AVR-Chat

Mago,
You need to match your output driver to the impedance of the load.

Regards,


Tim Gilbert
JEM Innovation Inc.
303-926-9053 (office)
303-437-4342 (cell)
720-890-8582 (fax)
www.jeminnovation.com
www.pdksolutions.com

  ----- Original Message ----- 
  From: magzky02 
  To: AVR-Chat@yahoogroups.com 
  Sent: Wednesday, December 30, 2009 6:45 PM
  Subject: [AVR-Chat] reducing signal overshoot/undershoot


    
  Hi everyone,

  May get ideas on how to create clean signal or reduce overshoot/undershoot. I want to create signals with variable amplitude from 1-5V, frequency is up to 20MHz and can drive up to 200mA. I have a programmable clock generator (CDCE925 from TI)which is controlled by my AVR. The freq gen output is connected to a buffer and inverter driving 2 mosfet connected together. One to switch to VIH (variable amplitude) and another to switch to GND. When i used scope to check the output, i can see overshoot and undershoot which are sometimes as big as the signal amplitude. Aside from using schottky diode, any ideas how to make reduce overshoot? or any ideas how to buffer high freq signals? 

  Regards,
  mago



  

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