FUSIBLE FILM RESISTORS,
GENERAL PURPOSE 1/8 WATT to 3 WATT
RESISTORSꢀCAPACITORSꢀCOILSꢀDELAY LINES
Term.W is
RoHS
compliant
& 260°C
compatible
BW/MBW SERIES
RoHS
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 SWIFTTM 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!
↓ D
← H →← L →
← A →
MBW
C
↓
↓ d
BW
B
↑
↑
Inch [mm]
↑
Dimensions BW Series (Axial Lead)
Dimensions MBW (MELF)
Wattage Resistance
Voltage
L
D
d
H
A
B
(Max.)
C
(Min.)
RCD Type
Rating 1
Range 1
Rating 1, 2
± .032 [.8]
± .024 [.6]
±.003 [.07] (Min.)
± .012[.3]
BW1/8F
1/8W
1Ω to 10K
200V
200V
250V
250V
300V
300V
350V
.145 [3.7]
.250 [6.4]
.354 [9.0]
.250 [6.4]
.375 [9.5]
.450 [11.4]
.067 [1.7]
.090 [2.3]
.128 [3.3]
.090 [2.3]
.135 [3.4]
.162 [4.1]
.020 [.5] 1.00 [25]
N/A
BW1/4F, MBW1/4F
BW1/2F, MBW1/2F
1/4W 0.1Ω to 10K
1/2W 0.1Ω to 24K
.022 [.55] 1.02 [26] .256 [6.5]
.118 [3]
.040 [1]
.025 [.6] 1.02 [26] .374 [9.5] .154 [3.9] .060 [1.5]
.022 [.55] 1.02 [26] .256 [6.5] .118 [3] .040 [1]
.026 [.65] 1.02 [26] .374 [9.5] .154 [3.9] .060 [1.5]
.031[.8] 1.02 [26] .441[ 11.2] .197 [5] .080 [2]
BW1/2FS, MBW1/2FS 1/2W 0.2Ω to 20K
BW1F, MBW1FS
BW2F, MBW2F
BW3F, MBW3F
1.0W 0.1Ω to 24K
2.0W 0.1Ω to 24K
3.0W 0.1Ω to 24K
.60±.062[15.2±1.6] .22±.032[5.6±.8] .031[.8] 1.37 [35] .598 [15.2] .220 [5.6] .080 [2]
1 Expanded range available 2 Maximum working voltage is determined by E = (PR)1/2, E should not exceed value listed.
FUSING CHARACTERISTICS
60
50
40
30
20
10
0
5
10
15
20
30
40
50
60
80
100
APPLIED POWER (WATTS)
APPLICATION NOTES:
TYPICALPERFORMANCE
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).
Temperature Coefficient
Load Life Stability
Operating Temp. Range
Power Derating
200ppm/°C
5%
-55 to +165°C
0.71%/°C >25°C
500V (300V BW1/8F)
Dielectric Strength
BW1F
- 101 J T W
P/N DESIGNATION:
RCD Type
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.
Options (leave blank if standard)
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
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.
(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