UC2843B

UNISONIC TECHNOLOGIES CO., LTD UC2843B LINEAR INTEGRATED CIRCUIT HIGH-PERFORMANCE CURRENT-MODE PWM CONTROLLERS  DESCRIPTION The UTC UC2843B provides off-line or DC-DC fixed-frequency current-mode control design with minimum external components. Internally-implemented circuits include an under-voltage lockout (UVLO) and a precision reference with accuracy at the error amplifier input. The UTC UC2843B also contain internal circuits which include a pulse width modulation (PWM) comparator providing current-limit control, logic ensuring latched operation, and a totem-pole output stage designed to source or sink high-peak current. The output stage is low when it is in off-state condition and suitable for N-channel MOSFETs driving. The UTC UC2843B also has following advantages: the start-up current lower than 0.5mA while the oscillator discharge current is specified to 8.3mA (Typ.). In UVLO conditions, the output has a maximum saturation voltage of 1.2V when sinking 10mA @ VCC = 5V. The typical UVLO threshold of the UTC UC2843B is 8.4V (on) and 7.6V (off) and can operate to duty cycles approximately 100%. DIP-8 SOP-8  FEATURES * Current mode operation:500 kHz * Low start-up current value<0.5mA * Latching PWM for cycle-by-cycle current limiting * Trimmed oscillator discharge current * Automatic feed-forward compensation * Internally trimmed reference with UVLO * High-current totem-pole output UVLO with hysteresis * Double-pulse suppression  ORDERING INFORMATION Ordering N...