The ADL5903 is a true rms responding power detector that has a 35 dB measurement range. It features low power consumption and an intrinsically ripple-free error transfer function.The ADL5903 provides a solution in a variety of high frequency systems requiring an accurate measurement of signal power. Requiring only a single supply of 3.0 V to 5.0 V and a few capacitors, it is easy to use and capable of being driven single-ended or with a balun for differential input drive. An on-chip matching network provides good return loss over the specified frequency range of the device. The ADL5903 can operate from 200 MHz to 6 GHz and can accept inputs from −30 dBm to +20 dBm.The ADL5903 can be used to determine the true power of a high frequency signal with a complex modulation envelope including large crest factor signals such as GSM, CDMA, W-CDMA, TD-SCDMA, and LTE modulated signals. The output is then proportional to the logarithm of the rms value of the input. In other words, the reading is presented directly in decibels and is scaled about 35.5 mV/dB at 900 MHz.The ADL5903 has low power consumption when operational and a disable mode that further reduces the power consumption. Power consumption is less than 100 μA when the ADL5903 enters power-down mode through a logic low at Pin ENBL. The ADL5903 is supplied in a 2 mm × 2 mm, 8-lead LFCSP for operation over the wide temperature range of −55°C to +125°C.ApplicationsPower amplifier linearization/control loopsTransmitter power controlsTransmitter signal strength indication (TSSI)RF instrumentationWireless repeaters