The devices are designed to operate from an input voltage supply range between 8 V and 32 V. This input supply should be well regulated. If the input supply is located more than a few inches from the UC1843B-SP converter, additional bulk capacitance may be required in addition to the ceramic bypass capacitors. A tantalum capacitor with a value of 100 µF is a typical choice; however, this varies heavily on the start up circuitry of the device. This is because the input voltage to the device will decrease during start up and the input capacitance will have to provide enough charge to allow the UC1843B-SP to initially switch.

Figure 15. Flyback Regulator