best design for a breakout board

Community PCB Design
1

Hi all,

I’m working on a camera design using a PIC to interface to a CMOS image sensor and I have a few questions about the best way to design/make a breakout board for the CMOS IC.

Basically i have to options, firstly i can just do a straight pin breakout where i run each pin on the chip to a header on the board and turn the IC into a 48pin DIL.

Alternately i could make a board that exposes just the pins i want and has all the voltage regulators and decoupling caps required already in place so i can just go straight to using it.

The first one is obviously much simpler and would require all the voltage regulators off the board ( i need 2.8 and 1.8 volts )

The second is more compact and more educational ( i’ll learn more about layouts and general circuit design from it ).

I’m torn between my two general engineering principles. Keep It Simple, and Keep It Neat.

Does anyone have any other pros/cons/general opinions that could help me formulate my decision? If it werent for the fact that the CMOS IC is fairly expensive (£16) and is going to be a bitch to solder (all the pins are below the chip) i’d just make both for the experience.

2

Just to add another dimension…

Some parts need to be very close to the chip. Decoupling caps and the like benefit only if very close to the part. You may as well not have them if you move them off the board.

3

speaking of decoupling caps, do you need one per Vin pin of an IC or is one that covers several good enough? the CMOS imaging sensor has about ten of them.

4

kolloth:
speaking of decoupling caps, do you need one per Vin pin of an IC or is one that covers several good enough? the CMOS imaging sensor has about ten of them.

The short answer is ‘it depends’. The long answer is the speed and internal switching currents of the IC and the manufacture’s recommendations. It is good practice to include a de-coupling cap on each pair of Vdd to Vss pins if possible.