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Texas Instruments SN74S374N3
- Part No.:
- SN74S374N3
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 20-DIP (0.300", 7.62mm)
- Datasheet:
-
SN74S374N3.pdf
- Description:
- BUS DRIVER, S SERIES, 8-BIT, TTL
- Quantity:
- Payment:
- Shipping:
Inventory:857
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Product details
Overview
SN74S374N from Texas Instruments is an octal edge-triggered D-type flip-flop with 3-state bus-driving outputs, clock-enable input with hysteresis for noise rejection, P-N-P inputs to reduce DC loading, and full parallel access for high-speed data latching in bus-organized systems. It operates at 5 V, supports up to 100 MHz clock frequency (with RL = 280 Ω, CL = 15 pF), and is used in bidirectional bus drivers and register file implementations.
For engineers reviewing the SN74S374N datasheet, SN74S374N pinout, SN74S374N application, or SN74S374N equivalent, this device is selected for high-speed synchronous data capture in legacy TTL-compatible industrial control, memory interface, and bus arbitration circuits where Schmitt-triggered clock enable and robust 3-state output control are required.
Technical Context
The SN74S374N implements eight independent positive-edge-triggered D-type flip-flops, each capturing the logic state of its D input on the rising edge of CLK. Its buffered OC (output control) input places all Q outputs simultaneously into high-impedance without affecting internal latch states - enabling true bus sharing without contention.
It features Schmitt-trigger hysteresis on both CLK and OC inputs (≈400 mV typical), improving ac/dc noise immunity in electrically noisy environments. P-N-P input structure minimizes DC loading on data lines, and the 3-state outputs drive highly capacitive or low-impedance loads directly - eliminating need for external pull-ups or interface buffers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | S-series TTL - higher speed and drive than LS, compatible with 5 V TTL/CMOS interfaces |
| Function | Octal positive-edge-triggered D flip-flop with 3-state outputs and clock-enable |
| Max Clock Frequency | 100 MHz (RL = 280 Ω, CL = 15 pF) - enables high-throughput data sampling in legacy backplanes |
| Propagation Delay (CLK→Q) | 7–15 ns (tPLH/tPHL) - ensures tight timing margins in synchronous bus designs |
| Output Drive | IOL = 20 mA, IOH = –6.5 mA - sufficient to drive multiple TTL loads or 50 Ω transmission lines |
| Input Hysteresis | ≈400 mV on CLK and OC - suppresses false triggering from EMI or ground bounce |
| Supply Voltage Range | 4.5 V to 5.5 V - tolerant of rail variation in industrial power supplies |
Pinout & Package
SN74S374N is housed in a 20-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width and through-hole mounting. Pin spacing conforms to JEDEC MS-001.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OC (Output Control) | Active-low 3-state enable; high-impedance output when high, normal logic output when low |
| 2–9 | D1–D8 (Data Inputs) | Asynchronous parallel data inputs feeding D-type flip-flop stages |
| 10 | GND | Ground reference for all internal circuitry and I/O |
| 11–18 | Q1–Q8 (Outputs) | Edge-synchronized, 3-state outputs - reflect D-input state captured at last CLK↑ |
| 19 | CLK | Positive-edge-triggered clock input with Schmitt-trigger hysteresis for noise immunity |
| 20 | VCC | +5 V supply terminal - powers internal logic and output drivers |
Key Features
| Feature | Design Value |
|---|---|
| Schmitt-trigger CLK and OC inputs | ≈400 mV hysteresis improves noise margin in industrial environments with ground bounce or EMI |
| P-N-P input structure | Reduces DC loading on data buses - critical for fan-out-limited TTL backplane designs |
| 3-state outputs with independent OC control | Enables shared-bus operation without contention; internal flip-flop state retained during output disable |
| High-speed S-series architecture | 100 MHz max clock rate and sub-15 ns propagation delay support legacy high-throughput bus protocols |
| Full parallel load capability | All eight D inputs sampled simultaneously on CLK↑ - ideal for register file and I/O port applications |
Applications
| Industrial Bus Interface | Legacy Memory Address Latching |
|---|---|
|
Use Scenario: Interfacing microprocessor address/data buses to peripheral controllers in PLCs and CNC machines. IC Role / Device Role / Timing Role: Edge-triggered register capturing address bits synchronously with CPU clock to isolate timing-critical peripherals. Use Value: Eliminates metastability risk via precise CLK↑ sampling and provides 3-state isolation during bus turnaround cycles. |
Use Scenario: Latching 8-bit segments of 16-bit memory addresses in vintage minicomputer memory subsystems. IC Role / Device Role / Timing Role: Holding upper/lower address byte during multiplexed bus cycles using OC-controlled 3-state outputs. Use Value: Enables clean address hold without external buffers; P-N-P inputs prevent excessive loading on address drivers. |
| Bidirectional Data Bus Driver | Expandable Register File |
|
Use Scenario: Implementing half-duplex data exchange between two microcontrollers over a shared 8-bit bus. IC Role / Device Role / Timing Role: Direction-controlled 3-state buffer using OC as direction select and CLK for synchronized data transfer. Use Value: Schmitt-triggered OC input rejects noise during bus arbitration; 20 mA drive supports long trace runs. |
Use Scenario: Constructing a 4×8-bit general-purpose register file in discrete logic-based CPU designs. IC Role / Device Role / Timing Role: One SN74S374N per 8-bit word, clocked by decoded word-select signals for parallel read/write. Use Value: Full parallel access and edge-triggered capture allow deterministic register update timing across all 8 bits. |
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 | Lower speed (50 MHz max), higher setup time (20 ns), no input hysteresis, LS-family propagation delays (~28 ns CLK→Q) | Used where lower power and cost outweigh speed requirements; less robust in noisy environments | Select SN74LS374N only if system clock < 35 MHz and noise immunity is not critical. |
| SN74ACT374N | CMOS-compatible 5 V operation, 10 ns max tPD, 24 mA drive, no hysteresis but higher noise immunity via rail-to-rail swing | Preferred for mixed-logic systems requiring TTL-level input thresholds with CMOS output drive | Choose SN74ACT374N when interfacing with modern microcontrollers or when lower ICC (20 mA vs. 180 mA) is essential. |
Compared with SN74LS374N, SN74S374N delivers 2× clock speed and superior noise rejection via hysteresis, while SN74ACT374N offers lower power and tighter timing but lacks the S-series' legacy bus drive strength and input structure.
Availability
SN74S374N is available at Aetrix Electronics and suitable for industrial bus interface, legacy memory address latching, and bidirectional data bus driver applications requiring stable component supply and long-term obsolescence management.
Supply support for SN74S374N 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 SN74S374N belongs to TI's legacy S-series TTL logic family, designed specifically for high-speed, noise-immune digital interfacing in mission-critical industrial control and computing systems of the 1980s–2000s.
FAQ
What is the primary function of the SN74S374N?
The SN74S374N 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 the CLK signal, and its OC input independently controls output enable/disable. This makes SN74S374N ideal for synchronous data latching and bus isolation in legacy TTL systems.
Does the SN74S374N have Schmitt-trigger inputs?
Yes, the SN74S374N features Schmitt-trigger hysteresis on both the CLK and OC inputs, providing ≈400 mV of noise margin. This design prevents false triggering due to slow-rising edges or electrical noise - a key differentiator from LS-series equivalents like SN74LS374N, which lack hysteresis.
What is the maximum clock frequency supported by the SN74S374N?
The SN74S374N supports a maximum clock frequency of 100 MHz under specified test conditions (RL = 280 Ω, CL = 15 pF). This rating assumes all outputs are loaded and reflects the device's S-series speed advantage over LS-family counterparts, which are limited to 50 MHz under comparable conditions.
Can the SN74S374N be used in place of the SN74LS374N?
The SN74S374N is pin-compatible and functionally similar to SN74LS374N but is not a direct drop-in replacement due to differences in speed, input structure, and noise immunity. SN74S374N requires careful review of timing margins and power supply decoupling due to higher ICC (180 mA vs. 40 mA) and faster edge rates.
What package type is used for the SN74S374N?
The SN74S374N uses a 20-pin plastic dual in-line package (PDIP-N), with 0.3-inch body width and through-hole mounting. This package is industry-standard for legacy board assembly and supports hand-soldering, wave soldering, and socket-based prototyping - consistent with its use in industrial control and retro-computing applications.
SN74S374N3 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74S
- Package/Case:
- 20-DIP (0.300", 7.62mm)
- 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:
- 100 MHz
- Max Propagation Delay @ V, Max CL:
- 17ns @ 5V, 15pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 6.5mA, -
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Iq):
- 110 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 20-PDIP
SN74S374N3 FAQ
1.How can I place an order for SN74S374N3 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74S374N3 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 SN74S374N3 reliable?
The price and inventory of SN74S374N3 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74S374N3 is usually 5 days.
3.What payment methods are accepted for SN74S374N3?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74S374N3 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74S374N3?
SN74S374N3 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74S374N3 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 SN74S374N3?
For technical support, including SN74S374N3 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74S374N3 requirements.
6.How does Aetrix verify that SN74S374N3 is sourced from the original manufacturer or authorized distributors?
All SN74S374N3 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 SN74S374N3 meets industry standards.
7.What is the process for return or replacement of SN74S374N3?
All SN74S374N3 units undergo pre-shipment inspection (PSI). If there is an issue with SN74S374N3, 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 SN74S374N3 part is unused and in its original packaging.
Return procedure for SN74S374N3:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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