Features
■ Superior circuit protection
■ Overcurrent and overvoltage protection
■ Blocks surges up to rated limits
■ High-speed performance
■ Small SMT package
■ RoHS compliant*
■ Agency recognition:
Applications
■ Voice / VDSL cards
■ Protection modules and dongles
■ Process control equipment
■ Test and measurement equipment
■ General electronics
TBU-CX Series - TBU® High-Speed Protectors
*RoHS Directive 2002/95/EC Jan. 27, 2003 including annex and RoHS Recast 2011/65/EU June 8, 2011.
Specifi cations are subject to change without notice.
Customers should verify actual device performance in their specifi c applications.
General Information
The TBU-CX Series of Bourns® TBU®
products are low capacitance dual bidirec-
tional high-speed protection components,
constructed using MOSFET semiconductor
technology, and designed to protect against
faults caused by short circuits, AC power cross,
induction and lightning surges.
The TBU® high-speed protector placed in the system circuit will monitor the current with
the MOSFET detection circuit triggering to provide an effective barrier behind which
sensitive electronics will not be exposed to large voltages or currents during surge
events. The TBU® device is provided in a surface mount DFN package and meets
industry standard requirements such as RoHS and Pb Free solder refl ow profi les.
Agency Approval
Description
UL File Number: E315805
Absolute Maximum Ratings (@ TA = 25 °C Unless Otherwise Noted)
Symbol Parameter Part Number Value Unit
Vimp Peak impulse voltage withstand with duration less than 10 ms
TBU-CX025-VTC-WH
TBU-CX040-VTC-WH
TBU-CX050-VTC-WH
TBU-CX065-VTC-WH
TBU-CX085-VTC-WH
250
400
500
650
850
V
Vrms Continuous A.C. RMS voltage
TBU-CX025-VTC-WH
TBU-CX040-VTC-WH
TBU-CX050-VTC-WH
TBU-CX065-VTC-WH
TBU-CX085-VTC-WH
100
200
250
300
425
V
Top Operating temperature range -40 to +125 °C
Tstg Storage temperature range -65 to +150 °C
Tjmax Maximum Junction Temperature +125 °C
ESD HBM ESD Protection per IEC 61000-4-2 ±2 kV
External Resistor
Line In/
Line Out
Line Out/
Line In
R
Electrical Characteristics (@ TA = 25 °C Unless Otherwise Noted)
Symbol Parameter Part Number Min. Typ. Max. Unit
Itrigger
Current required for the device to go from operating state to
protected state (Rexternal = 0 ohm) TBU-CXxxx-VTC-WH 500 750 1000 mA
Rdevice
Series resistance of
the TBU device
(Rexternal = 0 ohm)
Vimp = 250 V Itrigger (min.) = 500 mA
Vimp = 400 V Itrigger (min.) = 500 mA
Vimp = 500 V Itrigger (min.) = 500 mA
Vimp = 650 V Itrigger (min.) = 500 mA
Vimp = 850 V Itrigger (min.) = 500 mA
TBU-CX025-VTC-WH
TBU-CX040-VTC-WH
TBU-CX050-VTC-WH
TBU-CX065-VTC-WH
TBU-CX085-VTC-WH
2.6
3.6
5.0
7.0
10.7
3.0
4.2
5.7
8.0
13.0
Ω
tblock Time for the device to go from normal operating state to protected state 1 µs
IQCurrent through the triggered TBU® device with 50 Vdc circuit voltage 0.25 0.50 1.00 mA
Vreset Voltage below which the triggered TBU® device will transition to normal operating state 12 16 20 V
Rth(j-l) Junction to package pads - FR4 using recommended pad layout 98 °C/W
Rth(j-l) Junction to package pads - FR4 using heat sink on board (6 cm2) (1 in2) 40 °C/W
*RoHS COMPLIANT
CX85
0075
Specifi cations are subject to change without notice.
Customers should verify actual device performance in their specifi c applications.
TBU-CX Series - TBU® High-Speed Protectors
Reference Application
The TBU® devices are general use protectors used in a wide
variety of applications. The maximum voltage rating of the TBU
device should never be exceeded. Where necessary, an OVP
should be employed to limit the maximum voltage. A cost-
effective protection solution combines Bourns® TBU® protection
devices with a pair of Bourns® MOVs. For bandwidth sensitive ap-
plications, a Bourns® GDT may be substituted for the MOV. See
“Trigger Current vs External Resistor Value” graph for selecting
the optimum trigger current value using a 0 ohm – 50 ohm
resistor value.
Note: Line Resistance =
TBU® Device Resistance + Rexternal Resistance
The TBU® device, constructed using MOSFET semiconductor
technology, placed in the system circuit will monitor the
current with the MOSFET detection circuit triggering to provide
an effective barrier behind which sensitive electronics are not
exposed to large voltages or currents during surge events. The
TBU® device operates in approximately 1 μs - once line
current exceeds the TBU® device’s trigger current Itrigger.
When operated, the TBU® device restricts line current to less
than 1 mA typically. When operated, the TBU® device will
block all voltages including the surge up to rated limits.
After the surge, the TBU® device resets when the voltage
across the TBU® device falls to the Vreset level. The TBU®
device will automatically reset on lines which have no DC bias
or have DC bias below Vreset (such as unpowered signal lines).
If the line has a normal DC bias above Vreset, the voltage
across the TBU® device may not fall below Vreset after the
surge. In such cases, special care needs to be taken to ensure
that the TBU® device will reset, with software monitoring as one
method used to accomplish this. Bourns application
engineers can provide further assistance.
Basic TBU Operation
Performance Graphs
Typical Trigger Current vs. Temperature
Equip.
OVP
OVP
Line
Line
TBU
®
Device
TBU
External
Resistor
®
Device
R
External
Resistor
R
Typical V-I Characteristics (TBU-CX050-VTC-WH with Rext = 1 Ω)
CURRENT
(100 mA/div)
VOLTAGE
(5 V/div)
ITRIP
VRESET
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
-75 -50 -25 0 25 50 75 100 125
Junction Temperature (°C)
Normalized Trigger Current
TBU-CX Series - TBU® High-Speed Protectors
Specifi cations are subject to change without notice.
Customers should verify actual device performance in their specifi c applications.
Performance Graphs (Continued)
Trigger Current vs. External Resistor Value
10
100
1000
0.1 1 10 100
R (Ohms)
Trigger Current (mA)
3.40
(.134) 54321
0.30
(.012)
0.30
(.012)
1.85
(.073)
0.75
(.030)
0.75
(.030)
1.85
(.073)
0.50
(.020)
0.50
(.020)
0.70
(.028)
0.30
(.012)
0.45
(.018)
C PIN 1
0.25
(.010)
Product Dimensions
Pad # Pin Out
1 Line In/Out
2 External R Pad
3 External R Pad
4NU
5 Line Out/In
Pad Designation
PIN 1 & BACKSIDE CHAMFER
4.00 ± 0.10
(.157 ± .004)
0.00 - 0.05
(.000 - .002)
8.25 ± 0.10
(.325 ± .004)
0.85 ± 0.05
(.033 ± .002)
0.85
(.033)
0.85
(.033)
0.45
(.039)
0.30
(.012)
Typical Resistance vs. Temperature
2.2
1.6
1.8
2.0
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0.0
-75 -50 -25 0 25 50 75 100 125
Junction Temperature (°C)
Normalized Resistance
DIMENSIONS: MM
(INCHES)
Power Derating Curve
No Additional PCB Cu
0.5 sq. in. Additional PCB Cu
Ambient Temperature (°C)
20
3.0
2.5
2.0
1.5
1.0
0.5
0.0
40 60 80 100 120 140
Total Max. Power (W)
Specifi cations are subject to change without notice.
Customers should verify actual device performance in their specifi c applications.
TBU-CX Series - TBU® High-Speed Protectors
Refl ow Profi le
Profi le Feature Pb-Free Assembly
Average Ramp-Up Rate (Tsmax to Tp) 3 °C/sec. max.
Preheat
- Temperature Min. (Tsmin)
- Temperature Max. (Tsmax)
- Time (tsmin to tsmax)
150 °C
200 °C
60-180 sec.
Time maintained above:
- Temperature (TL)
- Time (tL)
217 °C
60-150 sec.
Peak/Classifi cation Temperature (Tp) 260 °C
Time within 5 °C of Actual Peak Temp. (tp) 20-40 sec.
Ramp-Down Rate 6 °C/sec. max.
Time 25 °C to Peak Temperature 8 min. max.
Recommended Pad Layout
Thermal Resistance vs Additional PCB Cu Area
Added Cu Area (Sq. In.)
0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
120
100
80
60
40
20
0
Thermal Resistance (°C/W)
TBU® High-Speed Protectors have a 100 % matte-tin termination
fi nish. For improved thermal dissipation, the recommended layout
uses PCB copper areas which extend beyond the exposed solder
pad. The exposed solder pads should be defi ned by a solder mask
which matches the pad layout of the TBU® device in size and spac-
ing. It is recommended that they should be the same dimension as
the TBU® pads but if smaller solder pads are used, they should be
centered on the TBU® package terminal pads and not more than
0.10-0.12 mm (0.004-0.005 in.) smaller in overall width or length.
Solder pad areas should not be larger than the TBU® pad sizes
to ensure adequate clearance is maintained. The recommended
stencil thickness is 0.10-0.12 mm (0.004-0.005 in.) with a stencil
opening size 0.025 mm (0.0010 in.) less than the solder pad size.
Extended copper areas beyond the solder pad signifi cantly improve
the junction to ambient thermal resistance, resulting in operation
at lower junction temperatures with a corresponding benefi t of reli-
ability. All pads should soldered to the PCB, including pads marked
as NC or NU but no electrical connection should be made to these
pads. For minimum parasitic capacitance, it is recommended that
signal, ground or power signals are not routed beneath any pad.
Dark grey areas show added PCB copper area for better
thermal resistance.
54321
54231
Specifi cations are subject to change without notice.
Customers should verify actual device performance in their specifi c applications.
TBU-CX Series - TBU® High-Speed Protectors
How to Order
TBU - CX 085 - VTC - WH
TBU® Product
Series
CX = Bi-Series
Impulse Voltage Rating
025 = 250 V
040 = 400 V
050 = 500 V
065 = 650 V
085 = 850 V
Trigger Current
VTC = Variable Trigger Current
Hold to Trip Ratio Suffi x
W = Hold to Trip Ratio
Package Suffi x
H = DFN Package
Typical Part Marking
“TBU” is a registered trademark of Bourns, Inc. in the United States and other countries.
REV. 11/11
Packaging Specifi cations
B
A
DC
NF
G (MEASURED AT HUB)
USER DIRECTION OF FEED
K0
B0
P2
D1
CENTER
LINES OF
CAVITY
EMBOSSMENT
tD
P0
TOP
COVER
TAPE
E
W
P
A0
DIMENSIONS: MM
(INCHES)
A B C D G N
Min. Max. Min. Max. Min. Max. Min. Max. Ref. Ref.
326
(12.835)
330
(13.002)
1.5
(.059)
2.5
(.098)
12.8
(.504)
13.5
(.531)
20.2
(.795) - 16.5
(.650)
102
(4.016)
A0 B
0 D D1 E F
Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. max.
4.3
(.169)
4.5
(.177)
8.45
(.333)
8.65
(.341)
1.5
(.059)
1.6
(.063)
1.5
(.059) -1.65
(.065)
1.85
(.073)
7.4
(.291)
7.6
(.299)
K0P P0 P
2 t W
Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max.
1.0
(.039)
1.2
(.047)
7.9
(.311)
8.1
(.319)
3.9
(.159)
4.1
(.161)
1.9
(.075)
2.1
(.083)
0.25
(.010)
0.35
(.014)
15.7
(.618)
16.3
(.642)
QUANTITY: 3000 PIECES PER REEL
PIN 1
MANUFACTURING
DATE CODE
- 1ST DIGIT INDICATES THE YEAR’S 6-MONTH PERIOD.
- 2ND DIGIT INDICATES THE WEEK NUMBER IN THE 6-MONTH PERIOD.
- 3RD & 4TH DIGITS INDICATE SPECIFIC LOT FOR THE WEEK.
6-MONTH PERIOD CODES:
A = JAN-JUN 2009 C = JAN-JUN 2010 E = JAN-JUN 2011
B = JUL-DEC 2009 D = JUL-DEC 2010 F = JUL-DEC 2011
MANUFACTURER’S
TRADEMARK
PRODUCT CODE
- 1ST & 2ND DIGITS INDICATE PRODUCT FAMILY:
CX = TBU-CX SERIES
- 3RD & 4TH DIGITS INDICATE IMPULSE VOLTAGE:
25 = 250 V 50 = 500 V 85 = 850 V
40 = 400 V 65 = 650 V
