Hello, I have a power supply design built around the LM5116MH, which was essentially copied from a third-party breakout board onto a custom PCB (we do not yet have a power engineer on staff, and were using a reference design to support another device from that vendor). However, while we're going through initial board bringup, we're finding that the output voltage is sagging by roughly 8% when under 50% of our rated load (Targeting 5V @ 2A, we're seeing 5.01V at no load, but 4.65V at around 1A, with some ripple visible). Oddly, the development board that we copied the design from doesn't have the same behavior, so I'm wondering if there is some component tolerance issue that could be causing this, or if it's likely to be a layout issue. I'm hitting the limit of my electrical engineering skills (I am an embedded software engineer by training), and am looking for other potential causes of this issue.
I've attached a screenshot of the power supply part of this circuit below, and the associated BOM information. Our general design spec is 33-60V battery input stepped down to a 5V 2A output. After digging through the datasheet, I found that the vendor design was running in diode-emulation mode, so I fly-wired a 10k resistor in between the DEMB pin and the Current-sense, but that didn't make any observable difference in the output behavior. Are there specific layout gotchas that could be causing this? Or specific components I should look more into? Thanks in advance!
/cfs-file/__key/communityserver-discussions-components-files/196/Power-Supply-BOM.csv
