DESCRIPTION
The SG1548 is an integrated circuit capable of monitoring up to four positive DC supply voltages simultaneously for overvoltage and undervoltage fault conditions. An on-chip inverting op amp also allows monitoring one negative DC voltage. The fault tolerance window is accurately programmable from ±5% to ±40% using a simple divider network on the 2.5V reference. A single external capacitor sets the fault indication delay, eliminating false outputs due to switching noise, logic transition current spikes, and short-term AC line interruptions. An additional comparator referenced to 2.5V allows the AC line to be monitored for undervoltage conditions or for generation of a line clock.

FEATURES
• Monitors four DC voltages and the AC line
• Precision 2.5V ±1% low-drift reference
• Fault tolerance adjustable from ±5% to ±40%
• ±3% trip threshold tolerance over temperature
• Separate 10mA, 40V overvoltage, undervoltage and AC line fault outputs
• Fault delay programmable with a single capacitor
• 30mV comparator hysteresis to prevent oscillations
• On-chip inverting op amp for negative voltage
• Open-collector output logic or expandability
• Operation from 4.5V to 40V supply

HIGH RELIABILITY FEATURES - SG1548
♦ Available to MIL-STD-883
♦ Radiation data available
♦ LMI level "S" processing available