2.8 to 5v amplifier HELP

• 2.8 to 5v amplifier HELP
  Posted by fox3d on 26 Mar, 2016 01:43
• Hi guys,
  
  I have been following EEV blog from the beginning, but this is my first post
  
  
  could somebody help me to build 2.8v to 5v  amplifier/converter?
  
  I have to amplify square wave signal from 2.8 to 5 or 6v. I have tried with arduino but delay was too big even if i used direct port commands.
  
  I know it is simple but I cant wrap my head around and i don't want to blow up expensive equipment that's why I'm asking pros here
  
  Thanks
  fox
  
• #1 Reply
  Posted by michaeliv on 26 Mar, 2016 02:05
• Some questions to help give better answers:
  Where is the signal coming from, where is it going to ?
  What power sources do you have in your system ?
  Is it a digital signal or analog signal ?
  What frequency range is the signal around ?
• #2 Reply
  Posted by tautech on 26 Mar, 2016 02:08
• Quote from: fox3d on 26 Mar, 2016 01:43

  Hi guys,
  
  I have been following EEV blog from the beginning, but this is my first post
  
  
  could somebody help me to build 2.8v to 5v  amplifier/converter?
  
  I have to amplify square wave signal from 2.8 to 5 or 6v. I have tried with arduino but delay was too big even if i used direct port commands.
  
  I know it is simple but I cant wrap my head around and i don't want to blow up expensive equipment that's why I'm asking pros here
  
  Thanks
  fox
  

  Welcome to the forum.
  
  Level shifting IC or Translator is what you need.
  Here's a few:
  http://www.nxp.com/products/discretes-and-logic/logic/level-shifters-translators:MC_29482?cof=0&am=0&tab=Products
  
• #3 Reply
  Posted by fox3d on 26 Mar, 2016 02:33
• Signal is digital 20Hz to 90Hz. And it is going also to digital after its amplified so the other device can read it. Power source which is available is 24v 2.2A.   
  But I can use converter 24v to 5v. Or use 24 to drive  opamp. I'm kinda scared to use 24v  in case of failure. So the 24v don't go to signal input. To me the safest way is to use opto relay. But those have too much of a delay.
• #4 Reply
  Posted by michaeliv on 26 Mar, 2016 03:31
• Your 5v thingy might recognize 2.8v as logic high. Check the datasheet if that is the case. If it is, you can connect it directly.
  I assume that you already have the 5v converter in your system, and won't need to add one just to get this 5v signal.
  Use the one on the left here : https://pbs.twimg.com/media/A7g86KCCQAAgwds.jpg Perhaps also increase the resistor value to 10k.
  It's converting 3.3v to 5v, exactly what you want.
  This will also work, if you prefer MOSFET's :

• #5 Reply
  Posted by Zero999 on 26 Mar, 2016 10:46
• The frequency is low enough that a simple transistor would work. You've mentioned the delay but not said what's acceptable?
  
  Doe it matter if the signal is inverted?
  
  If not, the 74HCT04 will do and is very easy yo get hold of.
  http://www.nxp.com/documents/data_sheet/74HC_HCT04.pdf
  
  If it needs to be non-inverting then you could use two of the 74HCT04's not gates in series or the 74HCT34, which isn't so widely available.
  https://www.engineering.uiowa.edu/sites/default/files/ees/files/NI/pdfs/00/53/DS005359.pdf
  
  The 74HCT series needs a 5V power supply, which can be obtained from the 24V supply, using the LM7805.