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OPA2189: about bias current

nnn sato
Prodigy 230 points

Part Number: OPA2189

Tool/software:

Does the bias current include leakage current from protective diodes?

  • 0
    TI__Guru* 77501 points

    Hi Sato-san,

    nnn sato said:
    Does the bias current include leakage current from protective diodes?

    Yes, Ib current specified below does include leakage current via ESD diodes. The leakage current dominates the Ib current specification, especially at elevated temperature. 

    The ESD diodes are shown within the dash box in the image below. 

    If you have other questions, please let me know. 

    Best,

    Raymond

  • 0 in reply to Raymond Zhang1
    Prodigy 230 points

    Regarding the bias current written in the datasheet, is it correct to assume that all other TI op amps also include the leakage current in the same way?

  • +1 in reply to nnn sato
    TI__Guru* 77501 points

    Hi Sato-san,

    nnn sato said:
    is it correct to assume that all other TI op amps also include the leakage current in the same way?

    It is correct to assume the ESD diode leakage current is a part of Ib current specification. However, not all TI op amps have the same ESD protection structure. The current leakage in BJT is different from CMOS and JFET topologies. The magnitudes and %leakage contribution is Ib are different including the temperature effect. 

    Typically the ESD %leakage in JFET is >CMOS and >BJT. Ib in JFET is typically in pA; Ib in CMOS is typically in pA to nA and Ib in BJT is typically in nA to uA range, and ESD %leakage in JFET is the highest due to the total low Ib current.

    If you have other questions, please let us know. 

    Best,

    Raymond