Tag Archives: DAC

A data-acquisition system on a chip

AD5592R-600x212

by Martin Rowe @ edn.com:

Multifunction data-acquisition systems have been around for a long time as stand-alone instruments, plug-in cards, cabled computer peripherals, and embedded in systems. Such systems are often designed with separate ADCs, DACs, and digital I/O devices. Many microcontrollers include ADCs and DACs, but that locks you into using that device. The AD5592R from Analog Devices combines all of these I/O functions, letting you use one chip to design measurement-and-control functions into systems.

A data-acquisition system on a chip – [Link]

XMega DAC

DAC-Internal-Block-Diagram

Shawon M. Shahryiar @ embedded-lab.com writes:

In embedded systems, oftentimes it is needed to generate analog outputs from a microcontroller. Examples of such include, generating audio tones, voice, music, smooth continuous waveforms, function generators, voltage reference generators, etc. Traditionally in such cases the most common techniques applied are based on Pulse Width Modulation (PWM), resistor networks and external Digital-to-Analog Converter (DAC) chips like MCP4921. The aforementioned techniques have different individual limitations and moreover require external hardware interfacing, adding complexities and extra cost to projects. XMega micros are equipped with 12 bit fast DACs apart from PWM blocks and again it proves itself to be a very versatile family of microcontrollers. In this post we will have a look into this block.

XMega DAC – [Link]

DIY USB DAC

iw48w41

A USB DAC designed using a TI PCM2707:

it was a very fun project and very fulfilling to make something that I actually use everyday. Overall the audio specs aren’t anything amazing, but it definitely is an improvement on the built in audio of my computer.

DIY USB DAC – [Link]

MAX5825PMB1 Peripheral Module Board

The MAX5825PMB1 peripheral module provides the necessary hardware to interface the MAX5825 8-channel DAC to any system that utilizes Pmod™-compatible expansion ports configurable for I²C communication. The IC features eight independent 12-bit accurate internally buffered voltage-output DAC channels. The IC also features an internal reference that is selectable between 2.048V, 2.500V, and 4.096V (4.096V reference operation is not supported with a standard 3.3V Pmod-port power supply).

MAX5825PMB1 Peripheral Module Board – [Link]

 

LTC2645 – Quad 12-/10-/8-Bit PWM to VOUT DACs

 

2645

by linear.com:

The LTC2645 is a family of quad 12-, 10-, and 8-bit PWM-to-voltage output DACs with an integrated high accuracy, low drift, 10ppm/°C reference in a 16-lead MSOP package. It has rail-to-rail output buffers and is guaranteed monotonic. The LTC2645 measures the period and pulse width of the PWM input signals and updates the voltage output DACs after each corresponding PWM input rising edge. The DAC outputs update and settle to 12-bit accuracy within 8μs typically and are capable of sourcing and sinking up to 5mA (3V) or 10mA (5V), eliminating voltage ripple and replacing slow analog filters and buffer amplifiers.

LTC2645 – Quad 12-/10-/8-Bit PWM to VOUT DACs – [Link]

 

MAX5825PMB1 Peripheral Module Board

The MAX5825PMB1 peripheral module provides the necessary hardware to interface the MAX5825 8-channel DAC to any system that utilizes Pmod™-compatible expansion ports configurable for I²C communication. The IC features eight independent 12-bit accurate internally buffered voltage-output DAC channels. The IC also features an internal reference that is selectable between 2.048V, 2.500V, and 4.096V (4.096V reference operation is not supported with a standard 3.3V Pmod-port power supply).

MAX5825PMB1 Peripheral Module Board – [Link]

Heatsink Tester

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bogdan @ electrobob.com wanted to know how much heat a heatsink can dissipate so he build a simple setup using a temperature sesnsor and a mcu. He writes:

It’s quite a common problem when building electronics that some components need cooling which is usually done through some sort of heatsink and optional fans. Choosing the right cooling solution can be a difficult task because the real life behavior of the system is hard to predict or model. In my case I have faced the simple question quite a few times: how much heat can a cooling system dissipate? The thermal resistance of a particular heatsink may vary quite a lot depending on the surroundings or it can simply be unknown to start with. The aluminum side wall of an enclosure made me build this thing.

This is why I have made this little device: a thermometer, a transistor and a microcontroller with a simple command line interface. I could have answered my questions in quite a lot of simpler ways, but since I made a simple thermometer not much else is needed to control the transistor when a DAC is available in the microcontroller.

Heatsink Tester – [Link]

Designing active analog filters in minutes

active_filter_designBy Bonnie Baker

Active analog filters can be found in almost every electronic circuit. Audio systems use filters for frequency-band limiting and equalization. Designers of communication systems use filters for tuning specific frequencies and eliminating others. To attenuate high-frequency signals, every data acquisition system has either an anti-aliasing (low-pass) filter before the analog-to-digital converter (ADC) or an anti-imaging (low-pass) filter after the digital-to-analog converter (DAC). This analog filtering can also remove higher-frequency noise superimposed on the signal before it reaches the ADC or after it leaves the DAC. If an input signal to an ADC is beyond half of the converter’s sampling frequency, the magnitude of that signal is converted reliably; but the frequency is modified as it aliases back into the digital output.

Designing active analog filters in minutes – [Link]

Interfacing the DAC7564 to an MSP430

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Juan has written an article detailing how to use an MSP430 with a DAC7564:

The DAC7564 is a low-power, voltage-output, four-channel, 12-bit digital-to-analog converter (DAC). The device includes a 2.5V, 2ppm/°C internal reference. The device is monotonic, provides very good linearity, and minimizes undesired code-to-code transient voltages (glitch).

[via]

Interfacing the DAC7564 to an MSP430 – [Link]

Sine Wave Example for MCP4725 DAC

adafruit.com writes:

There were a few questions in the forum about generating sine waves on the MCP4725 I2C DAC.  To show one way you might accomplish this, an example sketch was added to the Adafruit MCP4725 library.  You can set the resolution between 9-bit and 5-bit, depending on your requirements and how much flash space you can spare.  5 and 6-bit output would benefit from a basic filter to smooth the output out, but 7-bits and higher is reasonably smooth, as can be seen in the image above comparing the out from an Agilent function generator (in blue) and the MCP4725 sketch at 8-bit resolution (in yellow).

Sine Wave Example for MCP4725 DAC – [Link]