Tab on IRFZ44NPbF connects to ... ??? - Page 1
Forum section: electronics / projects

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 29, 2025, 06:57:19 pm
content: https://www.infineon.com/assets/row/public/documents/24/49/infineon-irfz44n-datasheet-en.pdf?fileId=5546d462533600a40153563b3a9f220dMaybe I'm missing something obvious, I can't find what the tab connects to. Is it some common knowledge about HEXFETs that I don't know?Infineon's chatbot is hilariously useless, asking me to click on a document to "summarize", like if it can't figure out I need the datasheet this isn't gonna end well, and all it showed me as options were all kinds of documents except the datasheet. And when it had its "results" I clicked on the link that went to a dead page.The links at the end of the datasheet also appear to go nowhere, all I get is "An error occurred while processing your request."... Which makes sense since there is no IRF anymore. Fine, but can they update the datasheet?

author: TimFox
author_rank: Super Contributor
timestamp: July 29, 2025, 07:28:10 pm
content: I looked elsewhere and found an image probably from IR, showing the tab connected to drain, as is the center pin. Other images on Google search ignored the tab.

author: edavid
author_rank: Super Contributor
timestamp: July 29, 2025, 07:35:11 pm
content: Quote from: Alex Eisenhut on July 29, 2025, 06:57:19 pmIt's common knowledge that the center pin of a TO220 always connects to the tab, which connects to the substrate of the die. Just think about how the package is made.

author: wraper
author_rank: Unknown
timestamp: July 29, 2025, 07:44:40 pm
content: ^Yes it's a common knowledge. Here's a datasheet from another manufacturer.

author: thm_w
author_rank: Super Contributor
timestamp: July 30, 2025, 12:49:59 am
content: Quote from: edavid on July 29, 2025, 07:35:11 pmThere are plenty of TO220 parts, like resistors and triacs, where the metal tab is electrically isolated.

author: wraper
author_rank: Unknown
timestamp: July 30, 2025, 08:33:21 am
content: Quote from: thm_w on July 30, 2025, 12:49:59 amResistors are normally two terminal parts, no center pin. Triacs with isolated tab specifically state it as it's not a normal TO-220 package but with a high voltage ceramic insulator inside.

author: Vovk_Z
author_rank: Super Contributor
timestamp: July 30, 2025, 11:49:19 am
content: Quote from: thm_w on July 30, 2025, 12:49:59 amBut all TO220 transistors I've seen had central pin and tab the one whole metal item. Both bipolar and FET types. Can't remember other design at the moment.Here is quite a good photo, inside this 2018 thread:TO-220 MOSFET, is the tab live?

author: TimFox
author_rank: Super Contributor
timestamp: July 30, 2025, 02:58:52 pm
content: Yes, the tab is usually connected to pin 2. I don’t understand why many of the data sheets for this part did not label the tab (either drain or no-connection).

author: langwadt
author_rank: Super Contributor
timestamp: July 30, 2025, 03:03:18 pm
content: Quote from: Vovk_Z on July 30, 2025, 11:49:19 amand a D2PAK/TO-263 is basically a TO-220 with pin two and most of the tap cut off

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: July 30, 2025, 07:56:48 pm
content: Oh I just want it explicitly shown, it can't be that hard, it just can't. This one has the pinout buried in the penultimate page in the smallest font possible. Here, in two minutes...

author: thm_w
author_rank: Super Contributor
timestamp: July 30, 2025, 10:06:26 pm
content: Quote from: Vovk_Z on July 30, 2025, 11:49:19 amYes the correct statement would be: TO-220 transistors have central pin connected to tab.

author: Whales
author_rank: Super Contributor
timestamp: July 31, 2025, 09:25:40 am
content: Yes it's commonly assumed, but yes also they should write it explicitly. It takes a few extra letters on the datasheet and helps everyone.Even worse is when they draw a top/bottom view of the pinout, but don't specify whichMost TO-220's are pinned G-D-S but not all TO-220's are mosfets and this is a problem I've had with some other parts (solution was to look at competitor/clone datasheets).