CM3842

CM3842/3843 CURRENT MODE PWM CONTROLLER GENERAL DESCRIPTION FEATURES The CM3842/43 are fixed frequency current-mode PWM ! controllers specially designed for OFF-Line switching ! power supply and DC-to-DC converters with a minimum ! number of external components. These devices feature ! a trimmed oscillator for precise duty cycle control, a ! temperature compensated reference, high gain error ! amplifier, current sensing comparator, and high current ! totem pole output which is suitable for driving ! MOSFETs. ! The under voltage lock-out (U.V.L.O.) is designed to operated with 200µA typ. start-up current, allowing an efficient bootstrap supply voltage design. The U.V.L.O. thresholds for the CM3842 are 16V (on) and 10V (off) which are ideal for off-line applications. The corresponding typical threshold for the CM3843 are 8.4V (on) and 7.6V (off). The CM3842/43 can operated within 100% duty cycle. Low Start-Up current ( typ. 200µA) Optimized for Off-Line and DC-to-D...