AnsweredAssumed Answered

AD9959 Evaluation Board 3.3V

Question asked by ecephys on Mar 2, 2015
Latest reply on Mar 3, 2015 by sitti

Hi,

 

I first want to confirm that the board was working well before the following incidents occurred.

 

I was observing some strange things when I accidentally set the jumper W11 to the External Crystal mode while I intended for REFCLK mode. I made this mistake 2 times:

- The first time, for the same amount of current supplied (100 mA for 3.3 V, and 120 mA for 1.8 V) to the board from an external power supply, the 3.3 voltage level was almost halved and the 1.8 voltage level was reduced to about 1.1 V. I did not know how to fix the problem, so I left it for few days, and frankly it was behaving well after few days.

- The second time, something very similar happened, and this time I cranked up the current of the 3.3 V line (to about 300mA) to enforce the voltage level to be at the designated level (3.3 V). By increasing the current I was able to meet the 3.3 V, the designated level, but it did not resolve the problem (USB not recognized), so I turned it down. As I did before, I left it for few days. This time, the 3.3 V line is only at about 1.5 V for 110 mA, while the 1.8 V line seems to be fine (1.8 V for 110 mA).

 

So my questions are:

- Have I fried something?

- What should I look into, in order to solve the problem?

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