I am designing two linear power supplies that will:
- Drop 9V DC to 5V DC to power a Raspberry Pi around 2.5A
- Drop 9V DC to 7.5V DC to power a DAC under 3A
I plan to use Texas Instruments LDO UCC283-ADJ. An adjustable LDO.
I have been reading the datasheet:
Which advises (see page 5) that a timing capacitor, C, is required:
CT: Short-circuit timing capacitor and shutdown input for the UCC283−ADJ version. Pulling CT below 0.25 V turns off the regulator and places it in a low quiescent-current mode. A timing capacitor, C, from CT to GND programs the duration of the pulsed short-circuit on-time. On-time, tON, is approximately given by:
tON = 750 k * C
Whilst the formula is given, I am at a loss as to what size capacitor I should use as C, for each of my implementations.
I was planning R1 to be 50kOhms and R2 to be 10kOhms.
Can anyone advise me on C?