OPA544: Prototype Tests Vs Simulation Results

Ponnusamy M

Part Number: OPA544

Hi Raymond,

We have performed tests with the circuit recommended by you (attached with the component value changes) with the change of the L&C values.

L & C Values recommended: 10mH & 1uF
L & C Values used in the circuit: 1.8mH & 10uF

Test Results Summary:

At 5KHz the circuit seems to be working fine
At 100KHz, we are able to get 30mVp-p for a Vin ripple of 96mV. But when the input ripple amplitude is increased to 104mV the output ripple jumps to 110mV. Similar behavior observed at higher frequencies also.

But in simulation, the circuit seems to be working fine.

Pl suggest if tuning of the component values will help to get a stable performance.

Best Regards,

Pons

opa544_08202021.TSC

over 3 years ago

0 Raymond Zhang1 over 3 years ago

TI__Guru 62061 points

Hi Pons,

Could you send me a scope shot of the behavior? My guess is that the circuit needs to be de-queued at higher frequency. I thought 100kHz may be ok (maybe Q effect in the circuit at higher frequency already started).

The circuit has a Q at lower frequency as well, but you do not go this low.

I just want to confirm the behavior, before I make some compensation. Does the circuit work for your application other than the gain peaking approx. 100kHz?

Best,

Raymond

0 kai klaas69 over 3 years ago in reply to Raymond Zhang1

Guru 140200 points

Hi guys,

the circuit seems to be instable:

pons_opa544.TSC

Kai

0 Raymond Zhang1 over 3 years ago in reply to Raymond Zhang1

TI__Guru 62061 points

Hi Pons,

Please try the following circuit and let me know.

Best,

Raymond

0 Raymond Zhang1 over 3 years ago in reply to Raymond Zhang1

TI__Guru 62061 points

Hi Pons,

I hope that your issues have been resolved. I am going to close this inquiry. If you have additional questions, you are still able to open the thread or create a new one via E2E Forum.

Best,

Raymond

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OPA544: Prototype Tests Vs Simulation Results