TISP61521 Bourns, Inc., TISP61521 Datasheet - Page 7

• Manufacturer Part Number: TISP61521
• Description: Dual Forward-conducting P-gate Thyristors Programmable Overvoltage Protectors
• Manufacturer: Bourns, Inc.

Application Circuit
Figure 6 shows a typical TISP61521 SLIC card protection circuit. The incoming line conductors, Ring (R) and Tip (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 TISP61521 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-conductor protection voltage is twice the conductor to ground value.
Relay contacts 3a and 3b connect the line conductors to the SLIC via the TISP61521 protector. The protector gate reference voltage comes
from the SLIC negative supply (V BATH ). A 220 nF gate capacitor sources the high gate current pulses caused by fast rising impulses.
TISP61521 SLIC Protector
Figure 5. Protector Fast Impulse Clamping and Switching Waveforms
-20
-40
-60
-80
-1
-2
-3
-4
-5
0
1
0
0.0
0.0
Q GS
V K
0.5
0.5
Time - µs
Time - µs
I G
1.0
Customers should verify actual device performance in their specific applications.
1.0
V BATH
I K
AI6XD E
1.5
1.5
Specifications are subject to change without notice.
APRIL 2001 REVISED JULY 2008