LNK305GN Datasheet, PDF (1/20 Pages) Power Integrations, Inc. – Lowest Component Count, Energy-Effi cient Off-Line Switcher IC

LNK302/304-306
LinkSwitch-^®TN Family
Lowest Component Count, Energy-Efficient
Off-Line Switcher IC
Product Highlights
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.
+
Wide Range
HV DC Input
FB BP
D
S
LinkSwitch-TN
DC
Output
PI-3492-111903
Figure 1. Typical Buck Converter Application (See Application
Examples Section for Other Circuit Configurations).
OUTPUT CURRENT TABLE¹
230 VAC ±15%
85-265 VAC
PRODUCT⁴
MDCM² CCM³ MDCM² CCM³
LNK302P/G/D 63 mA 80 mA 63 mA 80 mA
LNK304P/G/D 120 mA 170 mA 120 mA 170 mA
LNK305P/G/D 175 mA 280 mA 175 mA 280 mA
LNK306P/G/D 225 mA 360 mA 225 mA 360 mA
Table 1. Output Current Table.
Notes:
1. Typical output current in a non-isolated buck converter. Output power
capability depends on respective output voltage. See Key Applications
Considerations Section for complete description of assumptions,
including fully discontinuous conduction mode (DCM) operation.
2. Mostly discontinuous conduction mode.
3. Continuous conduction mode.
4. Packages: P: DIP-8B, G: SMD-8B, D: SO-8C.
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 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 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.
November 2008