Tool/software:
An evaluation board (4 layer PCB) has been designed for the LM27403, to evaluate the performance for 12V input, 9.6V output at 15A. Circuit was first created using Webench Power Designer, then component values have been tuned using the TI provided LM27403 regulator design tool spreadsheet.
The circuit fails to start when powered from a bench PSU 12V 5A capable, with no load, and appears to be in hiccup mode, although the delay between individual start-up sequences, as measured on SW node, appears to vary between 8-14mS which is outside datasheet spec for hiccup delay = 5mS.
When measuring the SS node, I observed a very short ~400uS rise time, which is far from the expected 5mS with a 27nF capacitor (C12). Additionally I have tried capacitor values up to 100nF with no observable change on the SS node rise time.
My SYNC pin has been left floating, an error on my part, but I have tried connecting it to GND, with no effect.
Is there a way to privately share my schematic and/or PCB design with TI Support?
Thanks!
