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I sincerely need some help with the ADCMP605 application? DUTY CYCLE?

Question asked by mikeyunhai on Jul 10, 2012
Latest reply on Jul 11, 2012 by mikeyunhai

I sincerely need some help with the ADCMP605 application?

 

The question goes: as the way I applied the ADCMP605, the ADCMP605 output signal pair not the 50% duty cycle as I expected. Here below attached with the ADCMP605 schematic, and the snapshots of the outputs we experimented in the lab. Would anyone who knows anything wrong with my application? I am very grateful if anyone could give a hand. Thanks very much.

 

Here attached with the schematic: signal generator inputs an analog signal, sine wave or rectangular, into pin VP of ADCMP605, both VP and VN provide a voltage bias around 2.5V as the threshold for comparison. LE/HYS is pulled down through 82K ohm resistor to GND as suggested in the Datasheet. However, the output goes like the snapshots below:

 

1.JPG


As shown in the shot, the yellow wave stands the rectangular input @2MHz, 5dBm, the blue one is the output in the pair. It’s seen worryingly in the snapshot that the output wave has the duty cycle far from 50%.

 

2.JPG


Hereby is the input signal from VP and VN, of which the blue wave stands for VN.

 

2.JPG


We tried enhancing the amplitude of the input signal to 12dBm and the output turns out to be better, the snapshot is shown below.

 

2.JPG


I am pretty much a freshman in this field, I read the Datasheet and maybe lack of understanding the manual completely. Therefore, I am sincerely asking for help here. Would anyone give me some help? Thanks very much.

 

I am anxiously looking forward to your reply. You can reach me at mikeyunhai@gmail.com or you can directly reply at this page. Thanks again.

 

Mike


 

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