Feature | Design Value |
|---|---|
| Bus-structured pinout | Alternating I/O layout (e.g., D1–Q1–D2–Q2…) minimizes trace crosstalk and simplifies PCB routing for parallel data buses. |
| High-current 3-state outputs | ±6mA drive strength enables direct connection to long or loaded PCB traces without external buffers or termination resistors. |
| Low input current | ≤1μA max - reduces loading on upstream drivers and preserves fan-out budget in multi-stage logic networks. |
| Edge-triggered latching | Rising-edge CLK synchronization ensures deterministic setup/hold timing (tsu = 25ns, th = 5ns at 5V), critical for synchronous bus handshaking. |
| TTL-input compatibility | Accepts standard TTL logic levels (VIH ≥ 2V, VIL ≤ 0.8V) - eliminates need for level translators when interfacing with legacy 74LS or microcontroller peripherals. |
Applications
| Industrial PLC I/O Expansion | Microcontroller Parallel Bus Interface |
|---|---|
|
Use Scenario: Adding 8-bit parallel input/output capability to a PLC backplane using shared address/data bus architecture. IC Role / Device Role / Timing Role: Acts as an output latch and input buffer, isolating CPU bus from field-side loads while synchronizing data transfers on clock edges. Use Value: Enables deterministic read/write timing via edge-triggered capture and 3-state bus release, eliminating metastability and contention risks. |
Use Scenario: Connecting an 8-bit microcontroller (e.g., 8051 or PIC18) to external SRAM or LCD controller with multiplexed bus signals. IC Role / Device Role / Timing Role: Buffers address/data lines during memory access cycles; OE pins coordinate with WR/RD strobes to gate bus visibility. Use Value: Provides ±6mA drive to overcome capacitive loading of long traces and multiple devices, maintaining signal integrity at 24MHz burst rates. |
| Legacy System Bus Repeater | Test Equipment Digital Pattern Generator |
|
Use Scenario: Extending signal reach between two segments of a vintage 5V ISA or VME bus where driver strength degrades over distance. IC Role / Device Role / Timing Role: Functions as a unidirectional or bidirectional repeater using dual OE control to manage direction and timing alignment. Use Value: Eliminates need for discrete transistor arrays or additional level-shifting ICs due to native TTL compatibility and high-current outputs. |
Use Scenario: Generating precise, synchronized 8-bit stimulus patterns for IC functional testing in ATE systems. IC Role / Device Role / Timing Role: Stores test vector data on clock edge and presents it stably on Q outputs until next update; OE enables pattern gating. Use Value: Guarantees <22ns tpd and <5ns hold time, ensuring sub-40ns timing resolution for high-speed digital validation sequences. |
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 |
|---|---|---|---|
| SN74HCT373N | Octal transparent latch (latch enable, not edge-triggered); identical 5V supply, ±6mA drive, and PDIP-20 package. | Suitable for address latching where data must pass through while LE is active; lacks clock-edge synchronization for sampled data capture. | Select SN74HCT373N when bus transparency during enable is required; choose SN74HCT574NE4 for edge-synchronized sampling. |
| 74ACT574PC | Higher-speed ACT family (tpd ≈ 9ns), 4.5–5.5V supply, same pinout, but higher ICC (20mA typical) and stricter noise immunity requirements. | Better suited for high-frequency clock domains (>50MHz); less tolerant of ground bounce and supply ripple than HCT. | Choose 74ACT574PC only when tpd <12ns is mandatory and board layout supports clean power/ground; otherwise prefer SN74HCT574NE4 for robustness and lower power. |
Compared with SN74HCT373N and 74ACT574PC, SN74HCT574NE4 uniquely balances edge-triggered precision, industrial temperature range, low ICC, and proven noise immunity - making it optimal for cost-sensitive, reliability-critical bus interface designs where timing determinism and power efficiency are jointly prioritized.
Availability
SN74HCT574NE4 is available at Aetrix Electronics and suitable for industrial PLC I/O modules, microcontroller peripheral interfaces, legacy bus repeaters, and automated test equipment requiring stable component supply and long-term obsolescence management.
Supply support for SN74HCT574NE4 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 experience in industrial-grade logic families.
The SN74HCT574NE4 belongs to TI's 74HCT logic series, engineered for 5V mixed-signal systems requiring TTL compatibility, low power, and robust noise immunity in harsh electrical environments.
FAQ
What is the maximum clock frequency supported by SN74HCT574NE4?
The SN74HCT574NE4 supports up to 24MHz maximum clock frequency under recommended operating conditions (VCC = 4.5V–5.5V, TA = –40°C to +85°C). This is derived from its minimum clock pulse width (tw = 20ns at 4.5V) and verified switching characteristics at CL = 50pF. Higher frequencies may be achievable at 5.5V with reduced load capacitance, but 24MHz is the guaranteed operational limit per datasheet specification for SN74HCT574NE4.
Does SN74HCT574NE4 require external pull-up or pull-down resistors on unused inputs?
Yes - all unused inputs of SN74HCT574NE4 must be externally tied to either VCC or GND to prevent floating states that cause excessive ICC, erratic output behavior, or increased EMI. The datasheet explicitly mandates this for proper operation; no internal pull-ups or pull-downs are integrated into SN74HCT574NE4. Leaving inputs unconnected violates recommended operating conditions and risks functional failure.
Can SN74HCT574NE4 drive a 50Ω transmission line directly?
No - SN74HCT574NE4 is not designed for 50Ω line driving. Its ±6mA output drive corresponds to ~830Ω effective impedance at 5V, optimized for LSTTL fan-out and PCB trace loads up to 15 units. Driving a true 50Ω line would exceed its output current rating and distort logic levels. For 50Ω applications, use dedicated line drivers or add series termination; SN74HCT574NE4 should be used behind proper impedance-matched interfaces.
Is SN74HCT574NE4 RoHS compliant?
Yes - SN74HCT574NE4 is RoHS compliant, as confirmed in TI's official Packaging Information document (Orderable Part Number Addendum, August 2024 revision). It carries "Yes" in the RoHS column and uses NiPdAu (NIPDAU) lead finish, meeting EU Directive 2011/65/EU requirements without exemptions. Full compliance documentation is available via TI's product folder for SN74HCT574NE4.
How does the dual output-enable (1OE/2OE) feature improve system design flexibility with SN74HCT574NE4?
The dual OE inputs (1OE and 2OE) in SN74HCT574NE4 independently control two groups of four outputs (Q1–Q4 and Q5–Q8), enabling granular bus arbitration without redesigning logic sequencing. This allows interleaved data transfers, partial bus updates, or fault-isolated channel shutdown - e.g., disabling sensor inputs while retaining actuator outputs active. Unlike single-OE latches, SN74HCT574NE4 supports asymmetric bus partitioning critical in modular I/O architectures.
SN74HCT574NE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- Packaging:
- Tube
- 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:
- 40 MHz
- Max Propagation Delay @ V, Max CL:
- 47ns @ 5.5V, 150pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 6mA, 6mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 8 µA
- Input Capacitance:
- 3 pF
- Operating Temperature:
- -40°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74HCT574NE4 FAQ
1.How can I place an order for SN74HCT574NE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT574NE4 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 SN74HCT574NE4 reliable?
The price and inventory of SN74HCT574NE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT574NE4 is usually 5 days.
3.What payment methods are accepted for SN74HCT574NE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT574NE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT574NE4?
SN74HCT574NE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT574NE4 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 SN74HCT574NE4?
For technical support, including SN74HCT574NE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT574NE4 requirements.
6.How does Aetrix verify that SN74HCT574NE4 is sourced from the original manufacturer or authorized distributors?
All SN74HCT574NE4 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 SN74HCT574NE4 meets industry standards.
7.What is the process for return or replacement of SN74HCT574NE4?
All SN74HCT574NE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT574NE4, 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 SN74HCT574NE4 part is unused and in its original packaging.
Return procedure for SN74HCT574NE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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