K1058/J162 FAKES? How to determinate or measure?

[raelman]

Hello everybody.

I have 8 pairs of K1058/J162 bought in supposed trustable shop and supposed paired too.

I bought them long time ago, more than one year.
Now I opened the drawer to use those MOSFETS in a project and what I see is no signal of pairing (no sticks or any sign visible) and lots of doubts if they are genuine or not.

The marks are not engraved and theres no brand (Hitachi, toshiba, renesas or whatever)

This is a picture. The scratches in the K1058 has been done by myself checking they were not engraved.

What do you think about?
Do you know any testing circuit to match them?

An externally hosted image should be here but it was not working when we last tested it.

Thank you

 

[ashok]

Check the junction capacitance using a capacitance meter and compare with genuine ones. Should lie in the same range . Apart from that testing it might be more complex like checking for transconductance etc.
Apart from that they are P and N types. How do you match them ? Between P types themselves ( or N type) you could possible get some match . But between P and N type ?

 

[raelman]

The matching is only essential within a given pair.
You do not have to match the Ps to the Ns, or match to devices in another channel.

 

[Dennis Hui]

Mr Pass had articles on mosfet testing and matching:

http://www.firstwatt.com/pdf/art_matching.pdf
http://www.firstwatt.com/pdf/art_mos_test.pdf

I suggest measuring the Vgs at some given current level
and see they compare with the datasheet. Please note that in Mr Pass'
articles he was talking mostly about the IRF devices (Vgs ~4-5V range)
while you have low Vgs ones (about 2-3?).

Cheers,
Dennis

 

[raelman]

It's not been very difficult to obtain VGS with PASS jig. All you need is power supply (from 12VDC to 22VDC, a resistor, and a DC voltimeter.

I have used a regulated PS with DC12V 300mA and a 10R/10W resistor.

 

[Sangram]

Those are not genuine.

The package seals should have the batch number and country of manufacture. There is a thread here that shows how genuine devices should look.

 

[Mooly]

Make sure they conform to G-S-D pinout and NOT G-D-S

Dead easy to rig a simple circuit up to test basic operation and that they begin to conduct at a low Vgs and not around 4 volts Vgs as a modern HEXFET would.

 

[jackinnj]

Make sure they conform to G-S-D pinout and NOT G-D-S

The Renesas/Hitachi devices are GSD

Dead easy to rig a simple circuit up to test basic operation and that they begin to conduct at a low Vgs and not around 4 volts Vgs as a modern HEXFET would.

The Renesas devices have a very low Vgst, start testing at 1V

Their thermal behavior is opposite that of vertical mosfets, as they heat they conduct less.

The upper left circle has inscribed the country of origin -- you'll need a high power magnifying glass to read it. Mine are from Malaysia.

 

[raelman]

GOOD NEWS (I GUESS)

All of them come from MALAYSYA as the upper left circle has inscribed that on it. Also inscribed some other data: EA9, FJ5, DD5, AK6... I suppose it is the batch they come from.

With the jig proposed and my PS with DC12V 300mA and a 10R/10W resistor I get VGS values from 1,242 to 1,277 VDC

 

[BenY]

GOOD NEWS (I GUESS)

With the jig proposed and my PS with DC12V 300mA and a 10R/10W resistor I get VGS values from 1,242 to 1,277 VDC

For the N & P??

Then there is a very good chance you have valid parts on your hands.
Congratulations..

 

[raelman]

For the N I get VGS values from 1,242 to 1,277 VDC
For the P I get values from 1,362 to 1,386 VDC

 

[Mooly]

Those Vgs values sound reasonable. Its not the way I would have done it tbh (I would have used a variable voltage on the gate and monitored the drain current) but your result looks promising.