Dual RF Power Detector Delivers 80dB Dynamic Range At 900 MHz
Sunnyvale, CA -- Maxim Integrated Products has introduced the MAX2016, a monolithic solution for low-frequency to 2.5 GHz VSWR, gain, and power measurements. Designers can configure the MAX2016 as a simple RF-power detector and comparator, or as a complete closed-loop gain and power controller. The combination of precision, channel-to-channel isolation, and dynamic range makes this SiGe IC useful in a variety of wireless applications, including dual-channel RF-power measurements, gain/loss detection, VSWR monitoring, load integrity detection, and automatic gain control (AGC).
The MAX2016 uses a pair of temperature-tracking logarithmic amplifiers to detect and compare the power levels of two RF input signals. The device internally subtracts one power level from the other to provide a DC-output voltage that is proportional to the power difference (i.e. gain). The MAX2016 can also measure the return loss/VSWR of an RF signal by monitoring the incident and reflected power levels associated with any given load. A window detector is easily implemented by using the on-chip comparators, OR gate, and 2V reference. This combination of circuitry provides an automatic indication of when the measured gain is outside a programmable range. Alarm monitoring can thus be implemented for detecting high-VSWR states, such as open or shorted loads.
As an added feature, the MAX2016 can also be employed as a fully integrated AGC loop controller. Built-in circuitry allows the device to detect and maintain either gain or power within a closed-loop system. Comparable functionality in discrete form would require twice the component count and over three times more board space.
While maintaining log conformance of ±3 dB over temperature, each detector on the MAX2016 can provide dynamic ranges of 80 dB, 67dB, 64dB, and 52dB at 900MHz, 1900MHz, 2170MHz, and 2500MHz, respectively. The cornerstone, however, to the MAX2016's performance is the performance of its on-chip RF comparator circuitry. At 900 MHz, the comparator output delivers 70 dB of dynamic range with ±1 dB of precision over -20 degrees Celsius to +85 degrees Celsius. Measurements at 1900 MHz, 2170 MHz, and 2500 MHz are equally impressive with dynamic ranges of 55 dB, 50 dB, and 45 dB, respectively, over the same precision and temperature constraints. This is due, in part, to the MAX2016's excellent channel-to-channel isolation. Typical isolation values range from 90 dB for the cellular band, 65 dB for the PCS band, and 55 dB for WLAN applications. The resulting performance greatly enhances the accuracy and range of any RF power measurement.
The MAX2016 comes in a compact 5 mm x 5 mm, 28-pin thin QFN. Lead-free packaging is also available.
Source: Maxim Integrated Products