App note: Replacing traditional optocouplers with Si87xx digital isolators


Digital isolator from Silicon Labs app note shows pin compatible plus high performance replacment of incumbent optoisolators, link here (PDF)

Opto-couplers are a decades-old technology widely used for signal isolation, typically providing safety isolation, signal level shifting, and ground loop mitigation. They are commonly used in a wide range of end applications, including data communication circuits, switch mode power systems, measurement and test systems, and isolated data acquisition systems. Optocouplers have several weaknesses, including parametric instability with temperature and device aging, significant internal parasitic couplings, long propagation delay times, narrow operating temperature ranges, and relatively low reliability.

Today’s advanced CMOS signal isolation products offer better timing performance, higher reliability, and lower power consumption compared to optocouplers and are capturing sockets traditionally held by optocouplers. However, converting to CMOS isolation devices has, most often, required circuit changes and PCB modifications that cost money and create design risks, until now.

App note: Introduction to gapped clocks and PLLs


App note from Silicon Labs on the introduction of gapped clocks, how they can be used in network timing, and their impact upon phase locked loop (PLL) technology. Link here (PDF)

Gapped clocks are periodic clock signals of a single clock frequency that have clock pulses removed from their stream. Well-formed gapped clocks do not have reduced width pulses (known as runt pulses). Rather, each individual clock pulse is either completely present or completely absent.

App note: Miniature, precision negative reference requires no precision resistors


App note from Maxim Integrated creating voltage negative reference from charge-pump inverter plus positive voltage reference combo. Link here (PDF)

This application note discusses how to build a negative voltage reference without using external resistors or a negative supply by simply combining a simple charge-pump inverter and a positive output voltage reference.

App note: Simple test method for estimating the stability of linear regulators


Tips from ROHM Semiconductor to estimate the stability of linear regulator using simple step response method. Link here (PDF)

Low drop-out (LDO) regulators developed back in the age when large-capacitance multi-layer ceramic capacitors (hereinafter, MLCCs) were uncommon cause a phase delay, leading to oscillation when connected to a low-ESR capacitor like an MLCC. Often, MLCCs are used to save board space and prolong the lives of electronic components. A resistor placed in series in the circuit increases apparent ESR and establishes a phase lead that enable the use of an MLCC as an output capacitor. Phase margin measurement is practical on an LDO having variable output voltage, since its feedback loop is outwardly exposed. However, on a fixed output voltage LDO, the phase margin cannot be measured because of its closed loop circuit.

App note: Receiving S/PDIF audio stream with the STM32F4/F7/H7 series


App note from STMicroelectronics about electrically connecting an external S/PDIF stream to an STM32 with an S/PDIFRX interface peripheral, Link here (PDF)

The Sony/Philips Digital Interface Format (S/PDIF) is a point-to-point protocol for serial and uni-directional transmission of digital audio through a single transmission line for consumer and professional applications. The transmission of data can be done in several ways, by electrical or optical means.

The S/PDIFRX peripheral embedded in STM32 devices is designed to receive an S/PDIF flow compliant with IEC-60958 and IEC-61937, which define the physical implementation requirements as well as the coding and the protocol. These standards support simple stereo streams up to high sample rates, and compressed multi-channel surround sound, such as those defined by Dolby or DTS.

App note: Addressing power supply challenges for after-market electronics and infrastructure

Addressing Power Supply Challenges for After-Market Electronics and Infrastructure

This application note discusses key market trends and customer needs that are presenting new challenges for power supply design for after-market technologies and transport infrastructure automation. This piece will also examine solutions to address these challenges, with a special emphasis on power architecture. Link here

After-market automotive products have driven remarkable innovation, from infotainment and telematics to advanced driver assistance systems (ADAS). Features like GPS, rear-view cameras, and parking sensors are now common in vehicles. There is also a continuous rollout of novel after-market technologies being developed by companies worldwide. Fleet management, on-board diagnostics, heads-up display, and freight control/monitoring are just a few examples of technologies found in cars and trucks, trains, ships, avionics, and defense applications.

App note: Linear regulator problem situations – Power supply does not start


App note from ROHM Semiconductor about various start up problem on 3 pins linear regulator. Link here (PDF)

Although linear regulators can be used to easily configure power supplies, the linear regulators may cause startup problems depending on the type of loads. This application note introduces cases where the power supplies do not start correctly in the linear regulators.

App note: Design considerations for a harsh industrial environment

Design Considerations for a Harsh Industrial Environment

This article discusses factors that influence the robustness of a circuit in a harsh environment, like you would find for industrial applications. The topics covered include ways to handle voltage transients and to protect against electrostatic discharge (ESD) and faults. Link here

Semiconductor (IC) robustness—what is the operating temperature range? How is high electrical noise handled? What about ESD and fault protection? These issues are not necessarily the first things that a design engineer thinks about when selecting an IC. Nonetheless, robustness is a key performance parameter for long-term operation and a reliable, reputable end product. This is especially true when designing a system for an industrial environment where harsh operating conditions are common. Industrial equipment can be exposed to a wide range of temperatures, high electrical noise on either the power-supply lines or data lines, and fault events like ESD or short circuits.