AMC7823 DAC's Souring current and capacitive load stability

Feng Li2

Other Parts Discussed in Thread: AMC7823, TINA-TI

1) If AMC7823's AVDD and DVDD is supplied by 5.5V, can it increase DAC's souring current when output range of DAC is configured to 0~5V?

2) What are capacitive load stability at infinite load and 3kohm load?

over 12 years ago

0 Kevin Duke over 12 years ago

TI__Mastermind 46290 points

Feng,

The DAC source current is primarily a function of the reference voltage which would set the output voltage range. Increase AVDD/DVDD by 0.5V may improve your results slightly. See figure 29 and 30 in the datasheet.
I don't have any data readily available for the AMC7823 output buffers and stability. Let me see if the output buffers are similar to anything else I can use to provide you a simulation model.

0 Kevin Duke over 12 years ago in reply to Kevin Duke

TI__Mastermind 46290 points

Feng,

What capacitance do you expect to see at the load?

0 Feng Li2 over 12 years ago in reply to Kevin Duke

Prodigy 80 points

Above 1uF.

0 Kevin Duke over 12 years ago in reply to Feng Li2

TI__Mastermind 46290 points

The AMC7823 is going to have issues driving a 1uF or greater load without adding some series resistance to isolate the output buffer from the load. Unfortunately I don't have a lot of information available to give you about the output amplifier at this time. I am going to work toward developing a model for the DAC outputs for TINA-TI but it may be a while until the complete model is available.

Attached is the only bit of information I've been able to dig up to this point.

2158.AMC7823 7824 DAC Buffer Design Review (3).pdf

0 Feng Li2 over 12 years ago in reply to Kevin Duke

Prodigy 80 points

Thx a lots.

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AMC7823 DAC's Souring current and capacitive load stability