Here’s an app note from Maxim describing the use of a digital potentiometer in analog circuits like amplifiers and filters. By using a digital potentiometer in an op-amps feedback loop, a digitally controllable variable gain amplifier is constructed. Variable gain amplifiers often use a mechanical potentiometer to set the gain. An example is a volume […]
Category Archives: app notes
App note: Diode turn-on time induced failures in switching regulators
A video from the comments on our post about fast diodes for switching regulators: Recently, switching regulator clock rate and transition time have become faster, making diode turn-on time a critical issue. A potential difficulty due to diode turn-on time is that the resultant transitory “overshoot” voltage across the diode, even when restricted to nanoseconds, […]
App Note: Linear Databook and the two-volume Linear Applications Handbook
Drone tipped us to scanned versions of the Linear Databook, and Linear Applications Handbook (vol.1 and vol.2) available online. These are collections of many app notes produced over the years by Linear Technology. Freely view/download the venerable set of Linear Technology Corporation’s Linear Databook and two-volume Linear Applications Handbook. Free to view online or download […]
SPICEing Op Amp Stability
Drone writes: Here is a nice little app-note that describes a quick test for op-amp stability using SPICE. (Actually the technique might be useful on the bench as well.) The approach involves applying a step directly to the op-amp input pin and observing the step response. The Author points out what to look for in […]
App Note: Practical guide to high-speed PCB layout
Here’s an article from Analog Devices going into the details of high-speed PCB layout design. While the article mainly focuses on analog electronics, lots of good tips can be picked up for digital designers as well. Intelligent circuit-board layout is important to successful op-amp circuit design, especially for high-speed circuits. A good schematic is the […]
App Note: Combining peripherals to implement a high resolution PWM
Here’s an app note from Microchip describing how to use the configurable logic cell (CLC) and the numerically controlled oscillator (NCO) peripherals to generate a high resolution pulse-width modulation signal. These peripherals are relatively new to Microchip’s product line and can only be found on some PIC10F and PIC16F devices: By itself, the NCO peripheral […]
App Note: DACs vs digital potentiometers
Here is an article from Maxim describing the differences between DACs and digital potentiometers. The article explains the characteristics and advantages of each, giving you a better idea of what you may need for your project. This application note compares digital to analog converters (DACs) to digital potentiometers. Traditionally digital potentiometers were meant to replace […]
App Note: Nuts and bolts of delta-sigma analog to digital converters
Here’s is a video from Texas Instruments describing the inner workings of delta-sigma analog to digital converters. The DS ADC is broken down into it’s basic parts. The delta-sigma modulator and digital decimating filter are then discussed. Delta-sigma converters are ideal for converting signals over a wide range of frequencies from DC to several megahertz […]
App note: Zero cross detector for AVRs
Atmel describes how to implement zero cross detection on an AVR. Zero cross detection is used to find the exact moment when a signal crosses from positive into negative, or vice-versa. This is useful in periodic AC signals as it gives you a reference point of when a new half period has started. This application […]
App note: Bootloading 101
Texas Instruments describes bootloaders and what they are all about. A bootloader is a piece of code that allows new firmware to be loaded into a microcontroller without a dedicated programmer. All of our projects use a bootloader so you can upgrade over a USB or serial connection. For PIC micros we usually use two […]
App note: Simulating fast transient loads for testing power supplies
How to implement a fast load transient simulator for power supply testing. One of important factor of power supplies is how they react to fast changing loads. This article describes how to design a system that measures power supply performance under quickly changing loads. To obtain fast load transients, we combine a power MOSFET and […]
App note: Digitally Addressable Lighting Interface
Microchip describes the digitally addressable lighting interface (DALI). This interface was designed to control dimmable fluorescent ballasts. Two wires are used to transmit Manchester coded message packets. The timing is standardized at 1200 bps so there is no need to transmit the clock signal, similar to how UART transmission works. The Digitally Addressable Lighting Interface […]
App note: Motor pre-drivers vs integrated drivers
Here is a video from Texas Instruments describing the differences in motor pre-drivers vs integrated drivers. Pre-drivers have all the control circuitry but the FETs are external, while in integrated drivers everything is on one IC. Because pre-drivers use external FETs, you can select the ones with much lower RDS-on resistance. This will give you […]
App Note: Various solutions for calculating a pulse and duty cycle
Here’s an app note from Microchip describing various methods for measuring pulse in periodic and non-periodic waveforms. Calculating duty cycle in periodic waveforms is also described. Many times it is desirable to quantify the pulse width of a periodic signal, such as that of a servo motor or duty cycle of a pulse-width modulated signal. […]
App note: Power supply over-current and over-temperature protection
Next up in our power supply theme is over-current and over-temperature protection for power supplies. The circuit cuts power in case one of these two events happen, it also has an external shutdown pin so the supply can be controlled by a switch or microcontroller. When it is necessary to plug in a board into […]
App note: Current limit circuit for buck topology switching regulators
Here’s a current limiting circuit for buck topology switching regulators. This design monitors a shunt resistor and overrides the feedback pin of the switching regulator when the current limit is reached. A current limit can be added to a step-down converter by using a MAX4173H current-sense amplifier to inject current into the feedback network. D1 […]
App note: Thermal characterization of IC packages
Here’s a tutorial from Maxim describing the thermal specifications in IC packages. All the devices used in a project dissipate heat, and if not properly cooled they will fail. This article will bring you closer to understanding the thermal specs quoted in datasheets. Thermal characterization of packages is critical for the performance and reliability of […]
App note: Driving capacitive loads fast by paralleling op-amps and transmission lines
Here’s a video from Linear Technology describing how to drive capacitive loads fast. The proposed solutions is to use multiple op-amps in a parallel configuration to achieve the high-speed requirements. Certain video and other technologies require driving planar conductive surfaces fast. Unfortunately, the surfaces can have high capacitance, which means that driving them fast takes […]
App note: Op-amps driving capacitive loads
Analog Devices describes why it’s a bad idea to drive capacitive loads with op amps. If you’re forced to drive a capacitive load, this video also provides a possible solution to the stability issues.
App note: EIA surface mount tape standard
Here is a paper from the Electronic Industries Alliance describing the standards for surface mount tape. We found it interesting that all surface mount tapes use the same pitch and diameter of the holes in the feeder mechanisms. The pitch being 4mm, and the hole diameter 1.5mm. Via Outguessing the machine.