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LSF0204 power consumption

Shu-Cheng LIN
Guru 11785 points
Other Parts Discussed in Thread: LSF0204, LSF0102

Hi Sirs,

Sorry to bother you

We would like check LSF0204 power consumption.

Because we saw there had discussed LSF0102 power consumption at E2E.

e2e.ti.com/.../1543671

Looks it's up to your VCCA-VCCB

" When the bias circuitry is connected correctly, there is about 10 uA (3.3V - 1.2V = 2.1V; 2.1V/200kohm ~= 10uA) of current constantly being pulled through the reference FET in order to turn on the device and produce the correct voltage on the gates of all the fets inside the device. 

So, could you help confirm how to calculate LSF0204 if our VCC is 1.8 and 3.3!!

Thanks for your reply.

  • 0
    Guru 317480 points
    As shown in the functional block diagram (section 10.2), there is a single 200 kΩ resistor, so the calculation is exactly the same.

    For the overall power consumption, also see the other currents in section 8.5. But the largest currents in your system are those through your own pull-up resistors when some data lines are driven low.
  • 0 in reply to Clemens Ladisch
    TI__Guru 62390 points
    Moved to the appropriate forum for support .
    Thank you Clemens for your response .
    The LSF0204 has integrated 200kohm resistor , so the power consumption calculation is limited by the 200kohm resistor. It also depends on the state of enable pin which is referenced to VrefA.
    The total current through gnd is given in the datasheet typically 0.2uA at 25C.
    As explained by Clemens , the total current consumption from the system will depend on the pullup resistance on the I/Os ; being smaller resistance increases the overall current through gnd.