App note: Secure hash algorithms back to basics

Maxim Integrated’s introduction to SHA security. Link here (PDF) This application note goes over the basics of Secure Hash Algorithms (SHA) and discusses the variants of the algorithm. It then briefly touches on how the algorithm is used for authentication, including the concept of a Hashed Message Authentication Code (HMAC). It concludes by looking at […]

App note: Optocouplers in on-board chargers and battery monitoring systems

App note from Vishay on how optocouplers play a role on safety for Electric vehicles. Link here (PDF) The number of electric vehicles on the roads is steadily growing, increasing the need for safe and reliable battery systems and high efficiency battery chargers. Modern electric vehicles use battery systems with voltages up to 1000 V […]

Reverse-engineering the classic MK4116 16-kilobit DRAM chip

Ken has written an article on reverse-engineering the classic MK4116 16-kilobit DRAM chip: Back in the late 1970s, the most popular memory chip was Mostek’s MK4116, holding a whopping (for the time) 16 kilobits. It provided storage for computers such as the Apple II, TRS-80, ZX Spectrum, Commodore PET, IBM PC, and Xerox Alto as […]

App note: Control solution using logic, analog switches, and discrete semiconductor devices for reversing a one-phase motor

App note from Littelfuse on solution to control split-phase motor using logic devices and triacs. Link here (PDF) In the huge variety of the AC motors, one-phase motors are an excellent option when only the single-phase power is available to supply electrical energy which motors require to operate. One of the most common single-phase motors […]

App note: Circuit protection solution for lithium cells

App note from Littelfuse on PolySwitch PPTC for lithium cells protection. Link here (PDF) Primary lithium cells (i.e., AA and 2/3A) and rechargeable lithium cells (i.e., 18650, 17500, and prismatic) are used in many portable electronics applications, such as laptop or notebook computers. Their popularity is based on the fact that they offer high energy […]

Reverse-engineering the carry-lookahead circuit in the Intel 8008 processor

Reverse-engineering the carry-lookahead circuit in the Intel 8008 processor: The 8008 was Intel’s first 8-bit microprocessor, introduced in 1972. While primitive by today’s standards, the 8008 is historically important because it essentially started the microprocessor revolution and is the ancestor of the modern x86 processor family. I’ve been studying the 8008’s silicon die under the […]

App note: How to determine if an eFuse system can be safely hot−plugged

This app note from ON Semiconductors linked here (PDF) System designers must account for voltage surges that occur when supplies or loads are connected. eFuses are integrated circuits with many features to protect loads from these surges. However, it is important to ensure that the eFuse itself will not receive excessive voltage on its input. […]

App note: Analysis of power dissipation and thermal considerations for high voltage gate drivers

App note from ON Semiconductors on ways to dissipate thermals or reduce junction temperature of HVIC. Link here (PDF) Gate drivers used to switch MOSFETs and IGBTs at high frequencies can dissipate significant amount of power depending on the operating conditions. It is important to determine the driver power dissipation and the resulting junction temperature […]

Low-cost open source ventilator-ish device

Johnny made a low-cost ventilator-ish device, that is available on GitHub: In the event that COVID-19 hospitalizations exhaust the availability of FDA approved ventilators. This project documents the process of converting a low-cost CPAP (Continuous Positive Airway Pressure) blower into a rudimentary non-invasive pressure support ventilator that could help with breathing during respiratory distress. It’s […]

App note: Termination recommendations for single-ended oscillator driving single or multiple Loads

Proper clock signal terminations app note from SiTime. Link here (PDF) Clock signals with fast edges see traces on Printed Circuit Boards (PCB) as transmission lines rather than simple wire connections. If the length of PCB trace exceeds certain limit it requires matching of the trace impedance to one or both of the source and […]

App note: Interfacing an STM32L1xx microcontroller with an external I2S audio codec to play audio files

I2S protocol interfacing with an STM32 microcontroller app note from ST Microelectronics. Link here (PDF) The I2S protocol is widely used to transfer audio data from a microcontroller/DSP to an audio codec in order to play melodies (stored in a memory) or, to capture analog sound (from a microphone). The STM32L1xx allows I2S audio communication […]

App note: Is the lowest forward voltage drop of real schottky diodes always the best choice?

App note from IXYS about the pros and cons of different forward voltage drop of real shottky diodes. Link here (PDF) According to the thermionic emission model, pure Schottky barriers exhibit a forward voltage drop, which decreases linearly as the barrier height diminishes; whereas the reverse current increases exponentially as the barrier height decreases. Consequently, […]

App note: Voltage vs. output speed vs. torque on DC motors

App note from Precision Microdrives about DC motor capabilities and their uses. Link here Why Change Torque? The most obvious benefit of varying the torque is to maintain a constant speed when the motor’s load varies, keeping in mind the interdependent nature of speed, torque, and voltage. Although this example may be outdated, audio cassettes […]

Designing a Memory/IO (ETA-3400) addon for the ET-3400 trainer

Dr. Scott Baker designed and built an ETA-3400 Memory/IO accessory for the vintage Heathkit ET-3400 trainer, that is available on GitHub: I’ve always wanted one of these Heathkit microprocessor trainers, and finally one caught my eye on eBay and I pulled the trigger. The basic interaction with the trainer is through the onboard keypad and […]

App note: TQFN package thermal pad via design guide

TQFN footprint pad via design guide for proper thermals from Diodes Incorporated. Link here (PDF) TQFN packages have exposed pads to provide excellent electrical grounding paths to the PCB and transfer the device heat through thermal vias on the PCB thermal landing to the internal copper planes. In order to maximize the removal of heat […]

App note: Understanding thermal resistance in the real world

App note from Diodes Incorporated about thermal resistance and how to manage them in real world scenario. Link here (PDF) There can be significant differences between the thermal characteristics stated on a device datasheet and what actually happens in a realworld application. Semiconductor manufacturers usually provide thermal resistance values for Junction to Case (RθJC) and […]

App note: Processing instructions for mounting of through-hole LEDs

Do and don’ts when mounting through-holes LEDs, app note from Vishay. Link here (PDF) Through-hole LED cases usually consist of epoxy casting compounds with duroplastic properties. It is in the nature of things that optical semiconductor devices require transparent materials with the best possible optical features. Unlike standard IC mold compounds, which use reinforcing fillers […]