U3018F

U3018F is a high-performance, low-cost PWM-controlled power switch designed for offline low-power buck applications, featuring a simple peripheral circuit with minimal component count. The device integrates a high-voltage startup MOSFET, which helps enhance the surge withstand capability of the system. Unlike conventional PWM power switches, U3018F has no fixed internal clock to drive the MOSFET; instead, the switching frequency adjusts automatically in response to load variations. The device employs multi-mode PWM control technology, which effectively simplifies peripheral circuit design, improves line regulation and load regulation, and eliminates audible noise during system operation. In addition, the internal peak current detection threshold adjusts automatically based on actual load conditions, helping to reduce standby power consumption at no load. U3018F integrates comprehensive self-recoverable protection features, including VDD undervoltage protection, cycle-by-cycle current limiting, output overvoltage protection, overtemperature protection, overload protection, and VDD overvoltage protection.

Applications

• Telecom 90V power systems
• Ethernet PoE
• Industrial control
• Inverter systems

Key features

• Input voltage range: 18~180V (output: 14.3V)
• Integrated 2.5A 180V MOSFET
• Integrated 200V high-voltage startup circuit
• Integrated freewheeling diode
• Multi-mode control, noise-free operation
• Supports buck and buck-boost topologies
• Default output 14.3V
• Standby power consumption below 50mW
• Excellent line regulation and load regulation
• Integrated soft-start circuit
• Overload protection
• Cycle-by-cycle current limiting
• Output overvoltage protection
• VDD overvoltage, undervoltage, and voltage clamp protection
• Ultra-low quiescent current, typical 200uA
• High-voltage startup and ultra-low standby power consumption (<50mW)
• Cycle-by-cycle peak current limiting with leading-edge blanking (blanking time ~350ns)
• Multi-mode PWM control (combined frequency and amplitude modulation)
• Integrated soft-start circuit with 4ms typical value
• Output overvoltage protection (triggered when VF voltage exceeds 2.4V for 3 consecutive cycles)
• Overload/short-circuit protection (triggers auto-restart after condition persists for 100ms typical)
• Abnormal overcurrent protection (detection threshold typical 0.6V, triggers frequency reduction)
• Thermal protection (triggers auto-restart when junction temperature exceeds 150°C typical)
• Optimized dynamic response, reduced output voltage drop during load transients
• Audible noise elimination
• VDD overvoltage protection (typical threshold 24V) and VDD voltage clamp (26V Zener)
• Auto-restart protection mechanism