Re: Improving glitch from DAC circuit
Not knowing how the DAC is architected, maybe these
suggestions are off base. However...
1) If your weighted resistor string is switched into the
output, put the resistor between the output and the
switch, to better isolate its charge injection
2) Switches to be no larger than necessary, and driven
no harder than necessary
3) If a current-mode into @-2R ladder style, switch the
currents by source-steering rather than drain switching.
4) Output capacitance will smooth out current spikes, at
the potential cost of settling time. Be sure you have
the load and parasitics represented well, before you
get all sad (or happy) about DAC glitch qualities. A
post-filter could be something to consider (series L
smooths current, shunt C smooths voltage, the two
together can make a nasty little tank).
Now, your glitch energy spec seems wrong. Calling out V*s
is not specifying an energy quantity, unless you have an
assumed load embedded in that number. V*I*s is energy.
V^2/R*s is energy.
If you showed a DAC bit cell and ladder schematic some
other ideas might occur to people. Topology suggestions
(useful ones) need some initial context.