• Optimized For Off-Line Control
• Low Start-Up Current (<1mA)
• Automatic Feed Forward Compensation
• Trimmed Oscillator Discharge Current
• Pulse-By-Pulse Current Limiting
• Enhanced Load Response Characteristics
• Under-Voltage Lockout with 6V Hysteresis (SG1842only)
• Double-Pulse Suppression
• High-Current Totem-Pole Output (1A Peak)
• Internally Trimmed Band-gap Reference
• 500kHz Operation Under-voltage Lockout: SG1842 - 16 volts, SG1843 - 8.4 volts
• Low Shoot-Through Current <75mA Over Temperature

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 band-gap reference is trimmed to ±1% over temperature.

Oscillator discharge current is trimmed to less than ±10%. The SG1842/43 has under-voltage 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.

Microchip Ordering Part  Standard Microcircuit Drawing (SMD) 

SG1842Y-DESC Cross Reference 5962-8670401PA

SG1842Y-DESC Cross Reference 5962-8670401PX