TISP3600F3 Bourns, Inc., TISP3600F3 Datasheet - Page 8

• Manufacturer Part Number: TISP3600F3
• Description: Dual Bidirectional Thyristor Overvoltage Protectors
• Manufacturer: Bourns, Inc.

IEEE Std 802.3, 2000 Edition (IEEE Standard for Information technology— Telecommunications and information exchange between sys-
tems— Local and metropolitan area networks— Specific requirements, Part 3: Carrier sense multiple access with collision detection
(CSMA/CD) access method and physical layer specifications) specifies three network insulation withstands: 1.5 kV rms a.c., 2.25 kV d.c.
and 2.4 kV 1.2/50 impulse. Under these conditions there shall be no insulation breakdown, as defined in IEC 60950:1991. Also, there is
a 2 MΩ insulation resistance minimum requirement measured at 500 V d.c. (250 µA maximum).
In Figure 8, at least one protection element of a TISP3700F3 must be used to give the 500 V working voltage (V
tion resistance requirement. To avoid breakover during the 2.4 kV impulse test, five TISP3700F3 protection elements (2.5 kV V
SL packages) or six TISP3600F3 elements (2.52 kV V
0.3/50 common-mode impulse. A TISP3700F3 (1 kV V
the impulse.
Figure 9a shows a traditional overvoltage protection scheme for a high power switching thyristor, Th1. The protection voltage level is set
by a BOD (BreakOver Diode) thyristor. Potentially damaging voltage transients cause the BOD to crowbar which turns on thyristor Th1.
The on state of thyristor Th1 causes the current drawn by the load from the d.c. voltage supply +V to continuously increase until the fast
acting fuse F1 operates.
Resistor R1 limits the peak BOD current and diode D1 protects the unidirectional BOD against reverse polarity voltage. Resistor R2 pro-
vides a d.c. return, and with capacitor C1, forms a low pass network to prevent false triggering from noise. Further trigger voltage dis-
crimination and isolation is given by the series combination of zener diode D2 and reverse blocking diode D3. Capacitor C2 and Resistor
R3 form the normal snubber network for the thyristor Th1.
Figure 9b shows the TISP3x00F3 replacing the unidirectional BOD and reverse polarity protection diode, D1. Reverse polarity protection
is not needed for the TISP3x00F3 as it is bidirectional.
LAN System Insulation Protection (continued)
BOD Replacement
TISP3600F3, TISP3700F3
+V
C1
BOD
R1
D1
a)
F1
R2
D2
LOAD
Th1
D3
DRIVE
GATE
Figure 9. Thyristor Protection
APPLICATIONS INFORMATION
DRM
DRM
R3
, 3 SL packages) are required. Transmitters are required to withstand a 1 kV
), from each conductor to ground at the transmitter, would not breakover during
C2
n
3x00F3
TISP
C1
+V
R1
b)
Customers should verify actual device performance in their specific applications.
F1
R2
D2
LOAD
Th1
D3
DRIVE
GATE
Specifications are subject to change without notice.
R3
AI3XAA
C2
NOVEMBER 1997 - REVISED JANUARY 2007
DRM
) to meet the insula-
DRM
, 2-1/2