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ADP160 drop out not meeting specs when testing EVAL board

I recieved this question from a customer that is testing the ADP160UJZ-REDYKIT

I installed the 2.8V regulator (that was what all the bags were about – the different voltage value regulators – needed to install your own).

The board comes up and runs – quiescent current hits the numbers. This is the big plus we were hoping for,

But when I apply 3.3 V and use a load of 70mA (40 ohm resistor) the output voltage drops from 2.8V to 2.6V (current sourced drops accordingly).

When I place a 100mA load (for a 2.8V source) the output voltage drops to 2.4V.

So I don’t see the 150mA load handling at all.

Next:

When I have a 50mA (not 150) load and lower the input voltage to 3V the output drops to 2.5. What happened to the 0.2V dropout spec’d at 150mA??? Doesn’t even hold at 50mA.

Not sure if it is me or what but I do not see this part meeting its spec. Tell me if I am flat out bungling this.

Any Ideas?

  • To determine what's going on I will need to ask a few question.

    with a multimeter.

    Can you measure the input voltage at the IC pins (the actual pins not the board) with and without the load?

    Can you measure the output voltage at the IC pins (the actual pins not the board) with and without the load?

    Do you have anything installed on J2, R1 or R2?

    Do you have a jumper on J1?

    Can you now measure the input and output voltages with a scope not a multimeter?

    Thanks,

    LucaV

    Luca

  • Below is the customer reply:

    1. Operator Error…… L

    My super advanced Agilent Voltmeter was not only measuring the voltage coming into the board but also the current being drawn (had a 10 ohm sense resistor in the line). I guess I have to be smarter than my equipment… DUH!

    This was dropping the voltage before it ever got to the board. Once I removed that sense resistor from the setup the chip seems to work fine.

  • It happens to the best too!

    LucaV

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