Is there any problems if I change 0805 too 0402 surface mount or smaller?

In order to reduce the size of a PCB, I will probably have to use smaller SM components. I currently use mostly 0805 passives, and am thinking about going to 0402 or smaller. Apart from power dissipation considerations, any pitfalls I should be aware of when making the transition?

0402 obviously is harder to hand assemble. If you need to get them assembled by machine, please notice the following tips.

  • The assembler’s pick & place machine can even handle 0402 at a good rate & yield.
  • Double-sided load. Some boards just need this assembly step, like BGA often puts decoupling caps on the bottom of the board.
  • Electrical properties. The obvious one is, of course, the power rating of resistors. Voltage rating is not only likely worse due to the physical smaller dimensions, but also consider the voltage bias degradation effect of ceramic class 2 capacitors. For smaller packages in same voltage/capacitance, this effect may be worse.

On the other hand, some properties, like lead inductance, is lower. In addition, sometimes you can put capacitors right at the chip pins for QFP style packages, while routing signals underneath the chip. In effect, the loop area for the decoupling capacitor is much much smaller than a larger size capacitor, which may be placed further away to comply with signal routing.

Read More: PCB Design and Layout Services

#PCB Design

Oliver Smith

Oliver Smith

Oliver is an experienced electronics engineer skilled in PCB design, analog circuits, embedded systems, and prototyping. His deep knowledge spans schematic capture, firmware coding, simulation, layout, testing, and troubleshooting. Oliver excels at taking projects from concept to mass production using his electrical design talents and mechanical aptitude.
Oliver Smith

Oliver Smith

Oliver is an experienced electronics engineer skilled in PCB design, analog circuits, embedded systems, and prototyping. His deep knowledge spans schematic capture, firmware coding, simulation, layout, testing, and troubleshooting. Oliver excels at taking projects from concept to mass production using his electrical design talents and mechanical aptitude.

What Others Are Asking

What’s the minimum distance from TQFP to chip cap on PCB assembly?

I want to put decoupling caps (0603) as close as possible to TQFP-48-7×7. So PCB/assembly wise how close I can put them (pad to pad, component to component)?
Does the ‘court yard’ need to be exactly square, or is it ok to place mentioned caps closer to TQFP in the corners where the TQFP pins leave kind of ‘free space’?

How can I determine BGA land pad diameter for given ball diameter?

I’m working on a project which requires the use of a CSP package. The product’s datasheet provides ball pitch and ball diameter but nothing about the preferred land pad diameter.
How can the pad diameter be worked out from these figures assuming an NSMD land?

Read Detailed Advice From Blog Articles

Why Opt for Outsourcing PCB Design Services
Ryan Chan

Why Opt for Outsourcing PCB Design Services?

More and more companies are turning to outsourcing PCB design services, especially those lacking PCB expertise and newly established companies, because designing a qualified printed

The Ultimate Guide to PCB Layout Design
Ryan Chan

The Ultimate Guide to PCB Layout Design

PCB layout design is a key step in the manufacture of circuit boards. A reasonable PCB layout is conducive to controlling the production cost and

Scroll to Top