The CD4025 is a CMOS IC that contains three independent NOR gates, each with three inputs and one output. The device is designed for use as a digital buffer or inverter in high-noise environments due to its high noise immunity.
Electrical Characteristics:
- Wide supply voltage range: 3V to 15V
- High noise immunity: 0.45 VDD (typical)
- Low power consumption: 10 μA (maximum)
- High speed: 10 MHz (typical)
- Output drive capability: 10 LS-TTL loads
- Pin and functionally compatible with CD4001 and CD4075
Pinout Configuration
The pinout configuration of the IC 4025 are as I have explained below:
As shown in the above diagram, the IC 4025 is built with 3 special NOR gates, each having 3 inputs and one output.
When the 3 inputs are applied with high or low signals with a specific pattern, the output pin produces a low or high depending on the input pattern.
The pinout details of the IC 4025 are provide in the following table:
VDD | 14 | Power | This pinout is the Supply Voltage input pin of the IC (+3 to +15V) |
GND | 7 | Power | This is the Ground (0V) pinout of the IC |
A1 to A3 | 1, 3, 13 | Input | These pinouts constitute Inputs A of the three NOR gates |
B1 to B3 | 2, 4, 12 | Input | These pinouts serve as the Inputs B of the three NOR gates |
C1 to C3 | 5, 8, 11 | Input | These pinouts work like the Inputs C of the three NOR gates |
Q1 to Q3 | 6, 9, 10 | Output | These pinouts operate like the Outputs from the three NOR gates |
Truth Table
The following truth table explains how the outputs of each gate of the IC 4025 will operate when their inputs are fed specific positive or negative
Input A | Input B | Input C | Output Q |
---|---|---|---|
0 | 0 | 0 | 1 |
0 | 0 | 1 | 0 |
0 | 1 | 0 | 0 |
0 | 1 | 1 | 0 |
1 | 0 | 0 | 0 |
1 | 0 | 1 | 0 |
1 | 1 | 0 | 0 |
1 | 1 | 1 | 0 |
As explained previously, each gate of the IC 4025 has 3 inputs and 1 output. Let's consider the 3 inputs to be as input A, input B, input C
Now, the output of each gate will produce either a high logic or a low logic depending upon the specific pattern in which their 3 inputs (A,B,C) are fed with positive or negative voltage signals.
For example, if all the 3 inputs are fed with a positive supply input, then the output will produce a low logic or a zero voltage. On the other hand if suppose all the 3 inputs are fed with a 0V or a negative supply input, then the output will generate a HIGH, which will equal to the positive supply voltage.
Likewise, depending upon how the inputs pins are fed with other voltage the output may produce a 0V or a high (positive supply voltage).
The details are as given in the above truth table.
Applications
Digital buffers: One of the main uses of the IC CD4025 is like a digital buffer. This helps to improve the signal quality of digital circuits. This may be also used to isolate a high impedance input from a low impedance output. This ensures that the input signal quality is not affected by loading effects.
Inverters: The CD4025 could be also be used like a signal inverter. This application simply invert the polarity logic level of a digital signal. This is useful when a digital signal needs to be inverted before it is used as an input to another logic circuit.
Noise reduction: The CD4025 features a high noise immunity, due to which it becomes useful in applications where there is a lot of electrical noise. It could be applied to filter out unwanted noise signals and ensure that the logic circuitry only responds to signals that are appropriate.
Counters: The CD4025 may be used in conjunction with other digital logic integrated circuits to construct digital counters. When a given requirement is fulfilled, it's possible to employ it to reset the count or to adjust the clock signal that operates the counter.
Signal gating: The CD4025 can serve as a signal gate in a circuit to control the movement of digital signals. Different elements of the circuit can be enabled or deactivated by selectively activating or disabling the gate.
Oscillators: The CD4025 may be used to construct basic digital oscillators capable of producing square waves at a given frequency. These oscillators have a wide range of applications, including timing circuits and tone generators.
Have questions? Please Comment! Once posted, your comment will be sent to me for moderation (Rest Assured!). Your comments must be related to the above article...