TC04A-200.TD Ver la hoja de datos (PDF) - Semtech Corporation
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TC04A-200.TD Datasheet PDF : 8 Pages
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TC04A-200
PROTECTION PRODUCTS
Applications Information (continued)
Operation of Battery Tracking TransClamp
Telecommunications lines are vulnerable to transient
disturbances from a variety of sources. Disturbances
strike the line or near it and are then propagated to
the extremities of the lines where sensitive electronics
are located. The TransClamp series of thyristor surge
suppressors are designed to protect sensitive telecom-
munications equipment from transient voltages result-
ing from lightning strikes and AC power line distur-
bances.
The TC04A-200 utilizes internal diodes connected from
each line to ground provide protection from positive
overvoltages. During a positive duration transient,
these internal diodes are forward biased shunting the
transient current to ground. The voltage seen by the
protected IC will be the forward clamping voltage (VCF)
of the diode. A gated TVS thyristor provides protection
against negative surges. When the voltage on the Tip
or Ring line falls below the reference voltage at the
gate, the triggering diode begins to conduct forcing the
TVS thyristor to crowbar (turn-on) to a low on-state
voltage. The current required to trigger the thyristor is
defined as the switching current (IS). The maximum
voltage seen by the protected IC will be the switching
voltage (VS). Once the transient subsides, the device
will return to a high impedance (off-state) when the line
current falls below the holding current (IH). The high
holding current of the TC04 prevents d.c. latch-up
because the holding current is higher than the SLIC
can source.
Protecting One SLIC Line Pair
The TC04A-200 battery tracking TransClamp is specifi-
cally designed to protect subscriber line interface
circuits (SLICs). The protection voltage of the device is
referenced to the systems DC battery voltage. There-
fore, the protection voltage will be essentially the same
as the SLIC supply voltage, minimizing the stress on
the protected device. The TC04A-200 may be refer-
enced to battery voltages ranging from -5V to -100V.
Pins 1-4 are connected to Tip line or A-lead and pins
13-16 are connected to the Ring line or B-lead. The
battery feed voltage source is connected to the gate of
the internal SCRs at pins 6 & 11. Pins 7-10 are
connected to ground. All ground pins should be con-
nected for best results. A 0.1µF capacitor is recom-
mended between the gate & ground to speed up the
triggering of the device.
ã 2000 Semtech Corp.
5
TC04 Connection Diagram
1
16
2
15
3
14
4
13
5
12
6
11
7
10
8
9
TC04 IV Characteristic Curve
Symbol
VDRM
VS
VT
VC
VF
VCF
IDRM
IS
IT
IH
IPP
Parameter
Reverse Stand-Off (Off-State) Voltage
Switching Voltage
On-State Voltage
Reverse Clamping Voltage
Diode forward Voltage
Forward Clamping Voltage
Reverse leakage (Off-State) Current
Switching Current (Gate Triggering Current)
On-State Current (Continuous)
Holding Current
Peak Impulse Current
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