# Decoupling Capacitor Calculation

I have few questions related to the schematics(BBB_SCH) sheet 2 in link

1. There is a bulk decoupling capacitor of 10uF,10V connected to the pin 10(AC) of the PMIC tps65217.pdf. Can some one please explain how is this value calculated now I know C = I * dt/dv but where in the data sheet can I find I , dt , dv.
2. There is a 100K ohm register R1 on the INT pin number 45. Can some one please let me know how is this value calculated.
3. Also on sheet 3 there is a SN74AUC1G74 which is connected to the CEC Clock for HDMI Framer. Can some please let me know is this a clock for the HDMI.

Regards

Nick

## 1 Answer

1. The input Capacitor should not be a critical value component. The datasheet recommends a typical value of 4.7uF, but others may be used. Since there's a lot of 10uF/10V around there, they may used one on this pin too to reduce BOM items.
2. Again, seems to be nota a critical value, just a pull-up resistor. Those usually range from a few Kilo-ohms to hundred ones. The 100k value appears in the 9.2 Functional Block Diagram on the datasheet.
3. Certainly it's a clock. Its role you will need to find in the datasheets of the components involved. Given the pin name of the TDA19988, I would guess it is only some kind of system clock for it.