A DAC is a Digital to Analog Converter.
2
votes
2answers
94 views
What does DAC resolution mean?
I am reading the specs of a DAC (this one), and it says the resolution is 10 bit. Does it mean it can generate 1024 voltage levels at the sample rate which is 12 GSa/s? It sounds pretty surreal. Can ...
4
votes
2answers
160 views
3.3V DAC output to 50V amplification
I have DAC 3.3V generated narrow square pulses that I need to amplify to 50Vdc. For this purpose an OPA551 single supply opamp works fine, but it's quiescent current of ~7mA @ 50V consumes too much ...
4
votes
1answer
34 views
Efficient way to get multiple analogue voltages out of an Arduino?
I've read in my research that most microcontrollers are not built with DAC outputs as they are expensive to include on silicon chips. Also applications that require analogue outputs typically need a ...
2
votes
2answers
92 views
Efficient way to get multiple Analogue voltages out of a microcontroller?
I've read in my research that most microcontrollers are not built with DAC outputs as they are expensive to include on silicon chips. Also applications that require analogue outputs typically need a ...
1
vote
3answers
128 views
Controlling 8-bit DAC Output over I2C— decimal to binary char conversion help
Clarifying my question a bit. We're using a PIC32 board with an MCP4706 8-bit DAC, controlled over I2C. If we write a binary value (e.g. 0b00000100) to the DAC, it outputs as expected. However, ...
0
votes
2answers
58 views
Why does my oscilloscope get no pulse wave when connected to my DAQ board?
I have created the following LabVIEW GUI to generate a square pulse train waveform:
As you move the frequency and pulse width knobs the waveform changes accordingly (pulse width is now 2ms).
...
0
votes
1answer
68 views
Load Cell DAQ via Arduino Mega
Background: I'm working on a project that involves tapping into the load cells of a scale and reading the differential output of the Wheatstone bridge. I need to keep all of the original functionality ...
3
votes
2answers
193 views
How to ensure that a pin never floats
I am making a DAC circuit with uses an AD7541A chip which is going to be connected to another board with a microcontroller on it. Now the AD7541A gets fried if someone turns it on while all the pins ...
1
vote
2answers
93 views
I2C with PIC32 and MCP4706 Not Working
We're working on a battery charger for an electric bicycle at the moment, but prototyping with a PIC32MX695F512H kit board and an MCP4706 DAC soldered onto a breakout board, programmed using a ...
0
votes
2answers
96 views
10-Bit DAC input to one binary output?
I'm a novice when it come to electrical engineering and I may be missing a few key concepts but I'll try my best to respond to questions.
I have a "Low Cost 10-Bit Monolothic D/A Converter" (AD561J) ...
-2
votes
1answer
198 views
DSP with ADC DAC SPDIF IO controlled with Microcontroller via USB
I'm looking for a board to process live music (sub-millisecond latency if possible). I'm thinking of a layout like the following:
So there are a few DACs and ADCs, S/PDIF inputs and outputs and a ...
18
votes
4answers
850 views
Do you recognise this signal?
The story for this signal is the following. I've bought an NAD C 356BEE amplifier with an integrated MDC DAC module. It has optical and USB input. The optical is OK, but if I connect the DAC to my ...
12
votes
4answers
460 views
What is a one-bit ADC good for?
I have recently heard of the concept of a one-bit ADC, and have seen it implemented in the context of a sort of digital-to-analog converter (oddly enough), and I'm wondering, what is the point? Why ...
0
votes
1answer
55 views
Voice playback IC
I was looking for cost effective voice playback IC and came up to ISD 1700 series. Another brief datasheet is here. I don't believe with the same footprint and only for 3-4 bucks I can get up to 16 ...
1
vote
1answer
50 views
Accuracy of a dac - INL rating how that relates to deviation in mV's
In the datasheets of a dac they talk about the INL error. As I understand this is to do with how much the output of the dac deviates from the output of an ideal DAC. So I was wondering how does that ...
6
votes
1answer
244 views
Adjusting offset (and possibly gain) of ADC preamp OPAMP with DAC
I am designing simple 200MHz scope for use with FPGA board and came up to idea of software adjustable offset and gain of input preamplifier.
It is using TI ADC08200 and since I am not much ...
0
votes
2answers
117 views
Using DAC to control supply voltage of bus transciever?
I am designing simple logic analyzer with SN74LVC16T245DGGR bus transceiver which could be used for 1.2V to 5V logic levels I would like to control supply voltage of input port with DAC, currently ...
0
votes
1answer
195 views
How to design the value of capacitor for Capacitive DAC based on noise and mismatch analysis?
In order to design the correct value for the capacitor in a capacitive DAC, we need to look at two possible causes of errors. Noise and Mismatch Analysis. sqrt(kT/C) should be less than 1/2 LSB. But, ...
0
votes
0answers
213 views
STM32F4 + MCP4922 DAC + SPI + DMA = 0
I want to transmit data to MCP4922 DAC using SPI with DMA but as with most non-audio DACs it requires a pin toggle to latch data in the DAC buffers after each TX. There is a Chip select associated ...
2
votes
1answer
126 views
How to say whether INL and DNL of a DAC is good enough?
The DAC has an INL of about 20 or so LSBs. DNL is +-2LSB.
Since it is a 14 bit DAC, is it safe to say that the DAC is monotonic for 13 bit use? (Since DAC is monotonic if DNL is not below -1LSB)
...
0
votes
2answers
144 views
DAC - how this particular dac works
I was reading an article on how to this guy was generating a sine wave digitally. He had a DAC made out of resistors. What I'm unsure about is what type of dac it is? To me it doesn't look like an ...
2
votes
1answer
103 views
viewing microcontroller's output
I'm trying to sample a(low frequency) signal I'm producing using Microchip's PIC16F1783 (which has an internal DAC).
I connect its output and ground my PC's audio jack (GND+Right Channel).
I then ...
1
vote
3answers
288 views
Scaling PWM amplitude by switching an analog DC voltage?
I'm trying to make a quick-and-dirty voltage-controlled volume control circuit, using a minimal number of components.
A microcontroller is outputting two 5V p-p, 625 kHz PWM signals: an audio ...
2
votes
2answers
100 views
What's the use-case for gain selection on a DAC?
I'm looking at the datasheet for an MCP4921 12-bit DAC (PDF), which describes the following feature:
Selectable Unity or 2x Gain Output - The user can configure the full-scale range of the device ...
2
votes
2answers
142 views
Can't figure out schematics error
ATTiny is generating PWM based tones with 32kHz sampling rate. Then I've created R-2R DAC and then trying to amplify it for speaker. However, LM386 is sinking signal from R-2R. If I don't connect ...
2
votes
2answers
404 views
Interfacing ultrasound receivers and emitters with a microprocessor
I have bought ultrasonic receivers and emitters to play with (see datasheet here). I also have an STM32 processor devkit with DAC and ADC pins readily available.
How should I connect the ultrasonic ...
3
votes
1answer
111 views
How do some SAR ADCs allow the input range to be 0 to 2xVref?
If the capacitive DAC on the ADC uses Vref, would it not output a signal from 0 to Vref to the comparator? How would the comparator work if the input signal is greater than Vref since it would always ...
5
votes
3answers
767 views
Possible to output sinusoidal signal with an Arduino?
Is there a way to output a sinusoidal wave with an arduino? Perhaps using PWM? It would be nice to be able to simulate something around 10kHz. Is this even possible with the hardware on the Uno?
0
votes
1answer
99 views
Pulse broadcasting circuit [closed]
I want to build a circuit that generates analog pulses at 1.8-2 MHz and amplifies those pulses and then broadcasts them using an antenna. I was thinking of using this DAC converter and connect this to ...
0
votes
1answer
241 views
If a DAC does USB in and S/PDIF out, what does it do?
I have a USB DAC (Creative SB1240) and their recommended connection is to take an S/PDIF or USB in (to the DAC) and an S/PDIF out (to a receiver). This is how I have connected it and it does sound ...
4
votes
4answers
469 views
Different decoupling capacitors in parallel
Page 29 of this DAC datasheet gives a typical operating circuit. I notice the power supplies have two decoupling capacitors in parallel: 100nF and 10μF.
What caught my eye is that there is a ...
2
votes
1answer
50 views
Multiple lengths in DAC datasheet
The last page of this DAC datasheet gives dimensions of the chip:
Some of these dimensions come is 3-tuples (such as the pin width: 0.30 | 0.37 | 0.45). What ...
3
votes
2answers
281 views
Units of noise spectral density
I'm reading the datasheet of a DAC (see page 6), and the "Output Noise Spectral Density" has units V / Hz^(1/2).
The Wikipedia article on noise spectral density ...
6
votes
2answers
472 views
What is a brownout condition?
I'm reading the datasheet of this DAC. Page 27 states:
In many industrial process control applications, it is vital that the
output voltage be controlled during power-up and during brownout
...
2
votes
4answers
243 views
How can I convert an irregular PWM signal with a duty cycle of 95 to 99% to an analog signal?
For the purpose of measuring particulate matter (PM) in air, I am trying to set up a DAC system for the PM sensor Shinyei PPD42NJ (info herehttp://www.seeedstudio.com/wiki/Grove_-_Dust_sensor) and ...
2
votes
1answer
87 views
Output voltage when turned off
I have a DAC (datasheet available here) that has a SLEEP mode (see page 14). When SLEEP mode is activated, my oscilloscope reads ...
0
votes
1answer
59 views
DAC: What waveform should I expect when ramping up?
I have a 14-bit DAC. Ramping the data pins linearly from the minimum of 0x0 to the maximum of 0x3FFF I see (using a scope) the ...
8
votes
5answers
3k views
how determine the RC time constant in PWM digital to analog low-pass filter?
I 'm looking for the best RC time constant and its reason in a PWM to convert digital signal to analog based on duty-cycle and frequency and other parameters. PWM frequency is 10 kHz.
2
votes
1answer
99 views
DAC not working
I have a DAC connected to an FPGA, which I cannot get to work. The FPGA, in a loop, sends in the maximum value to the data pins and incrementally goes down to 0.
I have checked with a scope that the ...
3
votes
1answer
338 views
Composite video and DAC pin protection
My question is regarding the protection needed at the DAC pin generating the video signal.
I am doing the generation on a STM32F4Discovery. The STM32F40x has a DAC built in and it can drive the signal ...
1
vote
3answers
264 views
MOSFET topology to switch between voltage and ground?
What topology am I seeking to switch a load between an arbitrary, positive voltage and ground? I am trying to operate the rungs of an R2R ladder so pull-ups and pull-downs are inappropriate. The ...
3
votes
3answers
129 views
Meaning of the data input pins of a DAC
I'm trying to understand what each of the 10 data input pins of a DAC mean. The datasheet for the AD9761 I am using is available here.
The pins' description is given as follows (see page 10):
...
0
votes
1answer
185 views
a lm336 5v ref feeding mcp4922 dac - not getting much vout
I driven the mcp4922 using my Arduino. I just used my power rail as the vref and t worked fine. However when I used my 5v ref it stopped working. Strange thing is the voltge reference is fine and I ...
15
votes
3answers
941 views
Why don't microcontrollers generally have on-chip DACs?
In this answer I read that microcontrollers usually don't have DACs, while they do have ADC. Why is that?
edit
I appreciate that integrating resistors like in an R-2R DAC is expensive in terms of ...
6
votes
1answer
669 views
With a uC, I can input analog voltage levels, how do I output them?
With a uC, I can input analog voltage levels, how do I output them?
I have a simple Arduino Uno R3 I had picked up, which has a few of each pin types (analog input, digital output/pwm, serial) and ...
5
votes
1answer
406 views
What does “limit cycle” mean in delta-sigma modulator?
Could anyone explain limit cycle related spurious tones? It is stated that a higher order modulator is better than low level one because of limit cycle related spurious tones, but I don't have picture ...
-2
votes
2answers
650 views
Principal of Analog to digital converter(ADC) and Digital to analog converter(DAC)
Analog to digital converter is one that converts analog output form sensors to digital one what are basic principal of Analog to digital converter(ADC) and the opposite of one that takes digital input ...
0
votes
3answers
552 views
R-2R for HQ sound output
I am building MP3 player. Some time ago I was asking about feasibility of building headphones driver based on D-class amplifier. Now I am tired, I want to go for simple R-2R network, followed by ...
2
votes
3answers
654 views
Picking a DAC for an audio amplfier
I'm trying to use a specific audio amplifier, TPA3111D1, to power a 10 watt speaker from a microcontroller. I would like to generate sound from a microcontroller that doesn't have a built in DAC, so ...
1
vote
1answer
627 views
Generating C code from a Matlab-Simulink: errors encountered during linking
I generated C code from a Matlab-Simulink model (In Matlab help is "Parametric Audio Equalizer"
-> "Task 6 - Integrate Device Drivers" -> "Configuration C") with a "Target Preferences" module
for ...
