4 2003 Semtech Corp. www.semtech.com
PROTECTION PRODUCTS
LC04-12
Figure 1 - Connection for Differential (Line-to-Line)
Protection of two Tip/Ring Line Pairs
IP 1
IP 2
RING 1
RING 2
Device Connection Options
The LC04-12 is designed to protect up to four high-
speed data lines (two differential pairs) from transient
over-voltages which result from lightning and ESD.
Differential protection of two line pairs is achieved by
connecting the device as follows (Figure 1): Pins 1-4
are connected to line 1 of the first pair (i.e. Tip 1) and
pins 13-16 are connected to line 2 of the first pair (i.e.
Ring 1). Pins 5-8 are connected to line 1 of the second
pair (i.e. Tip 2) and pins 9-12 are connected to line 2 of
the second pair (i.e. Ring 2).
Common mode protection of one line pair is achieved
by connecting the device as shown in Figure 2. The
protected lines are connected at pins 1-4 and pins 9-
12. connection to ground is made at pins 5-8 and 13-
16. optionally, the lines may be connected at pins 1-4
and 5-8 with pins 9-16 being connected to ground.
All pins should be connected for best results. Minimize
parasitic inductance in the protection circuit path by
keeping the trace length between the protected line
and the LC04-12 as short as possible. Ground con-
nections should be made directly to the ground plane.
ADSL Protection
Configuring The LC04-12 for Remote Terminal ADSL
Applications
A typical ADSL protection circuit for remote terminals is
shown in Figure 3. The LC04-12 is connected between
Tip & Ring on the transmit and receive line pairs. It
provides protection to common mode (line-to-ground)
lightning and ESD surges. It is designed to meet the
intra-building requirements of Bellcore GR-1089. To
complete the protection circuit, the LCDA12C-1 is
employed as the IC side protection element. This
device helps prevent the transceiver from latching up
by providing fine clamping of transients that are
coupled through the transformer.
Figure 2 - Connection for Common Mode (Line-to-
Ground) Protection of one Tip/Ring Line Pair
TIP
ND
GND
RING
Applications Information