# TO220 switchmode 7805T replacement?

A

#### [email protected]

Jan 1, 1970
0
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.

I think something like this
http://focus.ti.com/docs/prod/folders/print/pt5101.html
looks good, but I didn't check the pinout or the physical
compatibility. I think it's bigger than a TO-220.

B

#### budgie

Jan 1, 1970
0
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.

J

Jan 1, 1970
0
G

#### Gibbo

Jan 1, 1970
0
John said:

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

There isn't one as far as I know.

J

#### John Larkin

Jan 1, 1970
0
He asked for "drop-in switchmode replacements for the 7805T".

There isn't one as far as I know.

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

G

#### Gibbo

Jan 1, 1970
0
John said:
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.:

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?

J

#### John Popelish

Jan 1, 1970
0
Gibbo said:
He asked for "drop-in switchmode replacements for the 7805T".

There isn't one as far as I know.

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.:

G

Jan 1, 1970
0
J

#### John Popelish

Jan 1, 1970
0
John said:
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.

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.
http://www.cd4power.com/data/meters/dms-78xxsr.pdf

W

#### Winfield Hill

Jan 1, 1970
0
Gibbo said:
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?

TI's former Power Integrations, or was it Power Trends? stuff:
http://www.ti.com/lit/gpn/pt5101 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, http://www.ti.com/sc/docs/psheets/mechanic/E.htm W #### Winfield Hill Jan 1, 1970 0 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. http://www.cd4power.com/data/meters/dms-78xxsr.pdf 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.

B

#### budgie

Jan 1, 1970
0
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.

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

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
(http://www.recom-international.com/switching_regulator_R-78xx.html)
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.

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

B
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