Overview
The SN74AC74D is a dual positive-edge-triggered D-type flip-flop produced by Texas Instruments. This device is part of the 74AC series, known for its high-speed and low-power CMOS logic. The SN74AC74D operates over a wide voltage range from 2V to 6V, making it versatile for various applications. It features two independent D-type flip-flops, each with a positive edge-triggered clock input, data input, preset input, and clear input. The device is available in a 14-pin SOIC package, making it suitable for a range of digital circuit designs.
Key Specifications
| Parameter | Unit | Min | Typ | Max |
|---|---|---|---|---|
| VCC (Supply Voltage) | V | 2 | 6 | |
| VIH (High-level Input Voltage) at VCC = 5.5V | V | 3.85 | 3.85 | |
| VIL (Low-level Input Voltage) at VCC = 5.5V | V | 1.65 | 1.65 | |
| IOH (High-level Output Current) at VCC = 5.5V | mA | -24 | -24 | |
| IOL (Low-level Output Current) at VCC = 5.5V | mA | 24 | 24 | |
| TA (Operating Free-Air Temperature) | °C | -40 | 85 | |
| fclock (Clock Frequency) at VCC = 5V | MHz | 95 | 140 | |
| tPLH (Propagation Delay Time) at VCC = 5V | ns | 2.5 | 10 | |
| tPHL (Propagation Delay Time) at VCC = 5V | ns | 3 | 10.5 |
Key Features
- Dual positive-edge-triggered D-type flip-flops.
- Operates over a wide voltage range from 2V to 6V.
- Inputs accept voltages up to 6V.
- Maximum propagation delay time of 10 ns at 5V.
- High-level output current of -24 mA and low-level output current of 24 mA at 5.5V.
- Available in 14-pin SOIC, SSOP, PDIP, SOP, and TSSOP packages.
- Good bypass capacitor recommendations for power supply stability.
Applications
The SN74AC74D is suitable for a variety of digital circuit applications, including:
- Sequential logic circuits.
- Counters and timers.
- Shift registers.
- Memory elements in digital systems.
- General-purpose digital logic designs.
Q & A
- What is the operating voltage range of the SN74AC74D?
The SN74AC74D operates over a voltage range from 2V to 6V.
- What is the maximum clock frequency for the SN74AC74D at 5V?
The maximum clock frequency is 140 MHz at 5V.
- What are the input voltage levels for the SN74AC74D at 5.5V?
The high-level input voltage (VIH) is 3.85V, and the low-level input voltage (VIL) is 1.65V at 5.5V.
- What are the output current capabilities of the SN74AC74D?
The device can source up to -24 mA and sink up to 24 mA at 5.5V.
- What are the recommended power supply bypass capacitors for the SN74AC74D?
A 0.1-μF capacitor is recommended, and it is acceptable to parallel multiple bypass capacitors to reject different frequencies of noise.
- What are the package options available for the SN74AC74D?
The device is available in SOIC, SSOP, PDIP, SOP, and TSSOP packages.
- What is the propagation delay time of the SN74AC74D at 5V?
The propagation delay time (tPLH and tPHL) ranges from 2.5 ns to 10.5 ns at 5V.
- What is the operating temperature range for the SN74AC74D?
The operating free-air temperature range is from -40°C to 85°C.
- How should unused inputs be handled on the SN74AC74D?
Unused inputs must be held at VCC or GND to ensure proper device operation.
- What are some common applications of the SN74AC74D?
The device is commonly used in sequential logic circuits, counters, timers, shift registers, and general-purpose digital logic designs.
