A device for measuring voltage levels includes a root mean square (RMS) detector. The RMS detector includes a linear multiplier, a log converter, a low-pass filter and a temperature compensator. The linear multiplier multiplies a voltage of an input signal by the voltage of the input signal. The low-pass filter couples to an output of the linear multiplier. The log converter generates a logarithmic signal having a voltage that is logarithmically related to a voltage of an output of the low-pass filter. The temperature compensator adjusts the logarithmic signal based on a temperature of the RMS detector. The RMS detector is capable of determine an RMS voltage level of the input signal.