Need advice for an opamp to use

[weeb0]

Hi,

I tried to use a single supply opamp. (vcc = 10V).

The opamp drive directly a transistor, so the output current is minimal. The opamp I use is supposed to be rail-to-rail but when the input voltage is below 1V, the output is 0V.

I used the AD8662. I NEED to be able to output 400mV at the output, so which other opamp I can use ?

I will try the AD823, the minimum current to go near the rail is way less than the 8662.

Which other component you would suggest me ?

Thank you

 

[Khabree]

Go directly to www.nsc.com , here you can give parameters of an Op-Amp site will search the Op-amp that exactly matches. I think try LM324 (a very common one) if no other special requirment exist.

 

[FvM]

Hello,

from your report, it isn't possible to understand the problem. Most likely, this isn't a issue of OP parameters but of your circuits basic operation. I guess, searching various OPs wouldn't help at all. The said AD8662 is suited for single supply operation, although not input rail-to-rail cause input range doesn't reach positive supply. Thus most likely your circuit prevents the OP from operating correctly.

If you show the circuit including connected load, the problem may be understandable.

Regards,
Frank

 

[rokibulalam]

I don't think changing op-amps will do much. It's all about the parametres of passive elements connected outside to the op-amp. 741 is very much common op-amp. you can use it. for minimizing the load effect u can use three op-amp.

 

[hossein_samani]

it is just because of using single power supply so it dosnt work near 0V
if u use -vcc and +vcc even if ur negetive voltage is less than positive (about 1 or 2 for ur use in here) it will be work
i had this problem befor
LM358 is good too