TL082: Getting amplified output for buffer configuration

Santhosh Kumar S

Part Number: TL082
Other Parts Discussed in Thread: TLV9001, TLV9051, TL072

Hello Everyone,

I am using TL082CMNOPB amplifier IC in my design & configured as buffer as shown in the attached image.

For an Input of 0.8V DC, I am getting output of 1.4V. I don't know why the input is getting amplified for buffer configuration.

Can anybody please help me out for resolving issue.

Thank you

Regards,

Santhosh Kumar S

over 5 years ago

0 kai klaas69 over 5 years ago

Guru 140200 points

Hi Santosh,

the TL082 is no "rail-to-rail" OPAmp and you are violating the common mode input voltage range. You must stay 4V away from the supply voltages. Also, the minimum supply voltage of TL082 is 10V. So 5V would be way too small.

You could take the TLV9001 of the TLV9051, if you need something faster :-)

Kai

0 Santhosh Kumar S over 5 years ago in reply to kai klaas69

Intellectual 500 points

Hello Kai,

How am I violating the common mode input voltage range? Also, In datasheet, Where they have mentioned that the minimum supply voltage is 10V?

Please clarify my two questions.

Regards,

Santhosh

0 kai klaas69 over 5 years ago in reply to Santhosh Kumar S

Guru 140200 points

Hi Santosh,

see section 6.6 of datasheet :-)

Kai

0 Ron Michallick over 5 years ago

TI__Guru**** 170936 points

Santhosh,

Even if VCC was 12V this would be the typical behavior. Output voltage versus input voltage on left chart. The gain (slope, 1st derivative) is on the right chart. The increasing input offset error give a gain that appear to be greater than 1. (image from similar device ,TL072, data sheet)

0 Santhosh Kumar S over 5 years ago in reply to kai klaas69

Intellectual 500 points

Hello Kai,

According to datasheet, min VCC=5V, In my design it is 5V.

max VCM= Vcc-4 i.e 1V, in our design it is 0.8V so it is in the range. But still i am getting amplified output. what is the reason?

0 kai klaas69 over 5 years ago in reply to Santhosh Kumar S

Guru 140200 points

Hi Santosh,

minimum supply voltage of TL082 is a bipolar supply voltage of +/-5V, but not a single supply voltage of +5V. A bipolar supply voltage of +/-5V can be translated into a single supply voltage of +10V :-)

Kai

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TL082: Getting amplified output for buffer configuration