FA13843N

FA13842,13843,13844,13845 s Description The FA1384X series are CMOS current mode control ICs for off-line and DC-to-DC converters. These ICs can reduce start-up circuit loss and are optimum for high efficiency power supplies because of the low power dissipation achieved through changes in the CMOS fabrication process. These ICs can drive a power MOSFET directly. The high-performance, compact power supply can be designed with minimal external components . CMOS IC FA13842, 13843, 13844, 13845 For Switching Power Supply Control s Dimensions, mm SOP-8 8 5 1 4 4.9 +0.1 –0.05 s Features • • • • • • • CMOS process Low-power dissipation Standby current 2µA (max.), start-up current 30µA (max.) Pulse-by-pulse current limiting 5V bandgap reference UVLO (Undervoltage lockout) with hysteresis Maximum duty cycle FA13842, 13843: 96% FA13844, 13845: 48% • Pin-for-pin compatible with UC384X Note: Pins are fully compatible, but characteristics are not. When our ICs are applied to a power supply circuit designed for other manufactures' 384X series, the characteristics and safety features of the power supply must be checked. 6.0±0.2 3.9 0.4±0.1 1.27±0.2 DIP-8 8 5 s Types of FA1384X series Type UVLO Start threshold Stop threshold FA13842P 16.5V± 1V 9V± 1V FA13842N FA13843P 9.6V± 1V 9V± 1V FA13843N FA13844P 16.5V± 1V 9V± 1V FA13844N FA13845P FA13845N 9.6V± 1V 9V± 1V Maximum duty Package cycle 96% DIP SOP 96% DIP SOP 48% DIP SOP 48% DIP SOP 1 9.3 1.5 4 6.4 3.0min 4.5max 3.3 0~8° 0.05 0.25 – +0.1 7.62 2.54±0.25 0.46±0.1 0~15 ˚ 0~1 5˚ 1.7max 0.20 1 FA13842, 13843, 13844, 13845 s Block diagram FA13842, 13843 VCC 7 30V UVLO OUTPUT ENB Pin No. Symbol Function 1 COMP Compensating UVLO VCC 5V REF ENB 2.5V 8 VREF 2 3 4 FB ISNS RT/CT 6 OUT RT/CT 4 ER AMP FB 2 COMP 1 ISNS 3 2R 1R OSC 5 GND 1V SQ FF R QB 5 6 7 8 GND OUT VCC VREF 5V Controlled block FA13844, 13845 VCC 7 30V UVLO OUTPUT ENB Description Error amplifier output, available for loop compensation circuit Feedback Inverting input of the error amplifier Current sensing Input voltage proportional to inductor current Oscillator control Setting oscillation frequency and maximum duty-cycle with resistor RT and capacitor CT Ground Ground Output Output for driving a power MOSFET Power supply Power supply Reference voltage Reference voltage and current source charging capacitor C T through resistor RT UVLO VCC 5V REF ENB 2.5V 8 VREF 6 OUT RT/CT 4 ER AMP FB 2 COMP 1 ISNS 3 2R 1R OSC 5 GND 1V SQ FF R QB TFFQ CLK QB 5V ControlIed block s Absolute maximum ratings (Ta=25˚C) Item Supply voltage Zener current Output peak current FB/ISNS terminal input voltage Error amplifier sink current Total power dissipation Thermal resistance Junction temperature Ambient temperature Storage temperature Symbol VCC IZ IO VIN I SINK Pd Rθ j-a Tj Ta Tstg Test condition Low impedance source Zener clamp (Icc