Hi,
I'm trying to use a FAN5331 boost converter (www.fairchildsemi.com/ds/FA/FAN5331.pdf) but cannot get it working no matter what I try. I've followed the recommended schematic, layout as much as possible.
Here's my schematic (note that the VIN and enable pins are swapped on this schematic):
Here's my layout:
Here's what I get on the switching node (SW to GND)
Note that 1.6 MHz is the switching frequency of this device, and that Vpp/2 in this picture is approximately what my output should be.
Here's what I get on the output node (VOUT to GND)
PCB
As my output should be Vout = 1.23*(1 + (150/39)), I should expect 6v on that output. But I don't get htat !! If anyone has an idea of what I should loook into, that would be good.
I'm trying to use a FAN5331 boost converter (www.fairchildsemi.com/ds/FA/FAN5331.pdf) but cannot get it working no matter what I try. I've followed the recommended schematic, layout as much as possible.
Here's my schematic (note that the VIN and enable pins are swapped on this schematic):
Here's my layout:
Here's what I get on the switching node (SW to GND)
Note that 1.6 MHz is the switching frequency of this device, and that Vpp/2 in this picture is approximately what my output should be.
Here's what I get on the output node (VOUT to GND)
PCB
As my output should be Vout = 1.23*(1 + (150/39)), I should expect 6v on that output. But I don't get htat !! If anyone has an idea of what I should loook into, that would be good.