> hi joe, > > the DC-DC converters are standard on the roach boards, > so you only need to supply 3.3, 5 and 12 volts to the ATX connector. > > if you use john ford's $30 pico-PSU-90, then you only have to supply > one voltage: +12 Volts at 8 amps.
I'd echo this. The supplies to the FPGA are finicky and of course must be sequenced properly. I'd definitely not try to supply all the different voltages from external supplies. Also, the mail archive contains a more authoritative answer from Francois Kapp: http://www.mail-archive.com/[email protected]/msg00748.html John > > i'm not sure about the maximum currents for each of the > roaches three input voltages. > i'm cc'ing the casper lists - someone will know. > > i can measure these currents with our clamp on amp-meter, but these will > change a bit, depending on how heavily you load the FGPA and what > ADC's are plugged into the roach board. > > best wishes, > > dan > > > > > On Thu, Jan 19, 2012 at 10:53 AM, Joseph Greenberg > <[email protected]>wrote: > >> ** >> Hi Dan, >> Thanks for the reply. >> >> Dan Werthimer wrote: >> >> >> hi joe, >> >> can you leave the DC-DC converters on the roach board? >> >> Yes. Are they standard on all Roach I boards or do we have to specify >> them? >> >> then you only need to supply the 12, 5 and 3.3 volts that >> come from the ATX power supply. >> >> What is the maximum current we would need to supply for each of these >> Voltages? >> >> Thanks, >> Joe >> >> >> >> best wishes, >> >> dan >> >> >> On Thu, Jan 19, 2012 at 10:28 AM, Joseph Greenberg >> <[email protected]>wrote: >> >>> We at NRAO are going to mount the Roach I board on a custom board, >>> rather >>> than using the usual chassis. >>> We will have DC-DC converters on the board. >>> The Roach documentation states: >>> Voltages of 12V, 5V, 3.3V, 2.5V, 1.8V, 1.5V, 1V and 1.2V aux rails. >>> >>> Is there any specification of what maximum currents we need to supply >>> for >>> each voltage? >>> >>> Thanks, >>> Joe >>> >>> >> >> >
