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.
Tag Archives: maxim
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: Charge pump DC-DC converters
Here is an app note from Maxim describing the theory behind, and implementation of charge pump based DC-DC converters. Charge pumps are often the best choice for powering an application that requires both low power and low cost. This application note discusses integrated charge pumps and explains how to calculate power dissipation in a charge […]
App note: Need for power and ground cleanliness
Some tips and tricks on how to reduce noise on PCB power and ground traces. It warns digital engineers that the analog nasties are lurking in power supplies, and can cause unexpected surprises for inexperienced PCB designers. Many times electronic system failures are blamed on the parts when the real cause was human error. […]
App note: Common IC interface problems
A somewhat humorous app note describing the common IC interface protocols like I2C, SPI, and GPIO. Also covered are some problem with these interfaces that turn happy faces to sad. How can an interface change a happy face to a sad face? Engineers have happy faces when an interface works properly. Sad faces indicate failure […]
Dual 4 digit 7-segment display board with SPI interface
Raj built a dual, 7-segment, display board with SPI interface. The board is based around the MAX7219 8x 7-segment display driver, which receives commands over SPI, and drives the display accordingly. The new display features eight 7-segment displays arranged in two rows of four digits. The on-board MAX7219 driver enables you to easily add eight […]
App note: 112W Boost driver for long strings of LEDs
Maxim shows how to build a 112 watt DC-DC boost driver for long strings of LEDs. The driver is current controlled,with adjustable output from 0 to 1.5Amps. This reference design is for a high-voltage boost current source for very long strings of LEDs. Applications that use long LED strings include, but are not limited to, […]
Dual-output DC/DC power supply for AMOLED
Rsdio tipped us to a dual-output switch mode power supply reference design based on the MAX17116. The part and reference circuit can provide both negative and positive supplies to AMOLED displays. The MAX17116 includes two current-mode 1.4MHz switch mode power-supply (SMPS) regulators for active-matrix organic light-emitting diode (AMOLED) displays. The positive supply is provided by […]
App Note: Adjustable power supply using a digital potentiometer
How to use a digital potentiometer to calibrate and control an adjustable power supply. A resistive feedback network is often used to set the output voltage of a power supply, since fixed resistors are simple to use and low cost. However, because a fixed network is not adjustable, the output voltage cannot be accurately set. […]
App note: Low-cost, low-distortion square to sinewave signal converter
Convert square wave clock signals to low distortion sinewaves: This circuit derives a pure sinewave from a crystal-controlled clock source by using a ring counter to remove the highest-amplitude unwanted harmonics, and filtering the result with an 8th-order lowpass, switched-capacitor elliptic filter
App note: The FET-OR connection for power supplies
Here is a reference design from Maxim how to built a circuit that would seamlessly switch to the secondary power supply if the primary fails. This power-supply sequencer senses a loss of the main supply voltage and, by controlling the two FETs, automatically switches the load to the secondary (backup) supply.
App note: Calibration of touch-screens
Here is an app note from Maxim describing how to implement touch screen calibration. It provides the reader with the necessary mathematical tools needed to address issues with mechanical misalignment and scaling due to imperfections in the touch screen: Mechanical misalignment and scaling factors can lead to a mismatch between the values from a touch-panel […]
App note: Exposed pads on some IC packages
Some IC packages have a large exposed pad on the bottom. It’s usually connected to the chips ground, and helps cool the chip by transferring heat to the PCB. This app note from Maxim describes the functionality of exposed pads, as well as their proper use.
App note: Calculating the error budget in precision DACs
How to chose a voltage reference and digital to analog converter chips to get the precision and stability you need: This application note focuses on Maxim’s 3-terminal voltage references and precision DACs. To design a system, one must first understand how the parts are specified and then how their performance characteristics interact. Voltage references and […]
App note: Add high voltage capability to current sense monitors
Here is an app note from Maxim describing how to add high voltage capability up to 300V for the MAX47X (which have been replaced by MAX407X) bidirectional current sense monitors. Since the MAX47X draw low current, a simple floating power supply can be used to power the device even at 300V. The circuit of Figure […]
App note: Automatic current-limiting in hot-swap applications
Maxim describes how current limiting functions on their MAX5976 Hot-Swap IC. This chip is useful for hot-swap applications, it allows the safe insertion and removal of circuits while the power is applied. Because the MAX5976 and similar devices use a single resistor to set soft-start and overcurrent protection levels, simple changes to the basic application […]
Using the MAX11209 18bit ADC
Jbeale connected the MAX11209 18 bit ADC to his Seeeduino board and wrote up some test firmware. The MAX11209 can do 18 bits at sample rates up to 120 Hz (true) or 480 Hz (4x oversampled). It has both external analog and internal digital scaling. There is +Vref and -Vref, as well as +Vin and […]
App note: Find the right battery for your project
Maxim describes how to select the batteries best suited to a specific project. The main performance metric for batteries is, of course, battery life. On the surface, this is a simple spec, but in truth it has many dimensions. These include the system’s load profile (how much of the time it spends using full load […]
App note: Layout guidelines for DC/DC switching power supplies
Maxim describes how to design PCBs for DC/DC switching power supplies. Learn which traces to keep as short as possible, and the reasoning behind it. The diagram sums up our own approach nicely as well. When working with any buck or boot converter, we: Keep the main power path (shown in blue) straight and compact. […]
App note: Touch-screen technologies roundup
Common touch-screen types are resistive, capacitive, or haptic. This app note describes each: Touch screens are not a new concept. Where previously touch screens were merely designed to replace keyboards and mice, today they convey a completely new operating experience. Featuring greater interaction between the user and device, this new “touch” experience has been achieved […]