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OPA2209: OPA2209 back to back diodes on input terminals

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Replies: 5

Views: 698

Part Number: OPA2209

Hi All,

for the opamp OPA2209AIDR can you please let me know at what forward voltage does the back to back diodes on the opamp input terminals start conducting 10mA of current? 

5 Replies

  • Hello Siddharth,

    The OPA209 input diodes will not conduct a current of 10 mA until the forward voltage (VF) is in excess of 0.5 V (at TA = 25 C); more likely at a level greater than 0.6 V, but less than 0.75 V. It is difficult to put an exact number on VF because it is unique to each device due to minor processing differences, and the measurement temperature. VF has a temperature coefficient around -2.2 mV/deg-C.

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • In reply to Thomas Kuehl:

    thanks for the reply Thomas, so can i assume that the min voltage at which the diodes start conuduting is 0.5v beyond the supplies i.e. VCC+0.5 or VEE-0.5
  • In reply to SIDDHARTH MOHAN:

    sorry but seeking clarification again for the anti parallel diodes between the positive & negative terminals can i assume that a min voltage difference of 0.5v is needed for these diodes to start conducting 10mA current
  • In reply to SIDDHARTH MOHAN:

    also hope the back to back diodes are also present in OPA2209AIDR although datasheet mentions only about OPA209??
  • In reply to SIDDHARTH MOHAN:

    Hi Siddharth,

    Yes it is safe to assume that the diodes need at least 0.5V to conduct 10mA of current, and as Thomas mentioned the actual forward voltage will likely be a little higher. That is not to say there will be no conduction prior to this point, but it will not reach 10mA until you have sufficient forward voltage, i.e there is still leakage and the current will start to increase as you begin to forward bias the diode.

    The back to back diodes are also present in the OPA2209.

    Regards,

    Zak Kaye
    Precision Data Converter Applications

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