Difference between LT8645S and LT8645S-2

Hi LT staff,

Is there any answer to this please?

Thanks,

Hi,

You are correct.  There is no other difference.

Hello Fil,

I also see the difference in the application of the 2 chips. I have the following question:

1. INTVCC (Pin2) requires a Capacitance (CVCC) around 1uF tied to the pin wrt Ground. What would happen if this capacitor is not installed? Any change in operations? - THis is for LT8645S-2 chip
2. If we are not using the Burst mode operation, is it mandatory to install a 0.1uF boost capacitor to BST (pin 11) - this is for LT8645S-2 chip.

Kindly advise what would be the change in operation.

Hi Jambhumalamal

BST cap is needed for driving of Top MOSFET inside 8645-2. It is a boost capacitor, you should use min recommended value in datasheet for correct switching of this MOS.

IntVCC cap is for internal supply of IC (digital part, gate drive signal etc). The recommended capacitor also ensures correct functionality of the part.

For both caps do not forget to have some margins against possible change of capacitor itself over temperature, dc bias or lifetime. X7R MLCCs usually used for these.

LT8645S has these capacitors internally, freeing you of having to design them externally.