Category: Hardware
Product Number: LT8612
RT determination/switching frequency. Your formulae (3) and (4) given in the data sheet for this product do not seem to be very useful. If the minimum on time and the voltage drops across the output switches are correct, then the 12V output example given on p19 of the same would give a maximum switching frequency of 14.6MHz, which is out of the range of the device. Clearly this cannot be used to obtain the value of RT, so we are left wondering how a value of 1 MHz was obtained. The main offender in the formula (3) is the minimum on time (i.e. 20 x 10e-9 s) which will always produce a f(sw) way beyond the values given in your table. This may be a maximum, but it is not a useful maximum.