TNY274PG Ver la hoja de datos (PDF) - Power Integrations, Inc

Número de pieza

componentes Descripción

Fabricante

TNY274PG

Enhanced/ Energy Efficient/ Low Power Off-line Switcher

Power Integrations, Inc 

TOP VIEW

HV DC

INPUT

Input Filter

Capacitor

CBP

S SSS

TinySwitch-III

EN/UV BP/M D

Y1-

Capacitor

T

r

a

n

s

f

o

r

m

e

r

Opto-

coupler

TNY274-280

Output Filter

Capacitor

DC

Maximize hatched copper

OUT

areas (

) for optimum

heatsinking

Figure 15. Recommended Circuit Board Layout for TinySwitch-III with Under-Voltage Lock Out Resistor.

PI-4278-013006

Thermal Considerations

The four SOURCE pins are internally connected to the IC lead

frame and provide the main path to remove heat from the device.

Therefore all the SOURCE pins should be connected to a copper

area underneath the TinySwitch-III to act not only as a single

point ground, but also as a heatsink. As this area is connected

to the quiet source node, this area should be maximized for

good heatsinking. Similarly for axial output diodes, maximize

the PCB area connected to the cathode.

Y-Capacitor

The placement of the Y-capacitor should be directly from the

primary input filter capacitor positive terminal to the common/

return terminal of the transformer secondary. Such a placement

will route high magnitude common mode surge currents away

from the TinySwitch-III device. Note – if an input π (C, L, C)

EMI filter is used then the inductor in the filter should be placed

between the negative terminals of the input filter capacitors.

Optocoupler

Place the optocoupler physically close to the TinySwitch-III

to minimizing the primary-side trace lengths. Keep the high

current, high voltage drain and clamp traces away from the

optocoupler to prevent noise pick up.

Output Diode

For best performance, the area of the loop connecting the

secondary winding, the output diode and the output filter

capacitor, should be minimized. In addition, sufficient copper

area should be provided at the anode and cathode terminals

of the diode for heatsinking. A larger area is preferred at the

quiet cathode terminal. A large anode area can increase high

frequency radiated EMI.

11 E

2/06

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