# 0402 vs 0201

Discussion in 'General Electronics Chat' started by brucewayne, Sep 10, 2015.

1. ### brucewayne Thread Starter New Member

Aug 25, 2008
3
0
Hi,

I am trying to replace 0402 R, L, Cs with 0201s on my design on a Bluetooth and wireless charging board. How do I check which ones I can replace and which ones I shouldnt, or can I replace all? The use case requires me to minimize the board size even if the cost goes up a little. For example, for a 1K resistor, Digikey shows power of 0.063W for a 0402 with a cost \$0.004 for 100 pcs, while for a 0201 it shows power 0.05W and a price of \$0.0166 (all other characteristics are the same). So does power here matter much? Or if the price increase doesnt matter, is it ok to replace 0402 with 0201?

2. ### dl324 Distinguished Member

Mar 30, 2015
3,250
626
Can't say from the information given. Depending on the values of the components, compromises may have been made to fit the 0201 form factor that could affect characteristics critical for your circuit.

3. ### Lestraveled Well-Known Member

May 19, 2014
1,957
1,215
You have to calculate the actual wattage dissipation of each resistor to see if a 0201 will handle the power. You also need to de-rate the power. In other words, if a resistor actually dissipates .05 watts, a 0201 case is too small for that resistor. You would need the 0402 case for that power.

The capacitors are fine if the voltage and capacitance is matched. Check a few of the inductors in the power line for dissipation due to internal resistance.

4. ### brucewayne Thread Starter New Member

Aug 25, 2008
3
0
Thanks guys.
The circuit is something like this

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5. ### mcgyvr AAC Fanatic!

Oct 15, 2009
4,771
971
OK.. Should be excellent practice for you to calculate resistor dissipation.
Go for it..
Don't forget to multiply calculated power by 2 or 3 for "safety factor" to keep resistor surface temperatures low.