# Recom Power part number RPM5.0-3.0

**URL:** <https://forum.digikey.com/t/recom-power-part-number-rpm5-0-3-0/8199>\
**Category:** Power Supplies (board mount)\
**Tags:** power-supplies-board-mount, recom-power, power\
**Created:** [August 24, 2020, 6:50pm UTC](https://forum.digikey.com/t/recom-power-part-number-rpm5-0-3-0/8199 "2020-08-24T18:50:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![joshwhitlow](https://sea2.discourse-cdn.com/digikey/user_avatar/forum.digikey.com/joshwhitlow/32/7237_2.png) [@joshwhitlow](https://forum.digikey.com/u/joshwhitlow)\
**Post date:** [August 24, 2020, 6:50pm UTC](https://forum.digikey.com/t/recom-power-part-number-rpm5-0-3-0/8199/1 "2020-08-24T18:50:49Z")

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I recently had a customer that was applying 3V input, but was not able to get a 5V output.  
The part marking and data sheet both say input voltage of 3-17V.  
Recom Power has said that the [RPM5.0-3.0](https://www.digikey.com/short/zrdm0c) part needs at least 5V input to output the nominal 5V output.  
If the input voltage is in the range of 3V - 5.15V, the output voltage will be equal to the input voltage.  
The Recom Power data sheet team will add an explanation on the next version of the data sheet.

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**Author:** ![rick\_1976](https://sea2.discourse-cdn.com/digikey/user_avatar/forum.digikey.com/rick_1976/32/1571_2.png) [@rick\_1976](https://forum.digikey.com/u/rick_1976)\
**Post date:** [August 24, 2020, 7:36pm UTC](https://forum.digikey.com/t/recom-power-part-number-rpm5-0-3-0/8199/2 "2020-08-24T19:36:19Z")

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This limitation is communicated on the first page of the datasheet, though not with lights and sirens:  
 ![image](https://global.discourse-cdn.com/digikey/original/2X/b/b92eec2741b15d22161a5446df97a1453c74f6aa.png)

That the output can be trimmed to \<3V is where the 3v lower-limit input spec comes from. Availability of similar products capable of performing a buck/boost function makes the output\<input constraint of this one non-obvious based on the parametric values and the misunderstanding is, well, understandable…

It’s the sort of situation that illustrates the importance of reading datasheets carefully; things do not always mean what they seem to mean…