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LR2728
Metal Alloy
Low Resistance

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FEATURES

- Ideal for all types of current sensing, voltage division and Pulse applications including
  switching and linear power Supplies, Instruments, power amplifiers.
- Proprietary processing technique produces extremely low Resistance values.
- High-temperature performance (up to +170C)
- Metal Strip resistive material stable and ultra low TCR. Low and Stable TCR¡25ppm/
C
- Pure tin plating provides compatibility with lead (Pb) free and lead containing soldering processes.
- Compatible with Restriction of the use of Hazardous Substances (RoHS) directive 2002/95/EC (issue 2004).
- PFOS, PFOA, PAHs, Halogen free and REACH compliant.
- Excellent stability (|∆R/R|¡1.0% for 1,000 h at 70C) different environment conditions.
- High volume product suitable for commercial and special applications.
- Suitable for high precision current sensing circuit protection application.
- Miniature size suitable for compact Print Circuit Boards of high-precision electronic products.

APPLICATIONS

- Power Supply, Battery Pack, DIY Tools, Inverter/Converter (AC/DC, DC/DC, DC/AC)
- Measurable Instrument, Consumer Electrics, Note Book, PC Power Pack, LED Driver
  (Others:  i.e. Automotive electronics)

GENERAL SPECIFICATIONS

Model

Power Rating
at 70C

Max.

Rating
Current

Max.
Overload
Current

Operating Temp.
Range

TCR
[PPM/C]

Resistance Range [m]**

0.5%(D)

1.0%(F)
2.0%(G)
5.0%(J)

LR2728

3W

27.39A

47.43A

-55 to +170C

4.0~7.0m=25
7.1~100m=15

4.0~100

4.0~100

3.5W

29.58A

51.23A

4W

31.62A

63.25A

4.0~7.0m=25
7.1~50.0m=15

4.0~50.0

4.0~50.0

CHARACTERISTICS

Short Time Overload

(R/R1) ¡0.5%

3W,3.5W : 3times rated power, 5sec.
4W : 4times rated power, 5sec.

Insulation
Resistance

109

DC10015V for 1minute

Dielectric Withstanding Voltage

Without break down

AC500V for 1minute, Max.50mA

Resistance to
Solder Heat

(R/R1) ¡0.5%

Solder temp./immersion time : 2605C, 101sec.
and 35010
C, 3.50.5 sec.

Solderability
Test

95% coverage

Specimen prep. : 4hours 15 min. Steam
Aging : Solder Bath/Dip and Look Test, 2455C, 31sec.

Vibration

(R/R1) ¡0.5%

Frequency varied 55Hz in one minute,3 orientations,
Total duration 12hours

Resistance
to solvent

(R/R1) ¡0.5%

Immersion time : 605sec, 20C~25C

Mechanical
Shock

(R/R1) ¡0.5%

100 grams for 6 milliseconds, 5 pulses

Low Temperature Exposure(Storage)

(R/R1) ¡0.5%

1,000hours, -55C

High Temperature
Exposure(Storage)

(R/R1) ¡1.0%

1,000hours, +170C

Temperature Cycling
(Rapid Temp. Change)

(R/R1) ¡0.5%

Air to air, -55C to +150C, 1,000cycles,
15minutes at each extreme, transition time 2 to 3 minutes

Moisture Resistance
(Climatic Sequence)

(R/R1) ¡0.5%

Mil-STD-202, Method 106
0% power, 7a and 7b not required, t=24 h/cycle, 10cycles, Unpowered

Bias Humidity

(R/R1) ¡0.5%

+85%C,85% RH, 10% Bias, Extended Life
1000 hours, 1.5 hours On, 0.5 hours Off

Load Life

(R/R1) ¡1.0%

Rated continuous working voltage : 70C
1000hours, 1.5hours ON, 0.5hours Off

DIMENSIONS

Model

DIMENSIONS - in inches (millimetres)

Maximum Power Rating[W]

Resistance Range[m]

L

W

H

T

LR2728

3.0 & 3.5 & 4.0

4.0~100.0

0.2640.010
(6.7060.254)

0.2800.010
(7.1880.254)

0.0390.010
(0.9910.254)

0.0450.010
(1.1430.254)

SOLDER PAD DIMENSIONS

Maximum Power Rating[W]

SOLDER PAD Dimension - in inches (millimetres)

Resistance Range [ m]

a

b

i

3.0 & 3.5 & 4.0

4.0~100.0

0.108(2.75)

0.308(7.82)

0.138(3.51)

Remark : The total solder pad trace size are recommended as follows. 3.0W : 300mm / 3.5W : 350mm/ 4.0W : 400mm

DERATING CURVE

MARKING

PACKAGING

Item

W

P1

E

F

Do

D1

P0

Po*10

P2

Ao

Bo

Ko

t

Spec.

12.00

12.00

1.75

5.50

1.55

1.55

4.00

40.00

2.00

7.70

7.15

1.2

0.25

Tole.

0.15

0.10

0.10

0.10

0.05

0.10

0.10

0.20

0.10

0.10

0.10

0.10

0.05

Reel Type / Tape

W

M

A

B

C

D

7 reel for 12mm
embossed

16.20.5

1781.0

2.50.5

13.50.5

17.70.5

60.00.5

ORDERING PROCEDURE EXAMPLE

REMARKS

a. * normal product order information has 4digits,
    if includes one decimal point then the order information should be 5 digits(e.g. 0.5mis R0005),
    if includes 2 decimal points, then it should be 6digits (e.g. 0.25m is R00025).
b. The detail marking format please refer to MARKING
c. ** special tolerance and range of resistance are under requested.
d. *** the packing quantity : 1 means 1k pieces per reel.

Copyright©, RARA Electronics Corporation
Tel:82-32-817-4325 Fax:82-32-817-4329

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