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LM35 (DZ) problem with output voltage

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masab_ahmad

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I bought an LM 35 for temperature monitoring....its output voltage at room temp should be about 290mV...but when i measure it with a voltmeter it gives 2.9V, and with an increase in temperature,the output decreases...(it should increase), i bought like 3 of them and the same happened again..plz help....and putting capacitors as in its datasheet didnt help at all...
I gave an input of 5V using a 7805, and didnt connect the lm35 t anything yet..
i saw another post like this but it didnt help me much..
 

alexan_e

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Double check the correct pin connection maybe you made a mistake with the pin order.
Also check you voltmeter scale because your result is 10 times higher than it should.
If you have any resistor connected to the output pin remove it and try again.

Alex
 

muthukumar_ece2004

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Double check the correct pin connection maybe you made a mistake with the pin order.
Also check you voltmeter scale because your result is 10 times higher than it should.
If you have any resistor connected to the output pin remove it and try again.

Alex

10 times higher, ok. But how did it reduces output voltage during increase in temperature!

---------- Post added at 11:43 ---------- Previous post was at 11:42 ----------

Masab, better you give the schematics, it may helpful to double check your doubt!
 

muthukumar_ece2004

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I given schematics which is taken from datasheet,
 

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qwertyuiop415263

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check your pin connections. If you have bought lm35dz from hall road it dont follow the datasheet(in pin configuration). I guess once I have same problem.
 

alexan_e

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What do you mean by that, where did you find a device with custom pin configuration?
All LM35 depending on the case have the same pinout as shown in the datasheet.
TO-46 and TO-92 are shown from bottom, SO-8 from top, and TO-202 from front side,

Alex
 

qwertyuiop415263

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in pakistan sometimes ICs come from china (china make copies);not from the orignal manufacturer.
 

alexan_e

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and they don't follow the data sheet specification?
It seems very strange, why would someone make a custom pinout of a 3pin device?
It can be routed easily to a PCB so what would be the advantage of it?

Alex
 

qwertyuiop415263

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they work exactly as mentioned in the datasheet. but vcc and gnd were interchanged.
 

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