FUSIBLE FILM RESISTORS,
GENERAL PURPOSE 1/8 WATT to 3 WATT
RESISTORS CAPACITORS COILS DELAY LINES
BW/MBW SERIES
RoHS
Term.W is
RoHS
compliant
& 260°C
compatible
BW Series - Axial Lead
MBW Series - SM MELF
Industry’s widest selection of fusible film resistors -
1/8W to 3W, .1Ω to 24KΩ, 1% to 5%, leaded & surface mount
Low cost, quick delivery (available on
SWIFT
TM
program)
Flameproof (UL94V0), surface-mount versions available
Low Cost Circuit Protection!
RCD pioneered fusible film resistors in the early 1970’s as a
low cost approach to circuit protection in case of overload or
component failure. The component is designed to act as a
conventional resistor under normal operating conditions, but
open quickly under fault conditions. Series BW meets the
requirements of EIA RS-325 and can be useful in eliminating
circuit board damage and fire hazards. Standard fusing
characteristics can be altered to customer requirements.
OPTIONS
Modified fusing characteristics (fast blow, slow blow, etc.)
Increased pulse capability (Option P)
Dozens of additional options are available...
Mil-spec screening/burn-in, special marking, non-standard
values, custom lead forming, increased power or voltage, etc.
Customized components are an RCD specialty!
←
H
→←
L
→
BW
↓
D
↑
↓
d
↓
←
A
→
MBW
↓
Dimensions BW Series (Axial Lead)
RCD Type
BW1/8F
BW1/4F, MBW1/4F
BW1/2F, MBW1/2F
BW1/2FS, MBW1/2FS
BW1F, MBW1FS
BW2F, MBW2F
BW3F, MBW3F
1
Dimensions MBW (MELF)
H
(Min.)
A
± .012[.3]
B
(Max.)
N/A
.118 [3]
.118 [3]
.197 [5]
.040 [1]
.040 [1]
.080 [2]
.080 [2]
.154 [3.9] .060 [1.5]
.154 [3.9] .060 [1.5]
C
(Min.)
Wattage Resistance
Rating
1
Range
1
1/8W
1/4W
1/2W
1/2W
1.0W
2.0W
3.0W
2
Voltage
Rating
1, 2
200V
200V
250V
250V
300V
300V
350V
L
± .032 [.8]
.145 [3.7]
.250 [6.4]
.354 [9.0]
.250 [6.4]
.375 [9.5]
.450 [11.4]
1/2
D
± .024 [.6]
.067 [1.7]
.090 [2.3]
.128 [3.3]
.090 [2.3]
.135 [3.4]
.162 [4.1]
d
±.003 [.07]
1Ω to 10K
0.1
Ω
to 10K
0.1
Ω
to 24K
0.2
Ω
to 20K
0.1
Ω
to 24K
0.1
Ω
to 24K
0.1
Ω
to 24K
.020 [.5] 1.00 [25]
.022 [.55] 1.02 [26] .256 [6.5]
.025 [.6] 1.02 [26] .374 [9.5]
.022 [.55] 1.02 [26] .256 [6.5]
.026 [.65] 1.02 [26] .374 [9.5]
.031[.8]
.031[.8]
1.02 [26] .441[ 11.2]
.60±.062[15.2±1.6] .22±.032[5.6±.8]
1.37 [35] .598 [15.2] .220 [5.6]
Expanded range available
Maximum working voltage is determined by E = (PR) , E should not exceed value listed.
FUSING CHARACTERISTICS
FUSING TIME (SECONDS, TYP.)
60
50
40
1/2F, FS
1F, 1FS
30
1/8F
2F
10
0
5
10
15
20
30
40
50
60
80
100
APPLIED POWER (WATTS)
APPLICATION NOTES:
1. Fault level must be suitable to safely open the resistor quickly, especially surface mount
MBW models. If insufficent, the resistor may reach elevated temp. For this reason, the
fusing overload must be relatively large compared to rated W, 20 to 50x is common for
most axial-lead applications, 40 to 100x for most SM circuits. SM fusing times vary due to
mounting geometry/materials, so each application needs to be evaluated by user. The fault
condition must be at least equal to the minimum W indicated in each of the above curves,
and preferably double for SM applications. Fusing may still occur at W levels below the
levels graphed above but not consistently (fast-blow models available). Don’t exceed volt
rating or 200x W rating, whichever is less (increased levels available).
2. For customized models, complete RCD’s Fuse Questionnaire or advise the desired fusing
wattage or current, min.& max. blow time, continuous wattage, ambient temp., pulse
conditions, physical constraints, voltage to be interrupted, frequency, etc.
3. Maintain clearance from any heat-sensitive or flammable materials.
4. Fusing times vary depending on resistance value. Typical fusing times are given above
for 1Ω - 3.9K. Low values tend to fuse slower. Consult factory for assistance.
5. Residual resis. is
≥50x
initial value after fusing at 20x rated W (30x for BW1/8F & MBW)
6. Verify selection by evaluating under the full range of fault conditions. Place resistors
inside a protective case when testing.
TYPICAL PERFORMANCE
Temperature Coefficient
Load Life Stability
Operating Temp. Range
Power Derating
Dielectric Strength
200ppm/°C
5%
-55 to +165°C
0.71%/°C >25°C
500V (300V BW1/8F)
P/N DESIGNATION:
BW1F
RCD Type
Options
(leave blank if standard)
3F
20
1/4F
↑
Inch [mm]
↑
B
↑
C
- 101 J T W
Resis.Code 1%:
3 signif. figures & multiplier,
(R100=.1Ω,1R00=1Ω,10R0=10Ω,1000=100Ω, etc.)
Resis.Code 2%-10%:
2 signif. figures & multiplier,
(R10=0.1Ω, 1R0=1Ω, 100=10Ω, 101=100Ω, etc.)
Tolerance:
J=5% (std.) G=2%, F=1%
Packaging:
B=Bulk, T=Tape & Reel
Termination:
W = Lead-free, Q = Tin/Lead
(leave blank if either acceptable)
RCD Components Inc,
520 E.Industrial Park Dr, Manchester, NH, USA 03109
rcdcomponents.com
Tel: 603
-
669
-
0054 Fax: 603
-
669
-
5455 Email:sales@rcdcomponents.com
FA037D Sale of this product is in accordance with GF-061. Specifications subject to change without notice.
81
PCB Design
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