C650-180-WH_12 Datasheet, PDF (6/6 Pages) Bourns Electronic Solutions – C650 and C850 Series TBU® High-Speed Protectors

C650 and C850 Series TBU^® High-Speed Protectors
Reference Application
The C-series devices are general protectors that can be used in a variety of applications. The basic operation of the device will be
demonstrated using the single line application shown in the figure below. The test circuit was subjected to a 1000 V, 10/700 µs surge
waveform. The devices used were the TBU-C850-100-WH and a 2031-42T-SM-RPLF GDT (OVP) with a 10 ohm resistor for the load
impedance.
Line
OVP _{TBU® Device}
ZLOAD
General Application Circuit
The graph below shows the waveforms for the voltage across the overvoltage protector (GDT) and the current through the TBU^®
device. As the input line voltage increases, the current through the TBU^® device increases rapidly until the trip current is reached. Due
to finite reaction time for fast transients, the peak level may exceed the low frequency data sheet maximum for a very short period,
typically ~100 ns. After this initial overshoot, the TBU^® device will transition to the protected state, setting the current to the nominal
current limiting level (~150 mA for this example). The TBU^® device will then reduce the current down it to its very low quiescent level
of 1 mA, typically. As the input line voltage increases to about 500 V, the GDT is triggered, reducing the input line voltage to a very low
level which prevents the TBU^® device from being subjected to a voltage level which exceeds its maximum rating (850 V in this
example). The TBU^® High-Speed Orotector and the GDT will remain in these states until the surge ends, which is about 700 µs later
in this example. Only the first 4 µs of the surge are shown in the graph. For surges or AC voltages below the GDT breakover voltage,
the GDT will not activate, and the TBU^® device will stay in the protecting mode, blocking high voltages from the protected equipment.
900
800
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500
400
300
200
100
0
100
0
0.5 1
TBU^® Device Current
GDT Voltage
1.5
2 2.5
3 3.5
1000
800
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200
0
-200
-400
-600
-800
-1000
4
Time (µs)
TBU-C850-100-WH Response to a 1000 V, 10/700 µs Surge
REV. 06/12
“TBU” is a registered trademark of Bourns, Inc. in the United States and other countries.
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.