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 [email protected] 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) [email protected] Meder Americas (MA) +1.800.870.5385 [email protected] Standex-Meder Asia (Shanghai) +86.21.37820625 [email protected] Standex-Meder Europe (Germany) +49.7731.8399.0 [email protected]