AMC3330: DCDCout value

Harris Limasi1

Part Number: AMC3330

Tool/software:

Hi,

the objective my of my circuit is to measure the voltage across Rsns . When in run the simulation the DCDCout value is too large. Any advise how to resolve this issue ?. Thanks.

2 months ago

0 Harris Limasi1 2 months ago

Prodigy 160 points

Here is the schematic

AMC3330_TLV9001.TSC

0 Eva Mason 2 months ago in reply to Harris Limasi1

TI__Expert 5975 points

Hi Harris,

Thank you for your question. I cannot seem to open your schematic. Would you be able to send a photo of your schematic or reattach it?

Best regards,

Eva

0 Harris Limasi1 2 months ago in reply to Eva Mason

Prodigy 160 points

0 Eva Mason 2 months ago in reply to Harris Limasi1

TI__Expert 5975 points

Hi Harris,

What are the units of the graphs on the right? Typical value for Vdcdc_out is 3.5V. What is the input being applied?

A few things about the schematic. First is making sure you use separate ground for the low and the high side. Based on the screenshot both grounds appear to be the same, please make sure they are separate. Another thing from the schematic is the decoupling capacitors on the integrated DC/DC converter. They should be placed in decreasing order towards the device. So, the capacitor furthest from the device should have the largest value. Swapping C6 and C11 would be best practice.

Where does the LDOout trace lead to? A reminder that the low-side LDO does not output a constant voltage and is not intended for powering any external circuitry. It should not connect to external loads.

Best regards,

Eva

0 Eva Mason 2 months ago in reply to Eva Mason

TI__Expert 5975 points

Hi Harris,

Hope you are doing well. Upon looking into this question further, it looks like you are measuring DCDC_out with respect to the low side ground. Please try measuring this pin with respect to HGND. This should show a value closer to the expected.

Best regards,

Eva

0 Harris Limasi1 2 months ago in reply to Eva Mason

Prodigy 160 points

Hi Eva,

Thanks for the suggestion to separate the HGND and the low side ground. Now the DCDC_OUT reading is within the spec.

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AMC3330: DCDCout value