Power detectors offer 35dB dynamic range
Providing true power measurement of RF and microwave signals, independent of modulation and waveforms, the LTC5596 is a high frequency, wideband and high dynamic range RMS power detector. It responds in an easy-to-use log-linear 29mV/dB scale to signal levels from -37 to -2dBm, at accuracy better than ±1dB error over the full operating temperature range and RF frequency range, from 200MHz to 30GHz. This range is unprecedented, says Linear Technology.
In addition, response has ±1dB flatness within this frequency range. A wider range, from 100MHz to 40GHz, can be used, although accuracy is slightly reduced at the frequency extremes. RF input is internally 50Ohm matched from 100MHz to 40GHz.
Traditionally, microwave Schottky diodes are used as a detector element, but today’s 4G and 5G broadband communications systems use high order, multi-tone OFDM modulation to attain high data rates, meaning that microwave Schottky diodes face serious shortcomings when rectifying the RF or microwave signals while measuring only the peak of the waveform, explains the company. This misrepresents the real power of the signal. In contrast, RMS detectors perform an analogue root-mean-square computation of the waveform, and then average the result, for a true power representation of the input signal, regardless of its modulation, number of carriers and varying amplitudes. The ability to measure the true power is critical for equipment manufacturers to set the proper transmit power, ensuring the maximum transmission distance and to improve TX range while complying with regulatory power limits.
The wide bandwidth allows the detector to work seamlessly across multiple frequency bands using a common design with minimum calibration. For example, it works equally well in a sub-10GHz backhaul microwave link as with a 28GHz version, says the company. A single design with no recalibration can offer “significant” cost savings, it adds, The wide frequency range and improved sensitivity enables use in a variety of applications such as radar systems, avionics, wireless infrastructure base stations, satellite communications and test instrumentation.
The LTC5596 operates from a single 3.3V supply, drawing a nominal supply current of 30mA. ESD protection is built-in. All pins are capable of withstanding up to 3,500V discharge, human body model.
Two temperature grades are available. An I grade version for operation from -40 to 105 degree C case and a high temperature H grade model for environments subject to high temperature operating environments such as in high power RF power amplifiers. This model operates at -40 to +125 degree C case.
Both temperature versions are available in a 2.0 x 2.0mm, plastic eight-lead DFN package.