Power management solutions for aerospace & defence applications
01 February 2022
Figure 2. Power management tool suite
Semiconductor firm specialising in data conversion, signal processing & power management, Analog Devices’ broad portfolio of antenna-to-bits solutions helps make possible today’s mission-critical & rugged advanced aircraft, space systems & defence platforms.
This article was originally featured in the February 2022 issue of EPDT magazine [read the digital issue]. And sign up to receive your own copy each month.
Analog Devices, Inc. (ADI) components and high performance signal chain solutions are highly integrated to reduce size, weight and power (SWaP) requirements. And as Gabino Alonso, Director of Strategic Marketing for Analog Devices’ Power by Linear Group explains here, optimal performance of high performance signal chain devices requires complementary low noise and high efficiency power management solutions.
Power by Linear™ products for aerospace & defence power systems are designed, developed and factory tested to meet or exceed the performance and reliability standards of ruggedised systems. The wide selection of products also features unique combinations of high power density, high efficiency, low EMI performance and ease-of-use. ADI’s power products portfolio is broken down into two main categories: power regulation; and power monitor, control and protection. This article highlights a range of high reliability power management products that are ideal for next-generation aerospace & defence applications.
Figure 1. Sample electrical tested at hot and cold temperatures to datasheet electrical characteristics limits
At ADI, products have a vintage, not an age. ADI Power by Linear products are available decades after release, as we believe obsolescence should be avoided. When it cannot be avoided, customers are notified two years in advance via a Product Discontinuance Notice, in compliance with JESD48A. ADI continues to support the specialised needs of the ADEF (aerospace & defence) market with exceptional long-term support of legacy products. For more information, please review our Product Life Cycle Information at: https://www.analog.com/en/support/customer-service-resources/sales/product-life-cycle-information.html
100% factory tested
Solutions for aerospace & defence power management demand reliability, even when subjected to harsh environmental conditions. ADI’s Power by Linear portfolio continues to support the specific requirements of the ADEF power management market with industry-leading quality and reliability. LT, LTC, LTM and LTP prefixed products are available in a variety of temperature grades, and to guarantee performance, all are 100% electrical tested at room temperature to datasheet electrical characteristics limits. Furthermore, datasheet electrical characteristics that are highlighted with • are sample electrical tested at hot and cold temperatures to datasheet electrical characteristics limits. Zero failures are allowed. Please refer to individual datasheets for specific details on temperature grades.
Table 1. Aerospace & defence power management products temperature grade
Military plastic (MP) grade is a commercial off-the-shelf (COTS) solution with guaranteed performance over the military temperature range. MP-grade devices are 100% electrical tested at hot and cold temperatures, and include additional inspections, tight in-process controls, temperature cycling to eliminate infant mortality failures and enhanced reliability monitoring. Device options can be expanded by considering other temperature grades, such as high temperature automotive (H) and industrial (I). Filter for these temperature ranges in the analog.com parametric tables (at: https://www.analog.com/en/parametric-search/10734#/) by clicking Choose Parameters and checking the Temp Range Code option.
ADI offers several linear regulator and switching regulator solutions for space qualified radiation tolerant (RT) power products. Additional information on these products can be found on the Space Technology Solutions page at: https://www.analog.com/en/applications/markets/aerospace-and-defense-pavilion-home/space-solution.html
Powerful software tools to speed up designs
ADI offers complete power management tools to make designing power systems and circuits easier. Use LTpowerPlanner® for system-level power tree design; start with LTpowerCAD® to find solutions for and optimise supply designs; and use LTspice® for circuit simulations. For the ultimate in configuration, diagnostic and debug tools for complex multi-rail systems, check out LTpowerPlay®. World-class power design tools are available for download at no cost from: https://www.analog.com/en/design-center/design-tools-and-calculators/power-management-tools.html
Figure 2. Power management tool suite
µModule regulators for high efficiency power in tight spaces
µModule® regulators are exceptional, complete system-in-package power management solutions. The package includes controller ICs (integrated circuits), power transistors, capacitors, compensation circuitry and inductors. All products are tested in final package to datasheet electrical characteristics limits. Enhanced thermal performance and solution size are at the forefront of µModule design philosophy, keeping bulky mechanical and thermal mitigation at bay. High efficiency and low EMI (electromagnetic interference) are designed in, simplifying qualification and reducing design time. The µModule product family supports multiple topologies to include buck, boost, buck-boost, isolated and inverting regulators.
Many of the µModule products are available in BGA with SnPb finish and distinguished by the package top mark (e0), while also complying with JEDEC standard J-STD-609. More BGA manufacturing guidelines for PCB assembly are available on our µModule design and manufacturing resources page at: https://www.analog.com/en/products/landing-pages/001/umodule-design-manufacturing-resources.html To search for SnPb finish in additional product families, you can add and filter Terminal Finish (PB) on our website’s parametric tables.
Figure 3. Package & thermal image of LTM4700 (BGA) stepping down 12 V to 1 V at 100 A with 200 LFM airflow & no heat sink
Reduce EMI with Silent Switcher step-down regulators
The Power by Linear portfolio’s exclusive Silent Switcher® regulators offer high efficiency at high switching frequencies, while maintaining ultralow EMI emissions—easily passing CISPR 25 Class 5 peak EMI limits while operating at 2 MHz switching frequency and providing 95% efficiency. These no compromise, feature-rich switching regulators have a maximum input voltage range from 5.5 V to 65 V, provide 1.2 A to 20 A of output current, and have a programmable switching frequency from 200 kHz to 5 MHz. The second generation of this technology, Silent Switcher 2, adds internal bypass capacitors and an integrated substrate to further improve EMI. The integrated components make low EMI designs insensitive to PCB (printed circuit board) layout, simplifying design and production, and reducing performance risks. Silent Switcher µModule step-down regulators integrate the inductor, further minimising design and production risks.
Ultralow noise, high PSRR, low dropout linear regulators
Ultralow noise, ultrahigh PSRR (power supply rejection ratio) low dropout (LDO) linear regulators are an important part of supplying well-regulated power to precision sensors, high speed and high resolution data converters, frequency synthesizers and other noise sensitive devices. The Power by Linear family of positive and negative LDO regulators features products with ultralow output noise and ultrahigh power supply ripple rejection (PSRR). The LDO regulators cover a wide input voltage range, from 1.8 V to 20 V (–20 V to –1.8 V), and a wide output current range, from 200 mA to 500 mA.
Figure 4. Reduce EMI with dual-channel 4 A, 42 V, synchronous step-down Silent Switcher 2 technology with 6.2 µA quiescent current
Many Power by Linear LDO regulators can be easily paralleled to further reduce noise, increase output current and spread heat over a wider area of the PCB. Additional features include programmable current limit and power good, and VIOC capability, which maximises efficiency and system transient response when the LDO regulator is used with a switching regulator.
ADI also offers a broad line of high performance linear regulators, which includes hard-to-kill high voltage PNP linear regulators.
Surge stoppers: overvoltage & overcurrent protection
Front-end protection is especially important in tightly packed systems facing unpredictable inputs. Power by Linear surge stopper protection solutions cover the full range of surge and transient events documented in military and avionic standards, including ISO 7637-2, ISO 16750-2, MIL-STD-1275 and DO-160, without the use of bulky passive components — which do not guarantee power delivery, and can be permanently damaged when they shunt high energy to ground.
Table 2. High PSRR LDO regulators with PSRR greater than 70 dB
By using a MOSFET to clamp the maximum output voltage to a user-programmed level, Power by Linear protection solutions feature precise ride-through operation on transient events, ensuring reliable operation instead of disconnection. Surge stoppers also add the ability to disconnect the output on extended faults, allowing programmable current limit and undervoltage lockout, and often provide reverse battery protection when back-to-back MOSFETs are used.
To extend output current capability and reduce power loss during high voltage transients and faults, switching surge stoppers achieve high efficiency operation, while providing high reliability. For example, the LTC4366 and LT4363 high voltage surge stoppers can ease MIL-STD-1275D compliance.
ADI also offers a complete line of overvoltage and overcurrent protection solutions that includes products that disconnect on fault.
Figure 5. MIL-STD-1275D 100 V/500 ms surge stopper test using the DC2150A-C demo circuit
The broad Power by Linear portfolio of leading-edge solutions for next-generation aerospace & defence applications features high reliability, rugged products that meet long operating life and harsh environment standards. Visit our Aerospace & Defense site (at: https://www.analog.com/en/applications/markets/aerospace-and-defense-pavilion-home.html) for easy access to relevant product and technical design information. Additional online resources include product datasheets, an enhanced product recommended (AQEC) part list, application notes, technical articles, LTspice demo circuits, design tools and EngineerZone® forum. Local technical support experts are available to help you quickly turn design concepts into marketable, ruggedised solutions.
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