LNK305PN
Highly efficient buck converter with integrated protection features
- Spec name: Lowest cost and component count buck converter solution
- Spec name: Fully integrated auto-restart for short-circuit and open loop fault protection – saves external component costs
- Spec name: 66 kHz operation with accurate current limit – allows low cost off-the-shelf 1 mH inductor for up to 120 mA output current
- Spec name: Tight tolerances and negligible temperature variation
- Spec name: High breakdown voltage of 700 V provides excellent input surge withstand
- Spec name: Frequency jittering dramatically reduces EMI (~10 dB). Minimizes EMI filter cost
- Spec name: High thermal shutdown temperature (+135 °C minimum)
The LNK305PN 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 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 fly back converters.
The fully integrated auto-restart circuit in the LNK305 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.
Specification
- BYPASS Pin Voltage: 5.55 - 6.10 V
- BYPASS Pin Voltage Hysteresis: 0.8 - 1.2 V
- Minimum On Time: 280 - 475 ns
- Leading Edge Blanking Time: 170 - 215 ns
- Thermal Shutdown Temperature: 135 - 150 °C
- Thermal Shutdown Hysteresis: 75 °C
Related Document: LNK305PN IC Data Sheet
Images are for illustration only; actual product may vary.