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dac8551

Andrew Xiang

Prodigy 30 points

Other Parts Discussed in Thread: DAC8551

1. Can I use 5V for Vdd and 2.5v for Vref?

2. Can I connect a resistor between Vfb and Vout and increase the gain for the output stage. I added 20K ohm resistor between Vfb and Vout and noticed the voltage stabilize takes a long long time in minutes. What do I need to do to add some gain to the output?

over 10 years ago

0 Andrew Xiang over 10 years ago

Prodigy 30 points

The issue is after I put a 20K resistor between Vfb and Vout, the settling time becomes very long. 60 seconds?

I need more documentation on how to use the Vfb?

Also, I noticed some oscillation at the voltage output for dc voltage, but I thought I could remove that by adding a low pass filter.

0 Kevin Duke over 10 years ago in reply to Andrew Xiang

TI__Mastermind 46290 points

Andrew,

What is the load that the DAC8551 is driving in your tests?

0 Andrew Xiang over 10 years ago in reply to Kevin Duke

Prodigy 30 points

Going into a low pass RC filter, 4.7K ohm and 10uF.

After some tweaking, it is now working now. But a actual schematics for the Vout and Vfb would help.

0 Kevin Duke over 10 years ago in reply to Andrew Xiang

TI__Mastermind 46290 points

Andrew,

I'm afraid all I have to share with you right now is Figure 45 in the datasheet. I'm not sure if anything deeper can be shared on a public forum.

Can you explain what tweaking you had to do to improve performance?