Electronics > Projects, Designs, and Technical Stuff

Transistors - die pictures

<< < (164/167) > >>

You are right. These currents are just for advertising.

I don´t know thy they did the resistance measurement at 121A...  :-//

Yes Tim, it seems like they just sold even numbers of their HEXFETs.


--- Quote from: RoGeorge on April 17, 2024, 07:59:13 pm ---When they give 4m\$\Omega\$ and 202A, that made me curious.  I've doubted that the outside terminals can withstand at 200A without melting, or at least going red hot, let alone the bonding wires.

The fine print in the datasheet https://www.infineon.com/dgdl/irf1404pbf.pdf?fileId=5546d462533600a4015355dae92618b0 says that the 202A continuous current would be supported, just that those 202A are a calculated value, based on the thermal resistance and the max allowed junction temperature.  The package limit is 75A, so the 202A continuous drain current is a lie.  Quote from the datasheet, remark 6 regarding max Id:

--- Quote ---Calculated continuous current based on maximum allowable
junction temperature. Package limitation current is 75A.
--- End quote ---

The 4m\$\Omega\$ also seemed too small, and it has a fine print, too, remark 4 in the datasheet:

--- Quote ---Pulse width ≤ 400μs; duty cycle ≤ 2%.
--- End quote ---
That is because the value is specified at Vgs = 10V and Id = 121A, which Id is higher than the max 75A continuous supported by the package, thus the time and the duty factor limitations.  OK, understandable.

But why is the Rds value specified at such high Id.  Why didn't they measure it at a 10 times lower or so current, and no pulses?  Is it something in the MOSFET physics, that makes it achieve very low Rds only at huge drain current, so they took the extra effort measuring pulses only to obtain a much lower Rds value for the datasheet (similar with the 202A continuous but no more than 75A)?

Why did they bother using huge current and pulses to measure Rds on?

--- End quote ---

I think that the exaggerated claims of the marketing people are a potential threat to a brands credibility. If the claims have no relation to practical use why buy from these people ? I'd rather buy from somebody without a lot of disclaimers and smallprint in their datasheets.


--- Quote from: Wolfgang on April 18, 2024, 12:20:15 pm ---I think that the exaggerated claims of the marketing people are a potential threat to a brands credibility. If the claims have no relation to practical use why buy from these people ? I'd rather buy from somebody without a lot of disclaimers and smallprint in their datasheets.

--- End quote ---

I agree with you. I don´t like such marketing exorbitance either.  :-//


The International Rectifier IRF2804 shown here has the letter P in the second line. It is therefore the lead-free version IRF2804PbF. In contrast to the IRF1404PbF, the lead-free version of the IRF2804 allows less drain current. The datasheet specifies a maximum possible continuous current of 250A for the MOSFET itself, whereby the housing limits the continuous current to 75A. The maximum permissible peak current is 1080A. The resistance is specified as 2mΩ. The blocking voltage is 40V. Up to 300W can be dissipated via the TO-220 housing.

With 5,8mm x 4,3mm the die is slightly larger than the die of the IRF1404PbF. Here too, the source area is connected to the source pin with four thick bondwires. The frame structures are relatively similar, but not quite the same.

In detail it becomes even clearer that this is a different design to the IRF1404PbF. The metallization shows none of the underlying structures. Either the individual transistor elements are too small to be resolved or the source metallization is significantly thicker and thus conceals any unevenness.

Some masks appear to be depicted on the lower edge.




The Siemens ADY13 is a PNP germanium transistor in a TO-8 package. The blocking voltage is specified at 45V and the collector current at 600mA. Up to 250mW can be dissipated through the package. The cut-off frequency is 350kHz. S6 is a date code typical for Siemens, which could refer to the year 1962.

There is some solder on the top of the package. If you open the package, you will see that this solder closes a hole. Presumably the interior has been filled with an inert, dry gas. It is not just a simple hole. The depression was presumably intended to ensure that sufficient solder could accumulate above the hole without creating too much of an elevation on the top of the package.

There is a heatspreader in the package, which is rather unusual in this performance class and in this type of package.

The white potting does not appear to be electrical insulation, but rather an additional seal.

The pin that transmits the base potential is connected to a metal strip. The metal strip finally contacts the Germamium disc, which (as you know) is the actual transistor.

The structures that can be recognised on the germanium crystal are created when the surface is etched. The surface appears to become smoother towards the base contact. The surface structure also changes in the area where the emitter is contacted.

Viewed from the side, it is easy to see that the structure of the ADY13 resembles a power transistor. The round, approximately 30 µm thick germanium crystal is placed on a dome on the heat spreader in order to dissipate the power loss as effectively as possible.




[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod