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AD9665 design question

Question asked by YLin on Mar 28, 2016


Hi supporters,

I'm going to use AD9665 to modulate LED at around 30~50MHz sinusoidal or square wave, here i have something want to make sure. Before this post, i've already have a discussion in: Amplifying digital signal by ADA4870 , here i have several application question about this circuit design.Pleas take a reference as following:

1. The current signal which i want to amplified is sent input to WxSET, and the current signal of the input is V_WxSET / (200+4.32k), the formula is reference to Fig.14. So to my understanding, the controlling signal (FPGA, 30~50MHz LVDS signal) is sent into these pins which corresponding to the enable channel, is that right?

2. This IC provides intrinsic oscillator controlled mode and extrinsic signal controlled mode by DIS/EN the OSCEN, is this IC have a low cut off frequency while using extrinsic controlled mode? because the frequency diagram of oscillator is recorded from 200 MHz, i'd like to confirm that it's ok if i used extrinsic controlled mode to drive around 50 MHz.

3. What will be happened if the oscillator is enable and the WxSET also have a AC current signal input?

4. What's the difference between the read channel and write channel? only different from the current gain? (Sorry that i'm new in this region)

5. If i want to drive several LED (4 dice: http://www.ledengin.com/files/products/LZ4/LZ4-00DB00.pdf ) and synchronize their signal (ensure their initial phase and amplitude are same), i'm trying to use multiple AD9665 to drive them seperately, is it possible to connect all WxSET (i.e. W1SET of all AD9665) in parallel (schematic of the concept and one of the LED die design are shown in attached figure)? or are there any good idea for synchronizing?

6. Is it possible to modulate LED as sinusoidal by AD9665?

7. What type of junction is recommended to input the signal for WxSET (SMA, BNC or another?)

Any help would be appreciated

Lin

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