MTL Instruments CA Specifications

• Large bandwidth dc to 2GHz

• Robust — 10kA surge rating

• Range of connector styles to suit all

applications

• DC coupled

• Low insertion loss and VSWR

• Tested in accordance with

BS6651:1999

technical datasheet

CA Series

Wideband, high current devices for protection of radio transmitters and
receivers connected to coaxial feeders

The CA Series of surge protection
devices prevents surges and transient

over-voltages conducted through coaxial
cables from damaging electronic systems
such as telemetry outstations. They protect
vulnerable equipment without affecting
normal operation, passing high frequency
signals with little attenuation while diverting
surge currents safely to earth and clamping
output voltages to safe levels.

Typical applications for the CA Series
include the protection of radio telemetry
systems, mobile communications base
stations and, where high induced voltages
may be present, in aerial systems.

Receivers & transmitters are particularly
vulnerable to damage from the effects of

lightning. Their remote locations and physical
construction make them a likely target for
lightning activity. The use of semiconductors
and integrated circuits in transmitters and
receivers has rendered them particularly
prone to damage from these disturbances.

Excellent performance levels are
achieved using high energy gas
discharge tubes, in precision engineered

compact enclosures, to produce superior
surge suppression and transmission
characteristics. The protection circuitry is
capable of diverting 10kA impulses whilst
the brass bodies and connectors are silver
plated and are designed to meet harsh
environmental requirements.

A wide range of connector t ypes are
available (including BNC, N-type, TNC,
UHF and F-type) to suit all application

requirements. In addition, bulkhead mounting
options are provided for where insertion into
a panel is preferable. Models are supplied
with a choice of working voltage and
characteristic impedance (90V, 150V and
350V) are provided for most units in the range.

Mounting kits and enclosures to
simplify installation, are available for the

CA Series. Panel mounting can be achieved
using the MC range of mounting brackets,
or, for a larger number of units, the MK range
of busbar mounting kits can be supplied (for
mounting up to 20 units). IP65 weatherproof
enclosures are also available to suit every
application.

901-136 Rev F 020510

www.mtl-inst.com [e-mail]

TYPICAL PERFORMANCE

Limiting voltage

When choosing a surge protection device it
is important to determine the limiting voltage
for a given surge level. Figure 1 shows the
effectiveness of the CA350 series for a 6kV
overvoltage. The limiting voltage shows
the level of surge ‘let-through’ the surge
protection device - in this case just over 600V
for a fraction of a microsecond and represents
a very small amount of energy.

Attenuation characteristics

The inclusion of a surge protection device
should have minimal effect on a system other
than to safeguard vulnerable equipment. The
attenuation plot shown in figure 2 emphasises
how little the system is changed after fitting a
CA series SPD.

Figure 1 Typical limiting voltage for the CA350

Return Loss

Figure 3 shows the return loss for the N-type
variant of the CA series.

Equivalent circuit

An equivalent circuit model of the CAxx/N
is illustrated in figure 4. This model gives
reasonable agreement with measured
frequency response to 4.2GHz and return loss
to 2.5GHz.

Figure 2 Typical attenuation plot for N-type CA devices

Figure 3 Typical return loss for N-type CA devices

Figure 4 Equivalent circuit diagram

The give n data is only inten ded as a product de scription an d should not be reg arded as a lega l warranty of pro perties
or guara ntee. In the i nterest of fu rther te chnica l develop ments, we res erve the r ight to make de sign cha nges.

EUROPE (EM EA): [phone] THE AMER ICAS: [phone] ASIA-PACIF IC: [phone]

[e-mail] [e-mail] [e-mail] 901-136 Rev E 020510