OPA140: input common voltage range

Kailyn Chen

Part Number: OPA140
Other Parts Discussed in Thread: OPA2810

Hello,

The input common voltage range of OPA140 is (V-)-0.1~(V+)-3.5V which describes in datasheet Page7.

But the voltage follower of Figure21, we find that the input is 37Vpp(+-18.5V sine wave) with +-18V power supply, could you please help to explain it? Is it the printed error?

Best regards

kailyn

over 3 years ago

0 kai klaas69 over 3 years ago

Guru 140200 points

Hi Kailyn,

the one is the guaranteed behaviour between -40° and +125°C and the other is the typical behaviour at +25°C. So the discrepancy need not to be a mistake :-)

Kai

0 Michael Steffes over 3 years ago in reply to kai klaas69

Guru 47535 points

Figure 21 is trying to overdrive the amplify (note how the output goes flat at the peaks) to illustrate it has no phase reversal in overdrive so it is intentionally exceeding the input range- phase reversal used to be a common problem in circa 1980's op amps. I prefer to use a triangle wave as per say the OPA2810 plot,

0 JMac over 3 years ago

TI__Intellectual 1955 points

Hi Kailyn,

As Michael said, for this plot they are deliberately overdriving the amplifier input beyond the common mode range to prove a point about phase reversal (specifically, the lack thereof). In normal operation, to ensure the op-amp maintains a linear response, it is important to respect the input common-mode voltage limits in the table shown on Page 7. Please let us know if you have any other questions.

Cheers,

Jon