Altera 5M80Z CPLD programs ok but little current draw

• Altera 5M80Z CPLD programs ok but little current draw
  Posted by alexig on 18 Nov, 2018 11:56
• Hi there,
  
  I've got an Altera 5M80Z CPLD which I've programmed via JTAG and it succeeds however there is almost no current draw and I'm using 56 LEs. I'm only seeing 1.5mA current draw which was also the case when it was blank (likely just the LDO).
  
  I have used the older style 3.3V EPM3064 CPLDs without issues and could see the current draw change when they were programmed.
  
  Is there something I'm missing with the new style of CPLDs? I just have the 1.8V LDO with 1uF caps, the 3.3V being feed in directly, no pull-ups/downs on any pins.
  
  Thanks!
• #1 Reply
  Posted by Bassman59 on 18 Nov, 2018 21:46
• Quote from: alexig on 18 Nov, 2018 11:56

  Hi there,
  
  I've got an Altera 5M80Z CPLD which I've programmed via JTAG and it succeeds however there is almost no current draw and I'm using 56 LEs. I'm only seeing 1.5mA current draw which was also the case when it was blank (likely just the LDO).
  
  I have used the older style 3.3V EPM3064 CPLDs without issues and could see the current draw change when they were programmed.
  
  Is there something I'm missing with the new style of CPLDs? I just have the 1.8V LDO with 1uF caps, the 3.3V being feed in directly, no pull-ups/downs on any pins.
  
  Thanks!
  

  
  Is your clock running?
• #2 Reply
  Posted by alexig on 19 Nov, 2018 08:53
• Thanks for the reply!
  
  No clock is running as yet. I was just expecting to see a large difference in current like in the old ones, sounds like it's gotten way better now. Running a voltage on the clock line does seem to give 3.3V on the CPLD's outputs checking on the scope, so it's looking promising.
  
  I'll build up more of the board and see how it goes.
• #3 Reply
  Posted by Bassman59 on 19 Nov, 2018 16:30
• Quote from: alexig on 19 Nov, 2018 08:53

  Thanks for the reply!
  
  No clock is running as yet. I was just expecting to see a large difference in current like in the old ones, sounds like it's gotten way better now. Running a voltage on the clock line does seem to give 3.3V on the CPLD's outputs checking on the scope, so it's looking promising.
  
  I'll build up more of the board and see how it goes.
  

  
  Most of the current consumption is dynamic, so without a clock, your quiescent current draw should be about what is indicated on the data sheets.