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I have attached a schematic of a buck converter circuit I have designed. It's designed using a LMR16030 IC.

Input voltage: 12-14V

Output voltage: 5V

Switching frequency: 1MHz

Output Current: 2A

I'm carrying out a load regulation test by connecting a electronic load at the output. As I increase load current from 0 to 1.5 A, the output voltage seems to decrease at a steady rate from 5V to 4.55V.

What can I do/change to ensure a steady output voltage? (max 2% deviation)

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    \$\begingroup\$ What's your PCB layout look like? Are all power traces sufficiently large to carry this much current? How much does the voltage on the feedback pin change over this current range? \$\endgroup\$
    – Hearth
    Commented Mar 13, 2019 at 16:47
  • \$\begingroup\$ Measure your output voltage directly from pin 7 of your IC to the top of R4. (Put your probes right on the pins/pad.) Repeat the measurement and see what your regulation looks like. Or as @Hearth said measure the feedback pin to pin 7 and see if that's changing. \$\endgroup\$
    – John D
    Commented Mar 13, 2019 at 17:32
  • \$\begingroup\$ @JohnD Measuring the feedback is probably better, because that specifically is what the IC is acting on. It can't see the output voltage directly at all. \$\endgroup\$
    – Hearth
    Commented Mar 13, 2019 at 17:35
  • \$\begingroup\$ @Hearth looks like the voltage at the feedback pin is pretty much constant. I have a 35 mil trace from the output cap C16 to the load pin. So seems like the trace is providing too much resistance? \$\endgroup\$
    – Rohit Garg
    Commented Mar 13, 2019 at 17:56
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    \$\begingroup\$ You can also reinforce the trace with wire or extra solder if it's exposed. Discussing the width of a trace is not relevant without discussing it's thickness and length. If you're losing 0.45V at 1.5A, you have R=E/I=0.45V/1.5A=0.3\$\Omega\$ of unwanted resistance between your sense node and output. For 2% regulation(2%*5V=0.1V), you need to reduce this resistance to R=0.1V/1.5A=.0667\$\Omega\$ or less. It would be wise to include an inspection of your ground path as well. \$\endgroup\$
    – K H
    Commented Mar 14, 2019 at 3:39

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