iref DAC for AMU's

iref DAC for AMU's

In each case, I have checked that the AMU/ADC chip responds to the correct set of serial string bits. I have found an overall offset of one bit which occurs between the heap manager and the TGV serial string bits. It appears that the heap manager only captures 15 bits instead of the 16 bits it should take out of the input string. I do not fully understand the origin of this offset, but all of the tests below are with this offset included. If everything works with the exception of this one bit offset, I have marked that set of bits as "working".

Only 7 of the 8 AMU/ADC positions on the PC/MCM board have a chip installed.

This DAC can be tested at pin 7 or 8 (IREF_DAC on the schematic) on the AMU. This DAC is more or less consistent with numbers shown in the only documentation of this DAC's performance I found. Those points are shown as squares on this plot.

iref on AMU/ADC 1

Here is a plot of the DAC output current vs. the dac setting:

This plot is also available in postscript. The data points plotted are available here.

iref on AMU/ADC 2

Here is a plot of the DAC output current vs. the dac setting:

This plot is also available in postscript. The data points plotted are available here.

iref on AMU/ADC 3

Here is a plot of the DAC output current vs. the dac setting:

This plot is also available in postscript. The data points plotted are available here.

iref on AMU/ADC 4

Here is a plot of the DAC output current vs. the dac setting:

This plot is also available in postscript. The data points plotted are available here.

iref on AMU/ADC 5

Here is a plot of the DAC output current vs. the dac setting:

This plot is also available in postscript. The data points plotted are available here.

iref on AMU/ADC 6

Here is a plot of the DAC output current vs. the dac setting:

This plot is also available in postscript. The data points plotted are available here.

iref on AMU/ADC 7

Here is a plot of the DAC output current vs. the dac setting:

This plot is also available in postscript. The data points plotted are available here.

John Sullivan
updated 2-Mar-1999