Most standard 3.6V linear regulator ? - Page 1
Forum section: electronics / beginners

author: Jaunedeau
author_rank: Regular Contributor
timestamp: June 26, 2017, 10:54:11 am
content: Hi,I am looking for a linear regulator / LDO to produce 3.6V for a µC from the USB charger. I've found plenty of them (e.g.tlv704from TI in SOT23), but I wander if there is a "standard" reference that can be sourced from several manufacturers even in a few years (I think I'm looking for something like 7805, but in SMD package and 3.6V)thank you,John.nota : I need to drive apa102's from the mcu, so the LDO must be 3.6 or 3.5v

author: tszaboo
author_rank: Super Contributor
timestamp: June 26, 2017, 01:09:26 pm
content: 1117 + two resistors.Or just use an LDO from TI, which has -EP variant. It supposed to be in production forever*.*for all intended purposes

author: Cervisia
author_rank: Regular Contributor
timestamp: June 26, 2017, 01:33:26 pm
content: According tothis DigiKey search, the 3.6V regulators with the most available stock (and therefore most likely to be sold regularly) are the TCR2xx36 from Toshiba. (But the stock that is there is still less than two reels.)For something as common as the 78xx, you have to use an adjustable regulator.Quote from: NANDBlog on June 26, 2017, 01:09:26 pmNone of the EP LDOs has a 3.6 V option (see p. 15/16 of theEP Guide). And for an adjustable regulator, you don't need EP.

author: JPortici
author_rank: Super Contributor
timestamp: June 26, 2017, 04:01:02 pm
content: MIC553x should have a 3.6V variant. 6V in max, though

author: Belrmar
author_rank: Regular Contributor
timestamp: June 26, 2017, 08:03:23 pm
content: i would use a lm317 is always usefull as a variable linear regulator and asl oas a cc source

author: mikerj
author_rank: Super Contributor
timestamp: June 26, 2017, 08:12:54 pm
content: Quote from: Belrmar on June 26, 2017, 08:03:23 pmThe LM317 isn't a low dropout regulator. OP needs 3.6v from a nominal 5v USB charger, a drop out of 1.4v which would limit you to about 20mA or so with an LM317 to maintain regulation. However USB 2.0 voltage is permitted to drop down to as low as 4.4v, in which case you couldn't use an LM317 at all.

author: alm
author_rank: Super Contributor
timestamp: June 26, 2017, 08:19:51 pm
content: Sounds like that 3.6 V might be generated from a 5 VDC source, so the dropout voltage of the LM317 would be too close for comfort (especially since according to the USB spec the 5 V rail might be down to 4.6 V or so). An LD1117 seems to be the most common adjustable LDO, but I would still be worried about dropout voltage under worst case conditions. Also I seem to remember them being touchy about having low-ESR caps (e.g. ceramic) on the output.To meet the dropout spec with worst case USB voltage, I would go for one of the MOSFET-based LDOs, but I am not aware of anyone that is truly multi-source.

author: Jaunedeau
author_rank: Regular Contributor
timestamp: June 27, 2017, 01:41:27 pm
content: Thank you for all your answers, it helped me see better.I first re-did my schematif with a 1117, but in the end found those parts :-Microchip TC1054/TC1055/TC1186-Microchip TC1014/TC1015/TC1185-Micrel (now Microchip) MIC5205-TI TLV700They all are 3.6V LDO, available with 100mA or more max Iout, have adropoout of less than 0.3V (and 0.1 in my case where I need low current).The only difference is pin 4 :-MIC5205 and TC1014/TC1015/TC1185 have an optionnal cap to GND for ultra-low-noise-TLV700 has it unconnected-TC1054/TC1055/TC1186 uses it as an output for error detectionI'll save the two resistors and the cap (I'll put pads so I can add one if needed)Thank you,John.