1. What is Power Supply Rejection Ratio?

Power Supply Rejection Ratio (PSRR) is a measure of how well a circuit rejects ripple or noise coming from its power supply. It quantifies the ability of a circuit to maintain its output stability despite variations in the power supply voltage.

2. How Does the Calculator Work?

The calculator uses the PSRR formula:

Where:

• \( V_{in} \) — Input voltage ripple (V)
• \( V_{out} \) — Output voltage ripple (V)
• \( \log_{10} \) — Base-10 logarithm function

Explanation: The formula calculates the ratio of input ripple to output ripple in decibels (dB), indicating how effectively the circuit suppresses power supply noise.

3. Importance of PSR Calculation

Details: PSRR is crucial for designing stable electronic systems, particularly in applications where clean power is essential, such as in audio amplifiers, precision measurement equipment, and communication systems.

4. Using the Calculator

Tips: Enter input and output voltage ripple values in volts. Both values must be positive and greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is a good PSRR value?
A: Higher PSRR values indicate better noise rejection. Typically, values above 60 dB are considered good, while values above 80 dB are excellent.

Q2: How does PSRR vary with frequency?
A: PSRR typically decreases with increasing frequency. Most circuits have specified PSRR values at different frequency points.

Q3: Why is PSRR important in amplifier design?
A: High PSRR ensures that power supply noise doesn't appear at the output, maintaining signal integrity and reducing distortion.

Q4: How can PSRR be improved in circuit design?
A: PSRR can be improved through proper decoupling, regulator selection, circuit topology choices, and layout considerations.

Q5: What's the difference between PSRR and CMRR?
A: PSRR measures rejection of power supply variations, while CMRR (Common-Mode Rejection Ratio) measures rejection of common-mode signals at the input.