Message	Date	From	Subject
769	2007-05-14 20:53:27	Kevin Purcell	JH5ESM and diode switches
There are quite a few other interesting items on Cosy MUTO's site. Perhaps most interesting is looking at distortion in a 1S1553 silicon PN switching diode (similar to the 1n4148 but a bit less "beefy" -- lower current, lower PIV). <http://www.ortodoxism.ro/datasheets/lrc/1S1553.pdf> The diode switch is biased on from a 12 volt supply with either a 1.5k resistor (7.6mA) or a 3.3k (3.5mA). <http://homepage3.nifty.com/jh5esm/experiments/diode_sw.html> > Insertion loss is 1.5 to 2.0[dB] and not so different by bias > resistor. However, [saturation] and 2nd harmonic characteristics > are very different. > > Maximum allowable input levels determined by P1dB are 6[dBm] for > 1.5 [kΩ] bias resistor and -1[dBm] for 3.3[kΩ], respectively. > Second order harmonics are supressed by 20[dB] at P1dB. > > Bias resistor should be determined by carefully considering signal > level, otherwise some trouble would occur. > > Off isolation was -46.5[dB] at 0[dBm] input (RB=1.5 [kΩ]). -- Kevin Purcell kevinpurcell@pobox.com

There are quite a few other interesting items on Cosy MUTO's site.

Perhaps most interesting is looking at distortion in a 1S1553 silicon
PN switching diode (similar to the 1n4148 but a bit less "beefy" --
lower current, lower PIV).

<http://www.ortodoxism.ro/datasheets/lrc/1S1553.pdf>

The diode switch is biased on from a 12 volt supply with either a
1.5k resistor (7.6mA) or a 3.3k (3.5mA).

<http://homepage3.nifty.com/jh5esm/experiments/diode_sw.html>

> Insertion loss is 1.5 to 2.0[dB] and not so different by bias
> resistor. However, [saturation] and 2nd harmonic characteristics
> are very different.
>
> Maximum allowable input levels determined by P1dB are 6[dBm] for
> 1.5 [kΩ] bias resistor and -1[dBm] for 3.3[kΩ], respectively.
> Second order harmonics are supressed by 20[dB] at P1dB.
>
> Bias resistor should be determined by carefully considering signal
> level, otherwise some trouble would occur.
>
> Off isolation was -46.5[dB] at 0[dBm] input (RB=1.5 [kΩ]).

--
Kevin Purcell
kevinpurcell@pobox.com