TISP61060P-S Bourns Inc., TISP61060P-S Datasheet - Page 7

• Manufacturer Part Number: TISP61060P-S
• Description: Sidacs
• Manufacturer: Bourns Inc.

Specifications of TISP61060P-S

• Mounting Style: Through Hole
• Package / Case: PDIP-8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The electrical characteristics of a thyristor overvoltage protector are strongly dependent on junction temperature, T
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.
This section covers three topics. First, it is explained why gated protectors are needed. Second, the performance of the original IC (integrated
circuit) based version is described. Third, the performance improvements given by the TISP61060 are detailed.
Fixed voltage thyristor overvoltage protectors have been used since the early 1980s to protect monolithic SLICs (Subscriber Line Interface
Circuits) against overvoltages on the telephone line caused by lightning, a.c. power contact and induction. As the SLIC was usually powered
from a fixed voltage negative supply rail, the limiting voltage of the protector could also be a fixed value. The TISP1072F3 is a typical example
of a fixed voltage SLIC protector.
SLICs have become more sophisticated. To minimize power consumption, some designs automatically adjust the supply voltage, V
value that is just sufficient to drive the required line current. For short lines the supply voltage would be set low, but for long lines, a higher
supply voltage would be generated to drive sufficient line current. The optimum protection for this type of SLIC would be given by a protection
voltage which tracks the SLIC supply voltage. This can be achieved by connecting the protection thyristor gate to the SLIC supply, Figure 2.
This gated (programmable) protection arrangement minimizes the voltage stress on the SLIC, no matter what value of supply voltage.
In 1986, an IC based gated protector was proposed (A 90 V Switching Regulator and Lightning Protection Chip Set, Robert K. Chen, Thomas
H. Lerch, Johnathan S. Radovsky, D. Alan Spires, IEEE Solid-State Circuits Conference, February 20, 1986, pp 178/9 and pp 340/1). Commer-
cially, this resulted in the AT&T Microelectronics LB1201AB device and the higher current Texas Instruments Inc. TCM1060 device.
This implementation consisted of four diodes and two high holding current thyristors. Positive overvoltages on the line wires are clipped to
ground by forward conduction of the wire to ground diodes. Negative overvoltages are initially clipped close to the SLIC negative supply rail,
V
be about 1.5 V lower than the SLIC supply voltage. If sufficient current is available from the overvoltage, then the thyristor will switch into a
low voltage on-state condition. When the thyristor crowbars, the two series gate diodes prevent the SLIC supply from being shorted to ground
via the thyristor gate. As the overvoltage subsides the high holding current of the crowbar prevents d.c. latchup (see Figure 1).
SEPTEMBER 1995 — REVISED MARCH 2006
Specifications are subject to change without notice.
Customers should verify actual device performance in their specific applications.
Electrical Characteristics
Purpose of Gated Protectors
Gated Protector Evolution and Characteristics
IC Based Protectors
BAT
, by conduction of the thyristor cathode-gate and gate series diode. This means that the protection voltage level for slow wave forms will
TISP61060 Gated Protector Series
GENERATOR
RESISTANCE
GENERATOR
0 - 600 Vrms
SOURCE
600 Ω
600 Ω
A.C.
Figure 2. Simplified IC Based SLIC Protector Circuit
WIRE
WIRE
RING
TIP
50 Ω
50 Ω
R1
R2
APPLICATIONS INFORMATION
PROTECTOR
IC BASED
100 nF
SLIC
C1
Th4
Th5
I
G
I
SLIC
SLIC
I
BAT
SWITCHING MODE
V
D2
POWER SUPPLY
BAT
C2
D1
Tx
AI6XAD
J
. Hence a characteristic
BAT
, to a