TISPPBL3 Datasheet, PDF (10/14 Pages) Bourns Electronic Solutions – DUAL FORWARD-CONDUCTING P-GATE THYRISTORS FOR ERICSSON MICROELECTRONICS SUBSCRIBER LINE INTERFACE CIRCUITS (SLIC)

TISPPBL3 Programmable Protector
APPLICATIONS INFORMATION
TISPPBL3 Voltage Limiting Performance (continued)
40
30
20
SLIC MINIMUM VOLTAGE WITHSTAND
AND TISPPBL3 VOLTA GE LIMITING
vs
TIME
10
TISPPBL3
0
V_BAT
V_BAT - 10
V_BAT - 20
V_BAT - 30
V_BAT - 40
1 µs
0.25 µs
10 ms
0.7 V ISOLATION DIODE (D1)
VOLTAGE DROP FROM V _Bat
TISPPBL3
Time
Figure 9. SLIC Voltage Ratings And TISPPBL3 Protection Levels
AI6XDF
Application Circuit
Figure 10 shows a typical TISPPBL3 SLIC card protection circuit. The incoming line conductors, R and T, connect to the relay matrix via the
series overcurrent protection (RSA and RSB). Fusible resistors, fuses and positive temperature coefficient (PTC) thermistors can be used for
overcurrent protection. Normally, the SLIC reference designs recommend using 40 Ω matched fusible resistors, such as the Bourns 2x40 Ω,
2 % tolerance, 0.5 % matched 4B04B-523-400 or the 4B04B-524-400 with a thermal fuse. These resistors will reduce the prospective current
from the surge generator for both the TISPPBL3 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 TISPPBL3 protector. Closing contacts 3a and 3b connects the
TISPPBL3 protector in parallel with the ring/test protector. As the ring/test protector requires much higher voltages than the TISPPBL3 to
operate, it will only operate when the contacts 3a and 3b are open. Both protectors will divert the same levels of peak surge current, and their
required current ratings should be similar. The TISPPBL3 protector gate reference voltage comes from the SLIC negative supply feed (VB). A
local gate capacitor, C1, sources the gate current pulses caused by fast rising impulses.
OCTOBER 2000 - REVISED FEBRUARY 2005
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.