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Phone: (541) 496-0700
Fax: (541) 496-0408
e-mail: caddock@caddock.com • web: www.caddock.com
For Caddock Distributors listed by country see caddock.com/contact/dist.html
© 2004 Caddock Electronics, Inc.
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DOC
MP312 and MP330 Power Film Resistors
Type MP Chassis Mounted Power Film Resistors are made with Micronox®
resistance films fired onto a ceramic substrate which is thermally bonded to an
anodized aluminum base. By mounting this assembly directly to a metal
surface for improved heat transfer, the high power capabilities of these unique
resistors can provide increased packaging densities in many types of
electronic equipment.
The special performance features of these Type MP Chassis Mounted
Power Film Resistors include:
• Two case sizes that provide 15 Watt and 30 Watt ratings.
• Operation up to 275°C.
• Single screw mounting to simplify attachment to the chassis or other heat
conducting surface.
• A molded silicone case that encapsulates the resistor assembly to meet
stringent environmental specifications.
• Extended life stability better than 0.01% per 1,000 hours has been
demonstrated through a 51/2 year, 50,000 hour program of continuous
load life testing.
Specifications:
Resistance Tolerance: ±1% (other tolerances
on special order).
Insulation Resistance: 10,000 Megohms min.
Terminal Strength: Mil-Std-202, Method 211,
Cond. A (Pull Test) 5 lbs., and Cond. B (Bend
Test), ΔR 0.2% max. or 0.2 ohm max., whichever
is greater.
Thermal Shock: Mil-R-39009, ΔR 0.5% max. or
0.2 ohm max., whichever is greater.
Momentary Overload: 2 times rated power with
applied voltage not to exceed 1.5 times maximum
continuous operating voltage for 5 seconds,
Δ
R 0.5% max. or 0.2 ohm max., whichever is
greater.
Moisture Resistance: Mil-Std-202, Method 106,
Δ
R 0.5% max. or 0.2 ohm max., whichever is
greater.
Load Life: Mil-R-39009, 1,000 hours at rated
power, ΔR 1% max. or 0.2 ohm max., whichever
is greater. Power rating dependent upon chassis
area. See power rating graphs.
Shock, Medium Impact: 50G, Mil-Std-202,
Method 205, Cond. C.
Vibration, High Frequency: Mil-Std-202,
Method 204, Cond. B, ΔR 0.2% max. or 0.2 ohm
max., whichever is greater, through shock and
vibration sequence.
Terminals: Gold Plated Solder Lugs.
Chassis Mounted Precision Power Film Resistors with Center Screw Mounting
Stacked Type MP Power Film Resistor Assemblies
Stacked Type MP assemblies - constructed by bolting
resistors between aluminum heat dissipating plates - provide a
simple means of further improving packaging densities.
These charts of power ratings versus air flow and chassis
area show the high power levels that can be achieved with
forced air cooling and with convection cooling in either vertical or
horizontal orientation.
AIR FLOW (CFM)/EACH RESISTOR
10
4
2
0
.2 .3 .4
.7 1
2 3 4
7 10
20 30
6
8
12
14
16
18
FOR STACKED MP312 POWER RESISTORS
CONVECTION COOLING -
PLATES IN HORIZONTAL PLANE
CONVECTION COOLING -
PLATES IN VERTICAL PLANE
Data is for 25°C air at 1 atmosphere,
ducted around resistors in the stack
with 2" x 2" x .04" aluminum plates
between resistors. To derive total
airflow required for stack, multiply
airflow/each resistor by the number
of resistors in the stack. Ducting is
not required when designing for
convection.
CHASSIS AREA (SQ. IN.)
15
5
0
2
4 6 10
20
40 60 100
10
20
25
30
FOR CHASSIS MOUNTED SINGLE RESISTORS
Data is for 25°C still air at
1 atmosphere. Chassis material:
Aluminum, .040" thick.
1
Model
No.
MP
330
Model No.
MP312
POWER RATING
POWER RATING
C
CADDOCK
100
1%
MP312
15 W
40°
±
3°
D - HOLE FOR MOUNTING
B
2
B
A
ALUMINUM BASE
DIMENSIONS IN INCHES AND (MILLIMETERS)
.188 (4.78)
Dielect.
Strength
Watt-
age †
Model
No.
C
Dimensions in inches and (millimeters)
Resistance
Min.
MP312
.185 (4.70)
15
600
50
10 Ω 200 K
High
Temp
TC ††
Max.
Max.
Voltage
300
B
A
.600 (15.24)
.250 (6.35)
.250 (6.35)
.850 (21.59)
MP330
30
1,000
50
10 Ω 200 K
450
.142 (3.61)
.092 (2.34)
D
†† TC: 50 ppm/°C referenced to +25°C, ΔR
taken at +150°C and +275°C. (Low temp.
TC will be nominally -85 ppm/°C at -55°C.
See typical R-T curve.)
† MP312 15 Watt power rating based on chassis mounting on a
6" X 4" X 2" X .040" aluminum chassis, MP312 free air rating is
2.5 Watts at 25°C. MP330 30 Watt power rating based on
chassis mounting on a 7"X 5" X 2" X .040" aluminum chassis,
MP330 free air rating is 5.0 Watts at 25°C.
AMBIENT TEMPERATURE, °C
100
80
60
40
20
0
25
75
125
175
225
275
TEMPERATURE, °C
2
1
0
-1
0
50
100 150 200
-55
250
TYPICAL R-T CURVE
DERATING CURVE
28_IL123.1004
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