>>Using forward biased diodes as voltage references is shoddy
>>design.  It isn't just cheap, it's skanky.
>It's not just cheap, it's /very/ cheap.  You can get a dozen red leds
>for the cost of your inexpensive precision reference, and if you're
>building the thing and sourcing the parts then it's a completely valid
>design.  When you make a million of them, the 19 cents per LED you save
>ends up being nearly $200,000.  You can get red leds from hundreds of
>suppliers, and lead time is zero.
>
>So from a design perspective I can see it isn't ideal, but from a
>manufacturing, profit perspective it is /much/ better than a voltage
>reference.  Remember that this is a value added troubleshooting feature,
>and (IIRC when I built mine) it only gave the chip the ability to
>monitor the voltages used - it isn't part of any feedback loop.  And it
>gives you a power on indicator that you might've added anyway, so you
>are killing a few birds with a 1 cent part.