Other Parts Discussed in Thread: CSD17570Q5B
Hello,
My customer is designing a hotswap circuits using TPS2490 and CSD17570Q5B.
Their requirements are as follows.
Vin=Vo=12V, Io=25.4A(max), Ta：0～+75oC
Cout=2460uF, ILIM=33A, PLIM=150W, VPROG=0.545V, Vuvlo=9.8V
Their schematics are as follows.
Using the TPS249x_8x_Design_Calculator_REV_B.xlsx calculator, to get enough SOA margin during "hot-short" or "start-into short" at F91, my customer needed to select Ct=0.47uF. Then the Fault Timeout becomes 0.075ms. However, according to equation (17) and (18) in the datasheet, calculated tstart is ~1ms or ~1.8ms, this is larger than 0.075ms. So, the Fault Timeout always prevent correct start-up.
Please let my customer know how to fix this issue. (Please refer to the attached TPS249x_8x_Design_Calculator_REV_B 2020 2 16.xlsx)
TPS249x_8x_Design_Calculator_REV_B 2020 8 28.xlsx
Best regards,
K.Hirano
