Q.
I have used the AD8362 logarithmic detector in the past. Now I am starting a new design and am wondering if there are any newer alternatives.
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A.
The AD8362 is a really good part. It operates at frequencies up to 3.8 GHz with excellent rms accuracy and has up to 65 dB of detection range. However, if you are starting a new design, there are some alternatives you should consider. The ADL5902 (www.analog.com/ADL5902) also has up to 65 dB of detection range but operates at frequencies up to 9 GHz. Its temperature drift and transfer function ripple are also superior to the AD8362. Unlike the AD8362, the ADL5902 has a temperature compensation pin. By adjusting the voltage on the TADJ pin (you can do this with an external DAC or you can simply use a resistor divider along with the on-board 2.3 V reference voltage), you can fine tune the temperature drift compensation for a particular frequency.
Another device to consider is the AD8363. This device is very similar to ADL5902 but offers a little bit less detection range (approximately 50 dB).
