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Texas Instruments SN74AHCT74D
- Part No.:
- SN74AHCT74D
- Manufacturer:
- Texas Instruments
- Category:
- Flip Flops
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
SN74AHCT74D.pdf
- Description:
- IC FF D-TYPE DUAL 1BIT 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,178
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Product details
Overview
SN74AHCT74D from Texas Instruments is a dual positive-edge-triggered D-type flip-flop with independent asynchronous preset (PRE) and clear (CLR) inputs, operating at 4.5 V–5.5 V supply, delivering ±8-mA output drive at 5 V, TTL-voltage-compatible inputs, and latch-up performance exceeding 250 mA per JESD17 - used for clock division, signal debouncing, and synchronous control in industrial logic interfaces.
For engineers reviewing the SN74AHCT74D datasheet, SN74AHCT74D pinout, SN74AHCT74D application, or SN74AHCT74D equivalent, key selection criteria include its dual-edge-independent asynchronous control, guaranteed 5 ns setup/hold timing at 5 V, SOIC-14 package compatibility, and robust noise immunity in noisy digital systems.
Technical Context
The SN74AHCT74D implements two independent D-type latches triggered on the rising edge of CLK, with PRE and CLR overriding all other inputs asynchronously. Each flip-flop features complementary Q and Q̅ outputs, enabling direct toggle configuration when D is tied to Q̅.
Its TTL-compatible input thresholds (VIL = 0.8 V max, VIH = 2.0 V min) ensure interoperability with legacy 5-V TTL logic, while balanced CMOS push-pull outputs provide symmetrical sourcing/sinking capability and fast edge rates under light capacitive loads ≤50 pF.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | 4.5 V to 5.5 V - ensures stable operation across standard 5-V rail tolerances and brown-out resilience |
| Output Drive | ±8 mA at 5 V - supports direct interfacing with multiple 74-series TTL inputs without buffering |
| Input Compatibility | TTL-voltage compatible - accepts standard TTL logic levels (0.8 V/2.0 V thresholds) without level-shifting |
| Propagation Delay | 5.8 ns (tPLH/tPHL, CL = 15 pF, TA = 25°C) - enables reliable 100-MHz maximum clock operation |
| Quiescent Current | 10 µA max ICC - minimizes static power in battery-backed or low-power standby modes |
| Setup/Hold Time | 5 ns tsu, 0 ns th (at 5 V) - simplifies timing closure in synchronous designs with moderate clock skew |
| Latch-up Immunity | >250 mA per JESD17 - provides robustness against transient current faults in industrial environments |
Pinout & Package
SN74AHCT74D is supplied in a 14-pin SOIC (Small Outline Integrated Circuit) package measuring 8.7 mm × 6.0 mm (body size 8.7 mm × 3.91 mm), with gull-wing leads and standard JEDEC MO-002AC footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1CLR, 2CLR | Asynchronous Clear Input | Active-low reset forcing Q = L / Q̅ = H regardless of CLK or D state |
| 1PRE, 2PRE | Asynchronous Preset Input | Active-low set forcing Q = H / Q̅ = L regardless of CLK or D state |
| 1D, 2D | Data Input | Samples and transfers to Q on next positive CLK edge when PRE/CLR are high |
| 1CLK, 2CLK | Clock Input | Positive-edge-triggered sampling point; voltage-level sensitive, not rise-time dependent |
| 1Q, 2Q | True Output | Complementary to Q̅; drives downstream logic or feedback paths |
| 1Q̅, 2Q̅ | Inverted Output | Complementary to Q; enables toggle mode when connected to D |
| VCC (Pin 14) | Power Supply | 5-V nominal supply connection; requires local 0.1-µF bypass capacitor |
| GND (Pin 7) | Ground Reference | Return path for all I/O and supply currents; must be low-impedance |
Key Features
| Feature | Design Value |
|---|---|
| Dual independent flip-flops | Enables compact implementation of two synchronized storage elements in one SOIC-14 package |
| Asynchronous PRE/CLR per channel | Allows immediate initialization or reset without waiting for clock edge - critical for system startup and fault recovery |
| TTL-compatible inputs | Eliminates need for external level shifters when interfacing with legacy 5-V TTL families (e.g., 74LS, 74F) |
| Balanced CMOS push-pull outputs | Provides matched rise/fall times and equal sourcing/sinking strength for clean signal integrity into 50-pF loads |
| Low ICC quiescent current | Reduces system-level standby power - especially valuable in always-on industrial controllers and remote sensors |
Applications
| Toggle Switch Emulation | Controller Reset Hold |
|---|---|
Use Scenario: Replacing mechanical toggle switches with momentary push buttons in space-constrained HMI panels or IoT edge nodes. IC Role / Device Role / Timing Role: SN74AHCT74D configured as a toggle flip-flop (D → Q̅ feedback) converts each button press into a single clean clock-edge-driven output transition. Use Value: Eliminates mechanical wear, reduces BOM cost, and enables PCB miniaturization without sacrificing user interface functionality. |
Use Scenario: Maintaining stable enable/disable states during microcontroller reset sequences in motor drives or PLC I/O modules. IC Role / Device Role / Timing Role: SN74AHCT74D holds output state via asynchronous PRE/CLR until controller firmware reasserts control post-reset. Use Value: Prevents spurious actuator activation or data corruption during boot-up by decoupling logic state from processor availability. |
| Clock Division | Noise-Tolerant Signal Conditioning |
Use Scenario: Generating half-frequency clocks for peripheral interfaces (e.g., UART baud rate derivation, LED dimming PWM). IC Role / Device Role / Timing Role: SN74AHCT74D wired in toggle mode (Q̅ → D) divides incoming clock by two with deterministic edge alignment. Use Value: Provides glitch-free, duty-cycle-preserving frequency reduction without requiring PLLs or programmable logic. |
Use Scenario: Cleaning slow-rising or electrically noisy signals from sensors, encoders, or industrial fieldbus lines before MCU sampling. IC Role / Device Role / Timing Role: SN74AHCT74D acts as a synchronous synchronizer and edge cleaner - clocking metastable inputs into known logic states. Use Value: Improves system reliability in EMI-heavy environments (e.g., factory floors, automotive under-hood) by rejecting sub-threshold noise pulses. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual D-type flip-flop applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| 74HC74D | CMOS input thresholds (VIH = 3.15 V min), lower drive (±4 mA), wider VCC range (2–6 V) | Requires higher input voltage for HIGH recognition; unsuitable for direct TTL interface without pull-ups | Select when operating below 4.5 V or when lower power (2 µA ICC) outweighs TTL compatibility needs |
| SN74LVC74AD | 3.3-V optimized (1.65–3.6 V), LVCMOS inputs, ±24 mA drive, no TTL compatibility | Not interoperable with 5-V TTL; requires level translation if mixed-voltage design exists | Select for modern 3.3-V systems where higher speed (tpd = 4.5 ns) and stronger drive justify redesign effort |
Compared with 74HC74D and SN74LVC74AD, the SN74AHCT74D uniquely bridges legacy 5-V TTL and modern CMOS logic domains while maintaining robust noise margins and predictable timing - making it the preferred choice for industrial upgrades and mixed-signal control boards.
Availability
SN74AHCT74D is available at Aetrix Electronics and suitable for industrial automation controllers, embedded HMI interfaces, and motor drive logic circuits requiring stable component supply, long-term lifecycle assurance, and consistent SOIC-14 packaging.
Supply support for SN74AHCT74D 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 SN74AHCT74D belongs to TI's advanced high-speed CMOS (AHCT) logic family, designed specifically for seamless 5-V TTL-to-CMOS interoperability in noise-prone industrial control and instrumentation systems.
FAQ
What is the maximum clock frequency supported by the SN74AHCT74D?
The SN74AHCT74D supports a maximum clock frequency of 100 MHz under typical conditions (CL = 15 pF, VCC = 5 V, TA = 25°C), based on its 5.8-ns propagation delay and 5-ns minimum pulse width requirement for CLK. At elevated temperatures or heavier loads (e.g., CL = 50 pF), the usable frequency drops to 80 MHz to maintain timing margin.
Can the SN74AHCT74D operate reliably with a 3.3-V supply?
No - the SN74AHCT74D is specified only for 4.5 V to 5.5 V operation. Its TTL-compatible input thresholds and output drive characteristics are optimized for 5-V systems. Using 3.3 V violates the Recommended Operating Conditions and risks undefined logic states, excessive ICC, and potential latch-up.
How should unused inputs on the SN74AHCT74D be handled?
All unused inputs on the SN74AHCT74D - including PRE, CLR, D, and CLK - must be terminated to either VCC or GND. Floating inputs cause increased ICC, oscillation, and ESD susceptibility. TI recommends 10-kΩ pull-up or pull-down resistors for uncommitted pins, with PRE and CLR typically held high (via pull-up) to disable asynchronous control.
Is the SN74AHCT74D pin-compatible with other 74xx74 variants in SOIC-14 packages?
Yes - the SN74AHCT74D shares identical pinout and footprint with industry-standard 74xx74 dual D-flip-flops in SOIC-14 (D package), including 74HC74D, 74HCT74D, and SN74LVC74AD. However, functional behavior (e.g., input thresholds, drive strength, timing) differs, so electrical validation is required before substitution.
Does the SN74AHCT74D include internal ESD protection?
Yes - the SN74AHCT74D incorporates on-chip ESD protection diodes meeting ±2000 V HBM (Human Body Model) and ±1000 V CDM (Charged Device Model) per JESD22-A114 and JESD22-C101. This allows safe handling in standard manufacturing environments but does not eliminate need for proper ESD controls during board assembly.
SN74AHCT74D Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- 74AHCT
- 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:
- 140 MHz
- Max Propagation Delay @ V, Max CL:
- 8.8ns @ 5V, 50pF
- Trigger Type:
- Positive Edge
- Current - Output High, Low:
- 8mA, 8mA
- Voltage - Supply:
- 4.5V ~ 5.5V
- Current - Quiescent (Iq):
- 2 µA
- Input Capacitance:
- 2 pF
- Operating Temperature:
- -40°C ~ 125°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
SN74AHCT74D FAQ
1.How can I place an order for SN74AHCT74D through Aetrix?
Please submit a Request for Quotation (RFQ) for SN74AHCT74D 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 SN74AHCT74D reliable?
The price and inventory of SN74AHCT74D are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for SN74AHCT74D is usually 5 days.
3.What payment methods are accepted for SN74AHCT74D?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for SN74AHCT74D transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for SN74AHCT74D?
SN74AHCT74D orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your SN74AHCT74D 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 SN74AHCT74D?
For technical support, including SN74AHCT74D datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your SN74AHCT74D requirements.
6.How does Aetrix verify that SN74AHCT74D is sourced from the original manufacturer or authorized distributors?
All SN74AHCT74D 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 SN74AHCT74D meets industry standards.
7.What is the process for return or replacement of SN74AHCT74D?
All SN74AHCT74D units undergo pre-shipment inspection (PSI). If there is an issue with SN74AHCT74D, 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 SN74AHCT74D part is unused and in its original packaging.
Return procedure for SN74AHCT74D:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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