© 2013 TELEDYNE RELAYS (800) 284-7007 • www.teledynecoax.com CCR-38S/CR-38S Page 11
CCR-38S\CR-38S\072013\Q3
Series CCR-38S/CR-38S
Multi-Throw DC–18 GHz/DC-22 GHz
Normally Open Coaxial Switch
COAX SWITCHES
Actuator
An actuator is the electromechanical mechanism that
transfers the RF contacts from one position to another upon
DC command.
Arc Suppression Diode
A diode is connected in parallel with the coil. This diode
limits t he “revers e EMF spike” gener ated wh en the c oi l de -
energizes to 0.7 volts. The diode cathode is connected to
the po sitive side of the c oil and the ano de is connected to
the negative side.
Date Code
All sw itch es are m ar ked with ei ther a uni que se ri al numbe r
or a date code. Date codes are in accordance with MIL-
STD-1285 Paragraph 5.2.5 and consist of four digits.
The fi rst two digits defi ne the year and the last two digits
defi ne t he week of the year (YYWW). Thus, 1032 id entifi es
switches that passed through fi nal inspection during the
32nd week of 2010.
Indicator
Indicators tell the system which position the switch is in.
Other names for indicators are telemetry contacts or tellback
circuit. Indicators are usually a set of internally mounted DC
co nt ac t s linked to th e ac tu ato r. They ca n be w ir e d to digi t al
input lines, status lights, or interlocks. Unless otherwise
specifi ed, the maximum indicator c ontact rating is 30 Vdc,
50 mA, or 1.5 Watts into a resistive load.
Isolation
Isolation is the measure of the power level at the output
co nnecto r of an unco nnecte d RF chann el as referenc ed to
the power at the input connec tor. It is specifi ed in dB below
the input power level.
Multi-Throw Switch
A multi - th row sw itc h is a sw itc h wit h on e input an d thr ee o r
more output ports. The CCR-38 can switch a microwave
signal to any of 2,3,4,5 or 6 output from a single common
input.
Switching Time
Switching time is the total interval beginning with the arrival
of the leading edge of the command pulse at the switch DC
input and ending w it h t h e completi o n of t he sw itc h t r ansfe r,
including contact bounce. It consists of three parts: (1)
inductive delay in the coil, (2) transfer time of the physical
movement of the contacts, and (3) the bounce time of the
RF contacts.
TTL Switch Driver Option
As a special option, switch drivers can be provided for both
failsafe and latching switches, which are compatible with
industry-standard low-power Schottky TTL circuits.
TD-Option
This option includes a decoder. The 3-bit parallel command
is decoded to internally select the appropriate position. See
the logic tables. The TD -Option increases the Vsw supply
current demand by 50mA max at 28Vdc and +20°C.
Performance Parameters vs Frequency
Generally speaking, the RF performance of coaxial switches
is frequency dependent. With increasing f requency, VSWR
and insertion loss increase while isolation decreases. All
data sheets specify these three parameters as “worst case”
at the highest operating frequency. If the switch is to be
used over a narrow frequency band, better performance
can be achieved.
Actuator Current vs Temperature
The resistance of the actuator coil varies as a function of
temperature. There is an inverse relationship between the
oper ating temperatur e of the switch and t he actuator dri ve
current. For switches operating at 28 VDC, the approximate
actuato r drive cur rent at temperat ure, T, c an be cal culated
using the equation:
Magnetic Sensitivity
An electro-mechanical switch can be sensitive to ferrous
materials and external magnetic fi elds. Neighboring ferrous
materials should be permitted no closer than 0.5 inches and
adjacent external magnetic fi elds should be limited to a fl ux
density of less than 5 Gauss.
GLOSSARY
IA
[1 + .00385 (T-20)]
Where:
IT= Actuator current at temperature, T
IA = Room temperature actuator current –
see data sheet
T= Temperature of interest in °C
IT =
Carrier
Frequency 1 Carrier
Frequency 2 PIM 3rd Order
Frequency PIM 5th
Order Fre-
quency
870 MHz 893 MHz 847 MHz 824 MHz
3rd Order
Intermodulation 5th Order
Intermodulation
Multiple
Positions –96 dBm –115 dBm
–139 dBc –158 dBc
SPECIAL FEATURE
Switching High-Power or Highly Sensitive Signals
Ensure the most linear response with the best galvanically
matched contact system in the industry. Extremely low
passive intermodulation is standard on all of our switches.