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Part Number: LMP8640


We purchased this part and encounter some issues. Please see the attachment for the detailed problem and provide the feedback and solution. 


  • Hi,

    1)      This voltage is a result of internal circuit bias. However it is a lousy “voltage source” at best due to relatively large (output) impedance on the order of tens of KOhms.

    2)      It depends on the common mode voltage: at Vcm>=2.1V, the max current it can draw is 20uA; when Vcm is below 2.1V, Ib starts to reverse direction therefore the pin can source current. You can refer to figure 10 in the datasheet for details. The worst case is when Vcm=-2V, it can source about 800uA, which corresponds to about 1.28mW.

    3)      As long as the input pins are connected to the node 26V_A4, this voltage is going to appear. Other than physically disconnecting it, I’m not aware of a circuit configuration that can eliminate the voltage.

    Regards, Guang