SN74HCT74 - Dual D-Type Flip-Flop with Clear/Preset | TI
MPN: SN74HCT74 β Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $0.45 | $0.45 |
| 10 | $0.38 | $3.80 |
| 100 | $0.3 | $30.00 |
| 500 | $0.25 | $125.00 |
| 1,000 | $0.2 | $200.00 |
Drop-in alternatives for SN74HCT74 β same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
SN74HCT74N
β Drop-Inπ Reference alternative (not in catalog)
SN74HCT74D
β Drop-Inπ Reference alternative (not in catalog)
SN74HCT74PW
β Drop-Inπ Reference alternative (not in catalog)
CD74HCT74E
β Drop-Inπ Reference alternative (not in catalog)
MC74HCT74AN
β Drop-Inπ Reference alternative (not in catalog)
74HCT74D
β Drop-Inπ Reference alternative (not in catalog)
SN74HCT74 Maximum Ratings & Electrical Characteristics
| Number of Channels | 2 |
| Logic Family | HCT |
| Logic Type | D-Type Flip-Flop |
| Trigger Type | Positive Edge |
| Output Type | Complementary |
| Supply Voltage - Min | 4.5 V |
| Supply Voltage - Max | 5.5 V |
| Maximum Quiescent Current | 40 Β΅A |
| Propagation Delay Time | 15 ns (typical at 5V) |
| Output Current | Β±4 mA |
| Input Type | TTL-Compatible |
| Operating Temperature Range | -40Β°C to +85Β°C |
| Package Type | 14-DIP (N), 14-SOIC (D), 14-TSSOP (PW) |
| Mounting Style | Through Hole / SMD |
| RoHS Status | Compliant |
SN74HCT74 Pin Configuration
| Pin 1 | 1CLR β Clear input for flip-flop 1 (active low) |
| Pin 2 | 1D β Data input for flip-flop 1 |
| Pin 3 | 1CLK β Clock input for flip-flop 1 (positive edge) |
| Pin 4 | 1PRE β Preset input for flip-flop 1 (active low) |
| Pin 5 | 1Q β Output Q for flip-flop 1 |
| Pin 6 | 1QΜ β Complementary output for flip-flop 1 |
| Pin 7 | GND β Ground |
| Pin 8 | 2QΜ β Complementary output for flip-flop 2 |
| Pin 9 | 2Q β Output Q for flip-flop 2 |
| Pin 10 | 2PRE β Preset input for flip-flop 2 (active low) |
| Pin 11 | 2CLK β Clock input for flip-flop 2 (positive edge) |
| Pin 12 | 2D β Data input for flip-flop 2 |
| Pin 13 | 2CLR β Clear input for flip-flop 2 (active low) |
| Pin 14 | VCC β Positive supply voltage (4.5V to 5.5V) |
Safe Operating Area (SOA) & Thermal Characteristics
No official SOA curve available for this digital IC. Always operate within absolute maximum ratings specified in the datasheet. Ensure adequate cooling and derate as needed.
Typical Applications
SN74HCT74 is suitable for 6 applications: Data Storage Registers, Frequency Dividers, Control Logic in Microcontrollers, Industrial Automation, Consumer Electronics, Test and Measurement Equipment.
Data Storage Registers
The SN74HCT74 is used to build data storage registers in digital systems. Its dual flip-flops can store two bits of data, and the positive-edge triggering ensures synchronous operation with the system clock. The clear and preset inputs allow initialization to known states, which is critical for register-based state machines. With a propagation delay of 15 ns, it supports clock frequencies up to 66 MHz, making it suitable for moderate-speed data paths. The TTL-compatible inputs simplify interfacing with legacy TTL logic, and the low quiescent current of 40 Β΅A minimizes power consumption in battery-powered devices.
Recommended
Frequency Dividers
The SN74HCT74 can be configured as a frequency divider by connecting the Q output to the D input, creating a toggle flip-flop. Each flip-flop divides the clock frequency by two, and cascading two flip-flops provides a divide-by-4 function. The positive-edge triggering ensures clean division with minimal skew. The device's 5V operation and TTL compatibility make it ideal for dividing clocks in mixed-logic systems. The typical propagation delay of 15 ns limits the maximum input frequency to about 66 MHz, which is adequate for many microcontroller and FPGA applications. The clear input can be used to reset the divider to a known state.
Recommended
Control Logic in Microcontrollers
The SN74HCT74 is used in microcontroller systems for debouncing switches, generating interrupts, and implementing simple state machines. Its TTL-compatible inputs allow direct connection to microcontroller I/O pins without level shifting. The preset and clear inputs provide asynchronous control for resetting or setting flags. The low power consumption (40 Β΅A max ICC) is beneficial for portable and battery-operated devices. The device operates from 4.5V to 5.5V, matching typical microcontroller supply voltages. The 15 ns propagation delay ensures fast response for control signals, and the Β±4 mA output drive can directly drive LEDs or other loads.
Recommended
Industrial Automation
In industrial automation, the SN74HCT74 is used for sequence control, interlocking, and alarm logic. Its robust operating temperature range (-40Β°C to +85Β°C) and 5V operation make it suitable for harsh environments. The clear and preset inputs allow fail-safe initialization of control logic. The TTL-compatible inputs interface directly with industrial sensors and PLCs. The low quiescent current reduces heat dissipation in control cabinets. The device's dual flip-flop configuration saves board space and reduces component count. The 15 ns propagation delay ensures timely response in high-speed automation lines.
Recommended
Consumer Electronics
The SN74HCT74 is used in consumer electronics for remote control decoding, display multiplexing, and user interface logic. Its small package options (SOIC, TSSOP) enable compact PCB designs. The 5V operation is compatible with common consumer ICs. The low power consumption extends battery life in portable devices. The positive-edge triggering ensures reliable data capture in noisy environments. The preset and clear inputs allow resetting the device to a known state during power-up. The device's cost-effectiveness makes it ideal for high-volume consumer products.
Recommended
Test and Measurement Equipment
The SN74HCT74 is used in test and measurement equipment for signal conditioning, event counting, and timing generation. Its precise positive-edge triggering ensures accurate event capture. The TTL-compatible inputs interface with various test probes and sensors. The wide operating temperature range allows use in benchtop and field instruments. The low propagation delay (15 ns) enables high-speed counting. The clear input allows resetting counters to zero. The device's dual flip-flop configuration can be used to build frequency counters and time-interval meters.
Recommended
Recommended Products Summary
Engineering reference data for SN74HCT74 β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | SN74HCT74N | CD74HCT74E | MC74HCT74AN |
|---|---|---|---|---|
| Package | 14-DIP (N), 14-SOIC (D), 14-TSSOP (PW) | 14-DIP (N) | 14-DIP (N) | 14-DIP (N) |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | onsemi |
| Supply Voltage Range | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V | 4.5V to 5.5V |
| Propagation Delay (typ) | 15 ns | 15 ns | 15 ns | 15 ns |
| Max Quiescent Current | 40 Β΅A | 40 Β΅A | 40 Β΅A | 40 Β΅A |
| Output Drive | Β±4 mA | Β±4 mA | Β±4 mA | Β±4 mA |
| Operating Temperature | -40Β°C to +85Β°C | -40Β°C to +85Β°C | -40Β°C to +85Β°C | -40Β°C to +85Β°C |
| Input Type | TTL-Compatible | TTL-Compatible | TTL-Compatible | TTL-Compatible |
Key Differentiators
- TTL-compatible inputs (vs SN74HC74)
- Multiple package options (vs CD74HCT74E)
- Low power consumption (vs 74HCT74D (NXP))
Design Notes
Decouple the VCC pin with a 0.1 Β΅F ceramic capacitor placed as close to the pin as possible. For noisy environments, add a 10 Β΅F electrolytic capacitor in parallel. The SN74HCT74 operates from 4.5V to 5.5V, so ensure the supply is within this range to avoid undefined logic states.
For high-speed operation, keep traces short and avoid long parallel runs to reduce crosstalk. Use a solid ground plane to minimize noise. The 14-pin DIP package is through-hole, while SOIC and TSSOP are surface-mount; adjust pad sizes accordingly. Ensure adequate clearance for the active-low preset and clear inputs.
Unused preset and clear inputs must be tied high to VCC to prevent false triggering. The setup and hold times must be met relative to the clock edge; refer to the datasheet for specific values. Do not exceed the absolute maximum ratings, especially on input voltages, to avoid damage.
Compliance Information
RoHS compliant per TI product page. Not AEC-Q100 qualified for automotive.
