Microchip describes techniques to reduce acoustic noise in pulse width modulator controlled fans. One solution is to use an RC filter to decrease the slew-rate of the PWM pulses. Fan speed control extends fan service life and decreases airflow noise and average fan current. The most efficient way to implement fan speed control is to […]
Category Archives: app notes
App note: Comparing serial data protocols
This serial digital data network table compares 8 of the most popular serial communication protocols – 1-Wire, I2C, SMBus, SPI, MicroWire, M-Bus, CAN, and LIN.
App note: High-speed ADC Layout tips and tricks
Here is an article from Electronic design covering some interesting tips and tricks for high speed ADC layouts: There is no way to cover all the specifics when designing a high-speed, high-resolution converter layout. Each application is different and sometimes unique. However, these key points will be useful to designers in better understanding their future […]
App note: Power conversion, measurement and pulse circuit collection
Here is another circuit collection from Linear Technology. This one covers power conversion, measurement, and pulse circuits. This ink marks LTC’s eighth circuit collection publication. We are continually surprised, to the point of near mystifi cation, by these circuit amalgams seemingly limitless appeal. Reader requests ascend rapidly upon publication, remaining high for years, even decades.
App note: Switch mode regulators for battery powered systems
Maxim describes various SMPS regulator topologies for battery powered systems. Isolated and non-isolated topologies are covered: This tutorial presents an overview of regulator topologies for battery-powered equipment. The discussion covers linear regulators, charge pumps, buck and boost regulators, inverters, and flyback designs. The importance of peak current is explained, and schematics of each topology are […]
App note: Capacitive touch sensors with metal coverings
Usually capacitive touch interfaces can’t be used with metal coverings, but Microchip’s Metal Over Cap overcomes this limitation: As a user interface, capacitive touch has several advantages: it is low power, low cost, simple to implement, reliable mechanically, and it allows designers a great deal of freedom in the shape of the buttons. However, for all […]
App note: Theory behind ground loops
Analog Devices discusses ground loops and how to manage them: Transmitting data over long distances is fraught with potential problems. A ground loop can be a source of interference that can induce a noise voltage between the grounds on either end of the transmission. If this voltage is large enough, it can cause data errors […]
App note: Using and understanding voltage references
This tutorial on voltage references covers theory and how it works in practice: When specifying a reference, keep in mind that initial accuracy, temperature coefficient and long-term stability all play a role in overall accuracy of the finished product. By taking some care in applying the reference, and by avoiding some key pitfalls, the reference’s […]
App note: Circuits and principles of high side current measurement
Maxim describes several high side current measurement circuits: This application note describes the use of current sense amplifiers, differential amplifiers and instrumentation amplifiers to measure battery charge and discharge currents in portable equipment, computer notebooks and USB accessories. It compares high side current sense amplifiers with low side differential amplifiers and recommends selection criteria for […]
App note: IrDA stack for infrared data exchange
IrDA is a set of protocols for exchanging data over infrared light. It’s significantly more complicated at the protocol level and hardware level than simple IR transmitter like remote controls. To get started in IrDA you’ll need some software to encode and decode packets, Microchip describes their IrDA stack in this app note: The Microchip […]
App note: Understanding microphone sensitivity
Analog Devices discusses the sensitivity of analog and digital microphones. Sensitivity, the ratio of the analog output voltage or digital output value to the input pressure, is a key specification of any microphone. Mapping units in the acoustic domain to units in the electrical domain determines the magnitude of the microphone output signal, given a […]
App note: Ceramic input capacitors can cause overvoltage transients
This app note from Linear Technology describes why ceramic capacitors aren’t an ideal replacement for tantalum based caps. The higher internal inductance of ceramic capacitors creates high voltage spikes: Applying a voltage step to a ceramic capacitor causes a large current surge that stores energy in the inductances of the power leads. A large voltage […]
App note: Theory behind the CMOS analog switches
Maxim has a tutorial describing the theory behind CMOS analog switches, and tips for selecting the right ones for your projects. This tutorial presents the theoretical basis for analog switches and describes some common applications for them. The special features of calibration multiplexers (cal-muxes), fault-protected switches, and force-sense switches are discussed as well.
App note: Using PIC32s with wireless data and navigation equipment
Microchip covers how to use PIC32s with GSM/GPRS/GPS wireless data and navigation systems. It uses their Machine to Machine board with a GSM/GPRS/GPS communication module: [Machine-to-Machine] uses a device to capture an event, which is then relayed through a network to an application that translates the event into meaningful information. A common application of M2M […]
App note: Common audio inter-IC protocols
Here is a design article from EETimes about the common inter-IC audio protocols. The article covers the traditional audio signal chain, fully digital audio signal chains, I2S protocol, and PDM. As audio integrated-circuit (IC) designs move to finer geometries, it becomes more difficult to design, and less cost-effective to integrate, high-performance analog circuits on the […]
App note: Minimizing switching regulator residue in linear regulator outputs
Here is an app note from Linear Technology describing how to minimize switching regulator noise in linear regulator outputs. Linear regulators are commonly employed to post-regulate switching regulator outputs. Benefi ts include improved stability, accuracy, transient response and lowered output impedance. Ideally, these performance gains would be accompanied by markedly reduced switching regulator generated ripple […]
App note: Theory behind Delta-Sigma analog to digital converters
Maxim describes the theory behind Delta-Sigma ADCs: This in-depth article covers the theory behind a Delta-Sigma analog-to-digital converter (ADC). It specifically focuses on the difficult to understand key digital concepts of over-sampling, noise shaping, and decimation filtering. A description of new converter, the MAX1402, and several applications for Delta-Sigma converters are included. The 16bit ADC […]
App note: Extending the life cycle of emulated EEPROM in program memory
Some applications require you to store data that wont be lost if the power goes down. Usual solutions involve either using an on-chip EEPROM or external memory devices. This app note from Microchip provides an alternative that allows you to store your data in the programming memory without having the usual low rewrite cycles associated […]
App note: 2-wire virtual remote sensing for voltage regulators
Here is an app note from Linear Technology describing the use of virtual remote sensing of wiring voltage drops in power supply designs. Here, the LT4180 Virtual Remote Sense™ (VRS) IC alternates output current between 95% and 105% of the nominal required output current. The LT4180 forces the power supply to provide a DC current […]
App note: Understanding and interpreting logic IC datasheets
This app note from Texas Instruments focuses on understanding and interpreting datasheets for logic ICs. To assist component and system-design engineers in selecting Texas Instruments (TI) standard-logic products, this application report is a synopsis of the information available from a typical TI data sheet. Information includes a brief description of terms, definitions, and testing procedures […]