Voltage Regulator not working
Voltage Regulator not working
(OP)
Hi, I have just gotten my first pcb printed and back to me to start testing. I am having trouble figuring out what why my voltage regulator isn't working, it should be outputing 5V. I am using the LT3663 http://www.linear.com/product/LT3663
I have attached my schematic. One change is that the C7 is really 1uF and not 22uF(There was a mistake in that footprint so I had to size down the cap.) If that is what causing it not to work? If so could anyone suggest a common way fix the board by hand so I don't have to order a new one. Thanks in advance.
I have attached my schematic. One change is that the C7 is really 1uF and not 22uF(There was a mistake in that footprint so I had to size down the cap.) If that is what causing it not to work? If so could anyone suggest a common way fix the board by hand so I don't have to order a new one. Thanks in advance.





RE: Voltage Regulator not working
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Voltage Regulator not working
RE: Voltage Regulator not working
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: Voltage Regulator not working
We can't read minds through the internet (but I'm guilty at times of trying).
Good on ya,
Goober Dave
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RE: Voltage Regulator not working
Keith Cress
kcress - http://www.flaminsystems.com
RE: Voltage Regulator not working
RE: Voltage Regulator not working
Not to mention that when you pick one of these type of MHz range switchers your 6.8uH inductor has to be rated for the frequency. Now, if that inductor uses a powered-metal core rather than a ferrite (and it will have to be a ferrite rated for the frequency because not all ferrites go that high) then your inductor may be acting like no more than a few turns of wire. Given skin effect for the frequency, it may be acting like no more than a wire-wound resistor.
Now, if you do have good ground and power planes, and you selected your components with prior experience in switch mode at MHz range, then I would check that your pin 9 (ground pad under the part) was properly reflowed to your PCB - a common assembly-type issue.
These MHz range switch-mode parts are neat. But unless you take into account the component and layout limitations they will cause you to prematurely age. Unless you need the super-small size that comes from having a very small inductor, I suggest you choose a part that switches at a lower frequency.
RE: Voltage Regulator not working