Reverse current of zener diode at 125degC?

[cupoftea]

Hi,
Do you know the reverse current of the 4V7 zener (BZX84-C4V7) when it has 2.5V on it?..and at 125degC?

https://assets.nexperia.com/documents/data-sheet/BZX84_SER.pdf

Datasheet ony gives it at 25degC

 

[danadakk]

"Usually" that data is found in characterization data for the device. The fact
its not speced means it either is not reliable for spec sheet, eg. a part of
test procedure that could predict what performance would be or its simply
a parameter with bounds so great not worth repeating. Or given testing it
hot, there are simple methods to do that, test time too great a cost burden.

Contact production EE responsible for device, or rel department, to see if
they can lend any comment.


Regards, Dana.

 

[D.A.(Tony)Stewart]

For a significant temperature increase to 125°C, the leakage current could increase by a factor of approx. 10-50 times from 25'C

BZX84-C4V7 Spec: 3 uA max @ VR=2V @ 25'C
WAG result: 30 uA to 150 uA max @ 125'C

 

[stenzer]

Hi,

Rohm states about 10 µA for the BZX84C4V7LY.

BR

 

[D.A.(Tony)Stewart]

ON Semi who make Fairchild's diodes use the same spec as Philips with 3 uA @ Vr=2V but do not spec any voltages below Vr=1 on any Zener as they diverge quite a lot in impedance and leakage for different voltages. Ref

A different ON Semi diode spec BZX84C4V7ET1 shows a dramatic difference leakage ratios below 5V Zeners for 150'C/25'C
There seems to be variations in fabrication and specs for low Vz diodes but in any case, your guess is as good as mine if there are no specs.

REF

 

[stenzer]

Hi,

A different ON Semi diode spec BZX84C4V7ET1 shows a dramatic difference leakage ratios below 5V Zeners for 150'C/25'C

here the negative temperature coefficient of zener diodes with a zener voltage below 5V will contribute, see https://toshiba.semicon-storage.com...nsiderations-for-the-temperature-coeffic.html

BR

 

[D.A.(Tony)Stewart]

Hi,



here the negative temperature coefficient of zener diodes with a zener voltage below 5V will contribute, see https://toshiba.semicon-storage.com...nsiderations-for-the-temperature-coeffic.html

BR

Toshiba states the two types of breakdown : Avalanche & Zener. and that all Avalanche mode is PTC due to lower mobility.
Also, Zener types below 5V switch from PTC to NTC and Zener leakage exponentially increases with lower Vz and rises more 1st order effects with rising temp.(when Vz<5V)

Yet this unspecified quantity is unknown in the NExperia spce for (Leakage @ 125'C at 2.5V) which has a much lower leakage (3uA) at 25'C than Rohm.(10uA)

This only raises uncertainty about the unspecified quantity of leakage ratio of 125'C/25'C due to doping differences between manufacturers until more evidence is provided.

If the NTC leakage ratio is more important than the 25'C max. leakage, then one might choose Rohm's product or improve the design to tolerate both.

Note sale of mfg rights: NXP =2017> Nexperia =2024> Vishay.

 

[stenzer]

Hi,

Yet this unspecified quantity is unknown in the NExperia spce for (Leakage @ 125'C at 2.5V) which has a much lower leakage (3uA) at 25'C than Rohm.(10uA)

they have the same stated leakage.

BZX84C4V7LY:

BZX84-C4V7:

BR

 

[D.A.(Tony)Stewart]

Ok 10uA typical is the answer for Rohm
Case closed