| Description & Applications | BiCMOS Current-Mode PWM Controllers ;FEATURES •BiCMOS Current-Mode PWM Controllers • Fast 40ns output rise and 30ns output fall times • –40°C to +85°C temperature range meets UC284x specifications • High-performance, low-power BiCMOS Process • Ultralow start-up current (50µA typical) • Low operating current (4mA typical) • CMOS outputs with rail-to-rail swing • ≥ 500kHz current-mode operation • Trimmed 5V bandgap reference • Pin-for-pin compatible with UC3842/3843/3844/3845(A) • Trimmed oscillator discharge current • UVLO with hysteresis • Low cross-conduction currents Applications • Current-mode, off-line, switched-mode power supplies • Current-mode, dc-to-dc converters. • Step-down “buck” regulators • Step-up “boost” regulators • Flyback, isolated regulators • Forward converters • Synchronous FET converters |