TL062: Wrong output for voltage follower

Alvin P. Schmitt

Intellectual 940 points

Part Number: TL062
Other Parts Discussed in Thread: LM35, , TLV9102

I have the circuit of the second half of the TL062CP as a voltage follower as follows: IN2- (pin 6) connected to output pin 7 pin 4 ground pin 8 +12v pin 5 (IN2+) connected to output (pin 2) of LM35. Output of LM35 is .274 volts ; output at pin 7 of TL02CP is 0.675 volts instead of 0.274 . This is true when nothing but a dvm is connected to pin 7 of TL062CP (it output 2 ) . I have not cleaned the board. This same voltage appeared on the previous board I made and nothing else is connected to this circuit to cause this error.

over 3 years ago

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi Alvin,

you violate the common mode input voltage range of TL062. The LM35 generates an output voltage from 0V on but the TL062 needs an input voltage which is at least 4V higher than the negative supply voltage. Take a RRIO OPAmp for your circuit. (RRIO = input output rail to rail).

Kai

0 Ron Michallick over 3 years ago

TI__Guru*** 140126 points

Alvin,

In addition to the input common mode range, there is also an output range limitation. TL062 is not rail to rail input nor output. TL062 is also an old design and process device, I suggest the modern TLV9102 as a replacement.

0 Alvin P. Schmitt over 3 years ago in reply to kai klaas69

Intellectual 940 points

Thank you -- this helps me a lot.

0 kai klaas69 over 3 years ago in reply to Alvin P. Schmitt

Guru 140200 points

You are welcome :-)

Kai

Amplifiers

Amplifiers forum

TL062: Wrong output for voltage follower