**Part Number:**UCC28711

**Other Parts Discussed in Thread:**TIDA-00173,

When comparing TIDA-00173 reference design guide and design calculator spreadsheet * UCC28710-17 Excel Design Tool* , different formulas are used for calculating C

_{DD}capacitance (at pin VDD). Based on my 2 output design I would use following formulas following two approaches:

- TIDA-00173 uses:
**C**_{DD}= (I_{RUN}+ 1mA) x [(C_{OUT1}xV_{OUT1})/I_{OUT1}+ (C_{OUT2}xV_{OUT2})/I_{OUT2}] / (V_{VDD(on)}-V_{VDD(off)}- 1V) - Excel design tool formula is:
**C**_{DD}= I_{HV}x dt_{CDDS}/ V_{VDD(on)}

Please explain different approaches and recommend which formula to use.