TISP61511D Gated Protectors
APPLICATIONS INFORMATION
Electrical Characteristics
The electrical characteristics of a thyristor overvoltage protector are strongly dependent on junction temperature, T
J
. Hence a characteristic
value will depend on the junction temperature at the instant of measurement. The values given in this data sheet were measured on commercial
testers, which generally minimize the temperature rise caused by testing.
Application Circuit
Figure 3 shows a typical TISP61511D SLIC card protection circuit. The incoming line wires, R and T, connect to the relay matrix via the series
overcurrent protection. Fusible resistors, fuses and positive temperature coefficient (PTC) resistors can be used for overcurrent protection.
Resistors will reduce the prospective current from the surge generator for both the TISP61511D and the ring/test protector. The TISP7xxxF3
protector has the same protection voltage for any terminal pair. This protector is used when the ring generator configuration may be ground or
battery-backed. For dedicated ground-backed ringing generators, the TISP3xxxF3 gives better protection as its inter-wire protection voltage is
twice the wire to ground value.
Relay contacts 3a and 3b connect the line wires to the SLIC via the TISP61511D protector. The protector gate reference voltage comes from the
SLIC negative supply (V
BAT
). A 220 nF gate capacitor sources the high gate current pulses caused by fast rising impulses.
OVER-
CURRENT
PROTECTION
TIP
WIRE
R1a
RING/TEST
PROTECTION
Th1
S1a
Th3
S2a
TEST
RELAY
RING
RELAY
SLIC
RELAY
S3a
SLIC
PROTECTOR
Th4
SLIC
RING
WIRE
R1b
Th2
TISP
3xxxF3
OR
7xxxF3
S3b
S1b
S2b
Th5
TISP
61511D
V
BAT
220 nF
TEST
EQUIP-
MENT
RING
GENERATOR
AI6XAA
Figure 3. Typical Application Circuit
Impulse Conditions
Most lightning tests, used for equipment verification, specify a unidirectional sawtooth waveform which has an exponential rise and an
exponential decay. Wave shapes are classified in terms of Peak Amplitude (voltage or current), rise time and a decay time to 50 % of the
maximum amplitude. The notation used for the wave shape is
amplitude, rise time/decay time
. A 38 A, 5/310
µs
wave shape would have a
peak current value of 38 A, a rise time of 5
µs
and a decay time of 310
µs.
There are three categories of surge generator type; single wave shape, combination wave shape and circuit defined. Single wave shape
generators have essentially the same waveshape for the open circuit voltage and short circuit current (e.g. 10/1000
µs
open circuit voltage
and short circuit current). Combination generators have two wave shapes, one for the open circuit voltage and the other for the short circuit
current (e.g. 1.2/50
µs
open circuit voltage and 8/20
µs
short circuit current). Circuit specified generators usually equate to a combination
generator, although typically only the open circuit voltage waveshape is referenced (e.g. a 10/700
µs
open circuit voltage generator typically
produces a 5/310
µs
short circuit current). If the combination or circuit defined generators operate into a finite resistance the wave shape
produced is intermediate between the open circuit and short circuit values.
JULY 1995 — REVISED MARCH 2006
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.
BOURNS [ BOURNS ELECTRONIC SOLUTIONS ]
