A detection circuit that can accurately detect signal peak is described. In an exemplary design, the detection circuit includes a bias voltage generator and a MOS transistor. The bias voltage generator provides a bias voltage as a function of temperature. The MOS transistor receives an input RF signal and the bias voltage and provides a rectified signal, which may be a linear function of the input RF signal and may have reduced deviation with temperature due to the bias voltage. The bias voltage generator may generate the bias voltage based on a temperature-dependent current having a slope selected to reduce deviation in the rectified signal with temperature. An offset canceller may cancel a reference voltage from the rectified signal and provide an output signal. A bulk bias generator may generate a bulk voltage for the bulk of the MOS transistor as a function of temperature to improve operating speed at higher temperature.