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CDCLVP111-SP: The definition of I_EE and I_CC

Noriyuki Takahashi
Genius 11050 points
Part Number: CDCLVP111-SP

Hi team,

- Could you tell the definition of I_EE and I_CC?

- Does the value of I_CC include the value of I_EE? 

Customer wants to understand total current that is used in the IC.

Regards,

Noriyuki Takahashi

  • 0
    TI__Mastermind 33790 points

    Hello Takahashi-san,

    • IEE refers to the supply current with none of the outputs active. Since LVPECL is an open-emitter output, when the outputs are not terminated to 50Ω at VCC-2V, the outputs do not sink any current and all current for the device travels through VEE pin.
    • ICC refers to the total supply current with all of the outputs active. With outputs active some supply current goes through VEE pins, but there will also be some current through VCC pins flowing out of the outputs into the 50Ω termination at VCC - 2V. Because of this, the current through VCC pin is higher than the current through VEE pin.
    • ICC does include the value of IEE.

    Regards,

    Derek Payne

  • 0 in reply to Derek Payne
    TI__Genius 11050 points

    Derek

    Thanks!

    Customer wants to understand the maximum output current per each channel.

    At 125 degreeC,  the datasheet specifies as below.

    IEE: 85mA max

    ICC: 405mA max

    So, in this case, is it OK that the maximum output current per channel are specified as below?

    the maximum output current per channel = (405ｍＡ - 85mA)/10ch = about 32mA?

    Regards,

    Noriyuki Takahashi

  • 0 in reply to Noriyuki Takahashi
    TI__Genius 11050 points

    Derek,

    They have one more question.

    The ambient temperature is 85 degree C. They would like to estimate the maximum output current per channel roughly.

    To do that, they want to understand what brings the difference the max ICC  = 405mA at 125 degree C and the max ICC = 385mA at 25, -55 degree C. Could you give any suggestion to estimate it?

    Do you think they can use 405mA at 85 degree C?

    Regards,

    Noriyuki Takahashi

  • 0 in reply to Noriyuki Takahashi
    TI__Mastermind 33790 points

    Takahashi-san,

    about 32mA/CH -> I think this makes sense, yes

    I suspect the difference between 25°C and 125°C for ICC comes from the voltage bias changing at the output of the PECL/ECL structure. the 2mA difference per output channel corresponds to about 100mV shift in output common mode voltage at the output pins. The difference will grow larger as temperature increases, so 85°C 405mA is a safe estimate of total current consumption.

    Regards,

    Derek Payne