UC284XAM

UC184xA / 284xA / 384xA CURRENT MODE PWM CONTROLLER T HE I NFINITE P OWER OF I NNOVATION P RODUCTION D ATA S HEET DESCRIPTION The UC184xA family of control ICs provides externally programmable oscillator to set all the necessary features to implement off-line frequency and maximum duty cycle. The fixed-frequency, current-mode switching power undervoltage lock-out is designed to operate with supplies with a minimum of external 250µA typ. start-up current, allowing an efficient components. The current mode architecture bootstrap supply voltage design. Available demonstrates improved load regulation, pulse- options for this family of products, such as startby-pulse current limiting and inherent protection up voltage hysteresis and duty cycle, are of the power supply output switch. The IC summarized below in the Available Options includes: A bandgap reference trimmed to ±1% section. The UC184xA family of control ICs is accuracy, an error amplifier, a current sense also available in 14-pin SOIC package which comparator with internal clamp to 1V, a high makes the Power Output Stage Collector and current totem pole output stage for fast Ground pins available. switching of power MOSFET's, and an IMPORTANT: For the most current data, consult MICROSEMI’s website: http://www.microsemi.com KEY FEATURES LOW START-UP CURRENT. (0.5mA max.) TRIMMED OSCILLATOR DISCHARGE CURRENT. (See Product Highlight) OPTIMIZED FOR OFF-LINE AND DC-TO-DC CONVERTERS. AUTOMATIC FEED FORWARD COMPENSATION. PULSE-BY-PULSE CURRENT LIMITING. ENHANCED LOAD RESPONSE CHARACTERISTICS. UNDER-VOLTAGE LOCKOUT WITH HYSTERESIS. DOUBLE PULSE SUPPRESSION. HIGH-CURRENT TOTEM POLE OUTPUT. INTERNALLY TRIMMED BANDGAP REFERENCE. 500KHz OPERATION. LOW RO ERROR AMPLIFIER. PRODUCT HIGHLIGHT COMPARISON O F U C384XA SG384x Min. Limit V S. SG384 X DISCHARGECURRENT SG384x Max. Limit UC384xA TA=25 C KEY FEATURES ECONOMICAL OFF-LINE FLYBACK OR FORWARD CONVERTERS. DC-DC BUCK OR BOOST CONVERTERS. LOW COST DC MOTOR CONTROL. 7.5 7.8 -3 s 8.3 Mean 8.8 9.3 +3s Available Options Part# UCx842A UCx843A UCx844A UCx845A Start-Up Voltage 16V 8.4V 16V 8.4A Hysteresis 6V 0.8V 6V 0.8V Max. Duty Cycle