Hi Team,
Our customer would like to know PSRR at VIN=3.7V, VOUT=3.3V, IOUT=around 6mA, f=1kHz and 10kHz.
Could you please let us know if you have any information?
And I have one more question.
I understand that If voltage differences between VIN and VOUT are low, "PSRR" worsens.
So, if VIN=3.7V and VOUT=3.3V, PSRR is less than 82dB at f=1kHz and 65dB at f=10kHz.
Is my understanding correct?
Regards,
Kanemaru
Hi Kanemaru,
You are correct that a key factor for PSRR is how close you are to dropout. PSRR will decrease as the LDO approaches dropout. Since dropout is linear with respect to output current, your low load will actually benefit you despite the decrease in headroom. This is why Figure 20 from the datasheet shows PSRR increasing as the load current decreases.
I am also including a couple of additional PSRR curves that we have taken on LP5907 that show PSRR vs Vdo at a couple of load conditions.
Very Respectfully,
Ryan
