App note from Vishay about the dual terminator resistor network and how to check its internal resistor values. Link here (PDF)
One of the least understood resistor network schematics in the industry today is the dual-resistor terminator schematic shown in the 8-pin SIP and in the 16-pin DIP configuration.
This schematic shows up in both commercial / industrial parts and in military parts. Commercial parts are sometimes identified as TTL dual-line terminators or as pulse-squaring terminators.
App note from SiTime about phase noise, its fundamental and going to actual measurements. Link here
Phase noise is one of the fundamental metrics for oscillators. An experienced engineer can tell a lot about the quality of an oscillator and whether it fits the application by looking at the phase noise plot. RF engineers focus on the phase noise levels at certain carrier offset frequencies to make sure that the required modulation scheme can be supported. Professionals designing high speed serial links like 40GbE will apply a band pass filter to phase noise of a reference clock, integrate it, and convert it to phase jitter to predict the bit error rate of a system.
Old app note from ONSEMI but still a good reference when designing with high speed CMOS devices. Link here (PDF)
Unlike low-power, metal-gate CMOS, high-speed 54HC/74HC devices readily drive long cable runs and backplanes. While the family maintains CMOS’s traditional noise immunity, you must watch transmission-line effects in such applications.
Helpful app note from ONSEMI that will guide you to their IGBT parameters. Link here (PDF)
The Insulated Gate Bipolar Transistor is a power switch well suited for high power applications such as motor control, UPS and solar inverters, and induction heating. If the application requirements are well understood, the correct IGBT can easily be selected from the electrical properties provided in the manufacturers’ datasheet.
App note from ONSEMI about their high side SmartFETs and their specific application. Link here (PDF)
The “end requirement” from a high side SmartFET is to switch loads, and there are different alternatives, available in market, towards that end. Relays, for instance, have been used for long in the industry to switch various automotive loads, especially those requiring high current activation. With a continual reduction in the weight and size of automotive components and assemblies, there has been an evident transition from relays to semiconductor switches that take up less area and also offer improved noise immunity and lower electromagnetic interference as compared to relays.
Wide input voltage is a specialty of this type of DC-DC converter, here’s an app note from ON Semiconductors on SEPIC converters. Link here (PDF)
The single−ended primary−inductor converter (SEPIC) is a type of DC/DC converter that allows the electrical potential (voltage) at its output to be greater than, less than, or equal to that at its input.
Like other DC−DC switch−mode power supply converters, the SEPIC exchanges energy between inductors and capacitors to convert from one voltage to another voltage. Typical applications for a SEPIC regulator are:
• Battery−operated equipment and handheld devices
• NiMH chargers
• LED lighting applications
• DC power supplies having a wide range of input voltages
App note from ROHM Semiconductor about their shunt resistor mounting designs to keep heat away. Link here (PDF)
Shunt resistors are widely used for current sensing in automotive and industrial applications. In the automotive sector, as vehicles become more complex and the number of motors and ECUs grows, applications need to be configured in a limited space.
As a result, components are being mounted more intensively and customers require shunt resistors – one of the components mounted on vehicles – that are more power efficient and compact. Accordingly, the thermal design of products and circuit boards has become an important issue.
App note from ROHM Semiconductor on the importance of sense trace/line arrangement on PCB designs. Link here (PDF)
While resistance, power rating and size are important considerations when using shunt resistors, tolerances that affect the accuracy of the detected voltage must also be considered. These tolerances include the temperature coefficient of resistance and the tolerance of resistance at room temperature.
The temperature coefficient of resistance indicates the change in resistance value due to a change in temperature of the resistor. Since resistance is affected by component temperature rise as current flows through and power is consumed, and ambient temperature changes, the temperature coefficient of resistance is an important factor in accurately detecting current values.
Happy New Year!
Thank you for reading the blog and being part of our community in 2021! We’re looking forward to more open hardware projects, more how-tos, more videos, more free PCBs, and more hacking in 2022.
Another app note from ROHM Semiconductor on various capacitors used for output smoothing. Link here (PDF)
In recent years, it has become a common practice to recommend multilayer ceramic capacitors for the output smoothing of switching regulators due to the stability of their temperature characteristics and the reduction on the mounting area. On the other hand, they are increasingly being replaced by low-cost, high-capacity aluminum electrolytic capacitors and conductive polymer hybrid aluminum electrolytic capacitors.
A novel inverter design by ROHM and Power assist technology. Link here (PDF)
We employ trans-linked interleaved circuits as inverter circuits that utilize the high frequency switching performance of silicon carbide (SiC) MOSFET, achieving a power conversion efficiency of 99% or more at 5 kW. Since this circuit topology allows a reduction in the inductance of the smoothing reactor, the high efficiency is achieved by reducing the number of windings of the reactor to dramatically reduce the copper loss. This document introduces an example of this novel inverter design.
Merry Christmas and Happy Holidays to all. May you find many PCBs and other electronics wizardry under your tree or pole.
Remember, support is available on Christmas. Just give us a shout in the forum.
App note from AVX covering ideal connectors used on industrial applications. Link here (PDF)
Connectors used in industrial and solid-state lighting applications pose uniquely challenging design constraints on power density and form-factor while simultaneously demanding the highest reliability under harsh environmental conditions. As a designer in these spaces, one cannot simply prioritize piece cost in the connector selection process. The true value of a connector is much more nuanced and must include the amortized costs of manufacturability, reliability, and safety. Eliminating hand soldering, ease of use, and good yield are not free. Avoiding field failures and product recalls are not free. Regulatory compliance is not free. To best address these hidden costs, designers should choose connectors from suppliers that have already engineered them out.
App note from AVX about MLCC, Tantalum, Tantalum Polymer and Supercapacitors. Link here (PDF)
Tantalum, MLCC, and super capacitor technologies are ideal for many energy storage applications because of their high capacitance capability. These capacitors have drastically different electrical and environmental responses that are sometimes not explicit on datasheets or requires additional knowledge of the properties of materials used, to select the best solution for a given design.
App note from NXP Semiconductors helping you to use cheap OLED panels found on Taobao or Amazon to interface with their LPC5500 series micro using U8g2 graphics library. Link here (PDF)
The LPC5500 is an Arm® Cortex®-M33 based microcontroller for embedded applications.
There are many 128 × 64 resolution OLED panel modules on the market and they are very easy to purchase.
U8g2 is a monochrome graphics library for embedded devices. U8g2 supports monochrome OLEDs and LCDs.
App note from Precision Microdrives on new brushless motor design and how to drive them efficiently. Link here
For a long time, all motors driven by DC supplies relied on using metal or carbon brushes to provide electrical power to the motor’s internal components. Meanwhile, in larger motor designs it has also been possible for over 100 years to create a rotating motor without using brushes, by using an AC power supply.
In using the same design as traditional 3-phase AC motors, the problem with using ‘brushless motors’ powered from a DC source, was not the motor itself, but the driver. It wasn’t until digital signal processing and highly integrated circuits arrived, that driving brushless motors powered from a DC source became feasible.
These brushless motors tend to be more efficient, but the major benefit is the extended lifetime. This means they are popular in products that require prolonged or constant rotation. In the past, DC brushless motors have been used devices such as VCRs, printers and hard disk drives.
High time, therefore, to apply the reliability of brushless motors to vibration applications. In particular, fields like mechanical aid can require constant vibration to aid the flow of, for example, medicine pills through a chute. A well made brushed vibration motor may last up to a thousand hours or more, which is more than enough for a handheld product that rarely vibrates in short bursts. But when constantly running rates this would require a motor change every 5~6 weeks
App note from Precision Microdrives helping you model DC motors in SPICE. Link here
SPICE (Simulation Program with Integrated Circuit Emphasis) is an open-source program for simulating electrical circuits. It enables engineers to model the behaviour of their circuits in software, which reduces prototyping costs and time.
As DC motors have mechanical properties – i.e. they cannot be simulated accurately only considering electrical properties – it can be difficult to use them in SPICE. This Application Bulletin guides you through the principle of operation and extends the DC motor model for vibration motors and gear motors.
App note from STMicroelectronics. Link here (PDF)
This application note explains how to extend the common input voltage range of a standard operational amplifier (op amp) to realize a high-side current sensing.
App note from STMicroelectronics about comparators and their limitations, also info on substitution depending on the application. Link here (PDF)
After operational amplifiers (op amps), comparators are the most generally used analog, simple integrated circuits.
Operational amplifiers are well described in many publications and a lot of information can be found regarding the design and proper use of these devices. On the other hand, information concerning comparators is much harder to find as they are often considered as simple devices.
App note from Vishay about how modern power inductors are made and their performance. Link here (PDF)
Power inductors are typically used for energy storage in DC/DC converters or high current noise filter applications, including motor speed control, adjustable lighting, DC power conditioning, and more. Power inductors can be divided further into two groups – shielded and unshielded. Unshielded power inductors have an open magnetic circuit where the magnetic flux induced in the core by the current in the winding exits the core and extends through the air to the other side of the core where it completes the flux path.
