FSGM300N is an all‑in‑one offline flyback power‑switch IC from onsemi, housed in DIP‑8 through‑hole package. It integrates PWM control logic and 650V SenseFET MOSFET, eliminating separate external power MOSFET for flyback converter designonsemi.

It works at 67kHz switching frequency with random frequency dithering to reduce EMI interference. Burst‑mode function realizes ultra‑low standby power. Built‑in 15ms soft‑start suppresses inrush current at power‑on. Multiple protections include OVP, OLP, short‑circuit protection, thermal shutdown and AOCP, all with auto‑restart feature instead of latching‑off after fault eventsonsemi.

It supports universal 85‑265V AC mains input, delivers up to 30W output power. Main applications include set‑top‑box, DVD player, LCD auxiliary power and small‑size consumer adapters. Reference application circuit and transformer parameters must follow official datasheet during hardware design. Datasheet PDF is available for download

FSGM300N Green‑Mode Offline Flyback Power Switch Features

• 1. High Integration Design Reduces BOM Cost & PCB Space

  The FSGM300N is a high-performance green-mode offline flyback power switch tailored for 20-40W AC-DC power systems. It integrates a 650V high-voltage SenseFET and 67kHz fixed-frequency PWM controller into a compact DIP-8 package. This all-in-one design eliminates external startup resistors and extra peripherals, significantly cutting BOM costs and simplifying PCB layout. It serves as a premium cost-effective solution for mass-producing adapters, LED drivers and small household power supplies.

  2. Ultra-Low Standby Power & Excellent EMI Suppression

  Adopting advanced green-mode burst switching technology, the FSGM300N minimizes no-load and standby power loss to meet global energy-saving certification standards. Built-in random frequency modulation effectively suppresses high-frequency switching noise and reduces EMI interference. It lowers EMI filter debugging difficulty, maintains stable and clean system operation, and perfectly fits various commercial and industrial flyback power supply application scenarios.

  3. Precise Current Control & Stable Anti-Interference Operation

  This 650V PWM power IC features accurate pulse-by-pulse current limiting, with 1.6A maximum switching current and 2.2Ω ultra-low on-resistance for stable current output. A built-in 15ms soft-start circuit restrains startup inrush current to avoid component damage. The leading-edge blanking (LEB) function filters switching spike noise, prevents false triggering, and ensures long-term stable continuous operation of power supply equipment.

  4. Full-Range Auto-Recovery Protection Improves Safety

  The FSGM300N green-mode power switch integrates complete industrial-grade auto-recovery protection mechanisms. It supports output short-circuit, overload, VCC over/under-voltage, cycle-by-cycle current limit and thermal shutdown protection. Under abnormal working conditions, the chip triggers automatic restart and recovery, effectively reducing product failure rates, cutting after-sales costs, and enhancing the safety and durability of flyback power supply systems.

  5. Universal Voltage Input & Industrial-Grade Adaptability

  This flyback power switch supports 85-265Vac universal wide voltage input, compatible with global mains voltage standards. It works stably in a wide temperature range of -40℃ to +125℃, adapting to harsh industrial and high-temperature working environments. The standard DIP-8 through-hole package enables easy welding, assembly and replacement, ideal for product development, mass production and daily power supply maintenance.

Technical Specifications of FSGM300N Green‑Mode Offline Flyback Power Switch

Industrial Applications of the FSGM300N Green‑Mode Offline Flyback Power Switch

1. AC‑DC Power Adapters

   Cost‑effective flyback solution for 20‑30W wall adapters for consumer electronics, set‑top boxes and small household appliances.

2. Home Entertainment Equipment Power Supply

   Power supply unit for TV auxiliary boards, DVD players, IPTV set‑top boxes; low standby power meets energy‑saving regulations.

3. Industrial Auxiliary Power Modules

   Isolated auxiliary power for PLC, relay control boards, sensor power supply inside industrial equipment.

4. LED Driver Power Supplies

   Universal‑input constant‑voltage LED power unit for indoor lighting, signage and small‑size LED modules.

5. Household Appliance Control Power Boards

   Switch‑mode power for air conditioner, washing‑machine, kitchen appliance main control boards.

6. Consumer Electronic Repair & Replacement

   Widely used for power‑board maintenance, direct replacement for damaged FSGM series chips.

7. Open‑Frame Switching Power Supplies

   Compact open‑frame power modules for instrumentation, supporting up to 40W output under proper thermal design.

FAQ About FSGM300N Green‑Mode Offline Flyback Power Switch

Q1: What is FSGM300N?

A1: FSGM300N is onsemi integrated flyback power switch combining PWM controller and 650V SenseFET MOSFET, for 20‑40W offline isolated flyback SMPS, DIP‑8 through‑hole package.

Q2: What maximum output power can FSGM300N achieve?

A2: 30W typical for adapter design at 230Vac; 20‑30W for full‑range 85‑265Vac adapter; up to 40W for open‑frame with good heat dissipationonsemi.

Q3: Does FSGM300N need external startup resistor?

A3: No, internal high‑voltage startup circuit is integrated to simplify peripheral circuit.

Q4: What protections does FSGM300N have?

A4: Output short‑circuit, overload, over‑voltage, abnormal over‑current, thermal shutdown and under‑voltage lockout. Most faults trigger auto‑restart mode instead of permanent latch‑offonsemi.

Q5: What is the switching frequency of FSGM300N?

A5: Fixed 67 kHz, with random frequency fluctuation to suppress EMI noise.

Q6: Can FSGM300N be replaced with FSGM200N?

A6: Not direct pin‑to‑pin equivalent. Different current rating and power capability, need re‑check transformer and BOM parameters.

Q7: What package is FSGM300N?

A7: Through‑hole DIP‑8. There is no SMD version for FSGM300N.