www.powerint.com

A

11/02

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WORLD HEADQUARTERS

AMERICAS

Power Integrations, Inc.

San Jose, CA 95138 USA

Customer Service:

Phone:

+1 408-414-9665

Fax:

+1 408-414-9765

e-mail: usasales@powerint.com

CHINA

Power Integrations International

Holdings, Inc.

China

Phone:

+86-755-8367-5143

Fax:

+86-755-8377-9610

e-mail: chinasales@powerint.com

SINGAPORE

Power Integrations, Singapore

Republic of Singapore 308900

Phone:

+65-6358-2160

Fax:

+65-6358-2015

e-mail: singaporesales@powerint.com

JAPAN

Power Integrations, K.K.

Keihin-Tatemono 1st Bldg.

Japan

Phone:

+81-45-471-1021

Fax:

+81-45-471-3717

e-mail: japansales@powerint.com

EUROPE & AFRICA

Power Integrations (Europe) Ltd.

United Kingdom

Phone:

+44-1344-462-300

Fax:

+44-1344-311-732

e-mail: eurosales@powerint.com

KOREA

Power Integrations

International Holdings, Inc.

Seoul, Korea

Phone:

+82-2-782-2840

Fax:

+82-2-782-4427

e-mail: koreasales@powerint.com

TAIWAN

Power Integrations

International Holdings, Inc.

Taipei, Taiwan

Phone:

+886-2-2727-1221

Fax:

+886-2-2727-1223

e-mail: taiwansales@powerint.com

INDIA (Technical Support)

Innovatech

Bangalore, India

Phone:

+91-80-226-6023

Fax:

+91-80-228-9727

e-mail: indiasales@powerint.com

APPLICATIONS HOTLINE

APPLICATIONS FAX

World Wide +1-408-414-9660

World Wide +1-408-414-9760

Table 1. Transformer Construction Information.

Key Design Points

• Use of foil for the 3.3 V and 5 V windings also helps to

optimize cross-regulation.

• Optional capacitor C7 is the “soft-finish” capacitor and

prevents overshoot on startup.

• Compact layout for components D7, D10, D11, C11,

C12, C15 will improve cross-regulation and efficiency.

Compact layout for L2, L3, L4, C17, C18, and C20 will

achieve best output ripple.

• Figure 2 shows conducted EMI at 230 VAC full load, with

output “Artificial Hand” grounding. Floating output return

gives lower results.

• Table 2 shows the cross regulation of the supply over load

for both 115 VAC and 230 VAC.

Table 2. Worst Case Cross Regulation at 115 VAC and 230 VAC.

Output

Voltage

(V)

Load

Range

(%)

3.3

10-100

5

10-100

12

10-100

-12

100

Cross Regulation (%)

-4

-3

-2

-1

0

1

2

3

4

Figure 2. EMI at 230 VAC Full Load with "Artificial Hand"

Grounding of Output.

TRANSFORMER PARAMETERS

Core Material

EEL25

Himag MZ4 EEL25.4, Taiwan AL of

344 nH/T2

Bobbin

EEL25 Vertical 14 Pins

Primary Resonant

Frequency

Winding Order

(Pin Numbers)

Winding Details

Primary Inductance

(Pins 1-4 all others

open)

1.42 mH ±10% at 132 kHz

300 kHz minimum

Leakage Inductance

30 µH maximum

Shield: 32T x 2 x 32 AWG

Primary: 64T x 2 x 32 AWG

Bias: 10T x 4 x 32 AWG

Shield: 2T x 8 x 32 AWG

+3.3V: 4T x foil 0.052 x 14 mm

+5V: 1T x foil 0.052 x 14 mm

+12V: 4T x 4 x 32 AWG

-12V: 7T x 4 x 32 AWG

Shield (NC-5), tape, Primary (1-4), tape,

Bias (7-6), tape, Shield (5-NC), tape,

+12 V (13-8), +3.3 V (11,12-9,10), +5 V

(9-10,13), tape, -12 V (14-11, 12), tape

1.0

0.15

10.0

-100.0

-20

-10

0

10

20

30

40

50

60

80

70

MHz

QP

AV

Average

Quasi Peak

For the latest updates, visit our Web site: www.powerint.com

Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability.

Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it convey any

license under its patent rights or the rights of others. The products and applications illustrated herein (including circuits external to the

products and transformer construction) may be covered by one or more U.S. and foreign patents or potentially by pending U.S. and foreign

patent applications assigned to Power Integrations. A complete list of Power Integrations’ patents may be found at www.powerint.com.

The PI Logo, TOPSwitch, TinySwitch, LinkSwitch and EcoSmart are registered trademarks of Power Integrations, Inc.

PI Expert is a trademark of Power Integrations, Inc. ©Copyright 2002, Power Integrations, Inc.