hf/rf ZONE Products for the week of May 31, 2004
Analog Devices Says . . .
AD8318: Breakthrough IN RF Power Detection Up To 8
GHz
XFCB-3 SiGe process technology enables RF power measurement
from 1 MHz to 8 GHz
Analog Devices Inc., a global leader in high-performance semiconductors for signal-processing applications, unveiled a major breakthrough in radio frequency (RF) detection for wireless infrastructure equipment. 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, vice president
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."
analogZONE Says . . .
Analog Devices has taken the AD8313 design and ported it on to its latest version of its SiGe XFCB process, XFCB-3 in 0.35 micron, to increase the upper frequency limit of the new part, the AD8318, to 8 GHz besting the AD8313's range up to 2.5 GHz. This brings two major bands of interest into play at 3.6 GHz and 5.8 GHz, as well as opening the door ro a number of other applications, including radar. XVCB-3 offers an fT of 70 GHz and an fMAX of 130 GHz.
At 900 MHz the AD8318 is offering a ±1 dB dynamic range of 48 dB; at 1900 MHz it is 44 dB; at 2900 MHz it is 49 dB, at 3600 MHz it is 39 dB; at 5800 MHz it is 50 dB; and at the limit of the part's input range it offers a ±3 dB dynamic range of 58 dB. The maximum input level changes over frequency (not linearly) from -5 dBm to +3 dBm, with output voltages in the range of 1.7 V to 1.8 V when the input power is -50 dBm. Temperature sensitivity is a maximum of 0.0038 dB/°C (at 5.8 GHz) from +25°C to +85°C.
The AD8318 is a nine-stage demodulating log amplifier very similar to the AD8313 and can be used either in a measurement mode (with VOUT connected to VSET) or a controller mode (using a DAC controlling the VSET pin). A temperature sensor is also on-chip that can be used for general system monitoring, or can be used to provide extra temperature compensation: the output is 2 mV/°C. The part is also suitable for burst detection with an on response time of 8 ns and an off time of 13 ns.
This part keeps ADI ahead of the pack and will confirm its position as the leader in log amplifier devices. It has priced the part a little lower than the MAX2015, which is an AD8313 look-alike released in the last month of 2003. The AD8313 dates from 1999 (I accidentally broke an embargo date on the part with a story, because ADI posted data on its very public web site) and is in MSOP-8 and micro-SOIC-8, and we have a package change here with the AD8318. The new part is also a fixed-rail 5 V part, whereas the AD8313 offered more rail flexibility. Quiescent is a typical 65 mA and the part can drive 60 mA with -50 dBm input and 1.5 V on VSET.
The AD8318 is sampling in a 4 x 4 mm LFCSP-16 and will be priced at $5.99 in 1000-piece lots. Production will be in July 2004.