The CS2841B provides all the necessary features to implement off-line fixed frequency current-mode control with a minimum number of external components. The CS2841B (a variation of the CS2843A) is designed specifically for use in automotive operation. The low start threshold voltage of 8.0 V (typ), and the ability to survive 40 V automotive load dump transients are important for automotive subsystem designs. The CS2841 series has a history of quality and reliability in automotive applications. The CS2841B incorporates a precision temperature-controlled oscillator with an internally trimmed discharge current to minimize variations in frequency. Duty-cycles greater than 50% are also possible. On board logic ensures that VREF is stabilized before the output stage is enabled. Ion implant resistors provide tighter control of undervoltage lockout.