LNK304PN IC (SMD-SOP7) – Power Integrations – AC-DC Off Line Switcher IC

LNK304PN IC  (SMD-SOP7) – Power Integrations – AC-DC Off Line Switcher IC

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 simplified 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 filter cost

• High thermal shutdown temperature (+135 °C minimum)

Much Higher Performance Over Discrete Buck and

Passive Solutions

• Supports buck, buck-boost and flyback topologies

• System level thermal overload, output short-circuit and open

control loop protection

• Excellent line and load regulation even with typical configuration

• 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 efficiency than passive solutions

• Higher power factor than capacitor-fed solutions

• Entirely manufacturable in SMD

EcoSmart™– Extremely Energy Efficient

• 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 flyback 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

Description

LinkSwitch-TN is specifically 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 efficiency.

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

Figure 1. Typical Buck Converter Application (See Application Examples Section

for Other Circuit Configurations).

and thermal shutdown circuitry onto a monolithic IC. The start-up

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 flyback 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 nonsafety graded optocoupler acting as a level shifter to further

enhance line and load regulation performance in buck and

buck-boost converters, if required.