low@melair.UUCP (Rick Low) (09/29/89)
mark@mips.COM (Mark G. Johnson) writes: >I suggest that when you're building it, and afterward when you're >debugging and testing it, be sure to measure the actual observed >performance of the Burr-Brown part. Compare this to the datasheet; >is the datasheet dead-on, wildly optimistic, or conservatively pessimistic? >This will help other readers of these Newsgroups decide whether or >not to use the BB device in their own projects. >-- > -- Mark Johnson > MIPS Computer Systems, 930 E. Arques, Sunnyvale, CA 94086 > (408) 991-0208 mark@mips.com {or ...!decwrl!mips!mark} MY $.02 ON BURR-BROWN ADC SPECS: I evaluated the B-B ADC600, a 10MHz sample rate 12-bit subranging ADC. Right away I was impressed when the ADC arrived accompanied by printouts of test results for that particular ADC, done with tests and test jig shown in the data sheet. All we had to do was compare our printouts with the data sheet to ensure that our ADC was within published specs. However, we wanted to play, and needed experience interfacing the ECL outputs of this device to our digital filters, so we decided to build our own test jig, following the data sheet, but with different brands of test equipment. We got effectively the same results as the printouts that came with the ADC. These results were dead on the data sheet specs or slightly better than them. The only problem with Burr-Brown's specs, or any ADC manufacturer for that matter, is the treatment of aperture jitter in the sample- and-hold. Due the the bandwidth we were going to handle with this ADC, aperture jitter was second only to non-linearity in importance, but no one could tell us whether the spec was for peak or RMS jitter. The difference meant decreased S/N in a good chunk of the input band. It seems everyone publishes aperture jitter specs and either says "typical" (right! :-) ) or doesn't say anything and lets you decide. Don't get me wrong though; I like the B-B ADC600. It beat the competition when we looked at it. I also have had good experience with the B-B customer support people. -- Rick Low MEL Defence Systems Limited, Ottawa, Canada +1 613 836 6860 mitel!melair!low@uunet.UU.NET