LM3940 PDF

Texas Instruments LM Series LDO Voltage Regulators are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for Texas. LM are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for LM DESCRIPTION. The LM is a 1A low dropout regulator designed to provide V from a 5V supply. The LM is ideally suited for systems which contain.

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They just require two capacitors to make a fairly regulated output voltage opposite polarity of their input voltage. I can handle that. Thread starter radiodude Start date Apr 8, om3940 MathieuL How would you make an opamp output negative voltage without supplying one first?

Click here to register now. Home Questions Tags Users Unanswered. Thanks, mvs sarma; didn’t think of that. In general, you need a switch of some sort to produce a negative voltage through either a switched capacitive solution like above, or a switching regulator like the V series. In the schematic the top circuit works fine and I get 3. Sign up or log in Sign up using Google.

There’s only 3 pins: The attachments below are out of the datasheet. The largest cap I can find is only 10uF. That’s probably it then.

It’s just one of those cases where my intuition was wrong lm394 were optional. You can use any value of lm39440 capacitance on the LM so long as it is 33uF or more. Post as a guest Name. I’ve used other caps as well like 10uF, 47uF and even uF and they all give relatively the same Vout with and without load! Sign up using Email and Password. One other question, do I have to use the values on the datasheet?


I’m giving it exactly 5 volts directly from a DC Power Supply lk3940 the output voltage should be 3. The LM and the LM are completely different animals, and their capacitor requirements are quite different. Both the MAX and the V series regulators have internal switches. I thought they were optional i.

I wanted to use the same to make Articles Top Articles Search resources. It will not work.

voltage regulator – Negative supply from LM – Electrical Engineering Stack Exchange

Started by Silverboy Yesterday at 7: Vout seems to be Vin – X but X changes based on Vin. Use a om3940 regulator capable of providing a negative output. Sign up using Facebook. No load, no capacitors. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. I got a bunch of LM to convert 5V to 3. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated ml3940 of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.

I am posting lm3490 so you will know where the information came from.

Roff Well-Known Member Apr 9, The capacitors are generally needed to stabilize the regulator and prevent it from oscillating. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register. I guess a little extra height won’t hurt. LM regulator not putting out 3. Media New media New comments Search media. I mean I read all of it over and over in search of what I could possibly be missing. To participate you need to register. By continuing to use this site, you are consenting to our use of cookies.


As the comments suggest, you can’t produce a negative voltage from a simple linear regulator like that, unless you supply them with a negative voltage to begin with. Using cheap mobile phone to send an alarm Started by Western Yesterday at Forums New posts Search forums.

How can you expect the regulator to work without supplying a reference to it’s gnd? Electro Tech is an online community with overmembers who enjoy talking about and building electronic circuits, projects and gadgets. And does it have a load on it?

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I’m having a hard time finding a 33uF packaged capacitor. Started by rashan shrestha Yesterday at 9: Why not use op-amp inverter? I’ve tried one from a box of them just to be sure I hadn’t shorted the old one out.