when the current reaches the maximum value in one direction only, that is when
Pin 1 is positive in voltage with respect to Pin 2. No current limiting exists in the oppo-
site polarity, and the TBU
®
protector appears as resistive in nature. The reverse current
should not exceed the maximum trigger current level of the TBU
®
device. An external
diode may be used to prevent reverse current in DC biased applications.
The TBU
®
protector blocks surges and provides an effective barrier behind which sensi-
tive electronics will not be exposed to large voltages or currents during surge events.
After the surge, the TBU
®
device resets when the voltage across the TBU
®
device falls
to the V
reset
level. The TBU
®
device will automatically reset on lines which have no DC
bias or have DC bias below V
reset
(such as unpowered signal lines).
The TBU
®
device is provided in a surface mount DFN package and meets industry
standard requirements such as RoHS and Pb Free solder reflow profiles.
Absolute Maximum Ratings (@ T
A
= 25 °C Unless Otherwise Noted)
Symbol
V
imp
Parameter
Peak impulse voltage withstand with duration less than 10 ms
E
T
E
L
O
S
B
O
Part Number
TBU-KE025-xxx-WH
TBU-KE040-xxx-WH
TBU-KE050-xxx-WH
TBU-KE025-xxx-WH
TBU-KE040-xxx-WH
TBU-KE050-xxx-WH
Value
250
400
500
Unit
V
V
rms
T
op
T
stg
Continuous A.C. RMS voltage
Operating temperature range
Storage temperature range
100
200
250
-40 to +125
-65 to +150
V
°C
°C
Asia-Pacific:
Tel: +886-2 2562-4117 • Fax: +886-2 2562-4116
EMEA:
Tel: +36 88 520 390 • Fax: +36 88 520 211
The Americas:
Tel: +1-951 781-5500 • Fax: +1-951 781-5700
www.bourns.com
*RoHS Directive 2002/95/EC Jan. 27, 2003 including annex and RoHS Recast 2011/65/EU June 8, 2011.
Specifications are subject to change without notice.
The device characteristics and parameters in this data sheet can and do vary in different applications and actual device performance may vary over time.
Users should verify actual device performance in their specific applications.
Applications
■
Set top box LNB ports
■
Protection modules and dongles
■
Process control equipment
■
Test and measurement equipment
■
General electronics
TBU-KE Series - TBU
®
High-Speed Protectors
Electrical Characteristics (@ T
A
= 25 °C Unless Otherwise Noted)
Symbol
Parameter
Part Number
TBU-KExxx-050-WH
TBU-KExxx-100-WH
TBU-KExxx-200-WH
TBU-KExxx-300-WH
TBU-KExxx-500-WH
TBU-KE025-050-WH
TBU-KE025-100-WH
TBU-KE025-200-WH
TBU-KE025-300-WH
TBU-KE025-500-WH
TBU-KE040-050-WH
TBU-KE040-100-WH
TBU-KE040-200-WH
TBU-KE040-300-WH
TBU-KE040-500-WH
TBU-KE050-050-WH
TBU-KE050-100-WH
TBU-KE050-200-WH
TBU-KE050-300-WH
TBU-KE050-500-WH
Min.
50
100
200
300
500
Typ.
75
150
300
450
750
12.5
6.3
3.4
2.4
1.8
13.0
6.8
3.9
3.0
2.3
13.7
7.5
4.6
3.6
3.0
Max.
100
200
400
600
1000
14.6
7.5
4.1
3.1
2.3
15.2
8.1
4.7
3.7
2.9
16.0
8.9
5.5
4.5
3.6
1
0.50
14
116
96
1.00
18
µs
mA
V
°C/W
°C/W
Unit
I
trigger
Current required for the device to go from operating state to
protected state
mA
R
device
Series resistance of
the TBU
®
device
t
block
I
Q
V
reset
R
th(j-l)
R
th(j-l)
Time for the device to go from normal operating state to protected state
Current through the triggered TBU
®
device with 50 Vdc circuit voltage
Voltage below which the triggered TBU
®
device will transition to normal operating state
Junction to package pads - FR4 using recommended pad layout
Junction to package pads - FR4 using heat sink on board (6 cm
2
)
E
T
E
L
O
S
B
O
V
imp
= 400 V
V
imp
= 400 V
V
imp
= 400 V
V
imp
= 400 V
V
imp
= 400 V
V
imp
= 500 V
V
imp
= 500 V
V
imp
= 500 V
V
imp
= 500 V
V
imp
= 500 V
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
50 mA
100 mA
200 mA
300 mA
500 mA
50 mA
100 mA
200 mA
300 mA
500 mA
0.25
10
V
imp
= 250 V
V
imp
= 250 V
V
imp
= 250 V
V
imp
= 250 V
V
imp
= 250 V
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
I
trigger
(min.) =
50 mA
100 mA
200 mA
300 mA
500 mA
Ω
Specifications are subject to change without notice.
The device characteristics and parameters in this data sheet can and do vary in different applications and actual device performance may vary over time.
Users should verify actual device performance in their specific applications.
TBU-KE Series - TBU
®
High-Speed Protectors
Reference Application
The TBU
®
device can be used to protect against excessive
voltage surges in DC biased equipment, as shown in the figure
below. Diode D1 prevents reverse voltage surges from damaging
the equipment, and the TBU
®
protector prevents any positive
surges from causing damage. An overvoltage protection device,
such as an MOV, may be used to provide additional overvoltage
protection if the surge voltage is likely to be above the maximum
rating of the TBU
®
device. D1 reverse voltage rating should be
greater than that of the OVP device at the maximum surge cur-
rent level. Typically, a 1N4007 is a suitable choice. D2 should be
chosen to be above the normal working voltage of the protected
device, but below its absolute maximum rating.
Basic TBU Operation
The TBU
®
device is a silicon-based, solid-state, resettable
device which is placed in series with a signal path. The TBU
®
device operates in approximately 1 µs - once line current
exceeds the TBU
®
device’s trigger current I
trigger
. When oper-
ated, the TBU
®
device restricts line current to less than 1 mA
typically. When operated, the TBU
®
device will block all system
voltages and any other 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 V
reset
level. The TBU
®
device will automatically reset on lines which have no DC bias
or have DC bias below V
reset
(such as unpowered signal lines).
If the line has a normal DC bias above V
reset
, the voltage
across the TBU
®
device may not fall below V
reset
after the
surge. In such cases, special care needs to be taken to ensure
that the TBU
®
device will reset, otherwise an automatic or
manual power down will be required. Bourns application
engineers can provide further assistance.
D1
1
2
Line
Side
OVP
TBU
®
Device
Performance Graphs
V-I Characteristic - TBU-KE050-300-WH (Pin 2-1)
ITRIGGER
Normalized Trip Current (A)
E
T
E
L
O
S
B
O
D2
Equip.
Typical Trigger Current vs. Temperature
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
CURRENT
(100 mA/div.)
VRESET
VOLTAGE
(5 v/div.)
0.0
-75 -50 -25
0
25 50
75 100 125 150
Junction Temperature (°C)
Specifications are subject to change without notice.
The device characteristics and parameters in this data sheet can and do vary in different applications and actual device performance may vary over time.
Users should verify actual device performance in their specific applications.
TBU-KE Series - TBU
®
High-Speed Protectors
Performance Graphs (Continued)
Power Derating Curve
3.0
Typical Resistance vs. Temperature
2.2
No additional PCB Cu
0.5 sq. in. additional PCB CU
2.5
Normalized Resistance (Ω)
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
Total Max. Power (W)
2.0
1.5
1.0
0.5
0.0
20
40
60
Junction Temperature (°C)
Reflow Profile
Profile Feature
Average Ramp-Up Rate (Tsmax to Tp)
Preheat
- Temperature Min. (Tsmin)
- Temperature Max. (Tsmax)
- Time (tsmin to tsmax)
Time maintained above:
- Temperature (TL)
- Time (tL)
Peak/Classification Temperature (Tp)
Time within 5 °C of Actual Peak Temp. (tp)
Ramp-Down Rate
Time 25 °C to Peak Temperature
E
T
E
L
O
S
B
O
80
100
120
140
0.2
0.0
-75 -50 -25
0
25
50 75 100 125 150
Junction Temperature (°C)
Pb-Free Assembly
3 °C/sec. max.
150 °C
200 °C
60-180 sec.
217 °C
60-150 sec.
260 °C
20-40 sec.
6 °C/sec. max.
8 min. max.
Specifications are subject to change without notice.
The device characteristics and parameters in this data sheet can and do vary in different applications and actual device performance may vary over time.
Users should verify actual device performance in their specific applications.
TBU-KE Series - TBU
®
High-Speed Protectors
Product Dimensions
0.85 ± 0.05
(.033 ± .002)
5.00 ± 0.10
(.197 ± .004)
0.30
(.012)
0.60
(.024)
0.30
(.012)
0.75
(.030)
3.05
(.120)
2.50 ± 0.10
(.098 ± .004)
1.90
(.075)
PIN 1 & BACKSIDE CHAMFER
1.00
(.039)
Recommended Pad Layout
TBU
®
High-Speed Protectors have a 100 % matte-tin termination
finish. For improved thermal dissipation, the recommended layout
uses PCB copper areas which extend beyond the exposed solder
pad. The exposed solder pads should be defined 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
E
T
E
L
O
S
B
O
0.30
(.012)
C
0.25
PIN 1
(.010)
DIMENSIONS:
MM
(INCHES)
0.00 - 0.05
(.000 - .002)
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 significantly
improve the junction to ambient thermal resistance, resulting in
operation at lower junction temperatures with a corresponding
benefit of reliability. All pads should soldered to the PCB, includ-
ing 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.
Thermal Resistance vs. Additional PCB Cu Area
Pad Designation
Pad #
1
2
1
100
Pin Out
Line Side
Load Side
Thermal Resistance to Ambient (°C/W)
90
80
70
60
50
40
30
20
10
0
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
2
Dark grey areas show added PCB copper area for better
thermal resistance.
Specifications are subject to change without notice.
The device characteristics and parameters in this data sheet can and do vary in different
applications and actual device performance may vary over time.
Users should verify actual device performance in their specific applications.
1、引言 汽车污染是当前人们最为关心和急需解决的重要课题之一。作为汽车排气污染物的检测的重要方法,简易瞬态工况法（VMAS法，IG法）可以统计排放总质量，监控车辆的真实排放情况，设备成本不高，测量比较准确，与新车认证检测结果具有相关性，可以检测NO相关因子等一系列优点，成为人们研究的热点。VMAS（Vehicle Mass Analysis System）检测方法在美国和欧洲都有很好的应用基础，...[详细]
PCB设计
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