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Hand soldering SO8 with GND paddle

A

Andrew Holme

Jan 1, 1970
0
Any tips on ways to hand solder SO8 packages which have a GND pad
underneath? I'm doing a PCB layout for a hobby project using one of these
devices so I could for example put a large plated through via under the
device big enough to get my soldering iron tip into. Is that a bad idea?

The device is a high-speed prescaler which dissipates ~ 350mW. The GND pad
not only needs to be well grounded for RF but also needs a low thermal
resistance to remove all that heat.

My board is standard 2-layer FR4 with an almost continuous ground plane on
the bottom.

TIA
 
N

Nico Coesel

Jan 1, 1970
0
Andrew Holme said:
Any tips on ways to hand solder SO8 packages which have a GND pad
underneath? I'm doing a PCB layout for a hobby project using one of these
devices so I could for example put a large plated through via under the
device big enough to get my soldering iron tip into. Is that a bad idea?

The device is a high-speed prescaler which dissipates ~ 350mW. The GND pad
not only needs to be well grounded for RF but also needs a low thermal
resistance to remove all that heat.

My board is standard 2-layer FR4 with an almost continuous ground plane on
the bottom.

You better put 5 or 6 32 mil / 0.8mm vias underneath it. If you pour
solder in on or two vias it will come up through the other vias.
 
J

John Devereux

Jan 1, 1970
0
Andrew Holme said:
Any tips on ways to hand solder SO8 packages which have a GND pad
underneath? I'm doing a PCB layout for a hobby project using one of these
devices so I could for example put a large plated through via under the
device big enough to get my soldering iron tip into. Is that a bad
idea?

Sounds good to me for a hobby project - I did this for a QFN and it
worked fine.
 
Q

qrk

Jan 1, 1970
0
Any tips on ways to hand solder SO8 packages which have a GND pad
underneath? I'm doing a PCB layout for a hobby project using one of these
devices so I could for example put a large plated through via under the
device big enough to get my soldering iron tip into. Is that a bad idea?

The device is a high-speed prescaler which dissipates ~ 350mW. The GND pad
not only needs to be well grounded for RF but also needs a low thermal
resistance to remove all that heat.

My board is standard 2-layer FR4 with an almost continuous ground plane on
the bottom.

TIA
Large via under the thermal pad works.

You can also solder this in a toaster oven or waffle iron with the
flat plates. Tin both the thermal pad and PCB pad. The solder bumps
should touch, but don't make the bumps too big or the part will float.
Coat with a little flux and bake.
 
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