LR745N3-G Supertex, LR745N3-G Datasheet

Switching Converters, Regulators & Controllers Pwr Sup Start-Up IC

LR745N3-G

Manufacturer Part Number

LR745N3-G

Description

Switching Converters, Regulators & Controllers Pwr Sup Start-Up IC

Manufacturer

Supertex

Datasheet

1.LR745N3-G.pdf (7 pages)

Specifications of LR745N3-G

Output Voltage

25 V

Output Current

4 mA

Input Voltage

35 V to 450 V

Operating Temperature Range

- 55 C to + 150 C

Mounting Style

Through Hole

Package / Case

TO-92

Number Of Outputs

Lead Free Status / RoHS Status

Lead free / RoHS Compliant

Available stocks

Company

Part Number

Manufacturer

Quantity

Price

Company:

Bonase Electronics (HK) Co., Limited

Part Number:

LR745N3-G

Manufacturer:

ATMEL

Quantity:

5 287

Current page: 1 of 7
Download datasheet (545Kb)

Features

►

Applications

►

Absolute Maximum Ratings

Absolute Maximum Ratings are those values beyond which damage to the device

may occur. Functional operation under these conditions is not implied. Continuous

operation of the device at the absolute rating level may affect device reliability. All

voltages are referenced to device ground.

* Distance of 1.6mm from case for 10 seconds.

Ordering Information

-G indicates package is RoHS compliant (‘Green’)

Parameter

Input voltage

Output voltage

Operating and storage temperature

Soldering temperature*

Device

LR745

Accepts inputs from 35V to 450V

Output current limiting

For PWM ICs with start-up threshold voltage of

13.9 - 18.0V

Very low power consumption after start-up

Notebook and laptop computers

Telecommunication power supplies

Battery chargers

Motor controllers

LR745N3-G

TO-92

Package Options

High Input Voltage SMPS Start-up

●

TO-243AA (SOT-89)

1235 Bordeaux Drive, Sunnyvale, CA 94089

LR745N8-G

-55°C to +150

300

Value

450V

25V

General Description

The Supertex LR745 is a high input voltage SMPS start-

up circuit. The LR745 is ideally suited for use with industry

standard low voltage PWM ICs having start thresholds of 13.9

- 18.0V. It allows the PWM ICs to be operated from rectiﬁed

120 or 240VAC lines, and eliminates the use of power resistors

often used for this purpose.

The internal circuitry of the LR745 allows the PWM ICs to

operate at a V

after start-up. The auxiliary voltage can be less than the

start threshold voltage, which allows for improved efﬁciency.

Current from the high voltage line is drawn only during the

start-up period. After start-up, the internal high voltage line is

disconnected from the IC, thereby reducing the continuous

power dissipation to a minimum.

Pin Conﬁgurations

Package Markings

Package may or may not include the following marks: Si or

LR7W

TO-92 (N3)

VIN

Y W L L

7 4 5

S i LR

●

Tel: 408-222-8888

VOUT

TO-243AA (SOT-89) (N8)

voltage below their start threshold voltage

GND

W = Code for Week Sealed

Y = Last Digit of Year Sealed

W = Code for Week Sealed

L = Lot Number

TO-92 (N3)

= “Green” Packaging

●

= “Green” Packaging

www.supertex.com

TO-243AA (SOT-89) (N8)

GND

VIN

GND

LR745

VOUT

Related parts for LR745N3-G

LR745N3-G Summary of contents

Page 1

... Battery chargers ► Motor controllers Ordering Information Package Options Device TO-92 LR745 LR745N3-G -G indicates package is RoHS compliant (‘Green’) Absolute Maximum Ratings Parameter Input voltage Output voltage Operating and storage temperature Soldering temperature* Absolute Maximum Ratings are those values beyond which damage to the device may occur ...

Page 2

... Bordeaux Drive, Sunnyvale, CA 94089 2 Max Units Conditions OUT 24 -40°C to +85 OUT A 4.0 mA --- 450 V --- 500 µ 400V OUT 13.9 V --- 14 -40° 7.7 V --- 8 -40° µ 400V --- 500 µ 22V AUX 2.0 to 4.0mA V OUT R1 + – ● Tel: 408-222-8888 ● www.supertex.com LR745 ...

Page 3

... COMP1 will reset the D ﬂip ﬂop, thereby turning transistor M2 off and transistor M1 back on. Typical Application Figure 1 shows a simpliﬁed typical conﬁguration of a switch- , GND, mode power supply, SMPS, using the Supertex LR745 in the IN start-up circuit. , OUT The LR745’s V PWM IC, Unitrode part #UC3844 ...

Page 4

... AUX AUX OUT CC PWM IC UC3844 GND C1 Stage Stage I II PWM IC Start Threshold Voltage LR7 V ● 1235 Bordeaux Drive, Sunnyvale, CA 94089 4 Stage III Trip Point OFF Auxiliary Supply Powers PWM ≈ 0mA 12V AUX 20mA AUX t ● Tel: 408-222-8888 ● www.supertex.com LR745 ...

Page 5

... REF reaches16V, the UC3844 CC will increase from 0V to 5.0V. REF voltage of 11V (16V mi- OUT voltage to decrease. The PWM IC UC3844 ● Tel: 408-222-8888 ● www.supertex.com LR745 , OUT trip point of 13.25V voltage CC reaches the CC will start CC , with- OUT REF ...

Page 6

... MIN .170 Dimensions NOM - (inches) MAX .210 JEDEC Registration TO-92. * This dimension is not speciﬁed in the original JEDEC drawing. The value listed is for reference only. † This dimension is a non-JEDEC dimension. Drawings not to scale. Supertex Doc.#: DSPD-3TO92N3, Version D080408 Front View E 3 ...

Page 7

... Supertex inc. does not recommend the use of its products in life support applications, and will not knowingly sell them for use in such applications unless it receives an adequate “product liability indemnification insurance agreement.” Supertex inc. does not assume responsibility for use of devices described, and limits its liability to the replacement of the devices determined defective due to workmanship ...

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