TISP70XXF3 Bourns Electronic Solutions, TISP70XXF3 Datasheet - Page 15
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TISP70XXF3
Manufacturer Part Number
TISP70XXF3
Description
LOW-VOLTAGE TRIPLE ELEMENT BIDIRECTIONAL THYRISTOR OVERVOLTAGE PROTECTORS
Manufacturer
Bourns Electronic Solutions
Datasheet
1.TISP70XXF3.pdf
(16 pages)
www.DataSheet4U.com
DataSheet U .com
The protection voltage, (V (BO) ), increases under lightning surge conditions due to thyristor regeneration. This increase is dependent on the
rate of current rise, di/dt, when the TISP
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
breakdown region.
The off-state capacitance of a TISP
and the ac voltage, V d . All the capacitance values in this data sheet are measured with an ac voltage of 1 Vrms. When V D >> V d , the capaci-
tance value is independent on the value of V d . 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.
Longitudinal Balance
Figure 20 shows a three terminal TISP
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 C TG >C RG . Capacitance C TG is equivalent to a capacitance of C RG in parallel with the capacitive difference of (C TG - C RG ). The line
capacitive unbalance is due to (C TG - C RG ) and the capacitance shunting the line is C TR +C RG /2.
Off-State Capacitance
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
included.
Capacitance
Protection Voltage
4
TISP70xxF3 (LV) Overvoltage Protector Series
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device is sensitive to junction temperature, T J , and the bias voltage, comprising of the dc voltage, V D ,
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device with its equivalent “delta” capacitance. Each capacitance, C TG , C RG and C TR , is the true
device is clamping the voltage in its breakdown region. The V (BO) value under surge conditions can
APPLICATIONS INFORMATION
Figure 20.
Customers should verify actual device performance in their specific applications.
Specifications are subject to change without notice.
MARCH 1994 - REVISED MARCH 2006
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