Improving the Linearity of the AD8361 “Tru-Pwr” RF Detector IC
Authors: N. Greenough
Abstract:
The AD8361 is a wideband linear RMS radiofrequency
(RF) detector IC widely used in the RF industry.
This paper presents a method to extend the dynamic range of
the detector to nearly 40 decibels, over a range from less than -
30dBm to +8dBm with absolute accuracy typically +0.5 /-1dB.
In addition, most samples can be made to track to a very high
degree over an even wider range.
The increase in accuracy and tracking allows improved
power calibration, real-time power regulation, and calculation
of VSWR (voltage standing wave ratio) for the multimegawatt
RF transmitters used to heat plasmas on NSTX at
PPPL. The method presented here is simpler and lower cost
than the dual-detector-amplifier technique presented by its
manufacturer. Test results and distributions are presented for
approximately 20 samples of a dual-detector module built by
PPPL.
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Submitted to: 38th International Conference on Plasma Science & 24th Symposium on Fusion Engineering/ICOPS 2011 SOFE, Chicago, IL, June 26-30, 20011
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Download PPPL-4697 (pdf KB pp)
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