9.2.2.8 Choosing R_VCC and C_VCC

The VCC is used as internal supply rail and is a shunt regulator. To ensure stability of internal loop a minimum of 0.1 µF is required for C_VCC. To ensure reasonable power on time it is recommended to keep C_VCC below 1 µF. R_VCC should be sized in such a way to ensure that sufficient current is supplied to the IC at minimum operating voltage corresponding to the falling UV threshold. To allow for some margin it is recommended that the current through R_VCC is at least 1.2x of I_Q,MAX when RTN = Falling UV threshold and VCC = 10 V (minimum recommended operating voltage on VCC). For this example R_VCC of 16.2 kΩ was used.