Other Parts Discussed in Thread: LMV551
All,
My customer uses the LMV551QDCKRQ1 in a control system board and the reason why they selected that component is the low current consumption (typ 34uA, max 52uA).
Running tests on the consumption of the board in sleep mode they have noticed an abnormal consumption of the board and this behavior is related to the LMV551-Q1 and adjacent circuitry because in other boards with same PCB but without the LMV551-Q1 they do not experience this problem.
So after removing only the op-amp, they noticed that the power consumption was back to specification, around 150uA. Then they put the LMV551 keeping the power supply pin disconnected, in order to rule out possible anomalous paths due to the presence of the component alone, even though it was not powered. Even in this condition, the power consumption remained the same as in the specified condition, so they ruled out this possibility.
They measured the power pin absorption and noticed a value close to 330uA in the first 5-10 seconds after power up and then 213uA stable (considering the 4uA offset due to the instrument, around 217uA). They experienced this behavior also in other boards.
Below the schematic. The first op amp, operating at 3V3WU (always powered) is used to pass the A+_WU signal to the wake up micro (voltage divider with 100 and 470k). In the test bench A- is physically disconnected while A+ is connected to a led diode and a series resistor to ground (they have a switch that connects Vbat, thus switching on the led, which is left disconnected).
Do you have any ideas?
Thank you for your time,
BR
Riccardo
