Description
SN74LS76 Pin Configuration
| Pin Number | Pin Name | Description |
| 5 | Vcc | Powers the IC typically with 5V |
| 13 | Ground | Connected to the ground of the system |
| JK Flip Flop – 1 / JK Flip Flop – 2 | ||
| 1,6 | Clock-1/ Clock-2 | These pins must be provided with a clock pulse for the flip-flop |
| 2,7 | Preset-1 / Preset-2 | When the Preset is high the flip flop will set Q=1 and not Q=0 |
| 3, 8 | Clear-1/Clear-2 | When Clear is high the flip flop will set Q=0 and not Q=1 |
| 12,16 | K-1/ K-2 | Input pin of the Flip Flop |
| 4,9 | J-1 / J-2 | Another Input pin of the Flip Flop |
| 10,14 | Q-1(bar) / Q-2 (bar) | The inverted output pin of Flip Flop |
| 11,15 | Q-1 / Q-2 | Output Pin of the Flip Flop |
Features and Specifications
- Dual JK Flip Flop Package IC
- Positive edge triggered Flip-Flop
- Operating Voltage: 4.5V to 5.5V
- Minimum High-Level Input Voltage: 2 V
- Maximum Low-Level Input Voltage: 0.8 V
- Available in a 14-pin PDIP package
Where to use 7476 JK Flip-Flop
The SN7476 is a dual in-line JK flip flop IC, i.e. it has two JK flip flops inside it and each can be used individually based on our application. The term JK flip flop comes after its inventor Jack Kilby. The JK flip-flops are considered to be the most efficient flip-flops and can be used for certain applications on their own. The flip-flops are also called latching devices meaning they can remember one single bit of data and latch the output based on it, due to this property they are commonly used as shift registers, control registers, storage registers, or wherever a small memory is required. More than one Flip Flop can be used in series to act as an EEPROM for holding a small amount of data. The JK flip flop is considered to be more suitable for practical application because of its truth table that is the output of the flip flop will be stable for all types of inputs.
So if you are looking for an IC for latching purposes or to act as a small programmable memory for your project then this IC might be the right choice for you.
How to use 7476
As told earlier we have two JK flip flops in this IC, the IC is powered by +5V typically the minimum and maximum input and output voltage for the input (J, K) pins and the output (Q, Q bar) pins are discussed in the specifications above. The below circuit shows a typical sample connection for the JK flip-flop
The J and K pins are the input pins for the Flip-Flop and the Q and Q bar pins are the output pins. Note that the input pins are pulled down to the ground through a 1k resistor, this way we can avoid the pin in floating condition. That is the pin will held to the ground when the button is not pressed and when the button is pressed the pin will be held to supply voltage.
The reset button should be pulled up through a 1K resistor and when grounded will reset the flip-flop. The clock signal for the JK flip-flop is responsible for changing the state of the output. The flip-flop will change its output only during the rising edge of the clock signal. The clock signal here is just a push button but can be the type of pulse like a PWM signal. The output state of the flip-flops can be determined from the truth table below.
Normally during regular operation of the IC, the reset pin will be set high and the clock pulse of known frequency will be supplied to the clock pin, then the values of J and K will be varied based on the input signals and the respective output will be obtained on the Q and Q bar pins.
Applications
- Shift Registers
- Memory/Control Registers
- EEPROM circuits
- Latching devices
