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ocrdu
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Calculation of Pullup Resistorpull-up resistor for Open Drain Outputopen-drain output - Multiple Loadsmultiple loads

Link to voltage supervisor

Link to AND Gate: AND GateLink to AND gate

I would like to drive an open-drain output to multiple (5) loads of, all of the same type. 

I calculated the pulluppull-up resistor range needed and wanted to double check to make sure this is accurate and I am able to drive all of these loads. 

Circuit sketch

Here are my calculations:

  1. when output is floating high Ipullup = Ien + Ilkg Ipullup = 1uA *51μA * 5 + 1uA1 μA = 6uA6 μA
    Rpullup_max = Vout - Vih/Ipullup 
    Rpullup_max = 3.3-2.1/6uA6 μA = 200K200 kΩ max

  2. when output is low: Ipullup = Iol - Ien 
    Ipullup = 1.2mA2 mA - 6uA6 μA
    Rpullup_min = Vout/Ipullup = 3.3/1.2mA2 mA
    Rpullup_min = 2.75K75 kΩ min

So I was thinking of using a 4.7K7 kΩ pullup resistor for this circuit. Does this make sense?

Thanks!

Calculation of Pullup Resistor for Open Drain Output - Multiple Loads

Link to voltage supervisor

Link to AND Gate: AND Gate

I would like to drive an open-drain output to multiple (5) loads of all the same type. I calculated the pullup resistor range needed and wanted to double check to make sure this is accurate and I am able to drive all of these loads.Circuit sketch

Here are my calculations:

  1. when output is floating high Ipullup = Ien + Ilkg Ipullup = 1uA *5 + 1uA = 6uA Rpullup_max = Vout - Vih/Ipullup Rpullup_max = 3.3-2.1/6uA = 200K max

  2. when output is low: Ipullup = Iol - Ien Ipullup = 1.2mA - 6uA Rpullup_min = Vout/Ipullup = 3.3/1.2mA Rpullup_min = 2.75K min

So was thinking of using a 4.7K pullup resistor for this circuit. Does this make sense?

Thanks!

Calculation of pull-up resistor for open-drain output - multiple loads

Link to voltage supervisor

Link to AND gate

I would like to drive an open-drain output to multiple (5) loads, all of the same type. 

I calculated the pull-up resistor range needed and wanted to double check to make sure this is accurate and I am able to drive all of these loads. 

Circuit sketch

Here are my calculations:

  1. when output is floating high Ipullup = Ien + Ilkg Ipullup = 1μA * 5 + 1 μA = 6 μA
    Rpullup_max = Vout - Vih/Ipullup 
    Rpullup_max = 3.3-2.1/6 μA = 200 kΩ max

  2. when output is low: Ipullup = Iol - Ien 
    Ipullup = 1.2 mA - 6 μA
    Rpullup_min = Vout/Ipullup = 3.3/1.2 mA
    Rpullup_min = 2.75 kΩ min

So I was thinking of using a 4.7 kΩ pullup resistor for this circuit. Does this make sense?

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Matty
Matty
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Link to voltage supervisor

Link to AND Gate: AND Gate

I would like to drive an open-drain output to multiple (5) loads of all the same type. I calculated the pullup resistor range needed and wanted to double check to make sure this is accurate and I am able to drive all of these loads.Circuit sketch

Here are my calculations:

  1. when output is floating high Ipullup = Ien + Ilkg Ipullup = 1uA *5 + 1uA = 6uA Rpullup_max = Vout - Vih/Ipullup Rpullup_max = 3.3-2.1/6uA = 200K max

  2. when output is low: Ipullup = Iol - Ien Ipullup = 1.2mA - 6uA Rpullup_min = Vout/Ipullup = 3.3/1.2mA Rpullup_min = 2.75K min

So was thinking of using a 4.7K pullup resistor for this circuit. Does this make sense?

Thanks!

I would like to drive an open-drain output to multiple (5) loads of all the same type. I calculated the pullup resistor range needed and wanted to double check to make sure this is accurate and I am able to drive all of these loads.Circuit sketch

Here are my calculations:

  1. when output is floating high Ipullup = Ien + Ilkg Ipullup = 1uA *5 + 1uA = 6uA Rpullup_max = Vout - Vih/Ipullup Rpullup_max = 3.3-2.1/6uA = 200K max

  2. when output is low: Ipullup = Iol - Ien Ipullup = 1.2mA - 6uA Rpullup_min = Vout/Ipullup = 3.3/1.2mA Rpullup_min = 2.75K min

So was thinking of using a 4.7K pullup resistor for this circuit. Does this make sense?

Thanks!

Link to voltage supervisor

Link to AND Gate: AND Gate

I would like to drive an open-drain output to multiple (5) loads of all the same type. I calculated the pullup resistor range needed and wanted to double check to make sure this is accurate and I am able to drive all of these loads.Circuit sketch

Here are my calculations:

  1. when output is floating high Ipullup = Ien + Ilkg Ipullup = 1uA *5 + 1uA = 6uA Rpullup_max = Vout - Vih/Ipullup Rpullup_max = 3.3-2.1/6uA = 200K max

  2. when output is low: Ipullup = Iol - Ien Ipullup = 1.2mA - 6uA Rpullup_min = Vout/Ipullup = 3.3/1.2mA Rpullup_min = 2.75K min

So was thinking of using a 4.7K pullup resistor for this circuit. Does this make sense?

Thanks!

Source Link
Matty
Matty
  • 225
  • 2
  • 8

Calculation of Pullup Resistor for Open Drain Output - Multiple Loads

I would like to drive an open-drain output to multiple (5) loads of all the same type. I calculated the pullup resistor range needed and wanted to double check to make sure this is accurate and I am able to drive all of these loads.Circuit sketch

Here are my calculations:

  1. when output is floating high Ipullup = Ien + Ilkg Ipullup = 1uA *5 + 1uA = 6uA Rpullup_max = Vout - Vih/Ipullup Rpullup_max = 3.3-2.1/6uA = 200K max

  2. when output is low: Ipullup = Iol - Ien Ipullup = 1.2mA - 6uA Rpullup_min = Vout/Ipullup = 3.3/1.2mA Rpullup_min = 2.75K min

So was thinking of using a 4.7K pullup resistor for this circuit. Does this make sense?

Thanks!