personal I like the STM *LD39130SJ30R* <https://www.st.com/resource/en/datasheet/ld39130s.pdf>which is a good match for esp32 it will do 300ma with a 300mv drop the quiescent current is a remarkable 1 µA in green mode, 45 µA in normal mode which matched with the ULP mode on the esp32, Not a problem with a golf cart but important for low power sensor. and to top it of STM will send you a couple for just the shipping cost,
The package a somewhat of a pain. Nick I have a number of the regulator board I pictured earlier should you be near Apex and want one. nje On Wed, Nov 18, 2020 at 1:17 PM Josh Wyatt via TriEmbed < [email protected]> wrote: > This is awesome info John, I'm enjoying the read. > > From personal experience, the ESP32S (and ESP8266) can be pretty power > hungry when the radios are on, and are particularly sensitive to > brownouts... I try to use something with at least 300mA and with good, > stiff caps. > > Thanks, > Josh > > On Wed, Nov 18, 2020 at 9:42 AM John Wettroth via TriEmbed < > [email protected]> wrote: > >> Shane, >> There are a ton and its unfortunately one of these "it depends" kind of >> things. But here are a few and why. >> >> Most of the stuff I do is pretty small, low current stuff and 2.7 or >> 3.3v- an 8 bit uP and a display with some RF. Very low quiescent parts >> suitable for circuits with sleep mode, etc. A lot of my stuff lives >> outside and runs on a 12v battery so I try to shoot for -40C operation and >> 16v Max vin. Temp range matters for capacitors mostly and dropout. I buy >> almost exclusively from Digikey. Their search engine and service is >> amazing even if they cost a bit more. I tend to design very low power >> things and like low Iq for sleep operation. Generally very low Iq means >> poor HF rejection (you need loop gain)- in RF stuff, I'll compromise on Iq >> and shut the block down, etc. I prefer newer parts, there has been so much >> progress in the last 15 years, its amazing- there is no reason to use a >> 7805 for any real design- even cheap stuff. There are better and even >> cheaper alternatives if you're building more than a few hundred. At low >> volumes, 7805's can be awfully cheap but they're really only designed as >> 60/120 Hz type regulators in a traditional AC supply. >> >> Some old favorites- >> >> Micrel (Mchip owns Micrel linear now) MIC5203, 5205 series of BiCMOS >> types. PNP pass element but controlled drop out current. 16v 50/150 mA, >> Iq 1 mA max. Micrel invented BiCMOS pretty much and its good to see that >> Microchip is keeping a lot of their parts. >> >> Microchip 1791 is a great HV regulator- 30v max in, 70 mA out, load dump >> (48V), Iq 70 uA. Microchip makes tons of cheap analog parts these days and >> lot of good linears. They acquired Telcom semi many years ago which was a >> big CMOS linear company (like Maxim). Newer CMOS stuff is good but the >> older stuff is not so good- done on large processes and traded Low Iq for >> performance- very slow load and line transient recovery, no PSRR, etc. >> >> Toko TK11625 and TK1150, Digikey dropped Toko but I still have a lot of >> these around- they're officially obsolete but they're plentiful everywhere >> and there are newer alternatives. Available in TO-92, 100 mA, Tk71150 is 5v >> LDO with good HF rejection for low noise for a post after a switcher, >> Quiescent is OK at 300 uA, Seiko makes similar BiCMOS parts, can be hard >> to find these days. Microchip basically copied these regulators to create >> their line and DigiKey wants to keep Mchip happy. >> >> TI TLV1117 A "special" very low Iq LM1117 variant, quiescent of 100 uA. >> Better PSRR and dropout. Good in 3 Alkaline of 1 LiIon to 2.5v apps. Max >> Vin is 5.5v, only downside. >> >> Some favorites lately (doing low cost stuff) >> >> Diodes Inc AP-7381 series. Available in TO-92 option still for quick >> perfboard builds and breadboard. Cheap. Very low Quiescent, 50/150 >> mA variants. Digikey large stocks always. >> >> ABLIC S-812Cxx series. 1uA Iq, 10-100 mA output depend on voltage. >> Quiescent useful for running a real time clock or deep shutdown on a HV >> input. >> >> Anything that Maxim or LTC/ADI makes are invariably awesome but low >> volume pricing (<10k) is awful. Real customers pay nothing like those >> prices believe me. I have odds and ends of Maxim leftovers but never have >> what I need. TI has better pricing but isn't innovating much in this area- >> the TLV1117 is an exception- excellent. >> >> In your Golf Cart app, what's your load current min and max and vin min >> and max. Any big line or load steps? Temp range and size could help too. >> Any special operation needs like sleep? >> >> After 25 years in Standard Products at Maxim, I can talk Linear IC's more >> than anyone cares to listen. Take care- shoot me a private mail or call if >> you have specific questions. >> >> Regards, >> John M. Wettroth >> (984) 329-5420 (home) >> (919) 349-9875 (cell) >> >> >> ------------------------------ >> *From:* Shane Trent [mailto:[email protected]] >> *Sent:* Tuesday, November 17, 2020 9:57 AM >> *To:* [email protected] >> *Cc:* Pete Soper; TriEmbed Discussion >> *Subject:* Re: [TriEmbed] Powering ESP32 from an 8v golf cart battery >> >> John, >> >> Thank you for your breakdown on voltage regulators. Would you mind >> sharing some of your favorite part numbers in the "Modern BiCMOS LDOs"? >> >> Thanks! >> Shane >> >> On Mon, Nov 16, 2020 at 5:52 PM John Wettroth via TriEmbed < >> [email protected]> wrote: >> >>> I'll put my 2 cents in here for a few subtleties. I defined >>> probably 1000 different linear and switching regulators at Maxim in my 25 >>> years. >>> >>> >>> Vout plus dropout is pretty good overall. But don't forget that dropout >>> is defined where the output voltage drops 100 mV. Its coming out of >>> regulation and all the goodness that linears give you stops happening. You >>> also want to do this at max load, max output tolerance and worst temp. The >>> drop out for bipolars decreases for higher temps which helps but at very >>> cold temps, it can grow- a lot a very cold. This is not allways well >>> specified. >>> >>> There are several classes of dropout that are driven by the design of >>> the ouput stage >>> >>> Vdropout >>> >>> 2v standard bipolar linears like the 7805 use an NPN darlington >>> output- nice low impedance and easy to use. >>> 1v LM1117 type bipolar linears use a Sziklai modified darlington >>> with an NPN follower driven by a PNP- pretty good comprimise >>> .5v LM2940 PNP pass element parts have low dropout but some >>> squirelly stability issues at times and can have high quiescent at dropout >>> .1v PMOS or charge pumped NPN pass element types that looks like a >>> small resistance in dropout. Quiescent can be very low. >>> . >>> Depending on the type of regulator, there are subtlties that happen >>> around dropout. >>> >>> Old bipolar regulators like the 7805 have a drop out of about 2v >>> conservatively. The output is an emitter follower darlington stage which >>> is 2 vbe's (.7v each) and 2 Vce sat (about .2v each). This is about 1.8v. >>> Since the output is a follower, it has a gain of 1 and are generally very >>> well behaved with very little thought given to bypassing and stability. >>> High frequency rejection is poor and accuracy is somewhat poor. >>> >>> First generation bipolar LDO's like the LM2940 etc, used a PNP output >>> stage with a grounded NPN pulling its base down. These parts have two Vce >>> sats in the dropout path (about .5v). These transistors have gain on top >>> of the error amp gain and get unstable without following the the bypassing >>> instructions closely. The output cap becomes the dominant pole and the ESR >>> of the output cap has to in a specific range- neither two small or two >>> large. The other annoying feature of this class is as you approach >>> dropout- the beta provided by the PNP pass element goes south and they can >>> draw lots of current at or near dropout trying to keep the PNP in >>> saturation. In low power circuits, this can cause a sort of latching >>> action and flatten a battery in no time. >>> >>> The LM1117 type second gen bipolar LDO's have a NPN follower ouput. >>> These have the benefit of a follower but only moderate dropout >>> performance. They were basically invented to make 3.3v from 5v which a >>> 7805 couldn't do. Good for point of load but kind of mediocre otherwise. >>> >>> Modern BiCMOS LDO's generally have a PMOS pass element and some MOS and >>> Bipolar circuits.. These can have very low quiescent, very low noise and >>> the lowest dropout possible. They are also pretty stable with most loads >>> but take a signicant cap on the output usually. Something like a 10 uF >>> ceramic. Microchip make some good low cost parts in this class. Probably >>> my favorites. >>> >>> There are all CMOS LDO's that share most of features of the last >>> category but don't get the low noise and high accurancy generally. >>> >>> One other issue is your 8v battery. The charging voltage on a Lead Acid >>> could be over 10V which is a common abs max for many linears. >>> >>> My 2 cents. >>> >>> >>> >>> >>> >>> >>> >>> >>> Regards, >>> John M. Wettroth >>> (984) 329-5420 (home) >>> (919) 349-9875 (cell) >>> >>> >>> ------------------------------ >>> *From:* TriEmbed [mailto:[email protected]] *On Behalf Of *Pete >>> Soper via TriEmbed >>> *Sent:* Monday, November 16, 2020 10:46 AM >>> *To:* [email protected] >>> *Subject:* Re: [TriEmbed] Powering ESP32 from an 8v golf cart battery >>> >>> >>> On 11/15/20 10:34 PM, The MacDougals via TriEmbed wrote: >>> >>> _______________________________________________ >>> Triangle, NC Embedded Computing mailing list >>> >>> To post message: [email protected] >>> List info: >>> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org >>> TriEmbed web site: http://TriEmbed.org >>> To unsubscribe, click link and send a blank message: mailto: >>> [email protected]?subject=unsubscribe >>> >>> >> >> -- >> [image: photo] >> *Shane D Trent* >> Patent Agent >> >> 919-348-0061 | [email protected] >> >> ShaneTrent.com | Skype: skype:shane.trent1 >> <#m_133033098193379331_m_189338381597980778_SignatureSanitizer_SafeHtmlFilter_> >> Raleigh, North Carolina >> [image: Social icon] <http://www.linkedin.com/in/shanetrent> [image: >> Social icon] <http://twitter.com/sdtrent> >> Create your own email signature >> <https://www.wisestamp.com/create-own-signature/?utm_source=promotion&utm_medium=signature&utm_campaign=create_your_own&srcid=> >> _______________________________________________ >> Triangle, NC Embedded Computing mailing list >> >> To post message: [email protected] >> List info: >> http://mail.triembed.org/mailman/listinfo/triembed_triembed.org >> TriEmbed web site: http://TriEmbed.org >> To unsubscribe, click link and send a blank message: mailto: >> [email protected]?subject=unsubscribe >> >> _______________________________________________ > Triangle, NC Embedded Computing mailing list > > To post message: [email protected] > List info: http://mail.triembed.org/mailman/listinfo/triembed_triembed.org > TriEmbed web site: http://TriEmbed.org > To unsubscribe, click link and send a blank message: mailto: > [email protected]?subject=unsubscribe > >
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