Application_Alley_RF..

Application Alley
PARTNER
|
SOLVE
|
DELIVER
RF Attenuators - Reed Relays
RF Attenuators Use Reed Relays For Attenuating RF Signals
Application Alley
RF Attenuators - Reed Relays
RF Attenuators Use Reed Relays For Attenuating RF Signals
Introduction
Test equipment capable of use in RF evaluations will generally require attenuation circuits
to help them evaluate various aspects of RF
components and RF circuitry. These attenuators need a switching device to switch the
various dB levels that adjust the RF signals.
Since attenuators are typically used to calibrate
RF signal strength, the switching devices must
be very good at handling RF so they don’t end
up attenuating the signal strength themselves.
Also, the switching devices can be used on a
regular basis which add up to a switching life
concern. Electromechanical relays have been
used in this application but the mechanical life
is typically limited to less than one million operations. They can also be very expensive. New
high frequency reed relays from Standex-Meder
have become the design-in choice with their
greatly improved RF characteristics and long
life.
Figure 1. CRF physical layout
basis when testing RF components and RF
sub-assemblies and thereby require switches
that can last 10s of millions of operations. Electromechanical relays typically begin to run into
reliability problems once their mechanical life
exceeds 1 million operations. Reed relays on
the other hand, can switch into the billions of operations without any mechanical wear under low
signal conditions. Recent new RF reed relays
have flat insertion loss out to 20 GHz making
its long life and excellent RF characteristics an
ideal solution in RF attenuators.
Figure 2. Reed Relays switch low signals in electrometers.
Reed Relays Are Used in RF Circuits
Where Attenuators Are Used
Features
Attenuators are used throughout the RF world
particularly in the test equipment area. Most RF
circuits need to be calibrated. Attenuator circuits allow the RF designer and user to calibrate
their components and RF circuits. Attenuators
can be switched in and out on a production
• High reliability
• Ideal RF characteristics
• Ideal for carrying fast digital pulses with
skew rates less than 20 picoseconds.
• Ability to carry RF signals from DC up to 20
GHz (SRF)
© Standex-Meder Electronics. All Rights Reserved.
Application Alley
RF Attenuators - Reed Relays
RF Attenuators Use Reed Relays For Attenuating RF Signals
• 50 Ω characteristic impedance
• Switch to shield capacitance < 0.5 picofarads and < 0.2 pf across the open contacts.
• Dielectric strength across the contacts 200
volts
• Contacts dynamically tested
• Surface mounted
• Very low profile
• BGAs available
• Rugged thermoset over-molded packaging
• Quad-shield arrangement
Applications
• Ideal for use with systems that are switching
an assortment of signals from DC to 15 GHz
Specifications (@ 20°C) CRF Series
Min
Typ
Max
Coil characteristics
Coil resistance
Coil voltage
Pull-In
Drop-Out
Switch characteristics
135
150
5.0
0.85
165
3.75
Ω
V
V
V
Contact rating
Switching voltage
Switching current
Carry current
Static contact resistance
Dynamic contact resistance
Dielectric from voltage across
the contacts
210
V
Dielectric from voltage coil to
contacts
1500
V
Insertion Loss (@ the -3 dB
down point)
Operate time
Release time
Operate temp
Storage temp
10
170
0.5
0.5
250
250
Units
-10
-55
Watts
V
Amps
Amps
mΩ
mΩ
7
GHz
0.1
20
100
125
msec
µsec
°C
°C
Standex-Meder’s SRF series uses a quadshield that has only 0.5 pf from the open switch
to its shield and only 0.2 pf across the open
© Standex-Meder Electronics. All Rights Reserved.
contacts. This series can switch and carry pulses shorter than 50 pico-seconds with no discernible effect on the pulse’s leading and trailing
edge. So the series is excellent in a fast pulse
environment or a continuous wave environment.
Standex-Meder’s CRF series offers a flat insertion loss from DC up to 7 GHz, while the SRF
series offers an insertion loss from DC to 20
GHz. Both series are ultra small with surface
mount lead configurations
Standex-Meder’s reed relays use hermetically
sealed reed switches that are further packaged
in strong high strength thermoset molding compound, and can therefore be subject to various
environments without any loss of reliability.
The reed relay is an excellent choice because
it can operate reliably over a wide temperature
range, and represents an economical way to
carry out billions of switching operations.
Series
SRF
CRF
Surface Mount RF Reed Relay Series
Dimensions
Illustration
mm
inches
W
4.0
0.157
H
3.2
0.126
L
7.5
0.295
W
4.4
0.173
H
3.5
0.137
L
8.6
0.338
Find out more about our ability to propel your
business with our products by visiting
www.standexmeder.com or by giving us a
hello@standexelectronics.com today! One of
our brilliant engineers or solution selling sales
leaders will listen to you immediately.
About Standex-Meder Electronics
Standex-Meder Electronics is a worldwide market leader in the design, development and manufacture of standard and custom electro-magnetic components, including magnetics products and reed switch-based solutions.
Our magnetic offerings include planar, Rogowski, current, and
low- and high-frequency transformers and inductors. Our reed
switch-based solutions include Meder, Standex and OKI brand
reed switches, as well as a complete portfolio of reed relays,
and a comprehensive array of fluid level, proximity, motion, water flow, HVAC condensate, hydraulic pressure differential, capacitive, conductive and inductive sensors.
We offer engineered product solutions for a broad spectrum of product applications in the automotive, medical, test and measurement, military and aerospace,
as well as appliance and general industrial markets.
Standex-Meder Electronics has a commitment to absolute
customer satisfaction and customer-driven innovation,
with a global organization that offers sales support, engineering capabilities, and technical resources worldwide.
Headquartered in Cincinnati, Ohio, USA, Standex-Meder Electronics has eight manufacturing facilities in six
countries, located in the United States, Germany,
China, Mexico, the United Kingdom, and Canada.
For more information on Standex-Meder Electronics,
please visit us on the web at www.standexmeder.com.
Contact Information:
Standex-Meder Electronics
World Headquarters
4538 Camberwell Road
Cincinnati, OH 45209 USA
Standex Americas (OH)
+1.866.STANDEX (+1.866.782.6339)
info@standexelectronics.com
Meder Americas (MA)
+1.800.870.5385
salesusa@standexmeder.com
Standex-Meder Asia (Shanghai)
+86.21.37820625
salesasia@standexmeder.com
Standex-Meder Europe (Germany)
+49.7731.8399.0
info@standexmeder.com