# Advantage of using SMD components

I know that SMD components are smaller in size compared to their through-hole equivalents. They enable a designer to reduce overall pcb size.

Is there any other advantage of using SMD over through-hole components ? By other advantage i mean benifits in parameters like power dissipation, noise immunity, stability etc.

• lead inductance would be one. You cannot make a high frequency design with through hole. – efox29 Mar 28 '16 at 5:17
• @efox29: Nonsense. What do you think was used in HF gear before surface mount? – EM Fields Mar 28 '16 at 5:56
• @efox29: You wrote: You cannot make a high frequency design with through hole., which is wrong. Period. – EM Fields Mar 28 '16 at 6:07
• Parts cost (usually), assembly cost (in many cases), better power dissipation via the board. Many modern parts are only available in surface mount, so more available parts to pick from. – Spehro Pefhany Mar 28 '16 at 6:22
• Considering I maintained the AN-AWG-11 in the 70s as found in the F4K Phantom II (it was designed in the 60s as an update to earlier radars), I agree with EM Fields. This was an X-band radar operating at around 10GHz in a time far predating surface mount components. Does surface mount make some things easier? Yes. – Peter Smith Mar 28 '16 at 12:03

There is advantage for SMD components specially at high frequency and switching because the leads are shorter decreasing parasitic impedance/inductance.

In addition the small packages allows for tight power design because components can be places next to each other which also decrease trace length and power loops.

As far as i understand it this leads to less noise, EMI , and oscillations hence a better product.

Although Military applications still use through hole (in some designs) and NON-LEAD-FREE components and process, because they have advantage in resisting vibration and shock in harsh environment. (This is a mechanical advantage over SMD)

A major advantage of SMD is the ease of machine assembly .The automation of the assembly process gives more uniform results.When it comes to testing PCBs mistakes tend to also be uniform which makes things easier . If all assembly were to be done by machines then it does not matter much from a cost standpoint where the machine is located.This gives the customer the choice of where they want to do thier manufacturing .When you have through hole stuff with lots of flying leads and heatsinks there is a large part of the job that has to still be done by hand .The cost of hand assembly varies greatly from country to country .

Using SMD components allow parts to be placed on both sides of the board.

With through-hole parts, the pins go through the board (duh) so they take as much room on the bottom side of the board as they do on the top. Sometimes this can be an advantage because this provides a free via for each pin. But the holes for through-hole pins are much bigger than vias. And you normally wouldn't have a via for each pin of an SMD part.

You can't design Bluetooth chips in DIP package, you can't have 2.4 gigahertz circuit designed in thru hole form. Do you think any hobbyist can successfully built a circuit operates at 2 gigahertz using only discrete components? I'm damn sure parasitics capacitance and inductance will kill you at your first step. The task is not impossible but every single circuit elements, e.g. track length, distance between components, and their orientation needs serious look.

Smt in the other end having very much tight physical tolerance makes them more predictable in high frequency operation. There are buck and boost voltage regulators made in micro module form where their internal MOSFETs switching at 2MHz. This is possible entirely because of the surface mount design.

• I built a Ham radio setup for 10GHz using thru hole parts on duroid years ago, it worked just fine. Some of the multiplier chain was in carefully machined brass cavities, but the electronics was basically conventional. – Dan Mills Jan 4 '18 at 14:13