LinkSwitch-TN2

The LinkSwitch™-TN2 family of ICs for non-isolated off-line power supplies provide dramatically improved performance compared to traditional linear or cap-dropper solutions. Designs using the highly integrated LinkSwitch-TN2 ICs are more flexible and feature increased efficiency, comprehensive system level protection and higher reliability. The device family supports buck, buck-boost and flyback converter topologies. Each device incorporates a 725 V / 900 V power MOSFET, oscillator, On/Off control for highest efficiency at light load, a high-voltage switched current source for self-biasing, frequency jittering, fast (cycle-by-cycle) current limit, hysteretic thermal shutdown, and output and input overvoltage protection circuitry onto a monolithic IC.

LinkSwitch-TN2 ICs consume very little current in standby resulting in power supply designs that meet all no-load and standby specifications worldwide. MOSFET current limit modes can be selected through the BYPASS pin capacitor value. The high current limit level provides maximum continuous output current while the low level permits using very low cost and small surface mount inductors. A full suite of protection features enable safe and reliable power supplies protecting the device and the system against input and output overvoltage faults, device over-temperature faults, lost regulation, and power supply output overload or short-circuit faults.

Product Highlights

Highest Performance and Design Flexibility

• Supports buck, buck-boost and flyback topologies
• Excellent load and line regulation
• Selectable device current limit
• 66 kHz operation with accurate current limit
  - Allows the use of low-cost off-the-shelf inductors
  - Reduces size and cost of magnetics and output capacitor
• Frequency jittering reduces EMI filter complexity
• Pin-out simplifies PCB heat sinking

Enhanced Safety and Reliability Features

• Auto-restart for short-circuit and open loop faults
• Output overvoltage protection (OVP)
• Line input overvoltage protection (OVL)
• Hysteretic over-temperature protection (OTP)
• Extended creepage between DRAIN pin and all other pins improves field reliability
• 725 V MOSFET rating for excellent surge withstand
• 900 V MOSFET rating series for industrial or extra safety margin

EcoSmart™– Extremely Energy Efficient

• Standby supply current <100 μA
• On/Off control provides constant efficiency over a wide load range
• Easily meets all global energy efficiency regulations
• No-load consumption <30 mW with external bias