SG3843D

L I N D O C # : 1842 SG1842/SG1843 Series CURRENT MODE PWM CONTROLLER T HE I NFINITE P OWER OF I NNOVATION P RODUCTION D ATA S HEET DESCRIPTION The SG1842/43 family of control IC's provides all the necessary features to implement off-line fixed frequency, current-mode switching power supplies with a minimum number of external components. Current-mode architecture demonstrates improved line regulation, improved load regulation, pulse-by-pulse current limiting and inherent protection of the power supply output switch. The bandgap reference is trimmed to ±1% over temperature. Oscillator discharge current is trimmed to less than ±10%. The SG1842/43 has undervoltage lockout, current limiting circuitry and start-up current of less than 1mA. The totem-pole output is optimized to drive the gate of a power MOSFET. The output is low in the off state to provide direct interface to an N channel device. The SG1842/43 is specified for operation over the full military ambient temperature range of -55°C to 125°C. The SG2842/43 is specified for the industrial range of -25°C to 85°C, and the SG3842/43 is designed for the commercial range of 0°C to 70°C. K E Y F E AT U R E S s OPTIMIZED FOR OFF-LINE CONTROL s LOW START-UP CURRENT (