TISP4070L3BJ, TISP4350L3BJ
BIDIRECTIONAL THYRISTOR OVERVOLTAGE PROTECTORS
AUGUST 1999 — REVISED NOVEMBER 1999
power cross pass routes
This discussion covers typical modem flows.
FLOW
COMMENT
box A
A
Y
N
No tests
The criterion for box A is if the modem connects to an outside TNV
line.
The majority of modems will be connected to an outside line, so the
answer is
yes.
The
yes
path goes to box B.
B
box B
A
Y
B
Y
N
E
C
The criterion for box B is if the equipment has a limit of
≤
100 A
2
s at
600 V rms for Test 1. Many interpret this as a fuse with I
2
t
≤
100 A
2
s
and often miss the 600 V a.c. breaking requirement. However, the
current loop is completed by the fuse and other equipment
components. To ensure that the fuse I
2
t sets the equipment
performance, the other current loop components, such as the printed
wiring (PW), must have a higher I
2
t values than the fuse. Certainly the
fuse I
2
t needs to be lower than 100 A
2
s but other components, for
example IC packaging, may impose a hazard-free limit of 10 A
2
s. (This
conflicts with FCC Part 68 Type A surge pass requirement of 8 A
2
s.)
A
yes
leads to box C and a
no
to box E.
boxes E and I
E
Y
N
I
Y
N
The criterion for box E is for a minimum telecommunications line cord
of No. 26 AWG to be supplied or specified.
Fail
F
A
yes
leads to box F and a
no
to box I.
The criterion for box I is to pass Test 1.
If all the four pass criteria of Test 1 are met, this is a
yes
and the flow
goes to box F.
A
no
result fails the equipment.
PRODUCT
INFORMATION
7
POINN [ POWER INNOVATIONS LTD ]
