LNK306PN

LinkSwitch-TN is specifi cally designed to replace all linear and
capacitor-fed (cap dropper) non-isolated power supplies in the
under 360 mA output current range at equal system cost while
offering much higher performance and energy effi ciency.

LinkSwitch-TN devices integrate a 700 V power MOSFET,
oscillator, simple On/Off control scheme, a high voltage switched
current source, frequency jittering, cycle-by-cycle current limit
and thermal shutdown circuitry onto a monolithic IC.

The startup and operating power are derived directly from the voltage
on the DRAIN pin, eliminating the need for a bias supply and
associated circuitry in buck or fl yback converters. The fully
integrated auto-restart circuit in the LNK304-306 safely limits
output power during fault conditions such as short-circuit or
open loop, reducing component count and system-level load
protection cost. A local supply provided by the IC allows use
of a non-safety graded optocoupler acting as a level shifter to
further enhance line and load regulation performance in buck
and buck-boost converters, if required.

Cost Effective Linear/Cap Dropper Replacement
• Lowest cost and component count buck converter solution
• Fully integrated auto-restart for short-circuit and open
loop fault protection – saves external component costs
• LNK302 uses a simplifi ed controller without auto-restart
for very low system cost
• 66 kHz operation with accurate current limit – allows low cost
off-the-shelf 1 mH inductor for up to 120 mA output current
• Tight tolerances and negligible temperature variation
• High breakdown voltage of 700 V provides excellent
input surge withstand
• Frequency jittering dramatically reduces EMI (~10 dB)
– minimizes EMI fi lter cost
• High thermal shutdown temperature (+135 °C minimum)
Much Higher Performance over Discrete Buck and
Passive Solutions
• Supports buck, buck-boost and fl yback topologies
• System level thermal overload, output short-circuit and
open control loop protection
• Excellent line and load regulation even with typical
confi guration
• High bandwidth provides fast turn-on with no overshoot
• Current limit operation rejects line ripple
• Universal input voltage range (85 VAC to 265 VAC)
• Built-in current limit and hysteretic thermal protection
• Higher effi ciency than passive solutions
• Higher power factor than capacitor-fed solutions
• Entirely manufacturable in SMD
EcoSmart®
– Extremely Energy Effi cient
• Consumes typically only 50/80 mW in self-powered buck
topology at 115/230 VAC input with no load (opto feedback)
• Consumes typically only 7/12 mW in fl yback topology
with external bias at 115/230 VAC input with no load
• Meets California Energy Commission (CEC), Energy
Star, and EU requirements
Applications
• Appliances and timers
• LED drivers and industrial controls