LTO 150
www.vishay.com
Vishay Sfernice
Revision: 15-Feb-18
2
Document Number: 50071
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
CHOICE OF THE HEATSINK
The user must choose according to the working conditions of the component (power, room temperature).
Maximum working temperature must not exceed 175 °C. The dissipated power is simply calculated by the following ratio:
P: Expressed in W
T: Difference between maximum working temperature and room temperature
R
TH (j - c)
: Thermal resistance value measured between resistive layer and outer side of the resistor. It is the thermal resistance of the
component.
R
TH (c - h)
: Thermal resistance value measured between outer side of the resistor and upper side of the heatsink. This is the thermal resistance
of the interface (grease, thermal pad), and the quality of the fastening device.
R
TH (h - a)
: Thermal resistance of the heatsink
Example:
R
TH (c - h)
+ R
TH (h - a)
for LTO 150 power rating 10 W at ambient temperature +25 °C
Thermal resistance R
TH (j - c)
: 0.87 °C/W
Considering equation
(1)
we have:
T = 175 °C - 25 °C = 150 °C
R
TH (j - c)
+ R
TH (c - h)
+ R
TH (h - a)
= = = 15 °C/W
R
TH (c - h)
+ R
TH (h - a)
= 15 °C/W - 0.87 °C/W = 14.13 °C/W
Example with a thermal grease R
TH (c - h)
= 0.5 °C/W, we need a heatsink with R
TH (h - a)
= 13.63 °C/W
PERFORMANCE
TESTS CONDITIONS REQUIREMENTS
Momentary Overload
IEC 60115-1
1.5 Pr/5 s
U
S
< 1.5 U
L
± (0.5 % + 0.005 )
Load Life
IEC 60115-1
1000 h Pr (free air) at +25 °C 90/30
± (1 % + 0.005 )
High Temperature Exposure
AEC-Q200 REV D conditions:
MIL-STD-202 method 108
1000 h, +175 °C, unpowered
± (0.5 % + 0.005 )
Temperature Cycling
AEC-Q200 REV D conditions:
JESD22 method JA-104
1000 cycles, -55 °C to +125 °C
dwell time -15 min
± (1 % + 0.005 )
Biased Humidity
AEC-Q200 REV D conditions:
MIL-STD-202 method 103
1000 h, 85 °C, 85 % RH (10 % of free air power)
± (1 % +0.005 )
Operational Life
AEC-Q200 REV D conditions:
MIL-STD-202 method 108
1000 h, 90/30, powered (free air) at +125 °C
± (1 % +0.005 )
ESD Human Body Model
AEC-Q200 REV D conditions:
AEC-Q200-002 IEC 61000-4-2
25 kV
AD
± (0.5 % +0.005 )
Vibration
AEC-Q200 REV D conditions:
MIL-STD-202 method 204
5 g’s for 20 min, 12 cycles
test from 10 Hz to 2000 Hz
± (0.5 % +0.005 )
Mechanical Shock
AEC-Q200 REV D conditions:
MIL-STD-202 method 213
100 g’s, 6 ms, 3.75 m/s
3 shocks/direction
± (0.5 % +0.005 )
Terminal Strength
AEC-Q200 REV D conditions:
AEC-Q200-006
2 kgf, 60 sec
± (0.25 % +0.01 )
SPECIAL FEATURES
Resistance Values 0.015 0.1 > 20
Tolerances ± 1 % at ± 10 %
Typical Temperature Coefficient
(-55 ° to +175 °C)
± 900 ppm/°C ± 350 ppm/°C ± 200 ppm/°C
P =
T
R
TH (j - c)
R
TH (c - h)
R
TH (h - a)
++
-----------------------------------------------------------------------------------
1
