reg + reference
in [Design]
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From: John Larkin on 1 Apr 2010 10:04 On Wed, 31 Mar 2010 21:21:04 -0700, "JosephKK"<quiettechblue(a)yahoo.com> wrote: >On Wed, 31 Mar 2010 08:22:05 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Wed, 31 Mar 2010 04:37:14 -0700, >>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >> >>>On Fri, 26 Mar 2010 18:40:33 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>>On Fri, 26 Mar 2010 17:01:38 -0700 (PDT), "langwadt(a)fonz.dk" >>>><langwadt(a)fonz.dk> wrote: >>>> >>>>>On 26 Mar., 22:24, John Larkin >>>>><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>> On Fri, 26 Mar 2010 19:21:00 GMT, Jan Panteltje >>>>>> >>>>>> <pNaonStpealm...(a)yahoo.com> wrote: >>>>>> >On a sunny day (Fri, 26 Mar 2010 10:19:55 -0700) it happened John Larkin >>>>>> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote in >>>>>> ><13rpq5lqd1lj1k9flb9orfr2vcl2tuu...(a)4ax.com>: >>>>>> >>>>>> >>ftp://jjlarkin.lmi.net/V220_reg.JPG >>>>>> >>>>>> >>John >>>>>> >>>>>> >No money for a real current source or current mirror? >>>>>> >Does that 1M depending on beta circuit change a lot over temperature? >>>>>> >Its Vbe will change, so will the Ib. >>>>>> >>>>>> The current into the reference will be more constant than if I just >>>>>> used a resistor with a nominal 0.3 volt drop across it. The BCX71K has >>>>>> a very tight beta spec. It would probably be better than using the >>>>>> current mirror discussed in another thread recently. And we have >>>>>> BCX71Ks in stock for under 4 cents each. >>>>>> >>>>>> The +15 is not very well regulated, and I'm tight for space. >>>>>> >>>>>> I guess I could use a depletion mode fet from +15. That's just one >>>>>> part. The current regulation would be fair, but I wouldn't have any >>>>>> flexibility on setting current. An LND150 is 33 cents, no problem >>>>>> there, but Idss is 1 to 3 mA and it may change a bunch with >>>>>> temperature. >>>>>> >>>>>> Or maybe there exists a 3 volt 3-wire reference that would work from >>>>>> 3.3 volts. >>>>> >>>>>use the ~3.3V as reference, measure a 1.2V reference voltage and >>>>>correct for it? >>>> >>>>I could use a 1.2 volt shunt reference, with a reasonable resistor >>>>from 3.3, and use an opamp to scale the 1.2 up to 3. More parts! The >>>>National low-dropout reference is ideal, if it doesn't oscillate. >>>> >>>>> >>>>>> >>>>>> This will be the ADC voltage reference for an NXP ARM processor. I'm >>>>>> doing a 12-channel 4-20 mA thing, electrically isolated per channel, >>>>>> with an ARM per channel. The ARM and other stuff might need 45 mA or >>>>>> so, less if we can sleep the code a lot. >>>>> >>>>>why not pick an ARM with a build in reference? something like >>>>>stm32... ? >>>>>12 bits too, think the nxp is only 10bits >>>> >>>>The NXP LPC1768 we're going to use has a 12 bit mux'd ADC and a 10 bit >>>>DAC, and all the other stuff like ram, flash, SPI we need. It's a 100 >>>>MHz CPU with single-cycle multiply, pretty impressive for around $7. >>>>We're going to be running a couple of PID loops as fast as the ADC can >>>>feed us data, 100K hits a second maybe. >>>> >>>>Some of the ST parts look nice, but we already have the compiler/jtag >>>>infrastructure in place for the NXP, and we're blinking LEDs, so we'll >>>>stick with that. >>>> >>>>> >>>>>I'm sure analog has some too >>>> >>>>ARM seems to have won the embedded game. Freescale/Coldfire is rumored >>>>to be seriously ill. >>>> >>>>John >>> >>>Could you elucidate on the coldfire being seriously ill? Preferably with >>>references / links, as it may impact my employer. >> >>www.google.com. >> >> >>John > >Many device lines have lived decades under similar death threat. >If you cannot come up with better than that, i have no need to worry. It's not my function to prove to you that you may be facing a problem. A simple warning should be enough to get your attention. Ignore the issue if you think I haven't provided adequate research. There have in fact been recent articles in the electronic press about the Freescale and NXP situations. Both went private, under crushing debt loads, and both are fighting to survive. John
From: krw on 1 Apr 2010 18:52 On Thu, 01 Apr 2010 09:27:59 -0400, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >On 3/31/2010 11:53 PM, krw(a)att.bizzzzzzzzzzzz wrote: >> On Wed, 31 Mar 2010 22:14:16 -0500, "Tim Williams"<tmoranwms(a)charter.net> >> wrote: >> >>> "John Larkin"<jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message >>> news:2vt7r5p5qcrd78neuabj8b9gu837pecbt2(a)4ax.com... >>>> DEC loved wire-wrap, but as logic got faster the impedance and >>>> crosstalk issues became untenable. PCBs were cheaper anyhow. >>> >>> Ironically, ECL came out before TTL. >> >> Yes, IBM used all ECL until the mid '80s, then one generation of TTL[*] and >> back to ECL until CMOS knocked it out permanently. While ECL was faster, TTL >> has a nasty dI/dt issue. I did MECL 10K designs on wirewrap, too. Worked >> fine. >> > >I think the 3090 was the last ECL beast, and they went right to CMOS. I >was sort of in the middle of that, circa 1990. There were two generations, the "H2" and "H5", of ES9000s after 3090s that were also ECL. IBM didn't go CMOS until the 'z' series. The TTL generation was the 308x (before the 3090), and that may have been just the midrange models. <...>
From: JosephKK on 2 Apr 2010 00:32 On Thu, 01 Apr 2010 07:04:21 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Wed, 31 Mar 2010 21:21:04 -0700, >"JosephKK"<quiettechblue(a)yahoo.com> wrote: > >>On Wed, 31 Mar 2010 08:22:05 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>>On Wed, 31 Mar 2010 04:37:14 -0700, >>>"JosephKK"<quiettechblue(a)yahoo.com> wrote: >>> >>>>On Fri, 26 Mar 2010 18:40:33 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>>> >>>>>On Fri, 26 Mar 2010 17:01:38 -0700 (PDT), "langwadt(a)fonz.dk" >>>>><langwadt(a)fonz.dk> wrote: >>>>> >>>>>>On 26 Mar., 22:24, John Larkin >>>>>><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: >>>>>>> On Fri, 26 Mar 2010 19:21:00 GMT, Jan Panteltje >>>>>>> >>>>>>> <pNaonStpealm...(a)yahoo.com> wrote: >>>>>>> >On a sunny day (Fri, 26 Mar 2010 10:19:55 -0700) it happened John Larkin >>>>>>> ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote in >>>>>>> ><13rpq5lqd1lj1k9flb9orfr2vcl2tuu...(a)4ax.com>: >>>>>>> >>>>>>> >>ftp://jjlarkin.lmi.net/V220_reg.JPG >>>>>>> >>>>>>> >>John >>>>>>> >>>>>>> >No money for a real current source or current mirror? >>>>>>> >Does that 1M depending on beta circuit change a lot over temperature? >>>>>>> >Its Vbe will change, so will the Ib. >>>>>>> >>>>>>> The current into the reference will be more constant than if I just >>>>>>> used a resistor with a nominal 0.3 volt drop across it. The BCX71K has >>>>>>> a very tight beta spec. It would probably be better than using the >>>>>>> current mirror discussed in another thread recently. And we have >>>>>>> BCX71Ks in stock for under 4 cents each. >>>>>>> >>>>>>> The +15 is not very well regulated, and I'm tight for space. >>>>>>> >>>>>>> I guess I could use a depletion mode fet from +15. That's just one >>>>>>> part. The current regulation would be fair, but I wouldn't have any >>>>>>> flexibility on setting current. An LND150 is 33 cents, no problem >>>>>>> there, but Idss is 1 to 3 mA and it may change a bunch with >>>>>>> temperature. >>>>>>> >>>>>>> Or maybe there exists a 3 volt 3-wire reference that would work from >>>>>>> 3.3 volts. >>>>>> >>>>>>use the ~3.3V as reference, measure a 1.2V reference voltage and >>>>>>correct for it? >>>>> >>>>>I could use a 1.2 volt shunt reference, with a reasonable resistor >>>>>from 3.3, and use an opamp to scale the 1.2 up to 3. More parts! The >>>>>National low-dropout reference is ideal, if it doesn't oscillate. >>>>> >>>>>> >>>>>>> >>>>>>> This will be the ADC voltage reference for an NXP ARM processor. I'm >>>>>>> doing a 12-channel 4-20 mA thing, electrically isolated per channel, >>>>>>> with an ARM per channel. The ARM and other stuff might need 45 mA or >>>>>>> so, less if we can sleep the code a lot. >>>>>> >>>>>>why not pick an ARM with a build in reference? something like >>>>>>stm32... ? >>>>>>12 bits too, think the nxp is only 10bits >>>>> >>>>>The NXP LPC1768 we're going to use has a 12 bit mux'd ADC and a 10 bit >>>>>DAC, and all the other stuff like ram, flash, SPI we need. It's a 100 >>>>>MHz CPU with single-cycle multiply, pretty impressive for around $7. >>>>>We're going to be running a couple of PID loops as fast as the ADC can >>>>>feed us data, 100K hits a second maybe. >>>>> >>>>>Some of the ST parts look nice, but we already have the compiler/jtag >>>>>infrastructure in place for the NXP, and we're blinking LEDs, so we'll >>>>>stick with that. >>>>> >>>>>> >>>>>>I'm sure analog has some too >>>>> >>>>>ARM seems to have won the embedded game. Freescale/Coldfire is rumored >>>>>to be seriously ill. >>>>> >>>>>John >>>> >>>>Could you elucidate on the coldfire being seriously ill? Preferably with >>>>references / links, as it may impact my employer. >>> >>>www.google.com. >>> >>> >>>John >> >>Many device lines have lived decades under similar death threat. >>If you cannot come up with better than that, i have no need to worry. > >It's not my function to prove to you that you may be facing a problem. >A simple warning should be enough to get your attention. Ignore the >issue if you think I haven't provided adequate research. > >There have in fact been recent articles in the electronic press about >the Freescale and NXP situations. Both went private, under crushing >debt loads, and both are fighting to survive. > >John That is slightly more helpful.
From: Joerg on 4 Apr 2010 16:40 Fred Abse wrote: > On Thu, 01 Apr 2010 07:04:21 -0700, John Larkin wrote: > >> There have in fact been recent articles in the electronic press about the >> Freescale and NXP situations. Both went private, under crushing debt >> loads, and both are fighting to survive. > > The "technical" term is "leveraged buyout". > > Now, what does "leverage" remind me of? > > ;-) > Leverage the leverage that was already leveraged? :-) -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM.
From: krw on 4 Apr 2010 16:46
On Sun, 04 Apr 2010 13:40:51 -0700, Joerg <invalid(a)invalid.invalid> wrote: >Fred Abse wrote: >> On Thu, 01 Apr 2010 07:04:21 -0700, John Larkin wrote: >> >>> There have in fact been recent articles in the electronic press about the >>> Freescale and NXP situations. Both went private, under crushing debt >>> loads, and both are fighting to survive. >> >> The "technical" term is "leveraged buyout". >> >> Now, what does "leverage" remind me of? >> >> ;-) >> > >Leverage the leverage that was already leveraged? :-) Obama nationalized them too? |