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Energy Efficient Off-line Switcher IC with Best-in-Class Light Load Efficiency and Lossless AC Zero-Cross Detection


Product Details

The LinkSwitch-TNZ family of ICs combine power conversion with lossless generation of AC zero crossing signal used typically for system clock and timing functions. Designs using the highly integrated LinkSwitch-TNZ ICs are more flexible than discrete implementations reducing component count by 40% or higher. Besides enabling 80+ efficiencies in low power Flyback designs, very low consumption at light loads enabled by On/Off control allow for more functions (display, wireless connectivity, sensors etc.) to be active during system standby. The device family supports buck, buck-boost and flyback converter topologies.

Each device incorporates a 725 V power MOSFET, oscillator, 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-TNZ ICs consume <100 µA current in standby resulting in power supply designs that can meet no-load and standby regulations 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 enables 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

  • Lossless zero cross signal generation
  • Supports buck, buck-boost and flyback topologies
  • Enables ±3% regulation across line and load
  • 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
  • X capacitor discharge function (LNK331x only)

Enhanced Safety and Reliability Features

  • Soft-start limits system component stress at start-up
  • 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

EcoSmart– Extremely Energy Efficient

  • IC 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


Output Power (Max) - Open Frame, 230V 18.00 W
Output Power (Max) - Open Frame, Univ 12.00 W
Current - Output (Max, CCM, 230V) 360 mA
Current - Output (Max, MDCM, 230V) 225 mA
Current - Output (Max, MDCM, Univ) 225.00 mA
Current - Output (Max, CCM, Univ) 360.00 mA
Duty Cycle (Max) 0.69 %
Switching Frequency (max) 66 kHz
Breakdown Voltage 725 V
Voltage - Input (Min) 85 V
Voltage - Input (Max) 305 V
Auto-Restart & Overvoltage Response
IC Package SO-8C
Integrated X-Capacitor Discharge Yes
Internal Switch Yes
Max X Capacitance 100 nF to 6 µF
Over-Temperature Response
Temperature - Operating (Min) -40 °C
Temperature - Operating (Max) 150 °C
Total Series Resistance 7.5 MΩ to 142 kΩ
Control Scheme Primary-side
Protection Features
Input Overvoltage
Output Open Loop
Output Overload
Output Overvoltage
Output Short Circuit
Output Profile CV
Tapped Buck
Product Sub-Type PMIC
MSL Rating 3
Voltage - Start-up 18.00V