I would like to measure the ripple voltage on a DC-DC step down converter output.
The DC-DC step-down converter is using TPS5410 integrated switch IC from Texas Instruments, which has a switching frequency of 500 kHz. On the output I use 100uH/2A inductor and 100uF/50V low ESR capacitor for output filter. According my estimate calculation, and the TI SwitcherPRO simulation the ripple voltage should be less than 10mV or less.
The problem is: my PicoScope 2205 USB oscilloscope has a 8 bit vertical resolution, and for measuring the 5V output voltage on my DC-DC converter, the oscilloscope uses +/-10V measurement range.
This means, that the LSB of the ADC is 20V/256 = 79mV
And so measuring 10mV noise is impossible, since all I see is this 79mV noise, which comes from the LSB noise of the ADC.
Can somebody suggest a solution for this?