LM2940CT 5.0 PDF

Package. 0˚C ≤ TJ ≤ ˚C LMCT LMCT LMCT LMCT TO LMCS LMCS The LMCT/NOPB is a positive Voltage Regulator features the ability to source 1A of output current with a dropout voltage of typically V and a. Pin 5 and 6 need to be tied together on PCB board (5) ESD rating is based on the human body model, pF discharged through LMCT/NOPB.

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LDO – LM2940CT-5.0

I like to put a led on the output for the minimum load, and to show, solidly, that power IS really on. The power in Watts being dissipated within the regulator is the voltage drop across the regulator times the current passing through it. There is another possibility Furthermore, a quiescent current reduction circuit has been included which reduces the ground current when the differential between the input volt-age and the output voltage exceeds approximately 3V.

Larger values of output capacitance will give improved transient response. I have a 22uf cap between the output and ground as specified in the datasheet for stability. I can’t find a schematic of it.

LM2940ct 5.0 gets HOT quick.

Hi John, What is the input voltage to the regulator — can you measure it? The acceptable range of ESR plotted versus load current is shown in the graph below. It is essential that the output capacitor meet these requirements, or oscillations can result. Furthermore, hidden in the ap note the ones that I have seen is an admonition to have a minimum current load. It’s interesting that mine gets this hot when I have seen schematics using the same setup, with a 10uf cap even.


Familiar regulator features such as short circuit and thermal overload protection are also provided. During line transients, such as load dump when the input voltage can momentarily exceed the specified maximum operating volt-age, the regulator will automatically shut down to protect both the internal circuits and the load. The only things being powered in the circuit is the stamp and the LCD.

Check your caps, it might be leaky. I accept the Terms and Coditions. Also, remember the more voltage you have to drop and the more current you want to pull, the hotter the device will run. Photos – easier uploading and sharing. The burn your finger kind of hot. I haven’t experienced it personally, but you could have an issue there that might result in overheating. I will try it with the additional cap. What are the caps on the BS2P40 demo board?

Text in the Subject and Body of the message will be ignored. Comments 10 Comments sorted by Date Added Votes. Many of the regulators require capacitance on the input and output to minimize oscillation.

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Groups is subject to http: Keep in mind the adapter you have may be putting out more than 9 volts, or may not have a very clean output, both of which will make the regulator get hot.


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If you aren’t running very much current, and your Vin isn’t too high, a lm940ct clip-on heat sink can significantly reduce the regulator’s temperature. Your use of Yahoo!

Basic Stamp List Subject: Another data sheet says 0. Friday, December 05, Quick Links Categories Recent Discussions. Another, does your LCD has backlights? Here’s a snip from p. That would work lm29440ct. Write Your Own Review Only registered customers who has bought this product can write reviews.

LMCT-5 Datasheet

The ESR of the output capacitor will cause loop instability if it is too high or too low. Thank you for all the input.

Email to a Friend. Only registered customers who has bought this product can write reviews. Hello, All I have is a cap between the output and ground at 22uf. Otherwise the output impedance is too high and it oscillates. JavaScript seems to be disabled in your browser.

Thanks, John In basicstamps yahoogroups. The quiescent current with 1A of output current and an input-output differential of 5V is therefore only 30 mA. My input is 9V, I’m using the power supply that came with the P40 demo board. Be the first one to review this product.

Is ths just because of the load placed on it due to the lcd? Should I use some other voltage regulator? I .50 the data sheets show a 0.