TLV8812: PSRR variation with respect to Temperature

Hello Ashvin,

I tried to replicate this effect. I saw virtually no change with temperature.  How much did you see, please show the data and the Tina circuit.

TLV8812.TSC

There is gap between 1.8V and 3.6V, but no line slope with temperature.

Hello Ron,

We saw this change in a circuit we rigged up. The input to this opamp is from an INA500 (VS1). The circuit seems to be giving the right output at higher VS2 but  at VS2 of 1.8V, the output starts off at the desired value of 600mV but starts to drift upwards with respect to time. This happens only at -40 deg. C.

Also if we look at the model of the TLV8812, it does not show any dependence of the PSRR to temperature. What else could be causing this change in the output at low voltages and low temperature?

Ashvin,

Does this happen on more than one sample of TLV8812? Can you provide specific data? Does this drift stop after the op amp has soaked sufficiently; no longer changing temperature on the inside.

Yes, this happens on at least 4 samples. the drift stops after the opamp has soaked sufficiently.

Ashvin,

At cold, condensation could create a leakage path that could affect the output voltage. Other than that, the unspecified magnitude drift would be normal for TLV8812. 

In this type of circuit, how much would the output get affected if we do not have the minimum of 30K resistance at the output? Our load is the input of another TLV8812 through 10K as shown in figure: 

Ashvin,

Why is 30k a minimum, where does this come from?

Ashvin Srinivas15 said:

minimum of 30K resistance at the output?

In the schematic snippet, there is no closed loop for U2B

Section 7.4.4 Driving Capacitive Load  states that there could be oscillations due to a capacitive load and the output impedance of the amplifier.

Ashvin,

That could be, however I see no capacitive load.