Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Loop gain at -180° (dB)

Required number input.

Calculate loop gain margin from open-loop gain in decibels at the minus-180-degree phase crossover. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

Gain margin (dB)

The resulting gain margin returned as a number.

• PLL bandwidth, margin, lock time, output frequency, spur, and integrated-jitter estimates depend on loop order, charge pump, divider values, oscillator gain, reference noise, nonlinear acquisition, and the exact phase-noise integration limits. Simplified linear models primarily describe locked small-signal behavior.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• PLL Phase Margin

  Calculate loop phase margin from unwrapped open-loop phase at the unity-gain crossover frequency.

• Finite-Gain Closed-Loop Error

  Calculate feedback closed-loop gain A/(1+Aβ) and percent error relative to ideal 1/β. Assumes negative feedback with positive real open-loop gain and feedback factor; frequency dependence is excluded.

• Op-Amp Open-Loop Gain

  Calculate open-loop voltage gain A=Vout/(V+−V−) from an unsaturated operating-point measurement. Differential input cannot be zero; this scalar does not capture frequency-dependent gain.