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From: John O'Flaherty on 13 May 2010 12:02 On Thu, 13 May 2010 11:55:21 -0400, Spehro Pefhany <speffSNIP(a)interlogDOTyou.knowwhat> wrote: >On Thu, 13 May 2010 08:19:22 -0700, John Larkin ><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >> >> >>http://electronicdesign.com/article/power/non_inverting_level_shifter_requires_only_one_op_amp_one_supply_voltage.aspx >> >> >>Such brilliance! How do they keep doing it? >> >>Sarcasm aside, he made a mistake. >> >>And we should take up a collection and buy Pease some grid paper. >> >>John > >The article that links to is by a USSC summer student named Erik, not >Bob Pease. Nominal gain is 0.75 so it's doing more (less?) than level >shifting. I see attenuation of 1/2 at the input, gain of 4 (3+1), and attenuation of 1/2 at the output. LTSpice agrees, unless I made a mistake. Version 4 SHEET 1 880 680 WIRE 16 48 -80 48 WIRE 96 48 16 48 WIRE 304 48 176 48 WIRE -80 144 -80 128 WIRE 16 176 16 48 WIRE 224 176 16 176 WIRE 304 192 304 48 WIRE 304 192 288 192 WIRE 352 192 304 192 WIRE 480 192 432 192 WIRE 528 192 480 192 WIRE 224 208 176 208 WIRE -80 224 -144 224 WIRE 96 224 0 224 WIRE 176 224 176 208 WIRE 176 224 96 224 WIRE 480 224 480 192 WIRE -144 256 -144 224 WIRE 96 256 96 224 WIRE 480 320 480 304 FLAG -80 144 0 FLAG 480 320 0 FLAG 96 416 0 FLAG -144 336 0 SYMBOL res 192 32 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R1 SYMATTR Value 600 SYMBOL res -64 144 R180 WINDOW 0 36 76 Left 0 WINDOW 3 36 40 Left 0 SYMATTR InstName R2 SYMATTR Value 200 SYMBOL res 80 240 R0 SYMATTR InstName R3 SYMATTR Value 1200 SYMBOL res 16 208 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R4 SYMATTR Value 1200 SYMBOL res 464 208 R0 SYMATTR InstName R6 SYMATTR Value 75 SYMBOL res 448 176 R90 WINDOW 0 0 56 VBottom 0 WINDOW 3 32 56 VTop 0 SYMATTR InstName R5 SYMATTR Value 75 SYMBOL voltage 96 320 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V1 SYMATTR Value 1.5 SYMBOL voltage -144 240 R0 WINDOW 123 24 132 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName V2 SYMATTR Value SINE(0 .5 1e3) SYMATTR Value2 AC 1 SYMBOL Opamps\\opamp 256 128 R0 SYMATTR InstName U1 TEXT 320 40 Left 0 !.lib opamp.sub TEXT -178 444 Left 0 !.tran 2
From: Jim Thompson on 13 May 2010 12:13 On Thu, 13 May 2010 08:57:40 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 13 May 2010 08:45:17 -0700, Joerg <invalid(a)invalid.invalid> >wrote: > >>John Larkin wrote: >>> >>> http://electronicdesign.com/article/power/non_inverting_level_shifter_requires_only_one_op_amp_one_supply_voltage.aspx >>> >> >>"Firefox has detected that the server is redirecting the request for >>this address in a way that will never complete." >> >>Guess they want tracking cookies? >> >>> >>> Such brilliance! How do they keep doing it? >>> >>> Sarcasm aside, he made a mistake. >>> >>> And we should take up a collection and buy Pease some grid paper. >>> >> >>Bob made a mistake? Hard to believe, but can happen to anyone. Does he >>still have all those mini buses on his lot? > >Try this one: > >http://electronicdesign.com/authors/author.aspx?author=3324 > >It's Matlin who made the mistake. > >Pease just drew another one of his hideous scribbles. > >Yes, lots of rusty VWs on his lawn and on the street. > >John > > Appropriately joining Maxim :-) ...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 | The only thing bipartisan in this country is hypocrisy
From: Jim Thompson on 13 May 2010 12:17 On Thu, 13 May 2010 11:02:58 -0500, John O'Flaherty <quiasmox(a)yeeha.com> wrote: >On Thu, 13 May 2010 11:55:21 -0400, Spehro Pefhany ><speffSNIP(a)interlogDOTyou.knowwhat> wrote: > >>On Thu, 13 May 2010 08:19:22 -0700, John Larkin >><jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>> >>> >>>http://electronicdesign.com/article/power/non_inverting_level_shifter_requires_only_one_op_amp_one_supply_voltage.aspx >>> >>> >>>Such brilliance! How do they keep doing it? >>> >>>Sarcasm aside, he made a mistake. >>> >>>And we should take up a collection and buy Pease some grid paper. >>> >>>John >> >>The article that links to is by a USSC summer student named Erik, not >>Bob Pease. Nominal gain is 0.75 so it's doing more (less?) than level >>shifting. > >I see attenuation of 1/2 at the input, gain of 4 (3+1), and >attenuation of 1/2 at the output. LTSpice agrees, unless I made a >mistake. > [snip schematic] Larkin shoots from the hip, and is almost _always_wrong_ :-) ...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 | The only thing bipartisan in this country is hypocrisy
From: George Herold on 13 May 2010 12:20 On May 13, 12:02 pm, John O'Flaherty <quias...(a)yeeha.com> wrote: > On Thu, 13 May 2010 11:55:21 -0400, Spehro Pefhany > > > > > > <speffS...(a)interlogDOTyou.knowwhat> wrote: > >On Thu, 13 May 2010 08:19:22 -0700, John Larkin > ><jjlar...(a)highNOTlandTHIStechnologyPART.com> wrote: > > >>http://electronicdesign.com/article/power/non_inverting_level_shifter.... > > >>Such brilliance! How do they keep doing it? > > >>Sarcasm aside, he made a mistake. > > >>And we should take up a collection and buy Pease some grid paper. > > >>John > > >The article that links to is by a USSC summer student named Erik, not > >Bob Pease. Nominal gain is 0.75 so it's doing more (less?) than level > >shifting. > > I see attenuation of 1/2 at the input, gain of 4 (3+1), and > attenuation of 1/2 at the output. LTSpice agrees, unless I made a > mistake. Yeah the circuit looked OK to me too. (But I'm often wrong.) I didn't see an scribbles by B. Pease? Maybe John sent the wrong link? George H. > > Version 4 > SHEET 1 880 680 > WIRE 16 48 -80 48 > WIRE 96 48 16 48 > WIRE 304 48 176 48 > WIRE -80 144 -80 128 > WIRE 16 176 16 48 > WIRE 224 176 16 176 > WIRE 304 192 304 48 > WIRE 304 192 288 192 > WIRE 352 192 304 192 > WIRE 480 192 432 192 > WIRE 528 192 480 192 > WIRE 224 208 176 208 > WIRE -80 224 -144 224 > WIRE 96 224 0 224 > WIRE 176 224 176 208 > WIRE 176 224 96 224 > WIRE 480 224 480 192 > WIRE -144 256 -144 224 > WIRE 96 256 96 224 > WIRE 480 320 480 304 > FLAG -80 144 0 > FLAG 480 320 0 > FLAG 96 416 0 > FLAG -144 336 0 > SYMBOL res 192 32 R90 > WINDOW 0 0 56 VBottom 0 > WINDOW 3 32 56 VTop 0 > SYMATTR InstName R1 > SYMATTR Value 600 > SYMBOL res -64 144 R180 > WINDOW 0 36 76 Left 0 > WINDOW 3 36 40 Left 0 > SYMATTR InstName R2 > SYMATTR Value 200 > SYMBOL res 80 240 R0 > SYMATTR InstName R3 > SYMATTR Value 1200 > SYMBOL res 16 208 R90 > WINDOW 0 0 56 VBottom 0 > WINDOW 3 32 56 VTop 0 > SYMATTR InstName R4 > SYMATTR Value 1200 > SYMBOL res 464 208 R0 > SYMATTR InstName R6 > SYMATTR Value 75 > SYMBOL res 448 176 R90 > WINDOW 0 0 56 VBottom 0 > WINDOW 3 32 56 VTop 0 > SYMATTR InstName R5 > SYMATTR Value 75 > SYMBOL voltage 96 320 R0 > WINDOW 123 0 0 Left 0 > WINDOW 39 0 0 Left 0 > SYMATTR InstName V1 > SYMATTR Value 1.5 > SYMBOL voltage -144 240 R0 > WINDOW 123 24 132 Left 0 > WINDOW 39 0 0 Left 0 > SYMATTR InstName V2 > SYMATTR Value SINE(0 .5 1e3) > SYMATTR Value2 AC 1 > SYMBOL Opamps\\opamp 256 128 R0 > SYMATTR InstName U1 > TEXT 320 40 Left 0 !.lib opamp.sub > TEXT -178 444 Left 0 !.tran 2- Hide quoted text - > > - Show quoted text -
From: Joel Koltner on 13 May 2010 12:23
"John Larkin" <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote in message news:6r5ou5lcgjqv2cg8vbg1831506uqtmod4g(a)4ax.com... > Such brilliance! How do they keep doing it? A lot of graduating BSEEs today never really got that whole thing about superposition, I suspect? :-) Hmm... there might be a good interview question in there somewhere... "It's clear you can use an op-amp to sum an arbitrary number of inputs -- both with positive and negative gains -- but why is it that the vast majority of the time in an 'application example' you see people suggest only the inverting form?" Although I think it was Jim or someone who mentioned that these days some people don't even get past, "What's the approximate Vbe of any unremarkable transistor at reasonable currents?" :-) > And we should take up a collection and buy Pease some grid paper. Someone can send him a link to that grid paper generator piece of software that was being discussed about a month ago... ---Joel |