Temperature dependence of a silicon diodes reverse current?

[hrh1818]

I have two text books that say the reverse saturation current for
silicon semiconductor diodes will approximately double in magnitude for
every 10 degree C rise in temperature. Two other textbooks I have say
the reverse saturation current for silicon semiconductor diodes will
approximately double in magnitude for every 5 degree C rise in
temperatue. None of the 4 books provide an explanation of why the
reverse saturation current doubles for evrery 5 or 10 degree rise in
temperature. There for my question is why do some authors say the
reverse saturation current approximately doubles for every 5 degree C
rise in temperature and other authors say it approximately doubles for
every 10 degree C rise in temperature?

Howard

 

[Eeyore]

I have two text books that say the reverse saturation current for
silicon semiconductor diodes will approximately double in magnitude for
every 10 degree C rise in temperature. Two other textbooks I have say
the reverse saturation current for silicon semiconductor diodes will
approximately double in magnitude for every 5 degree C rise in
temperatue. None of the 4 books provide an explanation of why the
reverse saturation current doubles for evrery 5 or 10 degree rise in
temperature. There for my question is why do some authors say the
reverse saturation current approximately doubles for every 5 degree C
rise in temperature and other authors say it approximately doubles for
every 10 degree C rise in temperature?

The ones who say 5C got it wrong ?


Graham

 

[Adrian Jansen]

I have two text books that say the reverse saturation current for
silicon semiconductor diodes will approximately double in magnitude for
every 10 degree C rise in temperature. Two other textbooks I have say
the reverse saturation current for silicon semiconductor diodes will
approximately double in magnitude for every 5 degree C rise in
temperatue. None of the 4 books provide an explanation of why the
reverse saturation current doubles for evrery 5 or 10 degree rise in
temperature. There for my question is why do some authors say the
reverse saturation current approximately doubles for every 5 degree C
rise in temperature and other authors say it approximately doubles for
every 10 degree C rise in temperature?

Howard

The keyword is "approximately".

--
Regards,

Adrian Jansen adrianjansen at internode dot on dot net
Design Engineer J & K Micro Systems
Microcomputer solutions for industrial control
Note reply address is invalid, convert address above to machine form.

 

[Jim Thompson]

The keyword is "approximately".

Naaah! It *triples* for every 10°C ;-)

...Jim Thompson

 

[hrh1818]

I finally bumped into some information which helps explain the
inconsistency. According to "Microelectronics Circuits" Fourth
Edition by Sedra/Smith and on page 136 the authors say: "A good part
of the reverse leakage current is due to leakage effects. These
leakage currents are proportional to the jnnction area just as the
saturation current is. Leakage current dependence on temperature,
however, is different from that of saturation current. Thus, whereas
the saturation current doubles for every 5 degree C rise in
temperature, the corresponding rule of thumb for the temperature
dependnce of the reverse current is that it doubles for every 10 degree
C rise in temperature.

Howard