November 17, 2018

LM2940 PDF

The LM/LMC positive voltage regulator features the ability to source 1A of output current with a dropout volt- age of typically V and a maximum of. The LMN/LMC positive voltage regulator. 2• Dropout Voltage Typically V @IO = 1A features the ability to source 1A of output current with. The LM/LMC positive voltage regulator features the ability to source 1A of output current with a dropout voltage of typically V and a maximum of 1V.

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Posted by bobsuper in forum: Sorry, that was my mistake. Nov 13, 2. Case markings indicate 5v LMT- 5. Does anyone have any ideas how I might stabilize this output?

I’m encountering some instabilities in my regulated pm2940 supply. Please see updated question with attached schematic. Voltage Regulator Question Posted by pcon in forum: I believe that I have conformed to the guidelines in the datasheet.

When I specified the voltage regulator to order, I gave the part for the 5v. Alas the data on minimum ESR is rather sketchy nothing for “C” case for exampleso you have to guesstimate from just these two graphs or get an ESR meter and measure it, or even just with your scope and a function gen that can hit those MHz frequencies where you see oscillation.


Have you taken their compulsory advice re the output capacitor?

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See the LM datasheet for details. Russell McMahon k 9 The data sheet says the 22uF is required for stability.

They need to be rated above my voltages also. I live in Lincoln.

lk2940 Once the SX28 turns on, it displays a sequence on an 7 segment display, then rotates the motor for 2 to 5 seconds. LM will give all sorts of problems if you dont have input and output caps both connected, and pretty close to the pins of the regulator.

Schematic of the regulation circuit. Sign In or Register to comment. Jul 17, 22, 1, The power source is a 16v solar array Om2940 have assembled. Locate as close as possible to the regulator.

LM2940CT-12 = LM2940-12

I have a project I am tinkering with that needs to run the SX28 at 50Mhz. Nov 14, 7.

Ok, so I would also have to change both input and output caps as well since I am only using a 10uf axial cap and a. I tried this on two regulators, both are the same way. Ml2940, I have found that higher-frequency fluctuations in voltage are not properly regulated by the LM, causing intermittent brown-out of the MCU.

LM what capacitors?

Phil Pilgrim PhiPi Posts: I was reading it on my break and was in a hurry. You won’t have to worry about dropout until you get pretty far down there, and you can use a super capacitor or battery to handle low voltage situations.


Nov 14, 6. Tom Wilson 68 7. Tying down what manufacturers really mean can be a challenge. Why am I seeing You must be certain to use a low ESR capacitor on the output.

LM Regulator | Modern Device

ml2940 Your oscillations are at 18 Mhz where the ESR is hopefully very low. Sign up using Email and Password. Nov 14, 5. Could that contribute to the oscillation? Typically, these limits can be maintained with a solid tantalum polarized capacitor. You also have to pay attention to the capacitance tolerances. Home Questions Tags Users Unanswered.

I have been using one non polarize cap that is on the output pin of the In lm940, the LM Could I simply pull the out and replace it with a with no other modifications?

As Phil mentioned, this regulator has very specific capacitor requirements. The polarization or non-polarization is not important in and of itself.