TO220 switchmode 7805T replacement?

Feb 17, 2007 13 Replies

I think something like this

formatting link
looks good, but I didn't check the pinout or the physical compatibility. I think it's bigger than a TO-220.

Looking for info on available drop-in switchmode replacments for the 7805T regulator, for a 250mA-sized load. Have located the RECOM series, but I'm wondering who else does this type of device.



Tnx for all leads.


He asked for "drop-in switchmode replacements for the 7805T".

There isn't one as far as I know.

Gibbo This email address isn\'t real.

A couple of people do make tiny pc boards or potted gadgets that are dropins. Can't remember who, but google should turn them up.

John

Eh? Did your copy and paste not work properly?

tlc5620 - "quadruple 8 bit digital to analogue converter"

Or was it a joke that I missed?

Gibbo This email address isn\'t real.

That may be true if you want physical and well as electrical match. But if you have the space for a slightly bulbous replacement and perhaps, the need for an additional capacitor across the output and possibly some extra input voltage, there are some choices. i.e.:

formatting link

Nice!

Data sheet saved, Cheers.

Gibbo This email address isn\'t real.

Not as easy as you might think, since the same key words bring up so many integrated circuits and other references. I knew this one existed, but still had to go back through earlier correspondence to find it.

formatting link

I guess I have to copy *before* pasting. :-) try:

formatting link

John Popelish wrote: (snip)

The TI version has completely different specs, especially minimum output current:

formatting link

TI's former Power Integrations, or was it Power Trends? stuff:

formatting link
Only $12.25 each at DigiKey, stocking 7911 of the A, 3338 of C, and 1238 of the N packages.

The N package (outline EAD) stands up like a TO-220 LM7805 linear regulator, except it takes up more floor space, 0.42 x 1.06 inches, and 1" tall. The pcb can have four holes to position it properly. I'd want an additional mechanical securing of some kind, Sheesh! Are you allowed to drill any holes? Here are the EAA EAC and EAD package drawings,

formatting link

Very nice, much smaller than TI's part. It does 0.5A at 5V, compared to 1A for TI, but the small size is awesome. $9.90, Newark no inventory (74-day leadtime), but Mouser has 'em.

Wow, some of those devices have footprints like elephants!

The application is a batch rework of an existing product which uses a 7805T so there simply isn't the wad of room around it for any of these 1" wide jobs, nor the headroom for tall ones.

Unfortunately the orig design was poor both thermally and physically. The un-sunk 7805T runs way too hot (although it doesn't go into shutdown). It is placed away from the pcb edge and among other components. The board is in a plastic case so a heatsink connected to the case - apart from not being possible

- wouldn't do anything, and a clip-on sink isn't going to help, as it is still going to dissipate the same energy into the same confined airspace.

The rework solution has to get the heat dissipation down. Switcher.

The RECOM product I located

formatting link
will just fit in the available space, but before committing to that I was hunting for others of a similar size which may have had better price/availability.

Thanks guys for your input.

P.S. The designer HAS been *told*.

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required