Diodes VS Bridge Rectifiers

[Jason]

Hi all,

I have a quick question; What is the most significant difference between using a purpose built bridge rectifier diode (Such as BU2506-E3/45) VS just using 4 normal diodes (Like a 1n5404)? The reason I ask is that I have never seen any amateur electronics enthusiast use a purpose built diode package. I mean is it advantageous in any way? The only main difference I see is that you have the option of heat sinking the diode package and not the axial diode but maybe I'm missing something?

[Strada916]

Price, footprint, extra holes, extra tracks, higher PIV, higher current handling. to name a few

[SeanB]

No real difference, just the convenience of the package as you get to higher power of it being isolated and single hole fixing. Only disadvantage is that there are only half bridges available in Schottky diodes, so you need 3 packages to make a bridge rectifier with lower forward voltage drop. Single diodes are available in many package styles, and if space is constrained and the big bulky bridge will not fit you can put 4 packages in line on a heat sink instead.

[mariush]

The ones in a package are isolated (glass passivated, or other process) and can dissipate heat in the whole package and the package is easy to screw onto a heatsink. Individual diodes dissipate heat in the air through the small surface of the diode, and into the pcb through the leads.
You could also argue that since the diodes are in same package, they heat at the same rate so you can in theory predict better the influence of heat on the voltage drop of each diode.

Heatsinking ability is very important in some cases... open the datasheets and have a look at the graphs and you'll see for example that a 10A rectifier is only rated for 3A or 5A in open air and even then the graph shows it reaching 100+ C which is something you may not want.

Individual diodes dissipate a lot of heat through the leads and therefore through the PCB therefore if you don't have thick enough traces the diodes could overheat when you use them close to their maximum current limit.  The excess heat could also cause (in theory) weakened soldered joints.

[TechJunkie]

Price, footprint, extra holes, extra tracks, higher PIV, higher current handling. to name a few

...and convenience.