hi guys , I'm using mcp4725 with op_amp non inverting circuit (to have bigger voltage than 5 volt of the ads).
this is my circuit , when i used it the "mcp" gets hot and it's damaged ,what is th e issue of my circuit and how to fix it. Help me please.
Circuit seems fine.
Could be the way you build it.
Post a picture.
Leo..
Hi, @abd222
Welcome to the forum.
Does your circuit work OK if you do not connect the Vout to any load?
Do you have DMM?
What is your circuit connected to?
Thanks.. Tom.. 
Thanks for your answer.
It's too easy to wire and there is no wiring fault ,because i have tested this circuit too many times with power supply and it works fine !
But when I connected mcp insted of power supply for the input voltage it burend!
I don't know why ,know the mcp becomes hot when i wire it and it only make a voultage output 2 volt can't changed .
Is there a possibility to flow a current from common ground of 20volt source to the mcp and damaged it ?
There is nothing in the output just a volt meter
Thanks for answering.
I'm didn't connect any load at the output it was just a volt meter .
It worked fine with power supply ,but when i used mcp insted of it for input voltage it damaged!
Is there a possibility to flow a current from 20volt source via common ground and that what damaged the mcp?
Hi,
Can you please post some images of your project?
Is your controller also connected to the 4725 when you connect to the op-amp?
What is your 20V supply?
Thanks.. Tom..
Well, you dont give much information, and looking at the circuit, unless there is an issue with interference I'd have chosen slightly larger values.
However as others have already said, there must be an issue with the power supplies.
If its wired as you show, if the "grounds" on pins 2 and 6 are actually at different potentails it would cause a problem.
Is this your board?
thanks for your answer.
I didn't share the photos of the circuit because I don't think that you can follow the wires . whatever this is the circuit and all components . I'm sure that there is no wiring fault because I've tested the circuit too many times and it works perfect .
thanks for your answer.
I didn't share the photos of the circuit because I don't think that you can follow the wires . whatever this is the circuit and all components . I'm sure that there is no wiring fault because I've tested the circuit too many times and it works perfect .
writing mistake :Gnd of mcp4725 is connected with inverting pin op_amp
That is not according to your schematic...
The general idea is that all components are on one side of the board. The solder is on the other side.
Long legged components may easily bend and cause undesired connections. Dupont connectors are not meant to be soldered like that.
Your board does look dirty and oxidized...
Thanks dor answer.
So do you think that soldering is the issue ?!, If i use a breadbord would it work fine ?
I don't think so my friend.
I've tested this cirucit too many times and it works perfectly.
sorry, but the board on the picture definitely not looking like thing, maked by experiencing "plumber" (I don't know a correct word, sorry) ... so I am agree with @build_1971
Test your connections twice or, better, make a new board.
I'd suggest you start again - working on the principle that if it LOOKS presentable its more likely to work properly.
Check with a meter to make sure there is no potential diffrence between the arduino and 20v grounds.
If you dont have a meter give up.
Okay thanks.
Should i do that with the old one (burned mcp)?
What's your opinion about using "optocoupler"
to seperate the mcp and op_amp?
Youve had replies from a few very well respected members who have all said the same -
the circuit you have shown in the schematic SHOULD work as is. Its a very simple circuit.
This is a non-inverting amplifier with a gain of three. If Vin is 5.0 Vout should be 15V. That gives a current of 15V / 3k = 5mA to ground through the resistor chain R7 R6.
You say that all works "perfect" - as it should.
The problem arises when you connect the amplifier to the DAC. Again, if its EXACTLY as shown on the schematic there should be no issues.
I'm ALMOST certain that the problem is the 20V PSU. Unfortunately you put the text on the image.
To test that theory you can power the op amp circuit from a 9V battery.
...
Yes
Okay thank you i will build it again.
Hi, @abd222
Can you tell me what the value of the 3 resistors are, I have numbered them 1, 2, and 3?
Have you measured them with a DMM, DigitalMultimeter?
As mentioned before, all your components should be on one side of the board and your connections on the other.
Thanks.. Tom...
Isn't that value obvious from the colored bands?
And more or less consistent with values in the schematic?
Hi,
Resistor 1 in my pic is 560R, close enough to 500R in schematic.
Resistor 2 in my pic is 1K or 2K, between pins 1 and 2, 2K in schematic.
Resistor 3 in my pic is possibly 1K , 1K in schematic.
But we need to see a complete drawn schematic including the controller.
Hard to see but have you got the LM324 gnd/pin 11 connected to the signal input and output gnds?
Tom..
