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Texas Instruments SN74LS374DWR
- Part No.:
- SN74LS374DWR
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-SOIC (0.295", 7.50mm Width)
- Datasheet:
-
SN74LS374DWR.pdf
- Description:
- IC FF D-TYPE SNGL 8BIT 20SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:924
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Product details
Overview
SN74LS374DWR from Texas Instruments is an octal positive-edge-triggered D-type flip-flop with 3-state bus-driving outputs, designed for synchronous data latching in TTL-compatible digital systems. It features independent clock-enable control, buffered inputs, and operates at 5 V with 24 mA low-level output drive. It is used in address/data bus buffering, I/O port expansion, and register file implementation in legacy industrial controllers and test equipment.
For engineers reviewing the SN74LS374DWR datasheet, SN74LS374DWR pinout, SN74LS374DWR application, or SN74LS374DWR equivalent, key selection criteria include its edge-triggered capture timing (20 ns setup), 3-state output disable/enable performance (12–20 ns), 50 MHz maximum clock frequency, and SOIC-20 package compatibility with legacy PCB layouts requiring TTL-level logic interfacing.
Technical Context
The SN74LS374DWR implements eight independent D-type flip-flops synchronized to the rising edge of CLK, with separate OC (output control) enabling high-impedance state on all Q outputs without affecting internal latch states. Its TTL-compatible input thresholds (VIH = 2.0 V, VIL = 0.8 V) and Schmitt-trigger-free buffered CLK/OC inputs ensure robust noise immunity in mixed-signal environments.
Each flip-flop retains stored data during OC assertion, allowing asynchronous data retention while isolating the bus. The device uses standard bipolar TTL circuitry - not CMOS - resulting in higher ICC (27–40 mA) but predictable propagation delays (tPLH/tPHL ≤ 18 ns) under RL = 667 Ω / CL = 45 pF load conditions.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS (Low-power Schottky TTL) - ensures backward compatibility with legacy TTL systems and predictable DC loading. |
| Clock Trigger | Positive-edge-triggered - data at D inputs is sampled only on rising CLK transition, enabling synchronous system timing. |
| Output Type | 3-state (tri-state) - OC input places all eight Q outputs in high-Z mode, permitting shared bus arbitration without external isolation. |
| Max Clock Frequency | 50 MHz - validated under RL = 667 Ω / CL = 45 pF, suitable for high-speed data capture in instrumentation interfaces. |
| IOL / IOH | 24 mA / –2.6 mA - drives standard TTL loads directly; supports fan-out of ≥20 LS-TTL inputs without buffers. |
| Propagation Delay | tPLH/tPHL ≤ 18 ns (CLK→Q) - enables sub-20 ns cycle timing in tightly constrained control paths. |
| Supply Voltage | 4.75 V to 5.25 V - narrow tolerance range mandates stable 5 V rail; not compatible with 3.3 V or wide-range supplies. |
Pinout & Package
SN74LS374DWR is housed in a 20-pin SOIC (DW) package, 7.5 mm × 12.8 mm body, 1.27 mm pitch, with gull-wing leads. Pin numbering follows standard JEDEC MS-013, top-view orientation.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OC (Output Control) | Active-low enable for 3-state outputs; when low, Q outputs reflect registered data; when high, all Q go high-Z. |
| 2–9 | D1–D8 (Data Inputs) | Asynchronous data inputs; sampled on rising CLK edge and stored in respective flip-flops. |
| 10 | GND | Ground reference for all internal logic and output drivers. |
| 11–18 | Q1–Q8 (Outputs) | Registered, 3-state outputs; driven only when OC = low; high-Z otherwise. |
| 19 | CLK | Positive-edge-triggered clock input; rising edge captures Dn into Qn; no internal debouncing or hysteresis. |
| 20 | VCC | +5 V power supply; decoupling capacitor (0.1 µF) required adjacent to pin for noise suppression. |
Key Features
| Feature | Design Value |
|---|---|
| Edge-triggered storage | Ensures deterministic sampling at precise clock edges - eliminates metastability risks from level-sensitive latches in synchronous designs. |
| Independent output control | OC pin allows bus release without altering internal register state - critical for multi-master bus arbitration and hot-swap I/O. |
| TTL-compatible drive strength | 24 mA sink capability supports direct connection to legacy backplanes and unbuffered TTL loads without line drivers. |
| Full parallel access | All eight D inputs and Q outputs accessible simultaneously - enables byte-wide data transfer in microprocessor data/address buses. |
| Standard SOIC-20 footprint | Enables drop-in replacement in existing LS-TTL layouts; compatible with automated SMT assembly and reflow profiles (Level-1-260°C). |
Applications
| Microprocessor Address Latching | Industrial I/O Port Expansion |
|---|---|
|
Use Scenario: Holding 8-bit address segments during multiplexed bus cycles in 8080/Z80-based controllers. IC Role / Device Role / Timing Role: Edge-triggered latch capturing address bits on rising CLK, releasing bus via OC during data phase. Use Value: Eliminates need for external gating logic; enables clean separation of address and data phases using single clock edge. |
Use Scenario: Adding isolated 8-bit bidirectional I/O ports to PLC modules with limited GPIO resources. IC Role / Device Role / Timing Role: Registering host-side commands and buffering field-device responses with OC-controlled bus directionality. Use Value: Provides hardware-level bus contention protection and reduces firmware overhead for port state management. |
| Test Equipment Data Capture | Legacy Bus Interface Bridge |
|
Use Scenario: Capturing parallel sensor outputs (e.g., ADC result buses) at precise trigger points in benchtop analyzers. IC Role / Device Role / Timing Role: Synchronizing asynchronous analog-to-digital conversion results to system clock domain via CLK edge. Use Value: Guarantees setup/hold compliance (tsu = 20 ns, th = 5 ns) for reliable sampling at up to 50 MHz rates. |
Use Scenario: Interfacing modern microcontrollers to legacy 8-bit peripheral buses (e.g., EPROM, UART, PIO chips). IC Role / Device Role / Timing Role: Level-shifting and timing-aligning control signals between mismatched clock domains using OC-gated handshaking. Use Value: Maintains signal integrity across voltage and timing boundaries without custom ASICs or FPGA glue logic. |
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 PDIP-20 package (longer lead form, through-hole mount). | Used where manual prototyping, socket-based testing, or legacy through-hole assembly is required. | Select SN74LS374N for breadboarding, repair, or systems with mixed-technology PCBs containing both SMT and through-hole components. |
| SN74LS374NSR | Identical functionality in SOP-20 package (5.3 mm width), RoHS-compliant, same SOIC pinout but smaller body. | Suitable for space-constrained boards where SOIC-20 footprint must be minimized without changing layout. | Choose SN74LS374NSR when board area is critical and JEDEC-standard SOIC-20 is unavailable; verify land pattern compatibility before layout reuse. |
Compared with SN74LS374N and SN74LS374NSR, the SN74LS374DWR offers identical timing and drive characteristics in a widely adopted SOIC-20 package optimized for high-volume SMT production, with verified reflow compatibility (Level-1-260°C) and traceable sourcing for industrial OEM programs.
Availability
SN74LS374DWR is available at Aetrix Electronics and suitable for industrial control systems, legacy test equipment refurbishment, and embedded instrumentation requiring stable component supply with long-term lifecycle support.
Supply support for SN74LS374DWR 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 founded in 1930, specializing in analog, embedded processing, and logic solutions for industrial, automotive, and communications markets.
The SN74LS374DWR belongs to TI's legacy 74LS logic family, engineered for reliability and interoperability in mission-critical industrial control, instrumentation, and military-grade systems operating over extended temperature ranges.
FAQ
What is the function of the OC pin on the SN74LS374DWR?
The OC (Output Control) pin on the SN74LS374DWR is an active-low signal that enables or disables the 3-state outputs. When OC is low, the Q outputs reflect the registered D-input values; when OC is high, all eight Q outputs enter high-impedance state - preserving internal data while electrically isolating the bus. This behavior is confirmed in the function table and logic diagram of the SN74LS374DWR datasheet.
Does the SN74LS374DWR support 3.3 V operation?
No, the SN74LS374DWR does not support 3.3 V operation. Its recommended supply voltage is 4.75 V to 5.25 V, and absolute maximum VCC is 7 V. Operation below 4.75 V may cause unreliable switching or increased propagation delay; it is incompatible with 3.3 V logic families without level translation. This specification is explicitly defined in the "Recommended Operating Conditions" section for SN74LS374DWR.
What is the minimum data setup time required for reliable operation of the SN74LS374DWR?
The minimum data setup time (tsu) for the SN74LS374DWR is 20 ns before the rising edge of CLK, as specified under commercial temperature conditions (0°C to 70°C). This value ensures proper sampling of D-input states and is validated across process/voltage/temperature corners. Violating this timing may result in metastability or incorrect latched values - a hard constraint for synchronous design validation of the SN74LS374DWR.
Can the SN74LS374DWR be used as a transparent latch?
No, the SN74LS374DWR cannot be used as a transparent latch. It is strictly an edge-triggered D-type flip-flop: data is captured only on the rising edge of CLK. In contrast, the SN74LS373 variant provides transparent latching behavior (Q follows D while C is high). The SN74LS374DWR's function table and logic diagram confirm its positive-edge-triggered architecture - no transparency window exists.
Is the SN74LS374DWR pin-compatible with the SN74S374 series?
Yes, the SN74LS374DWR is pin-compatible with the SN74S374 series in the same package (e.g., DW, N, NS), sharing identical pinout, terminal functions, and package dimensions. However, electrical differences exist: SN74S374 offers higher speed (100 MHz fmax) and greater drive (–6.5 mA IOH), but consumes more current (140 mA ICC). System-level validation of timing and loading is required before substitution of SN74LS374DWR with SN74S374.
SN74LS374DWR Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 20-SOIC (0.295", 7.50mm 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:
- 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
SN74LS374DWR FAQ
1.How can I place an order for SN74LS374DWR through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS374DWR 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 SN74LS374DWR reliable?
The price and inventory of SN74LS374DWR are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS374DWR is usually 5 days.
3.What payment methods are accepted for SN74LS374DWR?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS374DWR transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS374DWR?
SN74LS374DWR orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS374DWR 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 SN74LS374DWR?
For technical support, including SN74LS374DWR datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS374DWR requirements.
6.How does Aetrix verify that SN74LS374DWR is sourced from the original manufacturer or authorized distributors?
All SN74LS374DWR 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 SN74LS374DWR meets industry standards.
7.What is the process for return or replacement of SN74LS374DWR?
All SN74LS374DWR units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS374DWR, 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 SN74LS374DWR part is unused and in its original packaging.
Return procedure for SN74LS374DWR:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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