
Features
n Compliant with AEC-Q200 Rev-D -
Stress Test Qualification for Passive
Components in Automotive Applications
n Small footprint size (1210)
n Operating temperature range up to 125 °C
n Low thermal derating factor
n Higher hold currents at elevated temperatures
n RoHS compliant*
n Agency recognition:
MF-USHT Series - PTC Resettable Fuses
Electrical Characteristics
**R1Max. measured 24 hours post reflow.
*RoHS COMPLIANT
*RoHS COMPLIANT
& AEC APPROVED
*RoHS COMPLIANT, **HALOGEN FREE
& AEC COMPLIANT
*RoHS and
AEC-Q200 COMPLIANT
LEAD FREE
*RoHS COMPLIANT
VERSIONS
AVAILABLE
LEAD FREE
VERSIONS ARE
RoHS COMPLIANT*
Model Vmax Imax
Ihold Itrip Resistance Max. Time To Trip Tripped
Power
Dissipation Agency Recognition
at 23 °C at 23 °C Ohms at 23 °C Watts at
23 °C cUL TÜV
Volts Amps Amps Rmin R1max** Amps Seconds Typ. E174545 R50384138
MF-USHT010KX 30 20 0.10 0.50 1.00 7.50 2.5 1.5 1.0
MF-USHT016KX 30 20 0.16 0.80 0.70 6.00 8.0 0.1 1.0
MF-USHT020KX 30 20 0.20 1.00 0.60 5.00 8.0 0.1 1.0
MF-USHT035KX 30 20 0.35 1.75 0.40 2.20 8.0 0.1 1.0 3 3
MF-USHT050KX 30 20 0.50 2.50 0.30 1.60 8.0 0.1 1.0 3 3
MF-USHT075KX 16 20 0.75 3.75 0.10 1.00 8.0 5.0 1.0
MF-USHT110KX 16 20 1.10 5.50 0.06 0.50 8.0 5.0 1.0
MF-USHT125KX 12 40 1.25 3.75 0.03 0.30 8.0 5.0 1.5
MF-USHT150KX 12 40 1.50 4.50 0.025 0.25 8.0 5.0 1.5
Environmental Characteristics
Item Condition Criteria
Operating Temperature -40 °C to +125 °C
Recommended Storage +40 °C max. / 70 % R.H. max.
Passive Aging +125 °C, 1000 hours R < R1max
Humidity Aging +85 °C, 85 % R.H. 1000 hours R < R1max
Thermal Shock -40 °C to +125 °C, 20 times R < R1max
Solvent Resistance MIL-STD-202, Method 215 No change (marking still legible)
Vibration MIL-STD-883C, Method 2007.1 Condition A No change (Rmin < R < R1max)
Moisture Sensitivity Level (MSL) See Note
ESD Classification Class 6 (per AEC-Q200-2, HBM)
Test Procedures and Requirements
Item Test Condition Accept/Reject Criteria
Visual/Mechanical Verify dimensions and materials Per MF physical description
Resistance In still air @ 23 °C Rmin ≤ R ≤ Rmax
Time to Trip At specified current, Vmax, 23 °C, still air T ≤ max. time to trip (seconds)
Hold Current 30 min. at Ihold, still air No trip
Trip Cycle Life Vmax, Imax, 100 cycles No arcing or burning
Trip Endurance Vmax, 48 hours No arcing or burning
Solderability 245 °C ±5 °C, 5 seconds 95 % min. coverage
* RoHS Directive 2015/863, Mar 31, 2015 and Annex.
Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.
WARNING Cancer and Reproductive Harm - www.P65Warnings.ca.gov

Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.
MF-USHT Series - PTC Resettable Fuses
DIMENSIONS: MM
(INCHES)
Typical Part Marking
Represents total content. Layout may vary.
How to Order
MF - USHT 050 K X - 2
Multifuse® Product
Designator
Series
USHT = 1210 High Temperature
Surface Mount
Component
Hold Current, Ihold
010 - 150 (0.10 - 1.50 Amps)
Material Specific Code
Multifuse® freeXpansion™ Design
Packaging
-2 = Tape and Reel
Packaged per EIA-481
Thermal Derating Table - Ihold (Amps)
Model Ambient Operating Temperature
-40 °C -20 °C 0 °C +23 °C +40 °C +50 °C +60 °C +70 °C +85 °C +125 °C
MF-USHT010KX 0.15 0.13 0.12 0.10 0.09 0.08 0.07 0.07 0.06 0.03
MF-USHT016KX 0.23 0.21 0.19 0.16 0.14 0.13 0.12 0.11 0.09 0.04
MF-USHT020KX 0.29 0.26 0.23 0.20 0.18 0.16 0.15 0.13 0.11 0.05
MF-USHT035KX 0.51 0.46 0.41 0.35 0.31 0.28 0.26 0.23 0.20 0.09
MF-USHT050KX 0.73 0.66 0.58 0.50 0.44 0.41 0.37 0.34 0.28 0.14
MF-USHT075KX 1.09 0.98 0.87 0.75 0.66 0.61 0.56 0.50 0.42 0.20
MF-USHT110KX 1.60 1.44 1.28 1.10 0.97 0.89 0.81 0.74 0.62 0.30
MF-USHT125KX 1.81 1.64 1.45 1.25 1.10 1.01 0.93 0.84 0.70 0.34
MF-USHT150KX 2.18 1.97 1.74 1.50 1.32 1.22 1.11 1.01 0.84 0.41
Product Dimensions
Model A B C D E
Min. Max. Min. Max. Min. Max. Min. Min.
MF-USHT010KX
3.00
(0.118)
3.43
(0.135)
2.35
(0.093)
2.80
(0.110)
0.40
(0.016)
0.85
(0.033)
0.30
(0.012)
0.05
(0.002)
MF-USHT016KX
MF-USHT020KX
MF-USHT035KX
MF-USHT050KX
MF-USHT075KX 3.00
(0.118)
3.43
(0.135)
2.35
(0.093)
2.80
(0.110)
0.60
(0.024)
1.20
(0.047)
0.30
(0.012)
0.05
(0.002)
MF-USHT110KX 3.00
(0.118)
3.43
(0.135)
2.35
(0.093)
2.80
(0.110)
0.80
(0.031)
1.60
(0.063)
0.30
(0.012)
0.05
(0.002)
MF-USHT125KX
MF-USHT150KX
Recommended Pad Layout
K
C
2.50
(0.098)
2.00
(0.079)
1.00
(0.039)
Bottom View
D E
A
B
C
Top View Side View Recommended Pad Layout
K
C
2.50
(0.098)
2.00
(0.079)
1.00
(0.039)
Bottom View
D E
A
B
C
Top View Side View
Terminal Material:
ENIG-plated terminals
MF-USHT010KX ~
MF-USHT075KX..........3000 pcs. per reel
MF-USHT110KX ~
MF-USHT150KX..........2000 pcs. per reel
Packaging Quantity
PART IDENTIFICATION:
MF-USHT010KX = B
MF-USHT016KX = D
MF-USHT020KX = E
MF-USHT035KX = F
MF-USHT050KX = K
MF-USHT075KX = L
MF-USHT110KX = N
MF-USHT125KX = P
MF-USHT150KX = S
BIWEEKLY DATE CODE:
WEEK 1 AND 2 = A
WEEK 51 AND 52 = Z
K
C

MF-USHT Series - PTC Resettable Fuses
Solder Reflow Recommendations
Notes:
• MF-USHT models are intended for reflow soldering (including, but not
limited to heating plate, hot air, IR, nitrogen, and vapor phase).
• Wave soldering is permissible only if the device is on the top of the
PCB, opposite the heat source.
• Hand soldering is not recommended for these devices.
• All temperatures refer to the topside of the device, measured on the
device body surface.
• If reflow temperatures exceed the recommended profile, devices may
not meet the published specifications.
• Compatible with Pb and Pb-free solder reflow profiles.
• Excess solder may cause a short circuit.
• Please refer to the Multifuse® Polymer PTC Resettable Fuse Soldering
Recommendations document for more details.
Temperature of Lead/Pad Junction
Process Materials Temperature Time
Description Interval
1. Apply solder paste to • Sn 96.5 / Ag 3.0 / Cu 0.5 Room temperature
test board (8 - 10 mil thick) Alloy water soluble or no
clean solder paste
(see note 1)
• single sided epoxy glass
(G10) (UL approved)
•PC board approx. 4x4x.06 in.
2. Place test units onto board 6 units/board
3. Ramp up Convection oven (see note 2) 2.5 °C ± 0.5 °/sec.
4. Preheat (TS.ces 03 ± 09C° 091 ot C° 051)
5. Time above liquidus (TL.ces 09-06C° 022)
6. Peak temperature (TP° 5-/° 0+ C° 052)
10-20 sec. within
5 °C of peak
.ces/C° 5.0 ± C° 3erutarepmet mooRnwod pmaR.7
(see note 2)
8. Cleaning water clean profile High pressure deionized 72 °F to 160 °F As required
water 65 PSI max. (22 °C to 71 °C)
Inspect solder joint to determine if solder joint is
acceptable (i.e. exhibits wetting of joint’s surface).
Use the following criteria (ref. acceptability of printed
board assemblies, IPC-A-610):
A) Acceptable (see Figure 1)
(1) The solder connection wetting angle (solder to
component and solder to PCB termination)
does not exceed 90 °.
(2) Solder balls that do not violate minimum
electrical clearances and are attached
(soldered) to a metal surface.
B) Unacceptable (see Figure 2)
(1) Solder connection wetting angle exceeding
90 °.
(2) Incomplete reflow of solder paste.
(3) Dewetting.
If unacceptable, determine cause and correct prior to
next run.
NOTES:
1. Water soluble solder paste only above 100K.
2. Refer to ref. temperature profile. Temperature at
lead/pad junction with “K” type thermocouple.
3. Units that are board mounted for environmental
testing must see a peak temperature in the reflow
zone, as specified. This is to ensure that all test
units will see “worst case conditions”.
4. Ramp down rate to be measured from 245 °C to
150 °C.
5. Process Description 8 does not apply to open
frame trimmers.
(Derived using 6-zone Convection Oven)
TP
TP
tp
ts
T TO
RAMP-UP L
TL
tL
25
Ts max
Ts min
PREHEAT
Temperature
Time
CRITICAL ZONE
RAMP-DOWN
t 25 °C TO PEAK
Profile Feature Pb-Free Assembly
Average Ramp-Up Rate (Tsmax to Tp) 3 °C / second max.
PREHEAT:
Temperature Min. (Tsmin)
Temperature Max. (Tsmax)
Time (Tsmin to Tsmax) (ts)
150 °C
200 °C
60~180 seconds
TIME MAINTAINED ABOVE:
Temperature (TL)
Time (tL)
217 °C
60~150 seconds
Peak Temperature (Tp) 260 °C
Time within 5 °C of Actual Peak Temperature (tp) 20~40 seconds
Ramp-Down Rate 6 °C / second max.
Time 25 °C to Peak Temperature 8 minutes max.
Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.

MF-USHT Series - PTC Resettable Fuses
MF-USHT SERIES, REV. E 08/19
“freeXpansion Design” is a trademark of Bourns, Inc.
Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.
Typical Time to Trip at 23 ˚C
The Time to Trip curves represent typical performance of a device in
a simulated application environment. Actual performance in specific
customer applications may differ from these values due to the
influence of other variables.
A - MF-USHT010KX
B - MF-USHT016KX
C - MF-USHT020KX
D - MF-USHT035KX
E - MF-USHT050KX
F - MF-USHT075KX
G - MF-USHT110KX
H - MF-USHT125KX
I - MF-USHT150KX
1
10
0.01
0.1
0.001
100.1 1 100
Fault Current (Amps)
Time to Trip (Seconds)
A
BC
D
E
F
HI
G
Asia-Pacific: Tel: +886-2 2562-4117 • Email: asiacus@bourns.com
EMEA: Tel: +36 88 885 877 • Email: eurocus@bourns.com
The Americas: Tel: +1-951 781-5500 • Email: americus@bourns.com
www.bourns.com

MF-USHT Series
Tape Dimensions per EIA-481
W 8.0 ± 0.30
(0.315 ± 0.012)
P0 4.0 ± 0.10
(0.157 ± 0.004)
10P0 40 ± 0.20
(1.575 ± 0.008)
P1 4.0 ± 0.10
(0.157 ± 0.004)
P2 2.0 ± 0.05
(0.079 ± 0.002)
A0 3.00 ± 0.10
(0.118 ± 0.004)
B0 (MF-USHT010KX~MF-USHT050KX) 3.65 ± 0.10
(0.144 ± 0.004)
B0 (MF-USHT075KX~MF-USHT150KX) 3.50 ± 0.10
(0.138 ± 0.004)
B1 max. 4.35
(0.171)
D0 1.5 + 0.10/-0.0
(0.059 + 0.004/-0)
F 3.5 ± 0.05
(0.138 ± 0.002)
E1 1.75 ± 0.10
(0.069 ± 0.004)
E2 typ. 6.25
(0.246)
T max. 0.6
(0.024)
T1 max. 0.1
(0.004)
K0 (MF-USHT010KX~MF-USHT050KX) 0.85 ± 0.10
(0.033 ± 0.004)
K0 (MF-USHT075KX) 1.22 ± 0.10
(0.048 ± 0.004)
K0 (MF-USHT110KX~MF-USHT150KX) 1.68 ± 0.10
(0.066 ± 0.004)
Leader min. 390
(15.35)
Trailer min. 160
(6.30)
Reel Dimensions
A max. 185
(7.28)
N min. 50
(1.97)
W1 8.4 + 1.5/-0.0
(0.331 + 0.059/-0.0)
W2 max. 14.4
(0.567)
MF-USHTSeriesTapeandReelSpecifications
B1
N(HUB DIA.)
(MEASURED
AT HUB)
A
T
COVER
TAPE
K0
T1A0
W2
(MEASURED
AT HUB)
W
1
P1
B0
F
D0P2
P
0
E2
E1
W
DIMENSIONS: MM
(INCHES)
Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.

3312 - 2 mm SMD Trimming Potentiometer
Application Notice
MFAN 12/18
Specifications are subject to change without notice.
Users should verify actual device performance in their specific applications.
The products described herein and this document are subject to specific legal disclaimers as set forth on the last page of this document, and at www.bourns.com/docs/legal/disclaimer.pdf.
Bourns® Multifuse® PPTC Resettable Fuses
• Users are responsible for independent and adequate evaluation of Bourns® Multifuse® Polymer PTC devices in the user’s
application, including the PPTC device characteristics stated in the applicable data sheet.
• Polymer PTC devices must not be allowed to operate beyond their stated maximum ratings. Operation in excess of such
maximum ratings could result in damage to the PTC device and possibly lead to electrical arcing and/or fire. Circuits with
inductance may generate a voltage above the rated voltage of the polymer PTC device and should be thoroughly evaluated
within the user’s application during the PTC selection and qualification process.
• Polymer PTC devices are intended to protect against adverse effects of temporary overcurrent or overtemperature
conditions up to rated limits and are not intended to serve as protective devices where overcurrent or overvoltage conditions
are expected to be repetitive or prolonged.
• In normal operation, polymer PTC devices experience thermal expansion under fault conditions. Thus, a polymer PTC
device must be protected against mechanical stress, and must be given adequate clearance within the user’s application to
accommodate such thermal expansion. Rigid potting materials or fixed housings or coverings that do not provide adequate
clearance should be thoroughly examined and tested by the user, as they may result in the malfunction of polymer PTC
devices if the thermal expansion is inhibited.
• Exposure to lubricants, silicon-based oils, solvents, gels, electrolytes, acids, and other related or similar materials may
adversely affect the performance of polymer PTC devices.
• Aggressive solvents may adversely affect the performance of polymer PTC devices. Conformal coating, encapsulating,
potting, molding, and sealing materials may contain aggressive solvents including but not limited to xylene and toluene,
which are known to cause adverse effects on the performance of polymer PTCs. Such aggressive solvents must be
thoroughly cured or baked to ensure their complete removal from polymer PTCs to minimize the possible adverse effect
on the device.
• Recommended storage conditions should be followed at all times. Such conditions can be found on the applicable data
sheet and on the Multifuse® Polymer PTC Moisture/Reflow Sensitivity Classification (MSL) note:
https://www.bourns.com/docs/RoHS-MSL/msl_mf.pdf

Legal Disclaimer Notice
This legal disclaimer applies to purchasers and users of Bourns® products manufactured by or on behalf of Bourns, Inc. and its
affiliates (collectively, “Bourns”).
Unless otherwise expressly indicated in writing, Bourns® products and data sheets relating thereto are subject to change
without notice. Users should check for and obtain the latest relevant information and verify that such information is current and
complete before placing orders for Bourns® products.
The characteristics and parameters of a Bourns® product set forth in its data sheet are based on laboratory conditions, and
statements regarding the suitability of products for certain types of applications are based on Bourns’ knowledge of typical
requirements in generic applications. The characteristics and parameters of a Bourns® product in a user application may vary
from the data sheet characteristics and parameters due to (i) the combination of the Bourns® product with other components
in the user’s application, or (ii) the environment of the user application itself. The characteristics and parameters of a Bourns®
product also can and do vary in different applications and actual performance may vary over time. Users should always verify
the actual performance of the Bourns® product in their specific devices and applications, and make their own independent
judgments regarding the amount of additional test margin to design into their device or application to compensate for
differences between laboratory and real world conditions.
Unless Bourns has explicitly designated an individual Bourns® product as meeting the requirements of a particular industry
standard (e.g., ISO/TS 16949) or a particular qualification (e.g., UL listed or recognized), Bourns is not responsible for any
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Bourns® products are not recommended, authorized or intended for use in nuclear, lifesaving, life-critical or life-sustaining ap-
plications, nor in any other applications where failure or malfunction may result in personal injury, death, or severe property or
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generally equivalent classifications outside of the United States.
Bourns expressly identifies those Bourns® standard products that are suitable for use in automotive applications on such
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PDF: http://www.bourns.com/docs/Legal/disclaimer.pdf
C1753 05/17/18R
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