LPS 300
www.vishay.com
Vishay Sfernice
Power Resistor for Mounting onto a Heatsink
Thick Film Technology
FEATURES
High power 300 W at 85 C bottom case
temperature
Wide resistance range: 0.3 to 900 k
E24 series
Non inductive
Easy mounting
Low thermal radiation of the case
Material categorization: for definitions of compliance
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DESIGN SUPPORT TOOLS
please see www.vishay.com/doc?99912
Models
Available
DIMENSIONS in millimeters
25.8 1
LPS 300
25.2
6K8 5 %
21.2
V2
60
15.2
0.5
36
64.7
2 x M4 useful depth: 8
2 x 4.2
20
13.6
34
57
Note
Tolerances unless stated: 0.2 mm
STANDARD ELECTRICAL SPECIFICATIONS
RESISTANCE RATED POWER LIMITING ELEMENT TEMPERATURE CRITICAL
TOLERANCE
MODEL RANGE P VOLTAGE U COEFFICIENT RESISTANCE
85 C L
%
W V ppm/C ()
LPS 300 0.3 to 900K 300 5K 1, 2, 5, 10 150, 300, 500 83.33K
MECHANICAL SPECIFICATIONS TECHNICAL SPECIFICATIONS
300 W at + 85 C
Mechanical Protection Insulated case UL 94 V-0
Power Rating and
bottom case temperature
Resistive Element Thick film Thermal Resistance
R : 0.112 C/W
TH (j - c)
Substrate Alumina
Temperature Coefficient
R 1 : 500 ppm/C
End Connections Screws M4 1 < R 10 : 300 ppm/C
-55 C / 120 C
Standard
10 < R: 150 ppm/C
IEC 60115-1
Tightening Torque
2 Nm
Connections Dielectric Strength
IEC 60115-1, 1 min, 7 kV or 12 kV
RMS RMS
Tightening Torque Heatsink 2 Nm
10 mA max.
Maximum Torque 2.5 Nm
Lightning test 1.2/50 s
Until 12 kV
Weight 83 g 10 % IEC 61000-4-5
4
Insulation Resistance 10 M
ENVIRONMENTAL SPECIFICATIONS
Inductance 0.1 H
100 pC/7 kV
Temperature Range -55 C to 120 C
Partial Discharge
10 pC/5 kV
Climatic Category 55/120/56 (for LPS 300 D only)
Other cases: Consult us
Revision: 06-Mar-18 Document Number: 50052
1
For technical questions, contact: sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000LPS 300
www.vishay.com
Vishay Sfernice
PERFORMANCE
TESTS CONDITIONS REQUIREMENTS
IEC 60115-1
Momentary Overload 4 x P /10 s (0.25 % + 0.05 )
r
U U = 5000 V
max. L
IEC 60115-1/IEC 30068-2-14 Test Na
Rapid Temperature Change 50 cycles (0.5 % + 0.05 )
-55 C to +120 C
IEC 60115-1
Load Life (0.5 % + 0.05 )
1000 h (90/30) P at 85 C
r
IEC 60115-1
Humidity (Steady State) (0.5 % + 0.05 )
56 days RH 95 %/40 C
MIL STD 202 method 204 cond. D
Vibration (0.25 % + 0.05 )
(10 g; 5/500 Hz)
IEC 60115-1
Climatic Sequence (1 % + 0.05 )
(55 / 120 / 56)
RECOMMENDATIONS FOR MOUNTING ONTO A HEATSINK
Surfaces in contact must be carefully cleaned.
The heatsink must have an acceptable flatness: From 0.05 mm to 0.1 mm/100 mm.
Roughness of the heatsink must be around 6.3 m. In order to improve thermal conductivity, surfaces in contact (alumina,
heatsink) should be coated with a silicone grease (type Bluesil Past 340 from BlueStar Silicones) or a thermal film (type Q Pad
II) easier and faster to install than the grease.
The fastening of the resistor to the heatsink is under pressure control of two screws tightened at 2 Nm for full power
availability.
LPS 300
Tightening Torque on Heatsink
2 Nm
The following accessories are supplied with each product:
- 2 screws CHC M4 x 25 class 8.8 and 2 M4 contact lock washers for heatsink mounting
- 2 screws TH M4 x 6/6 and 2 M4 contact lock washers for connections. 2 off CHC M4 x 16/16 class 8.
CHOICE OF THE HEATSINK
The user must choose the heatsink according to the working conditions of the component (power, room temperature).
Maximum working temperature must not exceed 120 C. The dissipated power is simply calculated by the following ratio:
T
P = -------------------------------------------------------------------------------------------
R ++R R
TH (j - c) TH (c - h) TH (h - a)
P: Expressed in W
T: Difference between maximum working temperature and room temperature
R : Thermal resistance value measured between resistive layer and outer side of the resistor.
TH (j - c)
It is the thermal resistance of the component: (see specifications environmental paragraph).
R : Thermal resistance value measured between outer side of the resistor and upper side of the heatsink.
TH (c - h)
This is the thermal resistance of the interface (grease, thermal pad), and the quality of the fastening device.
R : Thermal resistance of the heatsink.
TH (h - a)
Example:
R for LPS 300 power dissipation 180 W at + 50 C room temperature.
TH (c - a)
T 120 C - 50 C = 70 C
T 70
R + R + R = ------- = -------- = 0.388 C/W
TH (j - c) TH (c - h) TH (h - a)
P 180
R = 0.112 C/W
TH (j - c)
R + R = 0.388 C/W - 0.112 C/W = 0.276 C/W
TH (c - h) TH (h - a)
Revision: 06-Mar-18 Document Number: 50052
2
For technical questions, contact: sferfixedresistors@vishay.com
THIS DOCUMENT IS SUBJECT TO CHANGE WITHOUT NOTICE. THE PRODUCTS DESCRIBED HEREIN AND THIS DOCUMENT
ARE SUBJECT TO SPECIFIC DISCLAIMERS, SET FORTH AT www.vishay.com/doc?91000