DESCRIPTION

The SG1842/43 family of control ICs 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 under voltage lockout, current limiting circuitry and start-up current of less than 1mA.

KEY FEATURES

■ 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 (SG1842 only)
■ DOUBLE-PULSE SUPPRESSION
■ HIGH-CURRENT TOTEM-POLE OUTPUT (1AMP PEAK)
■ INTERNALLY TRIMMED BANDGAP REFERENCE
■ 500KHZ OPERATION
■ UNDERVOLTAGE LOCKOUT
SG1842 - 16 volts
SG1843 - 8.4 volts
■ LOW SHOOT-THROUGH CURRENT <75mA
OVER TEMPERATURE

HIGH RELIABILITY FEATURES

■ AVAILABLE TO MIL-STD-883B AND DESC SMD
■ SCHEDULED FOR MIL-M38510 QPL LISTING
■ RADIATION DATA AVAILABLE
■ LINFINITY LEVEL "S" PROCESSING AVAILABLE