const-current thing
in [Design]
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From: Jamie on 25 May 2010 18:53 John Larkin wrote: > Most cool: > > http://www.onsemi.com/pub/Collateral/NSI45020-D.PDF > > I've been wanting constant-current ICs for years. They are finally > starting to happen. > > This is 51 cents, q1. > > John > http://www.centralsemi.com/product/cld/index.aspx
From: David Eather on 25 May 2010 18:50 On 26/05/2010 3:28 AM, John Larkin wrote: > > Most cool: > > http://www.onsemi.com/pub/Collateral/NSI45020-D.PDF > > I've been wanting constant-current ICs for years. They are finally > starting to happen. > > This is 51 cents, q1. > > John > If you only need 10 ma and can tolerate using a resistor the LM334 is much better - lower voltage overhead, much higher impedance and most other specs better too. (That's why I suggested it for the low current, low noise , low drop-out project)
From: Jim Thompson on 25 May 2010 18:51 On Tue, 25 May 2010 18:33:55 -0400, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >On 5/25/2010 1:38 PM, Jim Thompson wrote: >> On Tue, 25 May 2010 10:28:42 -0700, John Larkin >> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>> >>> Most cool: >>> >>> http://www.onsemi.com/pub/Collateral/NSI45020-D.PDF >>> >>> I've been wanting constant-current ICs for years. They are finally >>> starting to happen. >>> >>> This is 51 cents, q1. >>> >>> John >> >> Fig 2 is pretty gross. Lousy headroom design. Sheeesh! >> >> ...Jim Thompson > >Figure 5 is what has me worried. A 15% current decrease occurs over >seconds. I didn't get to that ;-) That's down right shameful. So much for pulsed operation. I do stable CMOS mirrors all the time... 3% is trivial. > >Great idea, no cigar for the implementation. Still, it's a lot cheaper >than the LTC thing. > >Cheers > >Phil Hobbs ...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: John Larkin on 25 May 2010 18:56 On Tue, 25 May 2010 18:33:55 -0400, Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >On 5/25/2010 1:38 PM, Jim Thompson wrote: >> On Tue, 25 May 2010 10:28:42 -0700, John Larkin >> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >> >>> >>> Most cool: >>> >>> http://www.onsemi.com/pub/Collateral/NSI45020-D.PDF >>> >>> I've been wanting constant-current ICs for years. They are finally >>> starting to happen. >>> >>> This is 51 cents, q1. >>> >>> John >> >> Fig 2 is pretty gross. Lousy headroom design. Sheeesh! >> >> ...Jim Thompson > >Figure 5 is what has me worried. A 15% current decrease occurs over >seconds. > >Great idea, no cigar for the implementation. Still, it's a lot cheaper >than the LTC thing. > >Cheers > >Phil Hobbs It would be good for gross stuff, like pushing current into a zener to power some opamps floating on a power rail. It could also be a protective current limiter. Laser-trimmed precise 2-terminal current limiters would be great, in the 1 mA ballpark. Or 3-terminal, programmable with one resistor. John
From: John Larkin on 25 May 2010 19:06
On Tue, 25 May 2010 18:53:37 -0400, Jamie <jamie_ka1lpa_not_valid_after_ka1lpa_(a)charter.net> wrote: >John Larkin wrote: > >> Most cool: >> >> http://www.onsemi.com/pub/Collateral/NSI45020-D.PDF >> >> I've been wanting constant-current ICs for years. They are finally >> starting to happen. >> >> This is 51 cents, q1. >> >> John >> >http://www.centralsemi.com/product/cld/index.aspx > > That's a classic jfet thing. Kind of sloppy and expensive. John |