Analog Devices Unveils Logarithmic RF Detector With Range Up To 8 GHz
XFCB-3 SiGe process technology enables AD8318 to deliver RF power measurement from 1 MHz to 8 GHz
Norwood, MA -- Analog Devices has developed the industry's first logarithmic RF detector to accurately measure the power of radio signals from 1 MHz to 8 GHz, exceeding the previous maximum of 2.5 GHz. Accurate RF power measurement can reduce the size and cost of expensive RF power transmitters and is a key to easing wireless network management challenges. Maintaining the detector dynamic range up to 8 GHz has never before been possible.
The AD8318, a monolithic semiconductor-based detector, is superior to traditional alternatives because it is more cost-effective than module solutions and more accurate than discrete diode-based detectors. Its unique combination of accuracy and broad dynamic range allows the device to be used in many types of wireless communications infrastructure equipment, including GSM, CDMA, and W-CDMA cellular base stations (which operate up to 2 GHz), W-LAN 802.11 applications (which require 5 GHz), and point-to-point fixed wireless systems (which operate up to 30 GHz).
"The AD8318 is a major breakthrough in terms of input bandwidth, speed, accuracy, and temperature stability, setting a new performance level in RF power measurement and control," said Lew Counts, VP of Linear Products, Analog Devices. "Analog Devices continues to draw upon its extensive RF expertise and world-class process technology to meet the stringent performance and solution cost targets of our wireless infrastructure customers."
The AD8318 provides over 55-dB dynamic range with better than +/-1-dB accuracy up to 5.8 GHz. At 8 GHz, the AD8318 provides over 58-dB dynamic range with better than +/-3-dB accuracy. The temperature drift can be fine tuned to the band of interest, yielding better than +/-0.5-dB stability from -40 to +85 degrees C.
The AD8318 integrates an on-chip temperature sensor that provides a 2-mV/degree C output voltage that can be used for additional temperature compensation and/or system monitoring. The part also provides the fastest output response time of 8 ns, enabling the part to be used for RF burst detection.
The AD8318 is the next generation of Analog Devices' AD8313 for RF power measurement up to 2.5 GHz. The new logarithmic-based detector is fabricated on Analog Devices' proprietary XFCB-3 process, ADI's fourth-generation bonded-wafer silicon-on-insulator (SOI) XFCB (eXtra Fast Complementary Bipolar) process. XFCB-3 uses 0.35 micron lithography and a SiGe NPN to provide fT (transition frequency) of 70 GHz and fMAX (maximum frequency for unity power gain) of 130 GHz. XFCB-3 is a significant advance over previous generations of Analog Devices' XFCB processes, enabling 3 times more speed over devices fabricated on XFCB-2. Specific to the AD8318, combined with advanced design techniques, XFCB-3 enables operational accuracy that is superior to discrete implementations with higher operating frequencies and integrated lower-frequency competitive solutions.
Source: Analog Devices