Observing heating issues

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I'm using this Boost converter.

Below is the schematic:
Layout:

The IC , inductor and diode immediately gets heated up. Any idea why?
Also, there's always a 500mV drop on the output voltage. For 9V output, 8.5V is available when load current goes above 0.5A.
Any idea why?
 

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Hi,

please also show the bottom copper layer of the PCB.

added:
Datasheet: pin11: "Do not leave floating". But in your schematic the resistors are not assembled.

Why is your C37 value that far from datasheet recommendation?

Klaus
 
Last edited:

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Your schematic contains an extraneous text indicating that L2 is capable of handling 4A ( peak value? ); Should we assume that you have already reviewed the specification of L2 against the device actually mounted on the board ? BTW, nowardays I no longer design SMPS without performing electrical simulation before, did you do that ?
 

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Since you have not shown any signals, comparing your ground layout with the datasheet, I wonder if you have reasons for making such drastic changes to crosstalk and isolation of input and output and bridging Analog with Power ground. I would expect you have some resonant instabilities drawing more than rated current.

 

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What is the Fsw ? Oh - 1MHz

the capacitance in the choke may be upsetting the switching losses - also all COTS chokes are very lossy - esp at 1MHz

your diode may not be a fast enough type for 1MHz
 

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