current output vs voltage output

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.

1. 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

Thanks for your answer. I was wonmdering if you could explain the above in more detail or maybe steer me towards a website that has more information on this. Thanks, Amish

Sure!

Cheers! RIch

I was asking more info on the following particular subject: The dac technology (say, cmos switches and thinfilm resistors) isn't suitable for growing good opamps on the same chip. Amish

I'm not an IC designer, so I can't say a lot more. But bipolar processing makes fast, precise opamps, and CMOS makes good switches.

There are some mixed-process dacs with cmos switches and internal opamps, but they tend to be lower, specifically slower, performance parts.

Are there any ic design newsgroups?

John

I'll do more research. Thanks for your time. Amish