
5
SEPTEMBER 1995 - REVISED SEPTEMBER 1997
TISP61060D, TISP61060P
DUAL FORWARD-CONDUCTING P-GATE THYRISTORS
PROGRAMMABLE OVERVOLTAGE PROTECTORS
P R O D U C T I N F O R M A T I O N
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
minimise the temperature rise caused by testing.
gated protector evolution and characteristics
This section covers three topics. Firstly, 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.
purpose of gated protectors
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 minimise power consumption, some designs automatically adjust
the supply voltage, V
BAT
, to a 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 minimises the voltage stress on
the SLIC, no matter what value of supply voltage.
CROSS-REFERENCE FOR TISP61060 AND LB1201AB
TISP61060 PARAMETER
DATA SHEET
SYMBOL
ALTERNATIVE
SYMBOL
ALTERNATIVE PARAMETER
RATINGS & CHARACTERISTICS
LB1201AB
Non-repetitive peak on-state pulse current
I
TSP
I
TSM
V
T
I
S
V
(BO)
I
TM
I
FM
I
P
I
P
V
ON
I
t
V
T
I
C
I
C
Pulse current
Non-repetitive peak on-state current
RMS pulse current, 60 Hz
On-state voltage
On-state voltage
Switching current
Trip current
Breakover voltage
Trip voltage
Maximum continuous on-state current
On-state current
Maximum continuous forward current
On-state current
Gate voltage, (V
GG
is gate supply voltage referenced
to the A terminal)
V
G
V
S
Supply voltage
Off-state capacitance
C
O
C
OFF
Off-state capacitance
TERMINALS
LB1201AB
Cathode 1
K1
Tip
Tip
Cathode 2
K2
Ring
Ring
Anode
A
GND
Ground
Gate
G
V
S
Supply voltage