Jun 252012

Quite often I find that I need to use SMT devices when prototyping on a breadboard. The main reason for this is that many newer devices are simply not available as a THT part.

My solution is to build what I term ‘carrier’ boards, which are quite simply small PCB’s with the part soldered to it and a right angle header positioned along one edge. Pictured below is the simplest version of one of these which simply contains a SOT23 device. Because of the simplicity of these circuits it is possible to keep them as a single sided PCB which makes fabrication at home very simple. One thing that is important with many of the smaller devices is to label the boards with at least the part number, as many of these tiny devices only have a 2 digit code to identify them and it is quite difficult sometime to later figure out what the part is. In the past I have used a Dymo label printer to create these, but recently I have changed to just laser printing them on plain paper, cutting them out and attaching to the rear of the PCB with a glue stick. A fine tipped permanent marker also works for this (just not as neatly).

74VHC1GT125DT1G Carrier (front)

74VHC1GT125DT1G Carrier (rear)

I personally don’t use 22 gauge wires with my breadboards as it tends to make the connection points loose for most other components that normally have thinner (24 gauge) leads. Because of this I normally solder 24 gauge wires to the right angle connectors so that it matches the size of wire I use for jumpers.

With some of the carrier boards I also add support components. I do this when every time that I use that part I will use the same components with it. For example, in the pictures below I have added the capacitors required for the MAX3232CE to function.

MAX3232CE Carrier (front)

MAX3232CE Carrier (rear)

And finally here is an ATMEGA32U2 microcontroller complete with decoupling capacitors, USB socket and resistors (as well as a wire jumper to fix a stuff up).

ATMEGA32U2 Carrier (front)

ATMEGA32U2 Carrier (rear)