The ripple graphs in the datasheet and the EVM datasheet do not match, but are close in pk-pk amplitude.
Referencing Table 1 in the datasheet, I reconfigured the EVM for 5Vout output.
My conditions are:
12Vin
5Vout
3A load.
I measure 18.8mVpk-pk ripple using a differential probe across a 2-pin header I installed on the EVM. I scraped away the solder mask on the VOUT plane and GND plane, so I could measure VOUT ripple with a P6247 diff probe from Tektronix. My bandwidth is 20MHz.
The changes to the EVM are as follows:
Changed R1 and R2 to 47k and 8.87k respectively to match the IC datasheet Table 1 conditions. According to Table 1 with these component values and a configuration of12Vin, 5Vout, 3A I should expect 4mV (I presume peak, so 8mVpk-pk).
Below is a comparison of the EVM graph and my scope capture. The waveshape is similar, but the pk-pk values I measure are 3x higher.
I have tried measuring with a single-ended 1Mohm probe, 20MHz BW, with a pigtail across the 22uF C2A as well.
Is there an optimal point on the EVM that I should be measuring to match the performance shown in the IC and EVM datasheets?
Thank you for your support.
