gEDA-user: Question for DJ about his alarm clock

[Stuart Brorson <sdb@xxxxxxxxxx>]

I figured I'd ask this in public since it might be of general interest
to know the answer.  Also, I don't mind asking dumb questions in
public.  I hope I am not putting you on the spot, DJ!

I was looking at the alarm clock schematics on

http://www.delorie.com/electronics/alarmclock/

I noticed that on p. 3, the ST part (U300) has PVDD and PVSS
connections through 4.7 ohm resistors to PWR and GND, respectively.  I
can see using a small resistor + shunt cap to GND in series with the
power connection to attenuate power supply noise.  However, why is the
PVSS connection to GND also going through a resistor?

I guess I could look at the part's datasheet, but the resolution of
the PNG file isn't good enough for me to resolve the part no.  (Or
maybe my computer's screen doesn't offer enough resolution.....)

Cheers,

Stuart




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