On Tuesday, May 19, 2020 at 2:57:10 AM UTC+2, bloggs.fre...@gmail.com wrote:> On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: > > ST makes a nice little LDO, super-low dropout with an aux Vbias > > supply. Saves me from rolling my own with an opamp and a mosfet. > > > > It's an ST1L08. > > > > So why is the data sheet file en.DM00123507.pdf ? > > Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. >It's not crappy from my point of view Why would you use a ultra low dropout LDO, and have high headroom for the input? Cheers Klaus
why do they do this?
Started by ●May 18, 2020
Reply by ●May 21, 20202020-05-21
Reply by ●May 21, 20202020-05-21
On Thursday, May 21, 2020 at 10:44:39 PM UTC+2, John Larkin wrote:> On Thu, 21 May 2020 14:07:29 -0400, Phil Hobbs > <pcdhSpamMeSenseless@electrooptical.net> wrote: > > >On 2020-05-21 13:38, John Larkin wrote: > >> On Tue, 19 May 2020 09:55:39 -0400, Phil Hobbs > >> <pcdhSpamMeSenseless@electrooptical.net> wrote: > >> > >>> On 2020-05-19 09:50, jlarkin@highlandsniptechnology.com wrote: > >>>> On Tue, 19 May 2020 12:50:44 +0530, Pimpom <nobody@nowhere.com> wrote: > >>>> > >>>>> On 5/19/2020 9:31 AM, jlarkin@highlandsniptechnology.com wrote: > >>>>>> On Mon, 18 May 2020 17:57:06 -0700 (PDT), > >>>>>> bloggs.fredbloggs.fred@gmail.com wrote: > >>>>>> > >>>>>>> On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: > >>>>>>>> ST makes a nice little LDO, super-low dropout with an aux Vbias > >>>>>>>> supply. Saves me from rolling my own with an opamp and a mosfet. > >>>>>>>> > >>>>>>>> It's an ST1L08. > >>>>>>>> > >>>>>>>> So why is the data sheet file en.DM00123507.pdf ? > >>>>>>> > >>>>>>> Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. > >>>>>> > >>>>>> Lying? It's all over the data sheet. It's how they get the millivolts > >>>>>> of dropout. I do that when I make my own super-LDOs, power an opamp > >>>>>> from some higher voltage and over-drive an nfet follower down to > >>>>>> milliohms of Rds-on. > >>>>>> > >>>>>>> The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. > >>>>>>> > >>>>>> > >>>>>> I'm dropping a switched 1.8 to 1.5. That's 0.3 volts. Times 800 mA > >>>>>> would be 0.24 watts dissipated. Actually, I don't need that much > >>>>>> current to run a couple DRAM chips. > >>>>>> > >>>>> > >>>>> Not directly comparable to the ST1L08 but the Holtek HT75xx-1 > >>>>> series is nice. Max Vin 30V, 100mA, 2.5uA ground current, 25mV > >>>>> drop-out. 16 different fixed output voltages from 2.1V to 12V > >>>>> with 3% tolerance. As usual with products originating in the > >>>>> East, the datasheet is rather sparse about details, but I've used > >>>>> them and they do what I want. > >>>> > >>>> Is it stable with low ESR caps? We use polymers or ceramics mostly. > >>>> > >>>> We need so many goofy voltages that we usually buy adjustable > >>>> regulators for stock. The board that I'm doing now has a 24-channel > >>>> analog mux to BIST the power supplies, using the dreadful Xilinx > >>>> 1-volt XADC that's inside their FPGAs. Free and worth it. > >>>> > >>>>> > >>>>>> You sure are in a bad mood lately. > >>>>>> > >>>>> I've noticed that lately with some regulars here, including a few > >>>>> who normally exhibit decent manners. > >>>> > >>>> Well, some never show any sign of manners. They are repulsive but > >>>> you've got to feel sorry for them, stuck being around themselves all > >>>> day. > >>>> > >>>> There's a basically perfect -1 correlation between being obnoxious and > >>>> designing electronics. > >>> > >>> Well, now that Jim Thompson is apparently no longer with us. :( > >>> > >>> He was a bit of a statistical outlier. > >> > >> He was crabby and dismissive of people not as smart as he was, and > >> hostile to people that might have been smarter, but he was > >> occasionally helpful, and had a sense of humor, and was very brave at > >> the end. > >> > > > >When he wasn't busy accusing peoples' wives of immoral behaviour, > >threatening folks with lawsuits or bodily harm, or siccing the FBI on > >some deserving individuals. ;) > > Gosh, nobody's perfect. > > > > >He was probably nice enough in person--we collaborated a couple of times > >but never met in person or even talked on the phone together. > > > >I agree that he had guts and seems to have died very well. > > I used a version of his clever CD ignition (without his permission) as > a gain-switched laser driver. Nice circuit. >I talked to him a couple of times, one review on a design when I guess he was close to not being with us any more He did an ASIC gatedriver design for us, nice design, cheap like we like it Suddenly we did not hear from him again, so another ASIC designer took over at that point He did minimum dev cost design, using an old version of Pspice to simulate the design, and then had another designer lay out the chip Cheers Klaus
Reply by ●May 21, 20202020-05-21
On Thursday, May 21, 2020 at 5:49:54 PM UTC-4, Klaus Kragelund wrote:> On Tuesday, May 19, 2020 at 2:57:10 AM UTC+2, bloggs.fre...@gmail.com wrote: > > On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: > > > ST makes a nice little LDO, super-low dropout with an aux Vbias > > > supply. Saves me from rolling my own with an opamp and a mosfet. > > > > > > It's an ST1L08. > > > > > > So why is the data sheet file en.DM00123507.pdf ? > > > > Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. > > > > It's not crappy from my point of view > > Why would you use a ultra low dropout LDO, and have high headroom for the input? > > Cheers > > KlausOne reason might be power dissipation. If you have a switcher generating 1.5 volts and you need 1.2 volts it can be cost effective to use a linear and not much different in efficiency. Or you might not be able to draw power from the higher voltage. The bias input is the low operating current, not the larger regulated current. -- Rick C. ++ Get 1,000 miles of free Supercharging ++ Tesla referral code - https://ts.la/richard11209
Reply by ●May 21, 20202020-05-21
On Friday, May 22, 2020 at 1:18:23 AM UTC+2, Ricketty C wrote:> On Thursday, May 21, 2020 at 5:49:54 PM UTC-4, Klaus Kragelund wrote: > > On Tuesday, May 19, 2020 at 2:57:10 AM UTC+2, bloggs.fre...@gmail.com wrote: > > > On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: > > > > ST makes a nice little LDO, super-low dropout with an aux Vbias > > > > supply. Saves me from rolling my own with an opamp and a mosfet. > > > > > > > > It's an ST1L08. > > > > > > > > So why is the data sheet file en.DM00123507.pdf ? > > > > > > Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. > > > > > > > It's not crappy from my point of view > > > > Why would you use a ultra low dropout LDO, and have high headroom for the input? > > > > Cheers > > > > Klaus > > One reason might be power dissipation. If you have a switcher generating 1.5 volts and you need 1.2 volts it can be cost effective to use a linear and not much different in efficiency. Or you might not be able to draw power from the higher voltage. The bias input is the low operating current, not the larger regulated current. > > -- >The rhetorical question was actually a response to Slomans post. His point was that is was a bad device due to limited use of the dropout voltage was high. But my point was, that then just don't use that device for high dropout. Might as well use a LM78xx variant then Cheers Klaus
Reply by ●May 21, 20202020-05-21
On Thu, 21 May 2020 17:48:29 -0400, Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:>On 2020-05-21 12:18, jlarkin@highlandsniptechnology.com wrote: >> On Thu, 21 May 2020 07:44:44 -0700 (PDT), Michael Terrell >> <terrell.michael.a@gmail.com> wrote: >> >>> On Thursday, May 21, 2020 at 10:35:09 AM UTC-4, jla...@highlandsniptechnology.com wrote: >>>> On Thu, 21 May 2020 01:55:31 -0700 (PDT), Michael Terrell Wrote: >>>>> >>>>> We were just starting to automate testing, but that was almost 19 years ago. Documentation and board or model number matched the blank board, plus the BOM and test procedure for different versions but with over 20 modules in a unit, plus a separate plug in tuner for older models (depending on which microwave band) still complicated issues. Add that the company had been around since 1968 which was before most small businesses used computers, the system was deeply embedded in the daily operations. They had changed their part numbering system, once and it was a nightmare. Every BOM had to be rewritten, on a typewriter, then all old copies destroyed. >>>>> >>>>> On top of that, when they decided to close their original Rockville Maryland plant, the employees shredded every document in the vault, plus all working copies, leaving the engineers the task of reverse engineering the last complete units and to recreate the mountain of data. >>>> >>>> Some companies have a "configuration control" department, whose job is >>>> to control all the documents and their relationship, and make sure the >>>> right stuff gets manufactured and remembered. All documents have to be >>>> submitted to them. >>>> >>>> Makes sense; keeping this stuff organized is non-trivial, especially >>>> when mistakes can kill people. >>> >>> >>> We did a lot of work for NASA and NOAA. We supplied their 'Command Destruct Receivers. If one of those failed, a rocket could kill a lot of people. >> >> On the S1B moon rocket, there was one transistor that fired the >> destruct charge. It was the most tested and qualified transistor in >> history, and the only one on the rocket that was in a socket. > >After all that handling and abuse, it was probably among the least >reliable, too. ;)Studies showed that cheap plastic transistors were more reliable than super metal can burned-in JAN-TX parts.> >> >> I designed some flight hardware for the first stage, but it was >> noncritical telemetry so only got the normal levels of QC paranoia. >> >> We etched our own PC boards in the bathroom and got away with it. > >At IBM, if you needed to commit a safety violation to get your work >done, savvy folks did it in their offices, not their labs. Nobody ever >did a hazardous chemical audit of the offices for some reason. ;) > >It was pretty tame stuff usually--my lab didn't have a fume hood, and I >needed to be able to etch patterns into metallized PVDF. I kept a >RadioShack bottle of FeCl2 juice in my office, which was across the hall >from my lab, and shuttled some back and forth as necessary.Somebody here recommended the book Ignition! https://www.amazon.com/gp/product/0813595835/ref=ppx_yo_dt_b_asin_title_o06_s00?ie=UTF8&psc=1 It's great fun, if you skip over the chemical equations. -- John Larkin Highland Technology, Inc picosecond timing precision measurement jlarkin att highlandtechnology dott com http://www.highlandtechnology.com
Reply by ●May 21, 20202020-05-21
Am 22.05.20 um 02:52 schrieb John Larkin:>>> On the S1B moon rocket, there was one transistor that fired the >>> destruct charge. It was the most tested and qualified transistor in >>> history, and the only one on the rocket that was in a socket. >> >> After all that handling and abuse, it was probably among the least >> reliable, too. ;) > > Studies showed that cheap plastic transistors were more reliable than > super metal can burned-in JAN-TX parts.A friend of mine used to argue that there were so many resistors (then) in a color TV that the manufacturers could not afford bad ones or production had serious problems. He advocated Beyschlag, now part of Vishay. With our ESA project, we did not have a choice. But then I'm not qualified to solder them in. I had to call the solder lady for work on flight hardware. Cheers, Gerhard
Reply by ●May 21, 20202020-05-21
On Tue, 19 May 2020 15:02:32 -0700 (PDT), bloggs.fredbloggs.fred@gmail.com wrote:>On Tuesday, May 19, 2020 at 12:26:28 PM UTC-4, jla...@highlandsniptechnology.com wrote: >> On Tue, 19 May 2020 08:04:52 -0700 (PDT), >> bloggs.fredbloggs.fred@gmail.com wrote: >> >> >On Tuesday, May 19, 2020 at 9:50:43 AM UTC-4, jla...@highlandsniptechnology.com wrote: >> >> On Tue, 19 May 2020 12:50:44 +0530, Pimpom <nobody@nowhere.com> wrote: >> >> >> >> >On 5/19/2020 9:31 AM, jlarkin@highlandsniptechnology.com wrote: >> >> >> On Mon, 18 May 2020 17:57:06 -0700 (PDT), >> >> >> bloggs.fredbloggs.fred@gmail.com wrote: >> >> >> >> >> >>> On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: >> >> >>>> ST makes a nice little LDO, super-low dropout with an aux Vbias >> >> >>>> supply. Saves me from rolling my own with an opamp and a mosfet. >> >> >>>> >> >> >>>> It's an ST1L08. >> >> >>>> >> >> >>>> So why is the data sheet file en.DM00123507.pdf ? >> >> >>> >> >> >>> Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. >> >> >> >> >> >> Lying? It's all over the data sheet. It's how they get the millivolts >> >> >> of dropout. I do that when I make my own super-LDOs, power an opamp >> >> >> from some higher voltage and over-drive an nfet follower down to >> >> >> milliohms of Rds-on. >> >> >> >> >> >>> The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. >> >> >>> >> >> >> >> >> >> I'm dropping a switched 1.8 to 1.5. That's 0.3 volts. Times 800 mA >> >> >> would be 0.24 watts dissipated. Actually, I don't need that much >> >> >> current to run a couple DRAM chips. >> >> >> >> >> > >> >> >Not directly comparable to the ST1L08 but the Holtek HT75xx-1 >> >> >series is nice. Max Vin 30V, 100mA, 2.5uA ground current, 25mV >> >> >drop-out. 16 different fixed output voltages from 2.1V to 12V >> >> >with 3% tolerance. As usual with products originating in the >> >> >East, the datasheet is rather sparse about details, but I've used >> >> >them and they do what I want. >> >> >> >> Is it stable with low ESR caps? We use polymers or ceramics mostly. >> >> >> >> We need so many goofy voltages that we usually buy adjustable >> >> regulators for stock. The board that I'm doing now has a 24-channel >> >> analog mux to BIST the power supplies, using the dreadful Xilinx >> >> 1-volt XADC that's inside their FPGAs. Free and worth it. >> >> >> >> > >> >> >> You sure are in a bad mood lately. >> >> >> >> >> >I've noticed that lately with some regulars here, including a few >> >> >who normally exhibit decent manners. >> >> >> >> Well, some never show any sign of manners. They are repulsive but >> >> you've got to feel sorry for them, stuck being around themselves all >> >> day. >> >> >> >> There's a basically perfect -1 correlation between being obnoxious and >> >> designing electronics. >> > >> >Seriously! Rigging up your little pseudo-LDO is not "designing" electronics. That's like saying figuring the part number suffix for the fixed 1.5V output is "designing" electronics. >> >> Rolling your own opamp-nfet LDO is not designing electronics? > >Of course it is, but you're not doing that. > >> >> The loop could oscillate; transient load-step response matters; the >> fet could oscillate; the fet could fry; the loop dynamics changes >> radically at low dropout voltages, when the fet becomes ohmic; loads >> could have different C and ESR and stuff. This takes design. > >It would be foolish getting distracted by that minutia when you have a much bigger task to complete. Take the non-design off the shelf LDO approach.I did on this one. That little LDO is on there somewhere. https://www.dropbox.com/s/xywr3isogqnklm7/P901_E3.jpg?raw=1 The DRAM is just there for possible future use. It needs 1.5. The FPGA core needs 1.0. Aux is 1.8. Something else needs 1.2. All that from a 1.8v switcher. Prime input is +48. As people make fancy chips, we can quit doing stuff like home-brew LDOs, put more on a board, and move up the abstraction stack. It's still design. -- John Larkin Highland Technology, Inc Science teaches us to doubt. Claude Bernard
Reply by ●May 22, 20202020-05-22
On 2020-05-21 21:16, Gerhard Hoffmann wrote:> Am 22.05.20 um 02:52 schrieb John Larkin: > >>>> On the S1B moon rocket, there was one transistor that fired the >>>> destruct charge. It was the most tested and qualified transistor in >>>> history, and the only one on the rocket that was in a socket. >>> >>> After all that handling and abuse, it was probably among the least >>> reliable, too. ;) >> >> Studies showed that cheap plastic transistors were more reliable than >> super metal can burned-in JAN-TX parts. > > > A friend of mine used to argue that there were so many resistors (then) > in a color TV that the manufacturers could not afford bad ones or > production had serious problems. He advocated Beyschlag, now part > of Vishay. > > With our ESA project, we did not have a choice. > But then I'm not qualified to solder them in. > I had to call the solder lady for work on flight hardware. > > Cheers, GerhardOver here, MIL-HDBK-217 used to rule the roost in projects like that. I had one employer that tried it out, building satellite ground equipment for the first civilian DBS system in 1981-83. Among other things, '217 predicted that reliability would improve if you removed all the protection circuitry from your design. It was an early precursor of Total Quality Management, ISO 9000, etc., and ignored actual recent data on component reliability in favour of some 'golden' data set from long ago, based on ridiculously flawed studies that assumed that all failures had an Arrhenius temperature dependence, that nothing was ever learned from past failures, yada yada. Folks who knew how things actually worked left the protection circuitry in place, put in the paperwork, and (when necessary) gold-plated the BOM to hit the 'reliability' numbers. Fortunately I was able to move on and go to grad school instead. Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●May 22, 20202020-05-22
On 2020-05-21 17:39, Phil Hobbs wrote:> On 2020-05-21 16:44, John Larkin wrote: >> On Thu, 21 May 2020 14:07:29 -0400, Phil Hobbs >> <pcdhSpamMeSenseless@electrooptical.net> wrote: >> >>> On 2020-05-21 13:38, John Larkin wrote: >>>> On Tue, 19 May 2020 09:55:39 -0400, Phil Hobbs >>>> <pcdhSpamMeSenseless@electrooptical.net> wrote: >>>> >>>>> On 2020-05-19 09:50, jlarkin@highlandsniptechnology.com wrote: >>>>>> On Tue, 19 May 2020 12:50:44 +0530, Pimpom <nobody@nowhere.com> >>>>>> wrote: >>>>>> >>>>>>> On 5/19/2020 9:31 AM, jlarkin@highlandsniptechnology.com wrote: >>>>>>>> On Mon, 18 May 2020 17:57:06 -0700 (PDT), >>>>>>>> bloggs.fredbloggs.fred@gmail.com wrote: >>>>>>>> >>>>>>>>> On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: >>>>>>>>>> ST makes a nice little LDO, super-low dropout with an aux Vbias >>>>>>>>>> supply. Saves me from rolling my own with an opamp and a mosfet. >>>>>>>>>> >>>>>>>>>> It's an ST1L08. >>>>>>>>>> >>>>>>>>>> So why is the data sheet file en.DM00123507.pdf ? >>>>>>>>> >>>>>>>>> Who cares, it's a crappy regulator. And the lying bastards with >>>>>>>>> their fake dropout specs while conveniently omitting the fact >>>>>>>>> that Vbias must be greater than Vout + 1.5V. >>>>>>>> >>>>>>>> Lying? It's all over the data sheet. It's how they get the >>>>>>>> millivolts >>>>>>>> of dropout. I do that when I make my own super-LDOs, power an opamp >>>>>>>> from some higher voltage and over-drive an nfet follower down to >>>>>>>> milliohms of Rds-on. >>>>>>>> >>>>>>>>> The GND current at no load of 35uA, sucks , as does that showy >>>>>>>>> 80dB PSRR at 100 Hz. Battery operation usually doesn't care a >>>>>>>>> whole lot about PSRR. And the thermal impedance specs are so >>>>>>>>> bad, you just try getting 800mA out of it with any kind voltage >>>>>>>>> headroom without using a liquid nitrogen drip. >>>>>>>>> >>>>>>>> >>>>>>>> I'm dropping a switched 1.8 to 1.5. That's 0.3 volts. Times 800 mA >>>>>>>> would be 0.24 watts dissipated. Actually, I don't need that much >>>>>>>> current to run a couple DRAM chips. >>>>>>>> >>>>>>> >>>>>>> Not directly comparable to the ST1L08 but the Holtek HT75xx-1 >>>>>>> series is nice. Max Vin 30V, 100mA, 2.5uA ground current, 25mV >>>>>>> drop-out. 16 different fixed output voltages from 2.1V to 12V >>>>>>> with 3% tolerance. As usual with products originating in the >>>>>>> East, the datasheet is rather sparse about details, but I've used >>>>>>> them and they do what I want. >>>>>> >>>>>> Is it stable with low ESR caps? We use polymers or ceramics mostly. >>>>>> >>>>>> We need so many goofy voltages that we usually buy adjustable >>>>>> regulators for stock. The board that I'm doing now has a 24-channel >>>>>> analog mux to BIST the power supplies, using the dreadful Xilinx >>>>>> 1-volt XADC that's inside their FPGAs. Free and worth it. >>>>>> >>>>>>> >>>>>>>> You sure are in a bad mood lately. >>>>>>>> >>>>>>> I've noticed that lately with some regulars here, including a few >>>>>>> who normally exhibit decent manners. >>>>>> >>>>>> Well, some never show any sign of manners. They are repulsive but >>>>>> you've got to feel sorry for them, stuck being around themselves all >>>>>> day. >>>>>> >>>>>> There's a basically perfect -1 correlation between being obnoxious >>>>>> and >>>>>> designing electronics. >>>>> >>>>> Well, now that Jim Thompson is apparently no longer with us. :( >>>>> >>>>> He was a bit of a statistical outlier. >>>> >>>> He was crabby and dismissive of people not as smart as he was, and >>>> hostile to people that might have been smarter, but he was >>>> occasionally helpful, and had a sense of humor, and was very brave at >>>> the end. >>>> >>> >>> When he wasn't busy accusing peoples' wives of immoral behaviour, >>> threatening folks with lawsuits or bodily harm, or siccing the FBI on >>> some deserving individuals. ;) >> >> Gosh, nobody's perfect. >> >>> >>> He was probably nice enough in person--we collaborated a couple of times >>> but never met in person or even talked on the phone together. >>> >>> I agree that he had guts and seems to have died very well. >> >> I used a version of his clever CD ignition (without his permission) as >> a gain-switched laser driver. Nice circuit. >> > > I have a mirror of the last version of his web site at > <https://electrooptical.net/static/oldsite/www.analog-innovations.com/logo.html>. >Sorry, that's not where the interesting stuff links from. Should be <https://electrooptical.net/static/oldsite/www.analog-innovations.com/analog-innovations.html> Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●May 23, 20202020-05-23
Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote:> On 2020-05-21 00:44, Cydrome Leader wrote: >> Phil Hobbs <pcdhSpamMeSenseless@electrooptical.net> wrote: >>> On 2020-05-19 09:50, jlarkin@highlandsniptechnology.com wrote: >>>> On Tue, 19 May 2020 12:50:44 +0530, Pimpom <nobody@nowhere.com> wrote: >>>> >>>>> On 5/19/2020 9:31 AM, jlarkin@highlandsniptechnology.com wrote: >>>>>> On Mon, 18 May 2020 17:57:06 -0700 (PDT), >>>>>> bloggs.fredbloggs.fred@gmail.com wrote: >>>>>> >>>>>>> On Monday, May 18, 2020 at 7:41:34 PM UTC-4, John Larkin wrote: >>>>>>>> ST makes a nice little LDO, super-low dropout with an aux Vbias >>>>>>>> supply. Saves me from rolling my own with an opamp and a mosfet. >>>>>>>> >>>>>>>> It's an ST1L08. >>>>>>>> >>>>>>>> So why is the data sheet file en.DM00123507.pdf ? >>>>>>> >>>>>>> Who cares, it's a crappy regulator. And the lying bastards with their fake dropout specs while conveniently omitting the fact that Vbias must be greater than Vout + 1.5V. >>>>>> >>>>>> Lying? It's all over the data sheet. It's how they get the millivolts >>>>>> of dropout. I do that when I make my own super-LDOs, power an opamp >>>>>> from some higher voltage and over-drive an nfet follower down to >>>>>> milliohms of Rds-on. >>>>>> >>>>>>> The GND current at no load of 35uA, sucks , as does that showy 80dB PSRR at 100 Hz. Battery operation usually doesn't care a whole lot about PSRR. And the thermal impedance specs are so bad, you just try getting 800mA out of it with any kind voltage headroom without using a liquid nitrogen drip. >>>>>>> >>>>>> >>>>>> I'm dropping a switched 1.8 to 1.5. That's 0.3 volts. Times 800 mA >>>>>> would be 0.24 watts dissipated. Actually, I don't need that much >>>>>> current to run a couple DRAM chips. >>>>>> >>>>> >>>>> Not directly comparable to the ST1L08 but the Holtek HT75xx-1 >>>>> series is nice. Max Vin 30V, 100mA, 2.5uA ground current, 25mV >>>>> drop-out. 16 different fixed output voltages from 2.1V to 12V >>>>> with 3% tolerance. As usual with products originating in the >>>>> East, the datasheet is rather sparse about details, but I've used >>>>> them and they do what I want. >>>> >>>> Is it stable with low ESR caps? We use polymers or ceramics mostly. >>>> >>>> We need so many goofy voltages that we usually buy adjustable >>>> regulators for stock. The board that I'm doing now has a 24-channel >>>> analog mux to BIST the power supplies, using the dreadful Xilinx >>>> 1-volt XADC that's inside their FPGAs. Free and worth it. >>>> >>>>> >>>>>> You sure are in a bad mood lately. >>>>>> >>>>> I've noticed that lately with some regulars here, including a few >>>>> who normally exhibit decent manners. >>>> >>>> Well, some never show any sign of manners. They are repulsive but >>>> you've got to feel sorry for them, stuck being around themselves all >>>> day. >>>> >>>> There's a basically perfect -1 correlation between being obnoxious and >>>> designing electronics. >>> >>> Well, now that Jim Thompson is apparently no longer with us. :( >>> >>> He was a bit of a statistical outlier. >> >> Was that the guy who designed all the 2 digit LM series chips? What >> happened to him? >> > > He was more in the Motorola orbit back then, IIRC, but he was certainly > the most accomplished IC designer in the group. He disappeared a couple > of years ago, after having been diagnosed with early-stage pancreatic > cancer during tests for something else. He said that he thought he had > beaten it, but then just disappeared from the group. His website > subsequently disappeared as well. > > Various folks have looked for an obituary, but nothing turned up. (His > full name was James Elbert Thompson, and he lived most recently in Queen > Creek AZ.) He was a bit of a chingada but designed a lot of interesting > electronics and really helped keep the local leftists in check.This all sounds familiar now- the IC designer in AZ. I didn't realize he's been gone for years now.
