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Texas Instruments SN74HCT574PW
- Part No.:
- SN74HCT574PW
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-TSSOP (0.173", 4.40mm Width)
- Datasheet:
-
SN74HCT574PW.pdf
- Description:
- IC FF D-TYPE SNGL 8BIT 20TSSOP
- Quantity:
- Payment:
- Shipping:
Inventory:503
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Product details
Overview
SN74HCT574PW from Texas Instruments is an octal edge-triggered D-type flip-flop with 3-state outputs, designed for bus interface and data latching in 5V TTL-compatible digital systems. It operates from 4.5V to 5.5V, delivers ±6mA output drive, features 22ns typical propagation delay, and supports high-impedance bus isolation via dual output-enable inputs. It is used in microcontroller I/O expansion, memory address latching, and bidirectional data bus buffering.
For engineers reviewing the SN74HCT574PW datasheet, SN74HCT574PW pinout, SN74HCT574PW application, or SN74HCT574PW equivalent, this page provides verified functional identity, TSSOP-20 package mapping, bus-structured pin validation, timing parameters at CL = 50 pF and 150 pF, and confirmed alternatives for 5V logic-level register replacement.
Technical Context
The SN74HCT574PW implements eight independent D-type flip-flops, each triggered on the low-to-high clock transition, with synchronous data capture and asynchronous 3-state control via two separate output-enable (OE) inputs. Its TTL-compatible inputs accept 0.8V/2.0V thresholds across 4.5–5.5V VCC, enabling direct interfacing with legacy 74LS and microcontroller GPIOs.
Each output drives up to 15 LSTTL loads while maintaining high-impedance state when OE is asserted, allowing shared bus operation without pull-ups or external isolation. Internal logic retains stored data regardless of OE state, supporting transparent register hold during bus contention.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5V to 5.5V - Ensures compatibility with standard 5V logic rails and tolerance against supply ripple. |
| Propagation Delay (tpd) | 22ns typical at VCC = 5V, CL = 50 pF - Enables reliable operation up to 24MHz clock frequency in buffered bus applications. |
| Output Drive | ±6mA at VCC = 5V - Sufficient to directly drive 15 LSTTL loads without external buffers. |
| Input Current | ≤1μA max - Minimizes loading on upstream logic and enables high fan-out without signal degradation. |
| 3-State Leakage (IOZ) | ±5μA max at VCC = 5.5V - Guarantees negligible bus leakage during high-impedance mode, critical for multi-drop bus integrity. |
| Operating Temperature | –40°C to +85°C - Qualified for industrial-grade embedded control and instrumentation environments. |
Pinout & Package
TSSOP-20 (PW) package: 6.50mm × 6.4mm body size, 1.2mm max height, 0.65mm lead pitch, exposed pad optional per layout guidelines. Pin 1 index located at top-left corner with beveled edge marking.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1OE | Active-low output enable 1 | Controls Q1–Q4 outputs; assertion places them in high-impedance state independent of clock or data. |
| 1A1–1A4 | Data inputs for flip-flops 1–4 | Accept TTL-voltage-compatible signals; sampled on CLK rising edge. |
| 2Y1–2Y4 | Outputs for flip-flops 1–4 | Noninverting 3-state outputs driven by first four DFFs; enabled by 1OE. |
| GND | Ground reference | Primary return path for all logic and output currents; requires low-inductance connection. |
| 2A1–2A4 | Data inputs for flip-flops 5–8 | Second group of four D inputs, functionally identical to 1A1–1A4. |
| 1Y1–1Y4 | Outputs for flip-flops 5–8 | Noninverting 3-state outputs driven by last four DFFs; enabled by 2OE. |
| 2OE | Active-low output enable 2 | Controls Q5–Q8 outputs independently - enables split-bus or interleaved data routing. |
| VCC | Positive supply | Must be bypassed with 0.1μF ceramic capacitor near pin; supports 4.5–5.5V operation. |
Key Features
| Feature | Design Value |
|---|---|
| Bus-structured pinout | Alternating input/output layout minimizes trace crosstalk and simplifies PCB routing for parallel data buses. |
| Dual independent output enables | 1OE and 2OE allow simultaneous or staggered control of two 4-bit data groups - ideal for nibble-aligned I/O ports. |
| TTL-compatible inputs | VIH = 2.0V / VIL = 0.8V at VCC = 4.5–5.5V - eliminates level-shifting when interfacing with 74LS, microcontrollers, or FPGAs. |
| Low power consumption | ICC ≤ 80μA max at VCC = 5.5V - reduces system standby current in battery-backed or energy-sensitive designs. |
| High-current 3-state outputs | ±6mA drive capability ensures robust signal integrity into capacitive bus loads up to 15 LSTTL units. |
Applications
| Microcontroller I/O Expansion | Memory Address Latching |
|---|---|
Use Scenario: Expanding limited GPIO count of an MCU to drive 8-bit peripheral interfaces (e.g., LCD modules, keypad scanners). IC Role / Device Role / Timing Role: Acts as a synchronized output latch: data written to MCU port is captured on CLK edge and held stable on outputs until next update. Use Value: Eliminates need for discrete buffers or shift registers; supports direct 5V-tolerant peripheral control with deterministic timing. |
Use Scenario: Capturing and holding upper address bits (A8–A15) during multiplexed bus cycles in 8080/8051-based systems. IC Role / Device Role / Timing Role: Functions as an address register: samples ADx lines on ALE/CLK rising edge and presents latched values to memory chips during read/write phases. Use Value: Provides glitch-free address hold with 22ns tpd - meets setup/hold timing margins for 12MHz system clocks. |
| Bidirectional Data Bus Buffering | Digital Test Equipment Signal Conditioning |
Use Scenario: Isolating CPU data bus from test fixture or programmable logic during debug or boundary-scan operations. IC Role / Device Role / Timing Role: Serves as a controlled bus driver: 1OE/2OE selectively enable/disable two 4-bit lanes to prevent bus contention during probe insertion. Use Value: Enables hot-swappable test access without disrupting main system operation - high-Z state leakage <5μA avoids false reads. |
Use Scenario: Conditioning parallel stimulus/response signals in automated test equipment (ATE) channel cards handling multiple DUTs. IC Role / Device Role / Timing Role: Provides synchronized sampling and output staging: captures DUT response on CLK edge, holds result until host controller reads via 3-state outputs. Use Value: Delivers deterministic 22ns propagation and sub-5ns hold time - ensures accurate pass/fail evaluation at 20MHz test rates. |
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 |
|---|---|---|---|
| SN74HCT374PW | Identical pinout and electrical specs; differs only in output-enable polarity (active-high vs. SN74HCT574PW's active-low). | Requires inverted OE control logic; otherwise drop-in in bus-hold and latch functions where OE inversion is acceptable. | Select SN74HCT374PW if system OE signal is active-high; verify timing alignment with inverted enable path. |
| 74ACT574PW | Higher speed (tpd ≈ 9ns), wider VCC range (4.5–5.5V same), but higher ICC (1.6mA typ) and less noise immunity (VIH = 3.5V min). | Suitable for high-speed data acquisition where 22ns tpd is limiting, but not recommended for noisy industrial environments. | Choose 74ACT574PW only when >25MHz operation is required and power/noise trade-offs are validated. |
Compared with SN74HCT574PW, SN74HCT374PW offers identical functionality with active-high OE - simplifying control in some FPGA-based systems - while 74ACT574PW trades higher static current and reduced noise margin for nearly 2.5× faster switching, making it viable only in clean, speed-critical applications.
Availability
SN74HCT574PW is available at Aetrix Electronics and suitable for industrial control panels, test instrumentation, and legacy 5V embedded systems requiring stable component supply and long-term obsolescence management.
Supply support for SN74HCT574PW 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 SN74HCT574PW belongs to TI's 74HCT logic family, engineered for TTL-compatible 5V operation with low power, high noise immunity, and robust bus-driving capability in industrial and instrumentation applications.
FAQ
What is the maximum clock frequency supported by the SN74HCT574PW?
The SN74HCT574PW supports up to 24MHz maximum clock frequency under recommended conditions (VCC = 4.5–5.5V, TA = –40°C to +85°C, CL = 50 pF). At 5.5V supply, fmax reaches 27MHz; however, system-level timing margins must account for board trace capacitance and load variations. The SN74HCT574PW datasheet specifies tpd = 41ns max at 5.5V/CL = 50 pF, defining practical limit for synchronous bus operation.
Does the SN74HCT574PW require external pull-up resistors on its outputs?
No, the SN74HCT574PW does not require external pull-up resistors on its outputs. Its 3-state outputs provide active high/low drive (±6mA) when enabled and true high-impedance (IOZ ≤ ±5μA) when disabled. Pull-ups would interfere with bus contention resolution and violate the device's specified output behavior - proper operation assumes outputs connect directly to a shared bus or downstream CMOS/TTL inputs.
Can the SN74HCT574PW operate with a 3.3V supply?
No, the SN74HCT574PW is not rated for 3.3V operation. Its absolute minimum supply voltage is 4.5V, and TTL-compatible input thresholds (VIH = 2.0V min, VIL = 0.8V max) are defined only across 4.5–5.5V VCC. Applying 3.3V may result in undefined logic states, excessive ICC, or failure to meet timing specifications. For 3.3V systems, consider SN74LVC574A or SN74ALVC574 instead.
How are the two output-enable inputs (1OE and 2OE) used in practice?
In practice, 1OE controls outputs Y1–Y4 and 2OE controls Y5–Y8, enabling independent gating of two 4-bit data groups. This allows nibble-aligned bus partitioning - e.g., using 1OE for lower-nibble peripherals and 2OE for upper-nibble memory - or staggered enable timing to reduce simultaneous switching noise. Both OEs are active-low and do not affect internal flip-flop state, permitting data retention during bus isolation.
Is the SN74HCT574PW pin-compatible with other 20-pin TSSOP logic devices?
The SN74HCT574PW uses standard TSSOP-20 (PW) mechanical dimensions (6.50mm × 6.4mm, 0.65mm pitch), but pin compatibility is function-specific. It shares footprint compatibility with other TI PW-packaged 20-pin logic ICs (e.g., SN74HCT374PW, SN74HCT244PW), but signal mapping differs. Always verify pin functions using the SN74HCT574PW pin diagram - especially GND/VCC placement and OE/data/output assignments - before PCB reuse.
SN74HCT574PW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74HCT
- Package/Case:
- 20-TSSOP (0.173", 4.40mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- 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:
- Surface Mount
- Supplier Device Package:
- 20-TSSOP
SN74HCT574PW FAQ
1.How can I place an order for SN74HCT574PW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74HCT574PW 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 SN74HCT574PW reliable?
The price and inventory of SN74HCT574PW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74HCT574PW is usually 5 days.
3.What payment methods are accepted for SN74HCT574PW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74HCT574PW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74HCT574PW?
SN74HCT574PW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74HCT574PW 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 SN74HCT574PW?
For technical support, including SN74HCT574PW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74HCT574PW requirements.
6.How does Aetrix verify that SN74HCT574PW is sourced from the original manufacturer or authorized distributors?
All SN74HCT574PW 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 SN74HCT574PW meets industry standards.
7.What is the process for return or replacement of SN74HCT574PW?
All SN74HCT574PW units undergo pre-shipment inspection (PSI). If there is an issue with SN74HCT574PW, 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 SN74HCT574PW part is unused and in its original packaging.
Return procedure for SN74HCT574PW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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