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Texas Instruments SN74LS374DW
- Part No.:
- SN74LS374DW
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74LS374DW.pdf
- Description:
- IC FF D-TYPE SNGL 8BIT 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:664
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Product details
Overview
SN74LS374DW from Texas Instruments is an octal positive-edge-triggered D-type flip-flop with 3-state outputs, designed for bus-oriented systems requiring high-impedance isolation and parallel data latching. It operates at 5 V, supports 50 MHz maximum clock frequency, features 20 ns data setup time, and delivers ±24 mA output drive capability - enabling direct connection to TTL/CMOS buses in industrial control and legacy computing interfaces.
For engineers reviewing the SN74LS374DW datasheet, SN74LS374DW pinout, SN74LS374DW application, or SN74LS374DW equivalent, this device is selected for synchronous data capture in address/data multiplexing, I/O port expansion, and bidirectional bus buffering where edge-triggered registration and output enable control are required.
Technical Context
The SN74LS374DW implements eight independent D-type flip-flops, each triggered on the rising edge of the CLK input. Its internal latch structure captures D-input states only at clock transitions, providing deterministic timing behavior distinct from transparent latches like the SN74LS373.
It integrates a common output-control (OC) input that places all eight Q outputs simultaneously into high-impedance state without affecting internal register operation. The OC input is buffered and compatible with standard TTL logic levels, supporting bus arbitration and shared-line contention management.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS (Low-power Schottky TTL), ensuring compatibility with legacy 5 V TTL systems and predictable noise margins. |
| Function | Octal D-type positive-edge-triggered flip-flop with 3-state outputs - provides synchronized parallel data storage and bus isolation. |
| Max Clock Frequency | 50 MHz at VCC = 5 V, TA = 25°C, RL = 667 Ω, CL = 45 pF - suitable for high-speed data acquisition and control timing in embedded backplanes. |
| Data Setup/Hold | tsu = 20 ns, th = 5 ns (↑CLK) - defines minimum stable window before and after clock edge for reliable sampling of D inputs. |
| Output Drive | IOL = 24 mA / IOH = –2.6 mA - sufficient to drive multiple TTL loads or terminate unterminated traces in point-to-point bus segments. |
| Supply Range | VCC = 4.75 V to 5.25 V - tight tolerance ensures stable operation across industrial-grade 5 V rails with ripple or droop. |
| Operating Temperature | 0°C to 70°C - qualified for commercial and industrial ambient environments in non-military equipment. |
Pinout & Package
SN74LS374DW is housed in a 20-pin SOIC (DW) package with 0.300-inch body width and gull-wing leads, optimized for surface-mount assembly and moderate thermal dissipation (θJA = 58°C/W).
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1, 2, 3, 4, 5, 6, 7, 8 | D1–D8 Data Inputs | Asynchronous parallel data inputs; sampled on rising CLK edge and registered to corresponding Q outputs. |
| 9 | GND | Ground reference for all internal logic and output drivers; must be low-impedance to minimize ground bounce during switching. |
| 10, 11, 12, 13, 14, 15, 16, 17 | Q1–Q8 Outputs | 3-state outputs controlled by OC; drive high/low or enter high-Z when OC = HIGH, enabling bus sharing. |
| 18 | VCC | +5 V supply for logic core and output buffers; requires local 0.1 µF ceramic decoupling adjacent to pin. |
| 19 | CLK | Clock input with Schmitt-triggered buffer; rising-edge sensitive with hysteresis improving noise immunity on long traces. |
| 20 | OC | Active-HIGH output control; asserts high-impedance state on all Q outputs regardless of CLK or D activity. |
Key Features
| Feature | Design Value |
|---|---|
| 3-State Bus Driving Outputs | Enables direct connection to shared data/address buses without external pull-ups or interface logic, reducing component count and board space. |
| Rising-Edge Triggered Flip-Flops | Ensures deterministic, single-cycle data capture aligned to system clock edges - critical for synchronous bus protocols and state machine timing. |
| Buffered OC and CLK Inputs | Reduces loading on upstream drivers and improves noise rejection, allowing reliable operation in electrically noisy industrial enclosures. |
| Full Parallel Access | Supports simultaneous loading of all eight bits via D inputs and concurrent readout via Q outputs - ideal for byte-wide register files and I/O ports. |
| High-Impedance Output State | Eliminates bus contention during multi-master arbitration or peripheral disable sequences, preventing signal corruption and power surges. |
Applications
| Industrial PLC I/O Expansion | Legacy Computer Address Latching |
|---|---|
|
Use Scenario: Expanding digital input/output capacity in programmable logic controllers using shared backplane buses. IC Role / Device Role / Timing Role: SN74LS374DW acts as an output register, capturing CPU-written data on CLK and driving field actuators via OC-controlled 3-state outputs. Use Value: Enables hot-swappable I/O modules by isolating inactive modules via OC, preventing bus conflicts during module replacement. |
Use Scenario: Latching lower-address bits in 8086/8088-based systems where AD0–AD7 multiplex address and data. IC Role / Device Role / Timing Role: SN74LS374DW captures address information on ALE (as CLK) and holds it stable while data transfers occur on same lines. Use Value: Eliminates need for external address latch control logic, simplifying PCB layout and reducing BOM cost in retro-computing designs. |
| Test Equipment Digital Pattern Generator | Embedded System Bidirectional Data Buffer |
|
Use Scenario: Generating precise, synchronized digital stimulus patterns for IC functional testing. IC Role / Device Role / Timing Role: SN74LS374DW registers pattern data from microcontroller memory and outputs it synchronously on rising CLK edges. Use Value: Provides deterministic timing with 20 ns setup requirement, ensuring sub-50 ns pattern edge accuracy for high-speed digital validation. |
Use Scenario: Isolating MCU GPIO banks from external peripherals with mismatched voltage or timing requirements. IC Role / Device Role / Timing Role: SN74LS374DW serves as direction-controlled data buffer: OC enables MCU-to-peripheral writes; reverse flow uses separate path. Use Value: Prevents signal contention during mode transitions and allows safe level-shifting via open-collector or resistor networks on Q outputs. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar octal D-type flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS374N | Same logic function and electrical specs, but in 20-pin PDIP package with θJA = 69°C/W and through-hole mounting. | Preferred for prototyping, repair, or legacy through-hole PCBs; less suitable for automated SMT production. | Select SN74LS374N when manual assembly, socketing, or thermal margin above 58°C/W is acceptable. |
| SN74LS374NSR | Identical functionality in 20-pin SOP (NS) package with same 0 to 70°C rating and RoHS-compliant NIPDAU finish. | Offers finer pitch (0.635 mm) than DW (1.27 mm), enabling higher-density layouts but requiring tighter soldering process control. | Choose SN74LS374NSR for space-constrained boards where SOP footprint and RoHS compliance are prioritized over SOIC handling robustness. |
Compared with SN74LS374N and SN74LS374NSR, the SN74LS374DW offers optimal balance of SMT manufacturability, thermal performance (58°C/W), and mechanical reliability for mid-volume industrial electronics - making it the preferred choice when board-level reflow capability and thermal headroom are key constraints.
Availability
SN74LS374DW is available at Aetrix Electronics and suitable for industrial PLC I/O expansion, legacy computer address latching, and test equipment digital pattern generation requiring stable component supply and long-term obsolescence management.
Supply support for SN74LS374DW 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 50 years of innovation in industrial and automotive electronics.
The SN74LS374DW belongs to TI's classic 74LS logic family, engineered for robust 5 V TTL interoperability, noise immunity, and drop-in replacement in legacy digital systems spanning computing, instrumentation, and automation.
FAQ
What is the primary function of the SN74LS374DW?
The SN74LS374DW is an octal positive-edge-triggered D-type flip-flop with 3-state outputs. It captures and holds eight bits of data on the rising edge of its CLK input, then drives them onto Q outputs - which can be placed in high-impedance state via the OC pin. This makes SN74LS374DW ideal for synchronous bus interfacing and data registration in 5 V TTL systems.
Does the SN74LS374DW support 3.3 V operation?
No, the SN74LS374DW is specified only for 4.75 V to 5.25 V supply operation per its recommended conditions. It is not 3.3 V tolerant: applying 3.3 V to VCC will result in undefined logic levels, reduced noise margins, and potential failure to meet timing specs. For 3.3 V systems, consider modern alternatives like SN74LVC574A.
How does the OC pin affect internal register operation in the SN74LS374DW?
The OC (output control) pin in the SN74LS374DW affects only the output drivers - it has no effect on internal flip-flop state or clocked data capture. When OC = HIGH, all Q outputs go high-impedance; D inputs remain active, CLK continues to clock new data into the registers, and internal states update normally. This allows seamless bus arbitration without disrupting ongoing data flow.
What is the maximum clock frequency guaranteed for the SN74LS374DW?
The SN74LS374DW guarantees a maximum clock frequency of 50 MHz under standard test conditions: VCC = 5 V, TA = 25°C, RL = 667 Ω, and CL = 45 pF. At temperature extremes or with heavier capacitive loads, actual usable frequency may decrease - design margin should be applied for industrial 0°C to 70°C operation.
Is the SN74LS374DW pin-compatible with the SN74LS373?
No, the SN74LS374DW is not pin-compatible with the SN74LS373. While both are 20-pin octal devices in DW packages, the SN74LS373 uses C (enable) for transparent latching and lacks CLK functionality; its pin 19 is C, whereas SN74LS374DW pin 19 is CLK. Interchanging them without PCB revision will cause functional failure due to incompatible control logic and timing behavior.
SN74LS374DW Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 20-SOIC (0.295", 7.50mm 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:
- 50 MHz
- Max Propagation Delay @ V, Max CL:
- 28ns @ 5V, 45pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 2.6mA, 24mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Iq):
- 40 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 20-SOIC
SN74LS374DW FAQ
1.How can I place an order for SN74LS374DW through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS374DW 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 SN74LS374DW reliable?
The price and inventory of SN74LS374DW are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS374DW is usually 5 days.
3.What payment methods are accepted for SN74LS374DW?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS374DW transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS374DW?
SN74LS374DW orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS374DW 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 SN74LS374DW?
For technical support, including SN74LS374DW datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS374DW requirements.
6.How does Aetrix verify that SN74LS374DW is sourced from the original manufacturer or authorized distributors?
All SN74LS374DW 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 SN74LS374DW meets industry standards.
7.What is the process for return or replacement of SN74LS374DW?
All SN74LS374DW units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS374DW, 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 SN74LS374DW part is unused and in its original packaging.
Return procedure for SN74LS374DW:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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