Hi Haider
The ON-time issue is now resolved in simulation after using proper ripple injection circuit.
It is required to insert proper values of ripple injection network components [Excel tool https://www.ti.com/tool/LM25085-5085QUICK-CALC
is…
Hello Christopher,
Please can you fill out the calculator spreadsheet so I can review your design against your specification. I suspect you are unstable due to your ripple injection scheme. Thanks.
LM25085-5085QUICK-CALC Calculation tool | TI.com…
Hi,
You can download the quick tool in the link below, it should be no issues for the E37 tab.
https://www.ti.com/tool/LM25085-5085QUICK-CALC
Regards,
Hongjia
Hi Eli,
I reviewed your schematic, and notice that you do not appear to have an output ripple configuration shown.
This device uses a constant on time (COT) control architecture, which means that a certain amount of ripple is required on the FB pin…
Hi,
This quickstart spreadsheet attached will allow you to form a solution with your design parameters. In addition, TI's buck converter filtering site will allow you to narrow down similar parts. For EMC mitigation I highly recommend you take a look…
Hi Matt,
Please check your values using the LM251085 quickstart calculator: https://www.ti.com/tool/LM25085-5085QUICK-CALC . The injected ripple to FB should be in the 50-100mV range.
If you suspect noise affecting the circuit, please send the PCB…
Hi Martin,
That's an internal sharepoint site that I can't access. Please send the schematic as a PDF. Also, here is the link to the quickstart - https://www.ti.com/tool/LM25085-5085QUICK-CALC . It only takes a few mins to fill out and gives us an…
Hi Elvis,
Please check your values using the LM251085 quickstart calculator: https://www.ti.com/tool/LM25085-5085QUICK-CALC . Check the inductor ripple current, could be current limit engaging if the issue is occuring above a certain load current…
Hi Jared,
It appears that the pk-pk voltage injection amplitude is too high. Check the RC values from SW to VOUT as these set the ripple amplitude coupled to FB. It should be ~50mV (not more than 200mV at max Vin).The COT architecture regulates at…
