Power Management Solutions for Aerospace and Defense Applications

Power by Linear™ products for aerospace and defense power systems are designed, developed, and factory tested to meet or exceed the performance and reliability standards of ruggedized 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 few high-reliability power management products that are ideal for next-generation aerospace and defense applications.

 

Product Availability

At ADI, products have a vintage, not an age. ADI Power by Linear products are available decades after release, and 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 specialized needs of the ADEF market with exceptional long-term support of legacy products. For more information, please review our Product Life Cycle Information.

 

100% Factory Tested

Solutions for aerospace and defense 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 data sheet electrical characteristics limits. Furthermore, data sheet electrical characteristics that are highlighted with a • are sample electrical tested at hot and cold temperatures to data sheet electrical characteristics limits. Zero failures are allowed. Please refer to individual data sheets for specific details on temperature grades.

 

Regulated Output Voltage (Note 4)	VOUT = 0.6V, 10mA ≤ lOUT ≤ 2.5A, 0.90V ≤ VIN ≤ 1.05V	•	0.591	0.600	0.609	V
	VOUT = 1.0V, 10mA ≤ lOUT ≤ 2.5A, 1.3V ≤ VIN ≤ 1.45V	•	0.985	1.000	1.015	V
	VOUT = 1.2V, 10mA ≤ lOUT ≤ 2.5A, 1.5V ≤ VIN ≤ 1.65V	•	1.1850	1.200	1.2150	V
	VOUT = 1.5V, 10mA ≤ lOUT ≤ 2.5A, 1.8V ≤ VIN ≤ 1.95V	•	1.4812	1.500	1.5188	V
	VOUT = 1.8V, 10mA ≤ lOUT ≤ 2.5A, 2.1V ≤ VIN ≤ 2.25V	•	1.7775	1.800	1.8225	V
	VOUT = 2.5V, 10mA ≤ lOUT ≤ 2.5A, 2.8V ≤ VIN ≤ 2.95V	•	2.4687	2.500	2.5313	V
Regulated Output Voltage Margining	MARGA = 1.2V	•	9	10	11	%
	MARGA = 0V	•	-11	-10	-9	%
Line Regulation to VIN	VOUT = 0.6V, ΔVIN = 0.9V to 3.45V,VBIAS = 5.0V, lOUT = 10mA	•		0.002	1	mV
	VOUT = 1.2V, ΔVIN = 1.2V to 3.45V,VBIAS = 5.0V, lOUT = 10mA	•		0.002	2	mV
Line Regulation to VBIAS	VOUT = 0.6V, ΔVBIAS = 2.375V to 5.25V, VIN = 0.9V, lOUT = 10mA	•		0.2	1.5	mV
	VOUT = 1.2V, ΔVBIAS = 2.4V to 5.25V, VIN = 1.5V, lOUT = 10mA	•		0.2	3	mV
Load Regulation ΔlOUT= 10mA to 2.5A (Note 5)	VBIAS = 2.375V, VIN = 0.9V,VOUT = 0.6V	•		1.2	2.4	mV
					3.6	mV
	VBIAS = 2.375V, VIN = 1.3V,VOUT = 1.0V	•		2	4	mV
					6	mV
	VBIAS = 2.4V, VIN = 1.5V,VOUT = 1.2V	•		1.3	2.5	mV
					3.7	mV
	VBIAS = 3V, VIN = 2.1V,VOUT = 1.8V	•		1.9	3.7	mV
					5.6	mV
	VBIAS = 3.7V, VIN = 2.8V,VOUT = 2.5V	•		2.6	5.1	mV
					7.7	mV

Figure 1. Sample electrical tested at hot and cold temperatures to data sheet electrical characteristics limits. Image used courtesy of Bodo’s Power Systems

 

Military plastic grade, MP, 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 by clicking Choose Parameters and checking the Temp Range Code option.

 

Select Temp Grades	Data Sheet Performance over Temperature*	Test at Room (25°C)	Cold and Hot Test Temperatures*	Sample Test at Hot	Sample Test at Cold
MP	–55°C to +125°C or +150°C	100%	–55°C and +125°C or +150°C	100%	100%
H	–40°C to +125°C or +150°C	100%	–40°C and +125°C or +150°C	100%	1000 per lot
I	–40°C to +85°C	100%	–40°C and +85°C	1000 per lot	1000 per lot

* or as specified in data sheet

Table 1. Aerospace and Defense Power Management Products Temperature Grade

 

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.

 

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 optimize 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.

 

Figure 2. Power management tool suite. Image used courtesy of Bodo’s Power Systems

 

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, power transistors, capacitors, compensation circuitry, and inductors. All products are tested in the final package to data sheet 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 are designed in, simplifying qualifications and reducing design time. The µModule product family supports multiple topologies to include buck, boost, buck-boost, isolated, and inverting regulators.

 

Figure 3. Package and thermal image of LTM4700 (BGA) stepping down 12 V to 1 V at 100 A with 200 LFM airflow and no heat sink. Image used courtesy of Bodo’s Power Systems

 

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. To search for SnPb finish in additional product families, you can add and filter Terminal Finish (PB) on our website’s parametric tables.

 

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 layout, simplifying design and production, and reducing performance risks. Silent Switcher µModule step-down regulators integrate the inductor, further minimizing design and production risks.

 

Figure 4. Reduce EMI with dual-channel 4 A, 42 V, synchronous step-down Silent Switcher 2 technology with 6.2 µA quiescent current. Image used courtesy of Bodo’s Power Systems

 

Ultralow Noise, High PSRR, Low Dropout Linear Regulators

Ultralow noise, ultrahigh PSRR 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.

 

	LT3093	LT3094	LT3042	LT3045
Regulated Voltages	Negative	Negative	Positive	Positive
Output Current (mA)	200	500	200	500
Output Noise (10 Hz to 100 kHz) (µV)	0.8	0.8	0.8	0.8
Spot Noise at 10 kHz (nV/√Hz)	2.2	2	2	2
PSRR at 1 MHz (dB)	73	74	79	76
Programmable Current Limit	•	•	•	•
Programmable Power Good	•	•	•	•
VIOC Capability	•	•		–1 version
Parallelable	•	•	•	•
Fast Start-Up Capability	•	•	•	•

Table 2. High PSRR LDO Regulators with PSRR Greater than 70 dB.

 

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 maximizes 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 and 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.

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.

 

Figure 5. MIL-STD-1275D 100 V/500 ms surge stopper test using the DC2150A-C demo circuit. Image used courtesy of Bodo’s Power Systems

 

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.

 

Conclusion

The broad Power by Linear portfolio of leading-edge solutions for next-generation aerospace and defense applications features high reliability, rugged products that meet long operating life and harsh environment standards. Visit our Aerospace and Defense site for easy access to relevant product and technical design information. Additional online resources include product data sheets, 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, ruggedized solutions.

 

This article originally appeared in Bodo’s Power Systems magazine.