Axial Lead Battery
Strap PTC
0ZSA Series
belfuse.com/
circuit
-
protection
0ZSA
RoHS 2 Compliant
Application
Rechargeable battery packs, Lithium cell and battery packs
Product Features
Low
profile, Solid state
Operating (Hold Current) Range
1.2
A
–
4.2
A
Maximum Voltage
15V
–
30V DC
Temperat
ure
Range
-
40
℃
to 85
℃
Agency Approval
TUV (Std. EN62319
-
1
-
1, Cert. R50102187)
UL Recognized Component
(Std. UL1434, File E305051)
UL Conditions of Acceptability:
1. These devices have been investigated for use in safety circuits and are suitable
as a limiting device.
2. These devices have been calibrated to limit the current to 8 amps within 5
seconds, per ANSI/NFPA 70, “National Electrical Code”.
LEAD FREE =
HALOGEN FREE =
Electrical Characteristics (23
℃
)
Part Number
(Bulk)
Hold
Current
Trip
Current
Max Time to
Trip @ 5xIH
Rated
Voltage
Max
Current
Typical
Power
Resistance Tolerance
Agency Approvals
Rmin
Rmax
R1max
IH, A
IT, A
Seconds
Vmax, Vdc
Imax, A
Pd, W
Ohms
Ohms
Ohms
A
0ZSA0120FF1E
1.20
2.70
5.0
15
100
1.2
0.085
0.160
0.220
Y
Y
B
0ZSA0175FF1E
1.75
3.80
5.0
15
100
1.5
0.050
0.090
0.120
Y
Y
C
0ZSA0200FF1E
2.00
4.40
4.0
30
100
1.9
0.030
0.060
0.100
Y
Y
D
0ZSA0350FF1E
3.50
6.30
3.0
30
100
2.5
0.017
0.031
0.050
Y
Y
E
0ZSA0420FF1E
4.20
7.60
6.0
30
100
2.9
0.012
0.024
0.040
Y
Y
I
H
Hold Current
-
maximum current at which the device will not trip in still air at 23
℃
.
I
T
Trip current
-
minimum current at which the device will always trip in still air at 23
℃
.
Imax Maximum fault current device can withstand without dam
age at rated voltage (Vmax).
Vmax Maximum voltage device can withstand without damage at its rated current.
Pd Typical power dissipated by device when in tripped state in 23
℃
still air environment.
Rmin Minimum device resistance at 23
℃
.
Rmax
Maximum device resistance at 23
℃
.
R1max Maximum device resistance at 23
℃
, 1 hour after initial device trip, or after being soldered to PCB in end application.
Spe
cifications subject to change without notice
Type 0Z
SA
Series
2
/
4
Bel Fuse Inc.
206 Van Vorst Street
Jersey City, NJ 07302 USA
+1
201.432.0463
Bel.US.CS@belf.com
belfuse.com/circuit
-
protection
© 201
9
Bel
Fuse, Inc.
Rev.
0ZSA
J
an
2019
PTC’s
–
Basic Theory of Operation / “Tripped” Resistance Explanation
Fundamentally, a Bel PTC consists of a block of polymeric material containing conductive filler and bonded
between two conductive, planar terminations.
At currents below the device IHOLD
rating, AND at temperatures below 100C, the PTC maintains a
resistance value below its R1 MAX rating.
As the device's temperature approaches 130C, either due to an increase in ambient temperature or a
current exceeding its I TRIP rating, volumetric expans
ion of the filled polymer breaks apart the majority of
conductive pathways across the terminals created by chain contact of adjacent filler particles or device
resistance increases sharply by several orders of magnitude.
At the much higher “Tripped” resis
tance, there is just enough leakage current to allow internal heating to
“hold” the device in its tripped state (around 125C) until power is interrupted. Once power is removed, the
PTC's core cools and contracts allowing conductive chains to reform and ret
urn the device to its low
resistance state.
The catalog data for each device specifies a "Typical Power" value. This is the power required to exactly
match the heat lost by the tripped device to its ambient surroundings at 23C. By Ohm's Law, power can be
stated as: W = E^2/R. Thus the approximate resistance of a “Tripped” PTC can be determined by: R =
E^2/W, where "E" is the voltage appearing across the PTC (usually the supply's open circuit voltage), and
"W" is the Typical Power value for the particular P
TC.
Since the PPTC acts to maintain a constant internal temperature, its apparent resistance will change based
upon applied voltage and, to a lesser degree, ambient conditions. Consider the following example....
A PTC with a Typical Power of 1 watt protec
ting a circuit using a 60V supply will demonstrate an apparent,
tripped resistance "R" of:
R = 60^2/1 = 3,600 ohms
This same tripped device when used to protect a 12V circuit would now present an apparent resistance of:
R = 12^2/1 = 144 ohms
The valu
e for Typical Power is "typical" because any physical factors that affect heat loss (such as ambient
temperature or air convection) will somewhat alter the level of power that the PTC needs to maintain its
internal temperature. In short, PTCs do not exhibi
t a constant, quantifiable tripped resistance value.
Type Time
–
To
–
Trip at 23
℃
.
Spe
cifications subject to change without notice
Type 0Z
SA
Series
3
/
4
Bel Fuse Inc.
206 Van Vorst Street
Jersey City, NJ 07302 USA
+1
201.432.0463
Bel.US.CS@belf.com
belfuse.com/circuit
-
protection
© 201
9
Bel
Fuse, Inc.
Rev.
0ZSA
J
an
2019
Physical Specifications
Lead material:
0
.
13mm nominal thickness, quarter
-
hard nickel.
Insulating
material
:
Polyester tape
PTC Marking
“
bel” or “b”,
I
H
code and “SA
” .
Product
Dimensions
All dimensions in
mm.
T
hermal De
rating Curve
Cautionary Notes
1. Operation beyond the specified maximum ratings
or improper use may result in damage and
possible electrical arcing and/or flame.
2. These Polymer PTC (PPTC) devices are intended
for protection against occasional
overcurrent/overtemperature fault con
ditions and
may not be suitable for use in applications where
repeated and/or prolonged fault conditions are
anticipated.
3. Avoid contact of PTC device with chemical
solvent. Prolonged contact may adversely impact
the PTC performance.
4. These PTC de
vices may not be suitable for use in
circuits with a large inductance, as the PTC trip
can generate circuit voltage spikes above the PTC
rated voltage.
5. These devices are intended for use in DC voltage
applications only. Use in AC voltage applications
should be first discussed with Bel Fuse
engineering.
6. Not recommended for use on potted or conformal
coated PCB’s. Restriction of free air flow could
affect electrical performance and/or result in
de
vice failure. Consult Bel Fuse engineering.
Part Number
A
B
C
D
F
Min
Max
Min
Max
Min
Max
Min
Max
Min
Max
0ZSA0120FF
1
9.9
2
2.1
4.9
5.2
0.6
1.0
5.5
7.5
3.9
4.1
0ZSA0175FF
20.9
23.1
4.9
5.2
0.6
1.0
4.1
5.5
3.9
4.1
0ZSA0200FF
21.3
23.4
10.2
11.0
0.5
1.1
5.0
7.6
4.8
5.4
0ZSA0350FF
28.4
31.8
13.0
13.5
0.5
1.1
6.3
8.9
5.9
6.1
0ZSA0420FF
30.6
32.4
12.9
13.6
0.5
1.1
5.0
7.5
5.9
6.1
Spe
cifications subject to change without notice
Type 0Z
SA
Series
4
/
4
Bel Fuse Inc.
206 Van Vorst Street
Jersey City, NJ 07302 USA
+1
201.432.0463
Bel.US.CS@belf.com
belfuse.com/circuit
-
protection
© 201
9
Bel
Fuse, Inc.
Rev.
0ZSA
J
an
2019
P/N Explanation and Ordering Information
Standard Packaging
Packaging Option
Packaging
Quantity
Packaging
Code
Bulk
3000
1E
Spe
cifications subject to change without notice