PROTECTION PRODUCTS
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PROTECTION PRODUCTS
SI04-14
Surging Ideas
TVS Diode Application Note
Revision 04/27/2004
ESD Protection Solution for LVDS Interfaces
LVDS or Low-Voltage Differential Signaling is defined by
both the IEEE 1596.3 and the ANSI/TIA/EIA-644
standards to be a technology that performs high-speed
data transmission for communication applications such
as hubs, set-top boxes, and flat panel displays. In
general, the LVDS interface consists of a driver
connecting to a receiver via a cable. If not protected
properly, both the driver and the receiver are
susceptible to damages from threats such as
electrostatic discharges.
As the name implies, LVDS operates with low signal
levels. In order to maintain low stress level on the
interfaces, a protection device with low operating and
low clamping voltage is needed. LVDS also performs
high-speed data transmission greater than
155.5Mbps. The typical data transmission rate of
LVDS is 500Mbps. Although LVDS can theoretically
achieve a maximum of 1.923Gbps based on a loss-
less media, 655Mbps is the maximum data
transmission rate recommended by both the IEEE
1596.3 and the ANSI/TIA/EIA-644 standards. Having
high-speed data rate means the protection device
used to protect the LVDS interface must be low
capacitance to maintain signal integrity.
The Semtech SRV05-4 is a 5V TVS protection device
that offers low capacitance and low clamping voltage.
Figure 1 shows the connection of the Semtech
SRV05-4 to provide common mode and differential
mode protection for two LVDS interfaces. The figure
also shows how the Semtech SRV05-4 is used to
protect the lines on both the driver and the receiver
side. In the diagram, the Semtech SRV05-4 is
connected in both line-to-line and line-to-ground
configuration. The line-to-line connection provides
differential mode protection, while the line-to-ground
connection serves as common mode protection.
The typical differential mode capacitance of the
Semtech SRV05-4 is less than 1pF and the typical
common mode capacitance is 3pF. The low
capacitance of the Semtech SRV05-4 will ensure that
the signal integrity will not degrade at a data rate up to
655Mbps, the maximum data rate recommended.
Furthermore, the Semtech SRV05-4 provides
protection to and beyond Level 4 of IEC 61000-4-2
ESD (±8kV Contact, ±15kV Air) as well as protection to
IEC 61000-4-4 EFT (40A, 5/50ns) and IEC61000-4-5
lightning (12A, 8/20µs). Regardless of the level of the
threat environment, the Semtech SRV05-4 offers low
clamping voltage to provide superior protection for
LVDS interfaces.
With LVDS’s specific characteristics and functions, in
order to provide adequate ESD protection for its
interfaces, an appropriate protection device should
accommodate the high-speed applications and at the
same time, provide sufficient level of protection
against the threat environment. Low capacitance and
low clamping voltage coupled with multiple protection
capabilities allow the Semtech SRV05-4 to provide full
protection for LVDS interfaces without interfering with
the high data transmission rate.
Figure 1. Semtech SRV05-4 for LVDS Protection
