LNK353/354

LinkSwitch-HF

Family

Enhanced, Energy Efficient, Low Power

Off-Line Switcher IC

Figure 1. Typical Standby Application.

Product Highlights

Features Optimized for Lowest System Cost

• Fully integrated auto-restart for short-circuit and open

loop protection

• Self-biased supply – saves transformer auxiliary winding

and associated bias supply components

• Tight tolerances and negligible temperature variation on

key parameters eases design and lowers cost

• High maximum switching frequency allows very low

flux density transformer designs, practically eliminating

audible noise

• Frequency jittering greatly reduces EMI

• Packages with large creepage to high voltage pin

• Lowest component count switcher solution

Much Better Performance over Linear/RCC

• Lower system cost than RCC, discrete PWM and other

integrated solutions

• Universal input range allows worldwide operation

• Simple ON/OFF control – no loop compensation needed

• No bias winding – simpler, lower cost transformer

• High frequency switching – smaller and lower cost

transformer

• Very low component count – higher reliability and single

side printed circuit board

• High bandwidth provides fast turn on with no overshoot

and excellent transient load response

• Current limit operation rejects line frequency ripple

• Built-in current limit and hysteretic thermal shutdown

protection

– Extremely Energy Efficient

• No-load consumption <300 mW without bias winding at

265 VAC input

• Meets California Energy Commission (CEC), Energy

Star, and EU requirements

Applications

• Chargers for cell/cordless phones, PDAs, digital cameras,

MP3/portable audio devices, shavers etc.

• Standby and auxiliary supplies

Description

LinkSwitch-HF

integrates a 700 V power MOSFET, oscillator,

simpleON/OFFcontrolscheme,ahighvoltageswitchedcurrent

®

Table 1.

Notes: 1. Typical continuous power in a non-ventilated

enclosed adapter measured at 50 °C ambient. 2. Maximum practical

continuous power in an open frame design with adequate heat

sinking, measured at 50 °C ambient. 3. Packages: P: DIP-8B,

G: SMD-8B. For lead-free package options, see Part Ordering

Information. 4. For designs without a Y capacitor, the available power

may be lower (see Key Applications Considerations).

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 DRAIN pin,

eliminating the need for a bias winding and associated circuitry.

The 200 kHz maximum switching frequency allows very

low flux transformer designs, practically eliminating audible

noise with the simple ON/OFF control scheme using standard

varnished transformer construction. Efficient operation at this

high switching frequency is achieved due to the optimized

switchingcharacteristicsandsmallcapacitancesoftheintegrated

power MOSFET.The fully integrated auto-restart circuit safely

limits output power during fault conditions such as output short

circuit or open loop, reducing component count and secondary

feedback circuitry cost. The internal oscillator frequency is

jittered to significantly reduce both the quasi-peak and average

EMI, minimizing filtering cost.

DC

Output

Wide Range

HV DC Input

PI-3855-022704

+

+

LinkSwitch-HF

D

S

BP

FB

February 2005

OUTPUT POWER TABLE

230 VAC ±15%

85-265 VAC

(1)

Open

LNK353 P or G

3 W

4 W

3 W

LNK354 P or G

3.5 W

5 W

4.5 W