TLV9062: Why is the positive terminal not in a state of high resistance?

Hi Peng,

because there are internal protection diodes from the inputs to the supply rails. You just see the voltage drop across on of these protection diodes. Please read section 11.1 of datasheet.

Kai

Peng,

Kai is correct, this is caused by the forward voltage drop of the ESD diodes. 

Figure 2.2 of the Op Amp ESD Protection Structures App Note shows how the ESD diodes conduct when VCC is unconnected and IN+ has a positive voltage above the Vf of the ESD diodes

If this voltage cannot be tolerated, I suggest using a shutdown capable device such as the TLV9062S, or using a device without input protection diodes to V+ such as the OPA2310

Please let me know if you have any questions.

Best,

Jacob

See section 9.3.5.

When powered down, the TLV9062S does behave exactly the same way as the TLV9062. To make your application work, leave the TLV9062S powered, but put it into shutdown mode instead. In this state, you are allowed to apply voltages between V– and V+ to the inputs, and the outputs will be disabled.