Hi,
I would like to know why some DACs have current output instead of
voltage output. Is there any advantage with one or the other. Thanks.
Amish
The usual situation is that
1. The dac uses an inverted ladder architecture, where each bit switch
steers current into one node or into another. So the output is
inherently differential currents. Some architectures, like resistor
strings and delta-sigma, are inherently voltage generators, but are
usually slow.
2. The dac technology (say, cmos switches and thinfilm resistors)
isn't suitable for growing good opamps on the same chip. So they bring
out the differential currents so good, fast external bipolar opamps
can do the current-to-voltage conversion.
Current output DACs cn be very fast, gigasamples per second.
John