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Texas Instruments SN74LS74ADE4
- Part No.:
- SN74LS74ADE4
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74LS74ADE4.pdf
- Description:
- IC FF D-TYPE DUAL 1BIT 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,496
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Product details
Overview
SN74LS74ADE4 from Texas Instruments is a dual D-type positive-edge-triggered flip-flop in a 14-pin plastic DIP package, operating from 4.75 V to 5.25 V with typical propagation delay of 15 ns and maximum clock frequency of 30 MHz. It features complementary Q and Q̅ outputs per section, independent preset and clear inputs, and is used in synchronous logic control, data latching, and clock division circuits in industrial control panels and legacy instrumentation.
For engineers reviewing the SN74LS74ADE4 datasheet, SN74LS74ADE4 pinout, SN74LS74ADE4 application, or SN74LS74ADE4 equivalent, this page delivers verified electrical specs, package dimensions, functional alternatives, and real-world use context for legacy TTL system design and repair.
Technical Context
This device implements two independent edge-triggered D flip-flops with asynchronous active-low preset (PR̅) and clear (CLR̅) inputs. Each section samples the D input on the rising edge of the clock (CLK), latching the value to Q and its inverse to Q̅.
Designed for standard TTL logic families, SN74LS74ADE4 interfaces directly with 74LS, 74S, and 74F series ICs without level-shifting. Its output drive capability supports fan-out of up to 20 LS-TTL loads, and it meets JEDEC JESD78 Class II latch-up immunity requirements.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Logic Family | 74LS (Low-power Schottky TTL) - ensures compatibility with legacy TTL systems and predictable noise margins. |
| Supply Voltage | 4.75 V to 5.25 V - requires regulated +5 V rail; operation outside this range risks metastability or failure. |
| Propagation Delay (tPLH/tPHL) | 15 ns max (CL = 15 pF, VCC = 5 V) - defines minimum clock-to-output timing for synchronous state updates. |
| Maximum Clock Frequency | 30 MHz - sets upper limit for reliable toggle rate in counter or shift-register applications. |
| Input Threshold Voltage (VIL/VIH) | 0.8 V / 2.0 V - defines valid logic-low and logic-high voltage boundaries for robust signal interpretation. |
| Output Drive (IOL/IOH) | 8 mA / –0.4 mA - supports direct connection to multiple LS-TTL inputs without buffering. |
| Operating Temperature | 0 °C to +70 °C - rated for commercial-grade environments, not extended industrial or military ranges. |
Pinout & Package
SN74LS74ADE4 uses a 14-pin plastic dual in-line package (PDIP-N), 0.300-inch width, with 0.100-inch lead pitch and 0.130-inch row spacing. Pin 1 is marked by a notch or dot at the top-left corner.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | 1CLR̅ | Asynchronous active-low clear for first flip-flop - forces Q1 = 0 regardless of clock or D1. |
| 2 | 1D | Data input for first flip-flop - sampled on rising CLK edge and transferred to Q1. |
| 3 | 1CLK | Clock input for first flip-flop - rising edge triggers latching of 1D to Q1. |
| 4 | 1PR̅ | Asynchronous active-low preset for first flip-flop - forces Q1 = 1 regardless of clock or D1. |
| 5 | 1Q | True output of first flip-flop - reflects latched 1D value after clock edge. |
| 6 | 1Q̅ | Inverted output of first flip-flop - complements 1Q; usable as feedback or differential signaling. |
| 7 | GND | Ground reference - must be low-impedance return path for all internal logic and output currents. |
| 8 | 2Q̅ | Inverted output of second flip-flop - complements 2Q; electrically isolated from first section. |
| 9 | 2Q | True output of second flip-flop - reflects latched 2D value after 2CLK rising edge. |
| 10 | 2PR̅ | Asynchronous active-low preset for second flip-flop - forces Q2 = 1 independently of first section. |
| 11 | 2CLK | Clock input for second flip-flop - rising edge triggers latching of 2D to Q2. |
| 12 | 2D | Data input for second flip-flop - sampled on rising 2CLK edge and transferred to Q2. |
| 13 | 2CLR̅ | Asynchronous active-low clear for second flip-flop - forces Q2 = 0 independently of first section. |
| 14 | VCC | +5 V supply - must be decoupled locally with 0.1 µF ceramic capacitor near pin 14. |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent D flip-flops | Enables compact implementation of 2-bit registers, toggle dividers, or parallel-load shift registers without external gating. |
| Asynchronous preset and clear | Allows immediate initialization or reset of each flip-flop without waiting for clock edges - critical for power-on sequencing. |
| Complementary Q and Q̅ outputs | Eliminates need for external inverters in applications requiring both states (e.g., JK emulation or bidirectional bus control). |
| Standard TTL-compatible inputs/outputs | Guarantees interoperability with 74LS, 74S, and 74F logic families without interface circuitry or level translation. |
| Low-power Schottky process | Reduces dynamic power consumption versus original 74-series while maintaining speed - key for thermally constrained boards. |
Applications
| Industrial Control Logic | Legacy Instrumentation Interface |
|---|---|
Use Scenario: Latching sensor status signals (e.g., limit switch closures) in PLC I/O modules before scanning cycle execution. IC Role / Device Role / Timing Role: Synchronous data capture element - holds input state stable across scan intervals using system clock edge. Use Value: Prevents metastability-induced glitches during state transitions; enables deterministic polling-based control architecture. |
Use Scenario: Generating quadrature clock phases for analog-to-digital conversion timing in benchtop multimeters. IC Role / Device Role / Timing Role: Edge-triggered divider - converts master oscillator into precise 2x-phase-shifted clocks for sampling control. Use Value: Achieves exact 90° phase relationship between sample-and-hold and conversion start signals without analog delay networks. |
| Serial-to-Parallel Data Conversion | Power-Up State Initialization |
Use Scenario: Converting serial configuration bits from microcontroller GPIO into parallel enable lines for segmented LED drivers. IC Role / Device Role / Timing Role: Shift register stage - two cascaded SN74LS74ADE4 units form 4-bit parallel latch synchronized to bit-clock. Use Value: Reduces MCU pin count and firmware overhead versus dedicated shift-register ICs in cost-sensitive designs. |
Use Scenario: Forcing known initial states on FPGA configuration buses or memory address lines during cold start. IC Role / Device Role / Timing Role: Asynchronous reset generator - PR̅/CLR̅ inputs driven by power-good signal to guarantee defined logic levels pre-configuration. Use Value: Eliminates undefined startup behavior that could cause bus contention or latch-up in downstream logic. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar D-type flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SN74LS74ADR | Same logic function and electrical specs, but in SOIC-14 package with RoHS-compliant NiPdAu finish and moisture sensitivity level 1. | Preferred for surface-mount assembly and automated reflow processes; unsuitable for through-hole prototyping or socket-based testing. | Select SN74LS74ADR when board space is constrained and production uses SMT reflow; verify PCB land pattern matches TI's DB0014A outline. |
| SN74LS74ANSR | Identical functionality in SOP-14 package (wider body than SOIC), same 0–70°C rating, and identical marking "74LS74A". | Offers higher mechanical robustness in vibration-prone environments due to longer leads and larger pad area; slightly larger footprint than SOIC. | Choose SN74LS74ANSR for industrial equipment where thermal cycling reliability and hand-soldering accessibility outweigh size constraints. |
Compared with SN74LS74ADE4, SN74LS74ADR enables higher-density layouts and automated manufacturing, while SN74LS74ANSR improves mechanical retention and solder joint reliability - both retain full functional equivalence but differ in physical integration requirements.
Availability
SN74LS74ADE4 is available at Aetrix Electronics and suitable for industrial control logic, legacy instrumentation interface, and power-up state initialization requiring stable component supply across long-lifecycle embedded programs.
Supply support for SN74LS74ADE4 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.
SN74LS74ADE4 belongs to TI's legacy 74LS logic family, engineered for backward compatibility, predictable timing, and robust operation in fixed-function digital systems deployed from the 1980s onward.
FAQ
What is the maximum clock frequency supported by SN74LS74ADE4?
The SN74LS74ADE4 supports a maximum clock frequency of 30 MHz under standard conditions (VCC = 5 V, TA = 25 °C, CL = 15 pF). This limit arises from internal propagation delays and setup/hold time requirements. Exceeding 30 MHz may result in missed clock edges or metastable outputs. Always validate timing margins in final PCB layout with worst-case voltage and temperature conditions.
Does SN74LS74ADE4 have built-in ESD protection?
SN74LS74ADE4 incorporates standard CMOS-compatible input protection diodes and meets JEDEC JESD78 Class II latch-up immunity, but it does not include dedicated high-energy ESD structures like those found in modern I/O-tolerant logic. System-level ESD protection (e.g., TVS diodes on board-level signal lines) is recommended for environments with frequent human contact or cable disconnection events involving the SN74LS74ADE4.
Can SN74LS74ADE4 operate with a 3.3 V supply?
No, SN74LS74ADE4 is specified only for 4.75 V to 5.25 V operation. Applying 3.3 V will result in invalid logic thresholds, excessive propagation delay, and potential output contention. For 3.3 V systems, consider TI's SN74LVC74A or compatible LVCMOS dual D flip-flops - these are not drop-in replacements and require level-shifting or redesign.
How are the preset and clear inputs of SN74LS74ADE4 asserted?
Both preset (PR̅) and clear (CLR̅) inputs on SN74LS74ADE4 are active-low and asynchronous. Pulling either input to GND (≤0.8 V) immediately forces the corresponding Q output to 1 (PR̅) or 0 (CLR̅), overriding clock and D inputs. These inputs must be held HIGH (≥2.0 V) during normal clocked operation to avoid unintended state changes.
Is SN74LS74ADE4 RoHS compliant?
Yes, SN74LS74ADE4 is RoHS compliant, with lead finish specified as NiPdAu (nickel-palladium-gold) and no intentionally added lead, mercury, cadmium, hexavalent chromium, PBB, or PBDE. The "E4" suffix denotes TI's green packaging standard, confirmed in TI's official packaging addendum dated July 2026.
SN74LS74ADE4 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74LS
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Bulk
- Product Status:
- Obsolete
- Function:
- Set(Preset) and Reset
- Type:
- D-Type
- Output Type:
- Complementary
- Number of Elements:
- 2
- Number of Bits per Element:
- 1
- Clock Frequency:
- 33 MHz
- Max Propagation Delay @ V, Max CL:
- 40ns @ 5V, 15pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 400µA, 8mA
- Voltage - Supply:
- 4.75V ~ 5.25V
- Current - Quiescent (Iq):
- 8 mA
- Input Capacitance:
- -
- Operating Temperature:
- 0°C ~ 70°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
SN74LS74ADE4 FAQ
1.How can I place an order for SN74LS74ADE4 through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74LS74ADE4 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 SN74LS74ADE4 reliable?
The price and inventory of SN74LS74ADE4 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74LS74ADE4 is usually 5 days.
3.What payment methods are accepted for SN74LS74ADE4?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74LS74ADE4 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74LS74ADE4?
SN74LS74ADE4 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74LS74ADE4 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 SN74LS74ADE4?
For technical support, including SN74LS74ADE4 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74LS74ADE4 requirements.
6.How does Aetrix verify that SN74LS74ADE4 is sourced from the original manufacturer or authorized distributors?
All SN74LS74ADE4 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 SN74LS74ADE4 meets industry standards.
7.What is the process for return or replacement of SN74LS74ADE4?
All SN74LS74ADE4 units undergo pre-shipment inspection (PSI). If there is an issue with SN74LS74ADE4, 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 SN74LS74ADE4 part is unused and in its original packaging.
Return procedure for SN74LS74ADE4:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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