BUS PIRATE: three inexpensive SPI Digital to Analog Converters

As much as possible, we’d like to move control of all the Bus Pirate peripheral hardware to the FPGA. Then everything can be controlled through the state machine command pipeline. In Ultra v1c we moved analog voltage measurement to the FPGA by adding an SPI ADC. In a future revision it would make sense to […]

Building a bluetooth DAC with Raspberry Pi Zero W

Sami Pietikainen has written an article detailing the build of his Bluetooth DAC using Raspberry Pi Zero W: My car comes with a built-in Bluetooth hands-free but unfortunately it does not support audio streaming. Luckily there is an AUX input available which uses a regular 3,5 mm jack. Perfect opportunity for a DIY project. I built the […]

App note: 3V DACs used in ±10V applications

Boosting DAC’s output to drive larger voltage tackled in this app note from MAXIM Integrated. Link here (PDF) Many modern systems have the majority of their electronics powered by 3.3V or lower, but must drive external loads with ±10V, a range that is still very common in industrial applications. There are digital to analog converters […]

Simulating 3-phase AC for energy monitor testing

Tisham Dhar blogged about his 3-phase synthesizer: Finding 3-phase is difficult, convincing the owner of the said supply to test some home made hardware is even more so. After building a 3-phase energy monitor my testing options for it appeared very limited. So I set about making my own low-cost 3-phase energy monitor calibration system. See […]

App note: DAC ICs: How many bits is enough?

A very old application notes from Analog Devices that tells about Nyquist Theorem, sampling rate and quantization used on DACs. Link here (PDF) At the heart of every digital audio playback system lies the single-most critical component for high-fidelity audio: the digital-to-analog converter (DAC). These converters handle the delicate task of translating the 16-bit binary […]

App note: WM8731 Suggested power-On/Off sequence

Interesting app note from Cirrus Logic on how to minimize popping sound on the output when turning on/off the DAC on their WM8731 digital to analog converter. Link here (PDF) As with any consumer audio product, it is important that any on/off power noise be kept to a minimum. Generally, this is done with some […]

Output voltage control of DC/DC converters

Thomas Fischl writes: Some applications needs to control the output voltage of a dc/dc converter instead using a fixed output voltage. For example battery chargers has to adjust the output voltage to the current battery level. This page shows how to add such a control function to a buck converter circuit. Control output via external […]

App note: Using the DAC as a function generator

A function generator from an C8051 DAC application note(PDF) from Silicon Labs This document describes how to implement an interrupt driven multifunction generator on C8051 devices using the on-chip digital-to-analog converter (DAC). Four different waveforms expandable to any periodic function defined in a table. – Sine Wave (Table Defined) – Square Wave (Calculated) – Triangle […]

16F1509 ramp generator using the internal 5-bit DAC

Charles Douvier of PNW/Electronics writes: Turns out the DAC is probably the easiest peripheral I’ve used on the PIC. It took me longer to wait for the PICKit to update from 18F configuration to 16F. BUT.. if you’re having issues.. here you go: A simple voltage follower (or however you want to buffer the output) […]

Extending DAC resolution using digital potentiometer

Kerry Wong writes: One way to extend the resolution of a digital-to-analog converter (DAC) is by employing a sigma-delta converter in software. The main disadvantage of such approach is the slow speed. Alternatively, we can use some extra hardware to extend the usable resolution of a DAC. In this post, I will illustrate one such […]

App note: Audio and waveform generation using the DAC in STM32 microcontroller families

App note on utilizing the built-in DAC on your STM32 micro. This application note gives examples for generating audio output signals using the Digital to Analog Converter (DAC) peripheral embedded in the STM32F10xx microcontroller family. The STM32 DAC module is a 12-bit word converter, with two output channels for supporting stereo audio. The DAC can […]

An isolated DAC using PWM output

Kerry Wong writes: Arduino‘s (ATmega328P) PWM outputs via analogWrite can be conveniently turned into analog voltage levels through the use of simple RC filters. Since the PWM outputs are not isolated, using them to drive other devices directly could be potentially dangerous. This is especially true if the target circuit uses a higher supply voltage. […]

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: Digital to analog interface fundamentals

Analog Devices describes the fundamentals of working with digital-to-analog converters: This tutorial outlines some important issues regarding DAC interface circuitry including the voltage reference, analog output, data input, and clock driver. Because ADCs require references and clocks also, most of the concepts presented in this tutorial regarding these subjects apply equally to ADCs.

FIRST DRAFT: Programmable dummy load

  This is a programmable current sink, usually used to simulate  different current loads for power supplies. We have always wanted to build one, but we’ve stalled several times. This design is based on the simple analog load posted by Bearmos. It’s not intended to be a final project, it’s just an experimental prototype to […]

openHiFi open source digital music player update

Brian is hard at work designing an open source HiFi stereo digital music player. A Cortex M3 decodes various audio formats and sends them to a digital to analog converter audio IC via an I2S interface. This is all implemented on his Procyon development board. In this video he tests his firmware using a custom […]

App note: Building a stable DAC external reference circuit

Having a stable external reference is important in digital-to-analog converter design and this app note helps. For a DAC to function properly it must have a stable reference to create a precise output signal. Unfortunately because it is a simple concept, proper reference design is usually overlooked. In this app note from TI a simple force and […]