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From: Jim Thompson on 13 Jan 2010 16:04 On Wed, 13 Jan 2010 14:00:23 -0700, Jim Thompson <To-Email-Use-The-Envelope-Icon(a)My-Web-Site.com/Snicker> wrote: >On Wed, 13 Jan 2010 21:39:12 +0100, Fred Bartoli <" "> wrote: > [snip] >> >>Have a look at AD8605. Just amazing. >> [snip] > >Yep. Judging from the input bias specs, they've got some HUGE input >devices there. [snip] Looked it up... L=1u W=1600u !! ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
From: Spehro Pefhany on 13 Jan 2010 16:15 rOn Wed, 13 Jan 2010 21:39:12 +0100, Fred Bartoli <" "> wrote: >Jim Thompson a �crit : >> On Wed, 13 Jan 2010 08:40:14 -0800, "Joel Koltner" >> <zapwireDASHgroups(a)yahoo.com> wrote: >> >>> Did that design make it through fab, Jim, or did the company start imploding >>> first? >> >> It was fabbed at Polarfab. The company began disintegration while >> debugging the digital was in progress. >> >>> I thought that combined bipolar/CMOS ("BiFET?") processes were generally >>> considered too exotic/unnecessary-due-to-performance-improvements-in-CMOS >>> these days? Not so? >>> >>> ---Joel >> >> Not so for analog. Try making a low noise amplifier with only CMOS. > >Have a look at AD8605. Just amazing. 16nV/sqrt(Hz) at 40Hz typical, vs. more like 1nV/sqrt(Hz) for a good bipolar op-amp operating from a low source impedance. >> Try making a TVG that is stable/predictable over temperature. >> >> For quality, bipolar ROCKS ;-) >> >> ...Jim Thompson
From: John Larkin on 13 Jan 2010 16:08 On Wed, 13 Jan 2010 21:39:12 +0100, Fred Bartoli <" "> wrote: >Jim Thompson a �crit : >> On Wed, 13 Jan 2010 08:40:14 -0800, "Joel Koltner" >> <zapwireDASHgroups(a)yahoo.com> wrote: >> >>> Did that design make it through fab, Jim, or did the company start imploding >>> first? >> >> It was fabbed at Polarfab. The company began disintegration while >> debugging the digital was in progress. >> >>> I thought that combined bipolar/CMOS ("BiFET?") processes were generally >>> considered too exotic/unnecessary-due-to-performance-improvements-in-CMOS >>> these days? Not so? >>> >>> ---Joel >> >> Not so for analog. Try making a low noise amplifier with only CMOS. > >Have a look at AD8605. Just amazing. > Even better: http://focus.ti.com/docs/prod/folders/print/opa376.html It's 65 cents at 1K, a tad less than the ADI part. John
From: Jim Thompson on 13 Jan 2010 16:21 On Wed, 13 Jan 2010 16:15:23 -0500, Spehro Pefhany <speffSNIP(a)interlogDOTyou.knowwhat> wrote: >rOn Wed, 13 Jan 2010 21:39:12 +0100, Fred Bartoli <" "> wrote: > >>Jim Thompson a �crit : >>> On Wed, 13 Jan 2010 08:40:14 -0800, "Joel Koltner" >>> <zapwireDASHgroups(a)yahoo.com> wrote: >>> >>>> Did that design make it through fab, Jim, or did the company start imploding >>>> first? >>> >>> It was fabbed at Polarfab. The company began disintegration while >>> debugging the digital was in progress. >>> >>>> I thought that combined bipolar/CMOS ("BiFET?") processes were generally >>>> considered too exotic/unnecessary-due-to-performance-improvements-in-CMOS >>>> these days? Not so? >>>> >>>> ---Joel >>> >>> Not so for analog. Try making a low noise amplifier with only CMOS. >> >>Have a look at AD8605. Just amazing. > >16nV/sqrt(Hz) at 40Hz typical, vs. more like 1nV/sqrt(Hz) for a good >bipolar op-amp operating from a low source impedance. > >>> Try making a TVG that is stable/predictable over temperature. >>> >>> For quality, bipolar ROCKS ;-) >>> >>> ...Jim Thompson I didn't notice that... hiding the 1/f ;-) I'm working the other end of the spectrum right now... all CMOS, rail-to-rail input AND output, <1uA quiescent current, low-noise, BUT only _100kHz_ gain-bandwidth ;-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food.
From: Fred Bartoli on 13 Jan 2010 16:22
Spehro Pefhany a �crit : > rOn Wed, 13 Jan 2010 21:39:12 +0100, Fred Bartoli <" "> wrote: > >> Jim Thompson a �crit : >>> On Wed, 13 Jan 2010 08:40:14 -0800, "Joel Koltner" >>> <zapwireDASHgroups(a)yahoo.com> wrote: >>> >>>> Did that design make it through fab, Jim, or did the company start imploding >>>> first? >>> It was fabbed at Polarfab. The company began disintegration while >>> debugging the digital was in progress. >>> >>>> I thought that combined bipolar/CMOS ("BiFET?") processes were generally >>>> considered too exotic/unnecessary-due-to-performance-improvements-in-CMOS >>>> these days? Not so? >>>> >>>> ---Joel >>> Not so for analog. Try making a low noise amplifier with only CMOS. >> Have a look at AD8605. Just amazing. > > 16nV/sqrt(Hz) at 40Hz typical, vs. more like 1nV/sqrt(Hz) for a good > bipolar op-amp operating from a low source impedance. > Never said it could compete with a low noise bjt opamp. But 8nV/rtHz noise floor isn't common for cmos opamps, which often are at least 5 times that high. And a 140Hz fc with a 8nV/rtHz is pretty good too, as it is ordinary at least as high, but with a 5-10 times higher noise floor. Sure it can't compete, but so can't LN BJT opamps with my 200pV/rtHz preamp. Still, the AD8605 is amazing for a CMOS opamp. (and I like the tiny 5 balls WLCSP, despite they goofed the pinout). -- Thanks, Fred. |