Logarithmic Detector Controller Chip, 0.001 - 10 GHz

The HMC611 Logarithmic Detector/Controller generates a voltage that is proportional to the log of the RF Power envelop presented to its input. The HMC611 employs a successive compression topology which delivers extremely high dynamic range and conversion accuracy over a wide input frequency range. As the input power is increased, successive amplifi ers move into saturation one by one creating an accurate approximation of the logarithm function.
The output of a series of square law detectors is summed, converted into voltage domain and buffered to drive the LOGOUT output. For detection mode, the LOGOUT pin is shorted to the VSET input, and will provide a nominal logarithmic slope of -25 mV/ dB and an intercept of 9 dBm (24 dBm for 5.8 GHz). The HMC611 CAN also be used in the controller mode where an external voltage is applied to the VSET pin, to create an AGC or APC feedback loop.
By Hittite Microwave Corporation