DESCRIPTIONThe 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

Manufacturer	Microchip Technology
Product Category	AC DC Converters, Offline Switchers
Series	Military, MIL-STD-883B
Packaging	Tube
Package-Case	8-CDIP (0.300", 7.62mm)
Operating-Temperature	-55°C ~ 125°C (TA)
Mounting-Type	Through Hole
Supplier-Device-Package	8-CDIP
Watt	-
Output-Isolation	Isolated
Internal-Switch-s	No
Voltage-Breakdown	-
Topology	Flyback
Voltage-Start-Up	16V
Voltage-Supply-Vcc-Vdd	10 V ~ 30 V
Duty-Cycle	95%
Frequency-Switching	100Hz ~ 500kHz
Fault-Protection	Current Limiting
Control-Features	Frequency Control