N
[email protected]
- Jan 1, 1970
- 0
All, Thank you for the contributions to my question regarding by board
layout (Thread: http://groups.google.com/group/sci....read/thread/9bc920f3bc408a6a/ce50b32b5b8d0499)
Your help was very useful. I decided not to use any ground splits and
used a standard 200 kHz step down switcher from linear, using the
exact layout as in their eval board and sheilded inductors and LDOs to
split the power. I did use LDOs at the output with ceramics, and that
may or may not be causing issues (e.g. the bypass cap that linear
says will reduce output noise causes the LDO to flatline- but is ok
without it).
Also, I am yet to understand the workings of DACs. My ADI DAC (AD7302)
running off +5VA has +3.3V digital lines coming into it and once
supplies are powered up, the digital side goes up to 3.7V. ADI says
it is a protection diode latching problem - however, I have used other
DACs from ADI with similar topology with no issues. I moved the DAC to
the +3.3V supply and things are fine. But what is its analog voltage
output referenced to now? It does have an AGND and GND which are
connected together close by.
layout (Thread: http://groups.google.com/group/sci....read/thread/9bc920f3bc408a6a/ce50b32b5b8d0499)
Your help was very useful. I decided not to use any ground splits and
used a standard 200 kHz step down switcher from linear, using the
exact layout as in their eval board and sheilded inductors and LDOs to
split the power. I did use LDOs at the output with ceramics, and that
may or may not be causing issues (e.g. the bypass cap that linear
says will reduce output noise causes the LDO to flatline- but is ok
without it).
Also, I am yet to understand the workings of DACs. My ADI DAC (AD7302)
running off +5VA has +3.3V digital lines coming into it and once
supplies are powered up, the digital side goes up to 3.7V. ADI says
it is a protection diode latching problem - however, I have used other
DACs from ADI with similar topology with no issues. I moved the DAC to
the +3.3V supply and things are fine. But what is its analog voltage
output referenced to now? It does have an AGND and GND which are
connected together close by.
