I am designing a PCB for SIM7600 module. I am stuck at choosing right capacitors for it. The datasheet (Page 21 & 22) specifies the load transient of the module. You can found load transient below:
According to my calculations (considering the power supply is unable to supply transient), the capacitor should supply 1.154 X 10^(-3) Coulomb charge in 577 us (I X dt = 2A X 577us).
To calculate the capacitor value, I have divided charge required by max. ripple voltage (=300mV). The capacitor value (dQ/dV) came out to be 3.84 X 10^(-3) Farad. But the datasheet requires 1000uF capacitor if power supply is unable to supply the load transient. Am I doing it right?
I think I should consider the ripple current of the capacitor and ESR of the capacitor. Should I be selecting capacitor having ripple current more than 2A?
I have calculated max ESR by considering voltage shouldn't drop by 300mV while supplying 2A current. The max ESR obtained from my calculations is 0.15 ohm (dV/dI = 300mV/2A).
Am I calculating it the right way?
I am using
DC-DC regulator (AP6503). The load transient response of the regulator is:
It looks like my supply will be able to respond in a way that voltage deviation will be less than 300mV after 50 us of load transient. Do I need to use 50us time instead of 577us?