Re: Digital Question

Problem: =EF=BF=BDIf I go directly into a gate or D-input of a flop I can=

get

substantial overlap current rail-to-rail. =EF=BF=BD

Can you use a comparator (op-amp)? I have a specific part in mind, but I will have to dig into the G:\\ drive to come up with the part number. It was an "extremely low" current device, IIRC.

-mpm

Reply to
mpm
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I'm rolling my own, inside an IC. Already have the comparator at ~1uA, which is why it's _slow_. I have to get that into CMOS logic without excessive rail-to-rail overlap current.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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
Reply to
Jim Thompson

Jim Thompson a écrit :

Is hysteresis OK? I have a similar problem ATM and found an interesting "no current" Schmitt trigger in Jim Williams' art & science of analog circuit design p369. It uses an impractical high value resistor but you can probably add a few mosfets... You can also probably adapt the idea inside your comparator circuitry.

BTW I didn't tried it because I found a low current (4uA) comparator that have a fast enough output rise/fall time (40ns), so it appears it's doable. (ADCMP370).

--
Thanks,
Fred.
Reply to
Fred Bartoli

Can you post that page. I don't have a copy of that book.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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
Reply to
Jim Thompson

Really, get both of his books. No circuit designer should be without them. Chapters by people like Barrie Gilbert and George Philbrick and Richard Burwen and George Erdi and of course Bob Pease.

But I'm not impressed by the Schmitt thing.

John

Reply to
John Larkin

Turns out I DO have BOTH books... just couldn't initially find them on my chaotic book shelves. I have 13' wide by 6' tall of book shelves. I need to catalog everything, dump 'em all on the floor and re-stack.

I'll build up that Schmitt in PSpice and see how it goes. I question its efficacy also.

BTW, Walt Jung, Bob Pease and I (along with Tom Frederiksen) have been in E-mail communication establishing the historical development of that PNP/NPN turn-around current mirror I've mentioned before. I gather some of my E-mails will be included in one of Bob's columns.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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
Reply to
Jim Thompson

If it's any comfort, BP is a *lot* messier than you are.

John

Reply to
John Larkin

He was that way when we both were at MIT. Didn't know him personally, he was a year ahead of me, but he really stood out as he charged up the staircases.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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
Reply to
Jim Thompson

He lives near me. His front yard, and sometimes a few parking spots on the street, are usually full of old (as in OLD) rusty Volkswagens.

John

Reply to
John Larkin

[snip]

Seems to work, but it's not ZERO, more like 0.5uA averaged over my usage period, but it may serve my needs. I'll "massage" it to fit my situation and see how it looks.

...Jim Thompson

--
| James E.Thompson, P.E.                           |    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
Reply to
Jim Thompson

Google Books has most of it online:

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Reply to
Michael A. Terrell

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