High dynamic range 10 GHz RMS detector offers accurate RF power measurement

June 16, 2010 // Paul Buckley

Linear Technology has introduced a high dynamic range 10 GHz RMS detector that claims to set a new standard in measurement accuracy of RF signals.

The LTC5582 offers ±0.2 dB linearity over a 43dB dynamic range at 2.14 GHz, regardless of the high crest-factor modulations used in 3G and 4G broadband wireless networks, including LTE, WiMAX, TD-SCDMA, W-CDMA and CDMA2000. In addition, the LTC5582 can accurately measure signal levels as low as -56 dBm to 1 dBm to ±1 dB error, providing 57 dB dynamic range from 450 MHz to 2.7 GHz. The device is capable of operating at higher frequencies, providing 46 dB of useful dynamic range at 6 GHz, and 38dB at 10 GHz. Moreover, the device operates efficiently on a single 3.3 V supply. The device's RF input is designed to operate single-ended, requiring no external balun transformer, thus reducing the solution size and cost.     

From -40 to 85 degrees C, the LTC5582 can deliver 48 dB of dynamic range with a linearity accuracy of ±1 dB. This enables use of the LTC5582 in rugged environments such as RRUs (Remote Radio Units) or ODU (Outdoor Units) deployed on cellular towers with minimal calibration adjustments. Moreover, the device has on-chip provisions for first- and second-order temperature compensation which can be easily calibrated for improved temperature performance.     

The LTC5582 has a log-linear response which precisely converts the RF signal levels in dB scale into a linearly proportional DC voltage. Operating in the wireless network frequency range from 450 MHz to 2.7 GHz, the detector response maintains the industry's most constant slope as the signal frequency changes. This allows a single detector to operate in multiband environments with minimal calibration adjustments. Moreover, the LTC5582 has fast settling characteristics, acquiring a rising signal accurately in 500 ns and a falling signal in 4.5 µs. Its fast response supports a wide range of signal envelope tracking applications.     

The LTC5582's specifications apply to single-ended RF input, supporting single-ended applications without a need of an external balun transformer. So the RF input provides easy interface, and is cost-effective to implement in a high performance RF measurement circuit.     

The LTC5582 is powered from a single 3.3 V supply with an operating current of 42 mA, minimizing power consumption. The device has an Enable pin, allowing the chip to power down. When in shutdown mode, the device draws trickle current of less than 10 µA. The LTC5582 comes in a 3 mm x 3 mm 10-pin DFN package. Typical application circuits using the device require fewer external components, providing a compact solution footprint.      

Availability and Pricing     

The LTC5582 is available from stock. Pricing starts at 6.25 US Dollars in 1,000 piece quantities.      

Datasheet:  LTC5582 

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