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.

Bandwidth

Required number input.

Calculate kTB thermal noise power in dBm over a given bandwidth at room temperature. 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]

Thermal noise

The resulting thermal noise returned as a number.

• SNR, SINAD, THD, SFDR, and integrated-noise results require explicit bandwidth, weighting, reference amplitude, windowing, harmonic set, impedance, and RMS or peak conventions. Values measured under different conditions are not directly comparable.
• 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.

• Heatsink Junction To Case Resistance

  Calculate junction-to-case thermal resistance from junction and case temperatures under steady dissipated power; junction temperature must be no lower than case temperature.

• Receiver Sensitivity

  Compute the thermal-noise-limited receiver sensitivity as -174 dBm/Hz plus ten times the base-ten logarithm of the bandwidth plus the noise figure plus the required SNR.

• Resistor Thermal Noise Current

  RMS Johnson-Nyquist current noise over an equivalent noise bandwidth; assumes a resistor at thermal equilibrium.