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Output Miller Capacitance Formula:
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Output Miller Capacitance is a parasitic capacitance that exists between the drain and gate of a MOSFET. It represents the effective capacitance seen at the output due to the Miller effect, which amplifies the gate-drain capacitance by the voltage gain of the amplifier.
The calculator uses the Miller capacitance formula:
Where:
Explanation: The Miller effect causes the gate-drain capacitance to appear larger at the output by a factor of (Av+1)/Av due to the voltage amplification between gate and drain.
Details: Accurate calculation of Miller capacitance is crucial for analyzing high-frequency performance of MOSFET amplifiers, determining bandwidth limitations, and designing stable amplifier circuits with proper frequency response.
Tips: Enter gate-drain capacitance in Farads and voltage gain (dimensionless). Ensure gate-drain capacitance is positive and voltage gain is not zero.
Q1: What is the Miller effect?
A: The Miller effect is the phenomenon where a capacitance between input and output of an amplifier appears larger at both terminals due to voltage amplification.
Q2: Why is Miller capacitance important in amplifier design?
A: Miller capacitance limits the high-frequency response of amplifiers and can cause stability issues if not properly accounted for in the design.
Q3: How does voltage gain affect Miller capacitance?
A: Higher voltage gain increases the effective Miller capacitance, which further reduces the amplifier's bandwidth.
Q4: Can Miller capacitance be eliminated?
A: While it cannot be completely eliminated, techniques like cascode configuration can minimize the Miller effect by reducing the voltage gain across the capacitance.
Q5: What are typical values for gate-drain capacitance?
A: Gate-drain capacitance values typically range from femtofarads (fF) to picofarads (pF) depending on the MOSFET size and technology.