|TISP7150F3D||MEDIUM & HIGH-VOLTAGE TRIPLE ELEMENT BIDIRECTIONAL THYRISTOR OVERVOLTAGE PROTECTORS|
|TISP7150F3D Datasheet PDF : 19 Pages |
TISP7xxxF3 (MV, HV) Overvoltage Protector Series
rise, di/dt, when
), increases under
the TISP® device
is clamping the
due to thyristor regeneration. This increase is
its breakdown region. The V(BO) value under
dependent on the
surge conditions can
be estimated by multiplying the 50 Hz rate V(BO) (250 V/ms) value by the normalized increase at the surge’s di/dt. An estimate of the di/dt can
be made from the surge generator voltage rate of rise, dv/dt, and the circuit resistance.
As an example, the ITU-T recommendation K.21 1.5 kV, 10/700 surge has an average dv/dt of 150 V/µs, but, as the rise is exponential, the
initial dv/dt is three times higher, being 450 V/µs. The instantaneous generator output resistance is 25 Ω. If the equipment has an additional
series resistance of 20 Ω, the total series resistance becomes 45 Ω. The maximum di/dt then can be estimated as 450/45 = 10 A/µs. In
practice, the measured di/dt and protection voltage increase will be lower due to inductive effects and the finite slope resistance of the TISP®
The off-state capacitance of a TISP® device is sensitive to junction temperature, TJ, and the bias voltage, comprising of the dc voltage, VD,
and the ac voltage, Vd. All the capacitance values in this data sheet are measured with an ac voltage of 1 Vrms. When VD >> Vd, the capaci-
tance value is independent on the value of Vd. Up to 10 MHz, the capacitance is essentially independent of frequency. Above 10 MHz, the
effective capacitance is strongly dependent on connection inductance. For example, a printed wiring (PW) trace of 10 cm could create a circuit
resonance with the device capacitance in the region of 80 MHz.
Figure 35 shows a three terminal TISP® device with its equivalent “delta” capacitance. Each capacitance, CTG, CRG and CTR, is the true
terminal pair capacitance measured with a three terminal or guarded capacitance bridge. If wire R is biased at a larger potential than wire T,
then CTG > CRG. Capacitance CTG is equivalent to a capacitance of CRG in parallel with the capacitive difference of (CTG -CRG). The line
capacitive unbalance is due to (CTG -CRG) and the capacitance shunting the line is CTR +CRG/2 .
All capacitance measurements in this data sheet are three terminal guarded to allow the designer to accurately assess capacitive unbalance
effects. Simple two terminal capacitance meters (unguarded third terminal) give false readings as the shunt capacitance via the third terminal is
MARCH 1994 - REVISED MARCH 2006
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.
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