8
\$\begingroup\$

I know this is an elementary question.

I know that SMD design has the advantage of smaller board size but I dont know which design works better in higher frequencies.

\$\endgroup\$
10
\$\begingroup\$

It depends on your design but if I wanted use a design for high frequencies, I used through hole just for power/heating parts and used SMD for the rest because SMD design can reduce inductance and resistance of component parts .

Advantages of SMD:

1-Smaller components.

2- Much higher component density (components per unit area) and many more connections per component.

3-Lower initial cost and time of setting up for production. Fewer holes need to be drilled.

4-Simpler and faster automated assembly.

5- Small errors in component placement are corrected automatically as the surface tension of molten solder pulls components into alignment with solder pads.

6-Components can be placed on both sides of the circuit board.

7-Lower resistance and inductance at the connection; consequently, fewer unwanted RF signal effects and better and more predictable high-frequency performance.

8-Better mechanical performance under shake and vibration conditions.

9-Many SMT parts cost less than equivalent through-hole parts.

10-Better EMC compatibility (lower radiated emissions) due to the smaller radiation loop area (because of the smaller package) and the smaller lead inductance.

Disadvantages of SMD:

1- Manual prototype assembly or component-level repair is more difficult

2-SMDs cannot be used directly with breadboards

3-SMDs' solder connections may be damaged by potting compounds going through thermal cycling.

4- SMT is unsuitable for large, high-power, or high-voltage parts, for example in power circuitry.

5-SMT is unsuitable as the sole attachment method for components that are subject to frequent mechanical stress

|improve this answer|||||
\$\endgroup\$
  • 1
    \$\begingroup\$ Is advantage #5 really an advantage over through-hole? What is the initial placement tolerance for an 0402 SMT resistor vs a 0.1" 1/8W through-hole resistor? Is it an issue? \$\endgroup\$ – RedGrittyBrick Oct 10 '13 at 8:42
  • 1
    \$\begingroup\$ I agree with RedGrittyBrick, advantage #5 isn't really an advantage. In fact, it hides an unmentioned disadvantage: the fact that SMT components placed wrongly can result in shorts between individual pins. \$\endgroup\$ – Mels Oct 10 '13 at 8:56
  • \$\begingroup\$ @RedGrittyBrick I meant during "manual" placement, if the device is not properly put on the pads "before" soldering, the part automatically goes to correct position with molten solder.You are right I should explained it better \$\endgroup\$ – Aug Oct 10 '13 at 11:04
  • \$\begingroup\$ Why #4 is a disadvantage for large high power? I have seen several design with 250 V be decoupled with SMT capacitor ceramic. \$\endgroup\$ – user83494 Sep 25 '15 at 20:20

Not the answer you're looking for? Browse other questions tagged or ask your own question.