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New security standards for IoT devices are being released consistently, showing that security is no longer an afterthought in the design of embedded products. Last month, the White House launched the Cyber Trust Mark; a large move towards the security of IoT devices with a more robust concept of the “living label,” acknowledging the dynamic nature of security over time. The standard essentially requires prerequisite devices to be outfitted with a QR code that can be scanned for security information such as whether or not the device will have automatic software support such as security patches. Vendors of IoT products are now meant to partner up with an “accredited and FCC-recognized CyberLAB to ensure it meets the program’s cybersecurity requirements,” according to the FCC. 

In a conversation with Silicon Labs’ Chief Security Officer Sharon Hagi, EDN learned a bit more about this new standard, its history, and the potential future security application of this new QR code labelling scheme. 

In the IoT “boom” of the early 2000s that lasted well into the 2010s, companies were anxious to wirelessly-enable practically all devices, and when paired with the right MCU of choice, the applications seemed endless. Use cases from home automation and smart city to agritech and industrial automation were all explored, with supporting industry-specific or open protocols that could vary in spectrum (licensed or unlicensed), modulation technique, topology, transmit power, maximum payload size, broadcast schedule, number of devices, etc. With the growing hype and litany of hardware/protocol options, network security was still mostly discussed at the sidelines, leaving some pretty major holes for bad actors to exploit.  

With time and experience, it has become abundantly clear that IoT security is, in fact, pretty important. Undesirable outcomes like a Mirai botnet could lead to multiple IoT devices to be infected with malware at once allowing for larger-scale attacks such as distributed denial of service (DDoS). Moreover, a massive common vulnerability and exposure (CVE) found that lands a high score on the common vulnerability scoring system (CVSS) can potentially involve the US government’s cybersecurity and infrastructure security agency (CISA) and, if it’s not resolved, lead to fines. This is just adding insult to the reputational injury a company might experience with an exploited security issue. Sharon Hagi expands on IoT-device vulnerabilities, “these devices are in the field, so they’re subjected to different kinds of attack. There’s software-based attacks, remote attacks over the network, and physical attacks like side-channel attacks, glitching, and fault injection,” speaking towards how Silicon Labs included countermeasures for many of these attacks. The company’s initial developments in the area of security, namely centered around its “Secure Vault” technology with a dedicated security core with cryptographic functionality encapsulated within it. The core manages the root of trust (RoT) of the device, manages keys, and governs access to critical interfaces such as the ability to lock/unlock the debug port. 

Hagi went on to describe the background of the US cybersecurity standards that lead to the more recent regulatory frameworks, citing the NIST 8259 specification as the foundational set of cybersecurity requirements for manufacturers to be aware of (Figure 1). Another baseline standard is the ETSI european standard (EN) 303 645 for consumer IoT devices.

Figure 1 NIST 8259A and 8259B technical capabilities and non-technical support activities for manufacturers to consider in their products. Source: NIST

Hagi expanded more on the history of the Cyber Trust Mark, “The history of the Cyber Trust Mark kind of followed right after [the establishment of NIST 8259] in 2021 during the Biden administration with Executive Order 14028,” which had to do with security measures for critical software, “and that executive order  basically directed NIST to work with other federal agencies to further develop the requirements and standards around IoT cybersecurity.” He mentioned how this order specified the need for a labeling program to help consumers identify and judge the security of embedded products (Figure 2). 

Figure 2 NIST labeling considerations for IoT device manufacturers where NIST recommends a binary label that is coupled with a layered approach using either a QR code or a URL that leads consumers to additional details online. Source: NIST

“After this executive order, the FCC took the lead and started implementing what we now know as the Cyber Trust Mark program,” said Hagi, mentioning that Underwriter Laboratories (UL) was the de facto certification and testing lab for compliance with the US Cyber Trust Mark program as well as the requirements of the connectivity security alliance (CSA) with its product security working group (PSWG). 

In fact, the PSWG consists of over 200 companies with promoters that include tech giants like Google, Amazon, and Apple as well as OEMs such as Infineon, NXP Semiconductors, TI, STMicroelectronics, Nordic Semiconductor and Silicon Labs. The aim of the PSWG is to unite the disparate emerging regional security requirements including but not limited to the US Cyber Trust Mark, the Cyber Resilience Act (CRA) in the EU with the “CE marking”, and the Singapore Cybersecurity Label Scheme (CLS). 

Many of the companies within the PSWG have formulated their own security measures within their chips, NXP, for instance, has their EdgeLock Assurance program, and ST has their STM32Trust security framework. TI has an allocated product security incident response team (PSIRT) that responds to reports of security vulnerabilities for TI products while Infineon created a Cyber Defense Center (CDC) with a corresponding Computer Security Incident Response Teams (CSIRT/CERT) and PSIRT team for the same purpose. Hagi stated that Silicon Labs set itself apart by implementing security “down to the silicon level” in product design early on in the IoT development game. 

These wireless SoCs and MCUs are the keystone of the IoT system, providing the intelligent compute, connectivity, and security of the product. Using more secure SoCs will inevitably ease the process of meeting the ever-changing security compliance standards. Engineers can choose to enable features such as secure boot, secure firmware updates, digitally signed updates with strong cryptographic keys, and anti-tampering, to ultimately enhance the security of their end product. 

Perhaps the most interesting aspect of the interview were the potential applications of these labeling schemes and how to make them more user-friendly. “The labeling scheme could be compared to a food label,” said Hagi, “You go to the supermarket, take the product off the shelf and it shows you the ingredients and nutritional value and make a decision on whether or not this is something you want to buy.” In the future, a more objectively secure product could be a more pricey option to the more basic alternative, however it would be up to the consumer to decide. While this analogy served its purpose, its similarities ended there. While the label contains all “ingredients” of security built into the product, the Cyber Trust Mark is not meant to be static, since vulnerabilities can still be discovered well after the product is manufactured. 

“You might be able to see the software bill of materials (SBOM) where maybe there is a certain open source library that the product is using and there is a vulnerability that has been reported against it. And maybe, when you get home, you need to update the product with new software to make sure that the vulnerability is patched,” said Hagi as he discussed potential use cases for the label.  

The hardware BOM (HBOM) may also be very relevant in terms of security, bringing into light the entire supply chain that is involved in assembling the end product. The overall goal of the label is to incentivize companies to foster trust and accountability with transparency on both the SBOM and HBOM. 

Hagi continues to go down the checklist of security measures the label might include, “What is the original and development history of the product’s security measures? Can it perform authentication? If so, what kind of authentication? What kind of cryptography does it have? Is this cryptography certified? Does the manufacturer include any guarantees? At what point will the manufacturer stop issuing security updates for the product? Does the product contain measures that would comply with people in specific jurisdictions?” These regional regulations on security do vary between, for instance, the EU’s General Data Protection Regulation (GDPR) and of course, the US Cyber Trust Mark. 

ML brings on another dimension of security considerations to these devices, “The questions would then be what sort of data does the model collect? How secure are these ML models in the device? Are they locked? Are they unlocked? Can they be modified? Can they be tampered with?” The many attributes of the models bring other levels of security considerations with them and avenues of attack. 

Ultimately putting this amount of information on a box is impossible, even more pertinent is how users are meant to interpret the sheer amount of information. Consumers were more than likely to not really understand all the information on a robust security label, even if it was human-readable. “Another angle is providing some sort of API so that an automated system can actually interrogate this stuff,” said Hagi. 

He mentioned one example of securely connecting devices from different ecosystems, “Imagine an Amazon device connecting to an Apple device, with this API, security information is fetched automatically letting users know if it is a good idea to connect the device to the ecosystem.” 

As it stands, the labelling scheme is meant to protect the consumer in more of an abstract sense, however it might be difficult for the consumer to accurately understand the security measures put into the product. In order to make full use of a system like this, “it is likely that a bit of automation is necessary for consumers to make appropriate decisions just in time.” This could eventually enable consumers to make informed decisions on product purchasing, replacement, upgrades, connection to a network, and the security risks when throwing out an item that could contain private information in its memory. 

Aalyia Shaukat, associate editor at EDN, has worked in design publishing industry for six years. She holds a Bachelor’s degree in electrical engineering from Rochester Institute of Technology, and has published works in major EE journals as well as trade publications.

Related Content

• Navigating IoT security in a connected world
• Understand the hardware dependencies of IoT security
• 6 core capabilities an IoT device needs for basic cybersecurity
• 7 steps to security for the Internet of Things

The post The future of cybersecurity and the “living label” appeared first on EDN.

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India’s electronics manufacturing industry is experiencing rapid growth, driving a rising demand for high-performance reflow ovens—critical for soldering surface-mount components onto printed circuit boards (PCBs). To meet this demand, several Indian companies specialize in manufacturing and supplying reflow ovens, catering to both domestic and global markets. Here’s a look at some of the leading reflow oven providers in India.

1. Heller India

Heller India, a subsidiary of Heller Industries, is renowned for its advanced reflow soldering ovens. The company offers a range of products, including convection reflow soldering ovens, voidless/vacuum reflow soldering ovens, formic/fluxless reflow soldering ovens, pressure curing ovens, vertical curing ovens, and magazine curing ovens. Their reflow ovens are designed to meet the demands of surface-mount technology (SMT) reflow, semiconductor advanced packaging, consumer electronics assembly, and power device packaging. Heller India emphasizes efficiency and sustainability in its products, featuring low-height top shells, Industry 4.0 compatibility, and innovative flux management systems.

2. Leaptech Corporation

Based in Mumbai, Leaptech Corporation offers a comprehensive range of SMT equipment, including reflow soldering ovens. They are authorized distributors of ITW EAE Vitronics Soltec’s Centurion Reflow Ovens, known for their superior reliability and thermal performance. The Centurion platform features forced-convection SMT reflow systems with tight, closed-loop process control, suitable for high-throughput PCB assembly environments. Available in various zone configurations, these ovens cater to diverse production requirements. Leaptech also provides Tangteck reflow ovens, which include SMT reflow furnaces (IR & hot air), BGA soldering reflow furnaces, and curing or drying furnaces.

3. EMS Technologies

Located in Bengaluru, EMS Technologies specializes in manufacturing reflow ovens and other SMT equipment. Their product lineup includes the Konark 1020, a 10-zone reflow oven designed to cater to versatile industry needs and complex PCB types. The Konark 1020 features a PC with Windows 10 operating system, data logging traceability, adjustable blower speed, and PID closed-loop temperature control. The machine is equipped with 10 heating zones and 2 cooling zones, offering flexibility in manufacturing and higher throughput.

4. Mectronics Marketing Services

Headquartered in New Delhi, Mectronics Marketing Services provides a variety of electronic manufacturing equipment, including reflow soldering systems. They offer EPS reflow ovens designed with patented Horizontal Convection technology for even heating across the entire face of the PCB. Their product range includes traditional bench-top solder reflow ovens, batch ovens, automatic floor-style systems, hot plates, and vapor phase ovens, catering to various production scales and requirements.

5. Bergen Associates Pvt. Ltd.

Also located in New Delhi, Bergen Associates offers a range of PCB assembly equipment, including reflow ovens. They cater to both small-scale and large-scale manufacturing requirements, providing solutions that meet diverse industry needs.

6. NMTronics India Pvt. Ltd.

With offices across major cities, NMTronics is a leading provider of electronic manufacturing solutions. They supply reflow ovens from renowned global manufacturers, ensuring high-quality equipment for their clients. Their offerings are suitable for various production scales and are known for their precision and efficiency.

7. Sumitron Exports Pvt. Ltd.

Headquartered in New Delhi, Sumitron Exports provides a variety of soldering solutions, including reflow ovens. They represent several international brands and offer advanced reflow soldering systems to the Indian market, catering to the needs of modern electronics manufacturing.

8. Accurex Solutions Pvt. Ltd.

Based in Bengaluru, Accurex Solutions specializes in providing SMT and PCB assembly equipment. Their product lineup includes advanced reflow ovens designed for precision soldering, meeting the demands of high-quality electronics production.

9. Maxim SMT Technologies Pvt. Ltd.

Located in Pune, Maxim SMT Technologies offers a variety of SMT equipment, including reflow soldering machines. They focus on delivering high-performance solutions to meet the demands of modern electronics manufacturing, ensuring efficiency and reliability in their products.

10. Technosys Equipments Pvt. Ltd.

Headquartered in Bengaluru, Technosys Equipments provides a range of electronic manufacturing equipment, including reflow ovens. They emphasize innovation and quality in their product offerings, catering to various industry requirements.

These companies play a significant role in supporting India’s electronics manufacturing industry by providing reliable and advanced reflow soldering solutions. Their contributions ensure that manufacturers have access to the necessary equipment to produce high-quality electronic products efficiently.

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India’s drone industry has witnessed significant growth, driven by advancements in technology and a surge in demand across various sectors such as defense, agriculture, and infrastructure. Several companies have emerged as leaders in drone manufacturing and services, offering innovative solutions tailored to diverse applications. Here are the top 10 drone camera companies in India as of 2025:

1. IdeaForge Technology Pvt. Ltd.

Founded in 2007 by IIT Bombay alumni, IdeaForge is a pioneer in India’s UAV industry. The company specializes in designing and manufacturing drones for defense, homeland security, and industrial applications. Notable products include the Netra, a micro UAV designed for surveillance and reconnaissance missions, and the Switch UAV, known for its long-endurance capabilities. In December 2023, IdeaForge ranked 5th globally in the dual-use category (civil and defense) as per a report by Drone Industry Insights.

2. Asteria Aerospace Limited

Established in 2011 and headquartered in Bengaluru, Asteria Aerospace focuses on developing drones for defense and industrial applications. The company offers products like the A200, which received India’s first micro category drone certification in October 2022, and the A200-XT and A410-XT, both certified by the Directorate General of Civil Aviation (DGCA). Asteria also launched SkyDeck, a cloud-based drone operations platform that provides services such as flight planning, data processing, and AI-based analysis.

3. Garuda Aerospace

Based in Chennai and founded in 2015, Garuda Aerospace offers drone solutions across various sectors, including agriculture, disaster management, and defense. The company provides custom drones, sensors, and software for aerial surveys, mapping, and inspections. Garuda has collaborated with organizations like ISRO for delivering medicines and food using drones and has been active in disaster relief efforts, such as assisting in rescue operations during the Uttarakhand avalanche in 2021. Indian cricketer Mahendra Singh Dhoni is its brand ambassador and shareholder.

4. Skylark Drones Pvt. Ltd.

Skylark Drones provides drone-based solutions for industries like agriculture, mining, and construction. Their offerings include autonomous drones, custom payloads, and mapping software. The company has partnered with leading firms such as Tata Power and Mahindra & Mahindra to implement drone-based solutions, enhancing operational efficiency and data accuracy.

5. Aarav Unmanned Systems Pvt. Ltd.

Headquartered in Bangalore, Aarav Unmanned Systems specializes in manufacturing drones for defense and commercial applications. Their product lineup includes the Nayan series for surveillance and the Cheetah series for aerial surveys and mapping. Notably, Aarav has developed a drone-based delivery system for medical supplies and emergency response services, successfully tested in collaboration with the Karnataka government.

6. Aero360

Based in Delhi, Aero360 offers a range of drone services, including aerial surveys, mapping, and photography. The company has developed proprietary software capable of processing drone data to generate accurate 3D models and maps. Aero360 has collaborated with major companies like Larsen & Toubro and the Adani Group to provide drone-based solutions for various projects.

7. Sagar Defence Engineering Pvt. Ltd.

Located in Pune, Sagar Defence Engineering focuses on providing drone solutions for defense and homeland security applications. Their Garuda series drones are designed for high-altitude, long-endurance missions, suitable for surveillance and reconnaissance. The company has also developed a drone-based anti-poaching system, tested in partnership with the Maharashtra forest department.

8. Vignan Technologies Pvt. Ltd.

Operating out of Hyderabad, Vignan Technologies offers drone solutions for agriculture, mining, and construction industries. Their products include custom drones, agricultural sensors, and mapping software. The company has developed a precision agriculture system that provides farmers with real-time data on soil moisture, temperature, and other critical parameters to enhance crop yields.

9. Omnipresent Robot Technologies Pvt. Ltd.

Based in Bangalore, Omnipresent Robot Technologies provides drone solutions for industrial inspection and maintenance. Their offerings include custom drones, sensors, and software designed to inspect infrastructure such as buildings and pipelines. The company has partnered with industry leaders like Reliance Industries and Larsen & Toubro to implement drone-based inspection solutions.

10. Tata Advanced Systems Limited (TASL)

A subsidiary of Tata Sons, TASL is involved in aerospace and defense manufacturing. The company has agreements with Israel Aerospace Industries and Urban Aeronautics for the co-development of UAVs in India. TASL has developed and successfully flight-tested a long-range kamikaze drone known as the ALS-50, capable of striking targets beyond 50 km and returning if the mission is aborted. This drone is set to be inducted into the Indian armed forces.

These companies exemplify the rapid advancement of drone technology in India, offering a range of products and services that cater to both domestic and international markets. Their innovations are contributing significantly to sectors such as defense, agriculture, infrastructure, and emergency response, positioning India as a key player in the global drone industry.

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For many variable resistor (rheostat) applications, one of the device’s terminals is connected to a voltage source VS. Such a source might be a reference DC voltage, an op amp output carrying an AC plus DC signal, or even ground. If freed from the constraint of (programmable) “floating” rheostats satisfied by recently disclosed solutions in “Synthesize precision Dpot resistances that aren’t in the catalog” and “Synthesize precision bipolar Dpot rheostats,” there is a compelling alternative approach. Yes, it’s slightly simpler in that it avoids MOSFETs, and that the +5V supply for the digital potentiometer is the only supply needed (especially if rail-to-rail input and output op-amps are employed.) But more importantly, it’s distinct in that it exhibits no crossover distortion when there is a change in the sign of an AC signal between terminals A and VS.

Wow the engineering world with your unique design: Design Ideas Submission Guide

As seen in Figure 1, I’m shamelessly appropriating the same digital pot used in those other solutions. (Note the limited operating voltage range of potentiometer U2.)

Figure 1 A basic programmable rheostat leveraging the same digital pot used in other solutions.

The resistance between terminals A and voltage source VS looking into terminal A is res = R1/(1 – αa·α2·αb) where the alphas are the gains of U1a, U2, and U1b respectively. αa and αb are slightly less than unity at DC, falling in value with loop gain as frequency increases. α2 is equal to one of the numerator integers 0, 1, 2… 256 divided by a denominator of 256 as determined by the programming of U2.

By changing the numerator from 0 to 255, it would appear that resistor value ratios of 1:256 could be achieved. Unfortunately, U2’s integral non-linearity (INL) is specified as ± 1 LSB. Strictly following this spec, operation with a numerator of 255 could drive the value of res close to infinity at DC and so should be avoided. But that’s not the only concern. For an α2 numerator value “num”, a resistance error factor EF of roughly ± 1/(256-num) could be encountered because of the ± 1 LSB accuracy. To minimize uncertainty, num should be held to less than some maximum value (solutions in “Synthesize precision Dpot resistances that aren’t in the catalog” and “Synthesize precision bipolar Dpot rheostats” have similar problems for small values of “num”). Another reason for such a limit is that resistance resolution is much better with lower than higher values of “num”. For instance, the ratio of resistor values with numerators of 10 and 11 is 1.004. But the values of 240 and 241 yield a ratio of 1.07, and those of 250 to 251, 1.2.

The simple addition of U3 and R2 in the Figure 2 circuit mitigates these problems by reducing the required maximum value of “num”. For R2 greater than R1, resistances between R1 and R2 should be implemented by having analog switch U3 select R1 rather than R2. For larger resistances, R2 should be selected.

Figure 2 Enhanced programmable rheostat that mitigates the uncertainties problems of the basic programmable rheostat by reducing the required maximum value of “num”.

To see why Figure 2 offers an enhancement, consider a requirement to provide resistance over the range of 1k to 16k. In Figure 1 and Figure 2 circuits, R1 would be 1k. To produce a value of 1k, “num” would be 0. For 16k, “num” in Figure 1 would be 240, yielding a maximum EF of ± 1/(256 – 240) or approximately 6.3%. But in Figure 2, resistance values of 4K and above would be derived by having U3 switch R1 out in place of a 4k R2. The maximum required value of “num” would be 192, and EF would be reduced by a factor of 4 to 1.6%. It will also be seen that the Figure 2 circuit significantly relaxes op-amp performance requirements for limiting the errors due to finite open loop gains. To see this, some analysis is necessary. Given the maximum allowed fractional resistance error (OAerr) introduced by the op-amp pair, it can be seen that:

Therefore, for closed loop op amp gains:

At DC, op amp voltage follower closed loop gain α is 1/(1-1/a0L), where a0L is the op amp open loop DC gain. To satisfy requirements at DC:

Matters are more complicated with AC signals. At a frequency f Hz, the voltage follower open loop gain HOLG(j·f) is 1 / (1/A0 + j·f/GBW), where GBW is the part’s gain-bandwidth product and j = √-1.

The closed loop gain HCLG(j·f) is 1/( 1 + 1/ HOLG(j·f)). Substitution of HCLG(j·f) for αa and αb in Equation (1) yields a fourth order polynomial due to the real and imaginary terms of HCLG(j·f). It’s easier to solve the problem with a simulation in LTspice than to solve it algebraically.

LTspice offers a user-specifiable op-amp called…well, “opamp”. It can be configured for user-selected values of a0L and GBW. The tool is configured as shown in Figure 3 to solve this problem.

Figure 3 LTspice can be used to determine op-amp requirements for an AC signal application.

The a0L value required for AC signals will be larger than that calculated in equation (3). It’s suggested to start with an a0L default value of 10000 (100 dB) and try different values of GBW. Use the results to select an op amp for the actual circuit and either simulate it if a model exists or at least update the simulation with the minimum specified values of a0L and GBW for the selected op amp.

Table 1 shows some examples of the behaviors of the circuit with different idealized op-amps. It’s clear that DC performance in either circuit is not a challenge for almost any op-amp. But it’s also evident that the AC performance of a given op-amp is notably better in the Figure 2 circuit than in that of Figure 1, and that a given error can be achieved with a lower performance and less costly op-amp in the Figure 2 circuit.

Table 1 Examples of the circuits’ behavior producing 16kΩ with various op-amp parameters.

The approach taken in Figure 2 can be generalized by supporting not just two but four or more different resistors. Doing so further minimizes both op-amp performance requirements and worst-case errors by reducing the maximum required value of “num”. It also extends the range of resistor values achievable for a given error budget.

Christopher Paul has worked in various engineering positions in the communications industry for over 40 years.

Related Content

• Synthesize precision Dpot resistances that aren’t in the catalog
• Synthesize precision bipolar Dpot rheostats
• Error assessment and mitigation of an innovative data acquisition front end

The post A class of programmable rheostats appeared first on EDN.

India’s medical robotics sector is experiencing significant growth, driven by advancements in technology and a rising demand for innovative healthcare solutions. Several Indian companies have emerged as leaders in this field, developing cutting-edge robotic systems that enhance medical procedures and patient care. Here are some of the top medical robotics companies in India:

1. SS Innovations International

Founded in 2015 and headquartered in Gurugram, SS Innovations International specializes in developing robotic surgical instruments for cardiac procedures. Their flagship product, the SSI Mantra, is a surgical robotic system designed for minimally invasive surgeries across multiple specialties. The company also offers SSI Mudra endo-surgical instruments, SSI Maya mixed reality training, and SSI Yantra for multimedia recording and streaming. These innovations aim to provide a diverse range of minimally invasive robotic procedures, enhancing surgical precision and patient outcomes.

2. Makers Hive Innovations

Established in 2018 and based in Hyderabad, Makers Hive Innovations focuses on developing advanced prosthetic solutions. Their notable product, the KalArm, is a functional bionic hand designed to provide upper limb amputees with access to advanced prosthetic technology. The company aims to make this technology accessible, particularly in India and other developing countries, thereby improving the quality of life for individuals with limb loss.

3. Astrek Innovations

Astrek Innovations, founded in 2017 and headquartered in Kochi, specializes in wearable robotics for healthcare and rehabilitation. The company develops lower limb wearable robotic suits aimed at assisting gait training and rehabilitation in settings such as hospitals and physiotherapy clinics. Their products include Centaur, a gait training device, and Unik XO, an automated robotic suit designed to aid individuals with lower limb locomotion difficulties, thereby facilitating improved mobility and recovery.

4. Comofi Medtech

Comofi Medtech is a Bengaluru-based company that focuses on developing robotic solutions for surgical applications. Their innovations aim to enhance the precision and efficiency of surgical procedures, contributing to improved patient outcomes. The company’s commitment to integrating advanced robotics into healthcare addresses the growing demand for minimally invasive and accurate surgical interventions.

5. Curneu

Curneu is a medical robotics company dedicated to developing advanced robotic systems for healthcare applications. Their focus includes creating innovative solutions that assist in various medical procedures, aiming to improve accuracy and patient care. The company’s efforts contribute to the evolving landscape of medical robotics in India, addressing the need for technologically advanced healthcare solutions.

6. Theranautilus

Founded in 2020 and headquartered in Bengaluru, Theranautilus is a deep-tech company specializing in nanotechnology and healthcare. Initially a lab spin-off from the Indian Institute of Science, Bangalore, the company has developed devices capable of guiding nanorobots to targets deep inside dentinal tubules. Once at the site, these nanorobots can be remotely activated to deploy antibacterial mechanisms, offering a novel solution to minimize root canal failures. This innovation addresses a significant challenge in dental procedures, enhancing treatment efficacy.

7. DiFACTO Robotics and Automation

Based in Bengaluru, DiFACTO Robotics and Automation is a leading provider of robotic solutions for various industries, including healthcare. The company offers automation solutions that enhance efficiency and precision in medical applications. Their expertise in robotics and automation contributes to advancements in healthcare technology, supporting improved patient care and operational efficiency.

8. Stryker India Pvt. Ltd.

Stryker India, a subsidiary of Stryker Corporation is a global leader in medical technology. The company offers a range of surgical robots designed to assist in various medical procedures. Their robotic systems are utilized in applications such as orthopedic surgeries, providing surgeons with advanced tools to enhance precision and patient outcomes.

9. Titan Medical Inc.

Titan Medical Inc. is a medical device company that develops robotic surgical systems. With a focus on minimally invasive surgery, their technologies aim to enhance surgical capabilities and patient care. The company’s innovations contribute to the growing field of medical robotics in India, offering advanced solutions for healthcare providers.

10. Zimmer India Pvt. Ltd.

Zimmer India is a subsidiary of Zimmer Biomet, a global leader in musculoskeletal healthcare. The company offers robotic systems designed to assist in orthopedic surgeries, providing tools that enhance surgical precision and patient outcomes. Their commitment to innovation in medical robotics supports the advancement of healthcare solutions in India.

These companies exemplify the dynamic growth and innovation within India’s medical robotics sector. As technology continues to advance, these organizations are at the forefront, developing solutions that enhance medical procedures, improve patient care, and contribute to the evolving landscape of healthcare in India and beyond.

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Ensuring stable power management is crucial in modern electronics, and the power supply rejection ratio (PSRR) plays a key role in achieving this. This article serves as a practical guide to measuring PSRR for power management ICs (PMICs) and offering clear and comprehensive instructions.

PSRR reflects a circuit’s ability to reject fluctuations in its power supply voltage, directly impacting performance and reliability. By understanding and accurately measuring this parameter, engineers can design more robust systems that maintain consistent operation even under varying power conditions.

Figure 1 Here is the general methodology to measure PSRR. Source: Renesas

PSRR is a vital parameter that assesses an LDO’s capability to maintain a consistent output voltage amidst variations in the input power supply. Achieving high PSRR is crucial in scenarios in which the input power supply experiences fluctuations, thereby ensuring the dependability of the output voltage. Figure 1 below illustrates the general methodology for measuring PSRR.

The mathematical expression to calculate the PSRR value is:

PSRR = 20 log10 VIN/VOUT

Where VIN and VOUT are the AC ripple of the input and output voltage, respectively.

Equipment and setup

To ensure an accurate measurement of the PSRR, it’s essential to set up the test environment with precision. The following design outlines the use of the listed equipment to establish a robust and reliable test configuration.

First, connect the power supply—in our case it’s a Keithley 2460—to the input of the Picotest J2120A line injector. The power supply should be configured to generate a stable DC voltage while the AC ripple component is provided by a Bode 100 network analyzer output using the J2120A line injector to simulate power supply variations.

Note that J2120A line injector includes an internally biased N-channel MOSFET. This means that there is a voltage drop between the J2120A input and output. The voltage drop is non-linear, and its dependency is shown on Figure 2. This means that each time the load current is adjusted, the source power supply must also be adjusted to maintain a constant DC output voltage at the J2120A terminals.

Figure 2 J2120A’s resistance and voltage drop is shown versus output current. Source: Renesas

For example, to get 1.2 V at the input of the LDO regulator, and depending on the current load, it might be required to set the voltage on the input of the line injector from 2.5 V to 3.5 V. The MOSFET operates as open loop so not to become unstable when connected to the external regulator.

Next, a digital multimeter is used to monitor both the input and output voltages of the PMIC. Ensure that proper grounding is used, and minimal interference is present in the connections to maintain measurement integrity.

Finally, a Bode 100 from Omicron Lab is used to record and analyze the measurements. This data can be used to compute the PSRR values and evaluate the PMIC’s ability to maintain a stable output despite variations in the input supply.

By carefully following this setup, one can ensure accurate and reliable PSRR measurements, contributing to the development of high-performance and dependable electronic systems.

Table 1: Here is an outline of the instruments used in PSRR measurements. Source: Renesas

Table 2 See the test conditions for LDOs. Source: Renesas

Settings for PSRR bench measurements setup

Figure 3 Block diagram shows the key building blocks of PSRR bench measurement. Source: Renesas

The PSRR measurement is performed with the Bode 100. The Gain/Phase measurement type should be chosen in the Bode Analyzer Suite software as shown on Figure 4.

Figure 4 Start menu is shown in the Bode Analyzer Suite software. Source: Renesas

Set the Trace 1 format to Magnitude (dB).

Figure 5 This is how to set Trace 1. Source: Renesas

To get the target PSRR measurement, choose the following settings in the “Hardware Setup”:

1. Frequency: Change the Start frequency to “10 Hz” and Stop frequency to “10 MHz”.
2. Source mode: Choose between Auto off or Always on. In Auto off mode, the source will be automatically turned off whenever it’s not used (when a measurement is stopped). In Always on mode, the signal source stays on after the measurement has finished. This means that the last frequency point in a sweep measurement defines the signal source frequency and level.
3. Source level: Set the constant source level to “-16 dB” or higher for the output level. The unit can be changed in the options. By default, the Bode 100 uses dBm as the output level unit. 1 dBm equals 1 mW at 50 Ω load. “Vpp” can be chosen to display the output voltage in peak-to-peak voltage. Note that the internal source voltage is two times higher than the displayed value and valid when a 50 Ω load is connected to the output.
4. Attenuator: Set the input attenuators 20 dB for Receiver 1 (Channel 1) and 0 dB for Receiver 2 (Channel 2).
5. Receiver bandwidth: Select the receiver bandwidth used for the measurement. Higher receiver bandwidth increases the measurement speed. Reduce the receiver bandwidth to reduce noise and to catch narrow-band resonances.

Figure 6 The above diagram shows hardware setup in Gain/Phase Measurement mode and measurement configuration. Source: Renesas

Before starting the measurement, the Bode 100 needs to be calibrated. This will ensure the accuracy of the measurements. Press the “Full Range Calibration” button as shown in Figure 7. To achieve maximum accuracy, do not change the attenuators after external calibration is performed.

Figure 7 Press the “Full Range Calibration” button to ensure measurement accuracy. Source: Renesas

Figure 8 Here is how Full Range Calibration Window looks like. Source: Renesas

Connect OUTPUT, CH1, and CH2 as shown below and perform the calibration by pressing the Start button.

Figure 9 In calibration setup, Connect OUTPUT, CH1 and CH2, and press the Start button. Source: Renesas

Figure 10 This is how performed Calibration Window looks like. Source: Renesas

For all LDOs:

1. The input capacitor will filter out some of the signals injected into the LDO, so it’s best to remove the input capacitors for the tested LDO or keep one as small as possible.
2. Configure the network analyzer; use the power supply to power the line injector and connect the output of the network analyzer to the open sound control (OSC) input of the line injector.
3. Power up the device under test (DUT) and configure the tested LDO’s output voltage. To prevent damage to the PMIC, the LDO’s input voltage should be less than or equal to the max input voltage. It’s highly recommended to power up the LDO without a resistive load, then apply the load and adjust the input voltage.
4. Configure the LDO VOUT as specified in Table 2.
5. Enable the LDO under test and use a voltmeter to check the output voltage.
6. To ensure that the start-up current limit does not prevent the LDO from starting correctly, connect the resistive load to the LDO once the VOUT voltage has reached its max level.
7. Adjust the voltage at the J2120A OUT terminals to their target VIN.
8. Connect the first channel (CH1) of the network analyzer to the input of the LDO under test using a short coaxial cable.
9. Connect the second channel (CH2) of the network analyzer to the output of the LDO under test using a short coaxial cable.
10. Monitor the output voltage of the line injector on an oscilloscope. Perform a frequency sweep and check that the minimum input voltage and an appropriate peak to peak level for test are achieved. Make sure that the AC component is 200 mVpp or lower.

Figure 11 This simplified example shows headroom impact on the ripple magnitude. Source: Renesas

Note that headroom for the PSRR is not the same as the dropout voltage parameter (Vdo) specified in the datasheets (see Figure 11). Headroom in the context of PSRR refers to the additional voltage margin above the output voltage that an LDO requires to effectively reject variations in the input voltage.

Essentially, it ensures that the LDO can maintain a stable output despite fluctuations in the input power supply. Dropout voltage (Vdo), on the other hand, is a specific parameter defined in the datasheets of LDOs.

It’s the minimum difference between the input voltage (VIN) and the output voltage (VOUT) at which the LDO can still regulate the output voltage correctly under static DC conditions. When the input voltage drops below this minimum threshold, the LDO can no longer maintain the specified output voltage, leading to potential performance issues.

Figure 12 Example highlights applied ripple and its magnitude with DC offset for LDO’s input. Source: Renesas

11. Set up the network analyzer by using cursors to measure the PSRR at each required frequency (1 kHz, 100 kHz and 1 MHz). Add more cursors if needed to measure peaks as shown in Figure 13.

Figure 13 This is how design engineers can work with cursors. Source: Renesas

12. Capture images for each measured condition.

Figure 14 Example shows captured PSRR graph for the SLG51003 LDO. Source: Renesas

Figure 15 Bench measurement setup is shown for the SLG51003 PSRR.

Clear and precise PSRR measurement

This methodology provides a clear and precise approach for measuring the PSRR for the SLG5100X family of PMICs using the Omicron Lab Bode 100 and Picotest J2120A. Accurate PSRR measurements in the 10 Hz to 10 MHz frequency range are crucial for validating LDO performance and ensuring robust power management.

The accompanying figures serve as a valuable reference for setup and interpretation, while strict adherence to these guidelines enhances measurement reliability. By following this framework, engineers can achieve high-quality PSRR assessments, ultimately contributing to more efficient and reliable power management solutions.

Oleh Yakymchuk is applications engineer at Renesas Electronics’ office in Lviv, Ukraine.

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