TLV3604: Output waveform oscillation

Thanks for your post.  Please allow me to ask some clarification questions so I understand your setup.

It looks like your reference that is applied at P30 is somewhere in the 2.42V range.  You are utilizing hysteresis but one of the components is a pot.  Feedback resistor is 3k.  Can you confirm what you have the pot set to?  It appears you are using a diff probe to observe the output.  Is this correct?

You seem concerned about the chatter on the falling edge of the waveform but I am more concerned about the prop delay being in the 200ns range.  This seems to indicate something is not working at all as expected.

Likewise, since it appears you want to introduce hysteresis, is there a reason why you are using tlv3604 instead of tlv3605 which has a dedicated hysteresis pin?  are you not able to achieve the amount of hysteresis you desire with tlv3605?

Chuck

Thank you for your reply.

I am using hysteresis.

The reference voltage of P30 is about 1V.

The resistance of the potentiometer is approximately 500Ω.

A differential probe is used to observe the output.

The propagation delay is 200ns, and I have confirmed that this can be improved by adding a capacitor to P30.

I use the TLV3604 to set the hysteresis to an arbitrary value.

What I would like to ask this time is why chattering occurs.

the capacitor adds stability to your reference.  It appears the amplifier is struggling to maintain the point at a stable voltage and the capacitor is providing what the circuit needs.  How does your picture look now with the capacitor added?  I still don't understand why you can't adjust hysteresis with the tlv3605 hysteresis pin.  It is common for customers to drive this pin directly with a DAC if adjustable hysteresis is required.

Chuck

Thank you for your reply.
The propagation delay has been resolved by inserting a capacitor into P30. However, the ringing in the output waveform did not disappear.

What I would like to know this time is why ringing occurs on the falling edge of the TLV3604 output waveform. I would like a device designer to tell me the possible causes of ringing on the falling edge of the waveform.

Hi Funahahsi-san,

I could share this issue with our designers, and it would be more helpful if they can see your latest circuit and resulting waveforms.

Could you please share your latest image of the output ringing (with fixed propagation delay) as well as what you've added to the circuit? What value is the capacitor at P30, and is the capacitor connected from P30 to GND?