Regarding DC DC converter

Thread Starter

Nidhi123

Joined Jul 24, 2018
11
Hello,
I am using LT3840 DC DC converter in my project. but i have one problem that i have used same MOSFET M1 (BSC160N10NS3)and M2 (BSC160N10NS3) in my circuit.
But i have observed shorting in my PCB. Is it possible because of using same MOSFET M1 as in datasheet application note they have mentioned M2(BSC070N10NS3).
And i have checked all the connection in my schematic, and shorting in pcb, and both found ok.

Please suggest some solution of shorting as soon as possible.

Thank u.
 

LowQCab

Joined Nov 6, 2012
55
You must have meant to say that you have "burned" Traces on your Circuit Board.
this might have nothing to do with the selection of the MOSFETs,
unless the MOSFETs were first destroyed by over-heating, or voltage spikes,
and then that problem caused excessive current to flow, which then, burned the traces on your Board.
You must provide a schematic, and ALL information regarding the use of this Converter,
including why you are using this particular type of circuit,
Why you are building you own Converter with an all SMD Design,
Did you do all of the proper Math calculations for each component based on all relevant performance goals,
What type of Load,
how long does it run,
are the environmental conditions variable,
does the load change, etc.,
What type of Power Supply is supplying the Converter,
What type and size of Heat Sink, Fan Cooling, etc.,
Who made the Printed Circuit Board, how did you arrive at it's design and specifications,
What is the Current Limiting set for,
What Frequency has the Circuit been designed for,

Look at the Specs ......
(from the Data Sheet .....)

"""Complete a thermal analysis to ensure that the MOSFET’s junction temperatures are not exceeded. TJ = TA + P(TOTAL) • θJA where θJA is the package thermal resistance and TA is the ambient temperature. Keep the calculated TJ below the maximum specified junction temperature, typically 150°C. Note that when VIN is high and fSW is high, the transition losses may dominate. A MOSFET with higher RDSON and lower gate charge may provide higher efficiency. MOSFETs with a higher voltage BVDSS specification usually have higher RDSON and lower gate charge. A Schottky diode can be inserted in parallel with the synchronous MOSFET to conduct during the dead time between the conduction of the two power MOSFETs. This prevents the body diode of the bottom MOSFET from turning on, storing charge during the dead time and requiring a reverse recovery period. """

Are you sure that you have the expertise and experience to create an all SMD Design ???
It's MUCH easier, and usually cheaper, to create a design using all "Thru-Hole" components,
it's just not as sexy looking.
 
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