Suggestions for 5V switching regulator? - Page 1
Forum section: electronics / beginners

author: rcbuck
author_rank: Frequent Contributor
timestamp: January 13, 2019, 10:28:06 pm
content: I am working on a project that has a 12 volt supply as the main supply. I want to use a regulator to produce a 5V output that will have a current of around 500 ma max. I don't want to use a linear regulator due to the heat losses and heat sinking that would be needed. A switching supply is the option I want to use.I have sort of setteled on the Active-semi ACT4088. However, I'm not familiar with this company and would prefer something from one of the larger semiconductor companies.Any suggestions for a regulator in the $1 or so range that has simplified circuitry? Input voltage should be minimum of 15 volts since I am using 12 volts for the input. I prefer SMD but would use through hole if necessary. The closest to these requirements I have found is Microchip's LM2574-5.0YN that is in a DIP package.

author: langwadt
author_rank: Super Contributor
timestamp: January 13, 2019, 10:45:01 pm
content: if you are only building a few it is hard to beat the price and convenience of something like this:https://www.ebay.co.uk/itm/253861589475

author: beanflying
author_rank: Super Contributor
timestamp: January 13, 2019, 11:13:27 pm
content: +1 for those little boards. 500mA will be fine and I have used them on several projects. Put them on pins as a daughter board works well.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 13, 2019, 11:59:27 pm
content: I like these:https://www.digikey.com/product-detail/en/texas-instruments/LMR14006XDDCR/296-44318-1-ND/6110592Cost is under a buck in reels; you're spending more in assembly and design cost at lower quantities so I don't see any need for being more picky.There are cheaper regs, but you're on your own as far as fighting with their quirkiness, blowing up your load if they fail, and sourcing them, including avoiding even-more-inferior counterfeits. In short, there's always more cost.Tim

author: beanflying
author_rank: Super Contributor
timestamp: January 14, 2019, 12:44:24 am
content: Just checked one of mine the boards above use this regulatorhttps://media.monolithicpower.com/document/MP2307_r1.9.pdfor possibly a clone of it but as a circuit it works and it is more or less built to the circuit in the data sheet with an adjustable pot for output voltage.MPS has more Regulators than you can poke a stick at if you want to look at there list here is a link to their 14-19V Vinhttps://www.monolithicpower.com/en/products/dc-dc-power-conversion/switching-regulators/step-down-buck/converters/vin-max-14v-to-19v.html

author: jcw0752
author_rank: Contributor
timestamp: January 14, 2019, 02:33:53 am
content: I have had good luck with the Recom R78 series of switching voltage converter regulators.https://www.digikey.com/products/en?keywords=R78C5.0They are a little more expensive but have good stability and efficiency up to their current rating which in the case of this one is 1 AJohn

author: rcbuck
author_rank: Frequent Contributor
timestamp: January 14, 2019, 05:37:05 am
content: lagwadt and beanflying, could either one of you tell me the exact dimensions between centers for the Vin, Vout, and ground connections? I would need the dimensions to set the locations for the pins on my PCB.I will probably end up using the LMR14006 that T3sl4co1l suggested since it is made by TI. I only need 3 or 4 as this is for a personal project. Mouser has them for $2.07 and I need to place a Mouser order for other parts.But I would consider the modules for future projects. I will order 5 of them for testing purposes. So the dimensions for pin placement would be appreciated.

author: beanflying
author_rank: Super Contributor
timestamp: January 14, 2019, 05:50:23 am
content: Pins at 9 x 15mm Board dimensions vary a little but 12 x 18 mm was the largest I have. Measured with digital verniers so it should be fairly accurate.

author: rcbuck
author_rank: Frequent Contributor
timestamp: January 14, 2019, 06:14:13 am
content: Thank you beanflying. I ordered the modules from Ebay. They should arrive in a couple of weeks.

author: beanflying
author_rank: Super Contributor
timestamp: January 14, 2019, 06:20:31 am
content: No worries at all. It is a shame they didn't opt for 10 x 15mm pin spacing to make it bread and vero board compatible. Dropping a bit more filtering on the output might pay depending on the usage too.

author: jmelson
author_rank: Super Contributor
timestamp: January 14, 2019, 11:47:18 pm
content: I've used the LM2575-5.0 fixed "Simple Switcher" in a product, and have been happy with it. I use a Pulse Engineering inductor and a Schottky diode and a couple caps, and that is all. The inductor I chose might have a bit too much resistance, it starts to get just a LITTLE warm at 500 mA. Drastically cut the power consumption (and heat) from a linear regulator I used before.Jon

author: Lusu
author_rank: Contributor
timestamp: January 16, 2019, 09:18:14 am
content: How about drop-in replacements for the LM78XX liniar regulators? Something like the ones from Aimtec AMSR series:https://www.tme.eu/ro/Document/fbe51557a9f709febacd30dd3ccbacd8/AMSR1-78-NZ.pdfI see they are more expensive, like around 6 bucks, but may be others much cheaper on the "Chinese stores". (Share links if you know them)

author: rcbuck
author_rank: Frequent Contributor
timestamp: March 11, 2019, 11:54:36 pm
content: langwadt and beanflying, an update on these modules.I ordered 5 of them and they work very well. If you design your circuit board to match the input and output terminal spacing, they are easy to attach to the board.The only thing I did not like about the module is the pot that is used to set the voltage. Pots tend to have an effect on long term reliability of circuits. I took the pot off of one of the board and ran some tests.If you replace the pot with a 21K ohm, 1% resistor, you get 3.3 volts output. If you use a 37.4K ohm resistor, you get 5.2 volts output. An 0603 resistor fits perfectly across the two outside pads that the pot uses. The low side of the pot is tied to the wiper so putting the resistor across the two fixed terminal pads duplicates the pot functionality. I didn't test to see what value resistor is needed for any other voltage.