description The TL3842 series of controlintegrated circuits provide the features that are necessary to implement off-line or dc-to-dc fixed-frequency current-mode control schemes with a minimumnumber of external components. Some of the internally implemented circuits are an undervoltage lockout(UVLO), featuring a start-up current of less than 1 mA, and a precision reference trimmed for accuracy at theerror amplifier input. Other internal circuits include logic to ensure latched operation, a pulse-width modulation(PWM) comparator (which also provides current-limit control), and a totem-pole output stage designed to sourceor sink high-peak current. The output stage, suitable for driving N-channel MOSFETs, is low when it is in theoff state.
Major differences between members of these series are the UVLO thresholds and maximum duty-cycle ranges.Typical UVLO thresholds of 16 V (on) and 10 V (off) on the TL3842 devices make them ideally suitedto off-line applications. The corresponding typical thresholds for the TLx845 devices are 8.4 V (on)and 7.6 V (off). The TLx842 and TLx843 devices can operate to duty cycles approaching 100%. whichblanks the output off every other clock cycle.
The TL3842-series devices arecharacterized for operation from 0°C to 70°C
