Questions tagged [r2r]
An R-2R Ladder is a simple and inexpensive way to perform digital-to-analog conversion, using repetitive arrangements of precision resistor networks in a ladder-like configuration.
29
questions
0
votes
0
answers
100
views
Two R2Rs with different widths in parallel
There's LVC16374, it has 16 output pins. In one configuration I need 3 DACs 5 bits wide each, in another configuration I need 2 DACs 7 and 8 bits. I use R2R circuits for DACs.
I was hoping here's a ...
- 6,930
4
votes
0
answers
74
views
How to control DAC white noise at increasing sample rates?
A lot of background, the question is at the end:
I have made some simulations and experimental tests with the goal of achieving lowest possible noise floor using DACs with a sample rate of at least ...
- 19.7k
1
vote
3
answers
142
views
Using a "non-audio" oriented DAC IC as an audio DAC
I'm starting a project that consists of a simple embedded 16-bit PCM audio player, where no actual DSP takes place, only plays PCM and outputs something you can then amplify.
I am currently searching ...
- 75
0
votes
1
answer
228
views
Determining node voltages and ladder currents in R-2R DAC Ladder with Op-Amp
I'm really curious about the voltages at the nodes between the R resistors in the R-2R DAC ladder with an Op-Amp. I've tried using KCL and Ohm's law to find them, but I haven't been able to. ...
-1
votes
1
answer
206
views
Why is my LM386 reducing voltage and not amplifying it?
LM386 datasheet.
I'm working with an 8-bit, R2R-ladder DAC that is connected to the LM386 that is then connected to an 8ohm/3W speaker.
The output of the DAC is connected to pin 3 of the amplifier, ...
- 1
-1
votes
2
answers
308
views
R-2R ladder connected to amplifier causes voltage to DECREASE
I'm working on a project and requires 4-bits of data from a micro-controller. I chose R to equal 1k ohms and the max V_out from the DAC (V_R-2R) without the amplifier measures around 1.6V and the ...
- 1
2
votes
2
answers
1k
views
Why is my basic DAC incorrect?
I tried to make a basic R2R digital to analog converter in a simulator.
Even with all bits set, I get an output of 4.98V rather than the 5V I would expect. I expected 5V since so many online resources ...
- 29
0
votes
2
answers
1k
views
16 bit R2R DAC?
I want to build a 16 bit R2R DAC using two 74HC595 chip. I need the DAC to replace the potentiometer of a lab PSU.
While researching, in the forums and basically everywhere they suggested that R2R ...
- 2,324
4
votes
2
answers
2k
views
Is this how a R-2R DAC for VGA should work?
I'm trying to wrap my head around if this is how a R-2R DAC should work. I say should for two reasons: (1) because I think I understand the theory behind the resistor ladder of subsequent voltage-...
17
votes
5
answers
7k
views
Why can't this LM324 op amp reproduce a signal above a certain frequency?
There seems to be no shortage of circuits like this that attempt to use an R2R as a DAC and an op. amp. as an output buffer. These make sense to me so I decided to try and construct one.
I ...
- 1,249
8
votes
1
answer
2k
views
How Significant is VGA Impedance Matching?
I've seen a multitude of different resistor DAC solutions for a VGA signal, however they almost always have an impedance of >200 ohms per color, e.g.
when I've been lead to believe that we want to ...
- 281
0
votes
1
answer
106
views
converting digital signals to analog
I'm trying to take 12 digital signals and convert them to a linear analog signal (0-10 V or 0-20 mA). In an ideal world each digital signal would increase the analog output by 0.83 V and it wouldn't ...
- 126
1
vote
0
answers
92
views
Precision battery voltage meter, Auto adjustment by R-2R
For a more precise measurement of a battery voltage I'd like to apply auto adjustment. The input voltage ranges from 2.5V-4.2V (single cell) to 20V-72V (module). At the moment the input voltage is ...
- 11
0
votes
0
answers
278
views
What could cause a gain error in the R-2R DAC?
I was studying R-2R ladders and I still what causes a gain error in the R-2R. I assume that it could be caused by an error in the R or 2R resistors. I don't think that a mismatch in the feedback ...
- 310
0
votes
2
answers
815
views
R-2R Ladder Resistors Mismatch
I am still trying to understand what kind of errors are caused in the R2R ladder depending on the amount of resistor mismatch relative to the others. For example if you have a mismatch of 12% in the ...
- 310
2
votes
1
answer
675
views
How do you output whole number voltages (1-4V) from an Arduino/5V source using only digital pins and passive components?
I would like to output whole number voltages 0V,1V,2V,3V and 4V from two digital pins on an arduino/5V source. A simple r2r ladder doesn't seem like it would work because it would split its definition ...
1
vote
1
answer
560
views
Please review my schematic design
This is my first design, a 4-Bit stereo DAC with LM386 amplifier.
I'm using it to interface with my FPGA eval board which doesn't have any audio connector. My board uses a 2x6 'PMOD' connector. My ...
- 163
0
votes
2
answers
785
views
Add a voltage offset to a resistor ladder R-2R
I want a cheap DAC from a microcontroller for audio output. A resistor ladder is one solution. The output needs to be buffered by an op amp. Most op amps have some limitation on how close the input ...
- 411
4
votes
3
answers
4k
views
Output impedance of the current output DAC
As known there are two types DAC using R-2R ladder. One is voltage output and another is current output. The voltage output type has a constant output impedance which equal to R. The current output ...
- 5,838
11
votes
2
answers
3k
views
Reason for brief spike in op amp output when crossing 0V?
Does anyone recognize this spike in the output of an op amp when the signal crosses 0V? It spikes up when crossing up and down when crossing down. In one of the EEVBlog videos, Dave pointed to ...
- 1,237
2
votes
2
answers
966
views
R-2R ladder D/A converter with mutilple non-zero inputs
PROBLEM:
So I am not used to r-2r ladders where 3 out of 4 inputs are 0V. Here both A and B are 5V, so I don't know how to approach this problem.
This is what i get when i simplify the ladder:
I ...
- 21
0
votes
1
answer
700
views
R2R DAC in reverse
Knowing how voltage dividers work, this probably isn't possible. But, is there a way to run an audio signal back through an R2R arrangement and get 8bit digital signals back out without complex ...
- 43
1
vote
2
answers
1k
views
Signal generator: PWM or R2R?
I want to build a signal generator using a ATmega 328P on an Arduino. Which way would be better. Using one of the timers (8bit or 16bit) built in to generate a PWM and then low-pass filter it, or ...
- 71
2
votes
2
answers
692
views
Converting Pulses to Analog Input for Mic
A continuation of this question.
I am attempting to read two flow meters through the mic port of a phone/tablet. The flow meters' pulse pins toggle between +0V and +5V as their pinwheels rotate. I ...
- 231
7
votes
4
answers
1k
views
Counteracting Sound Card AC Coupling for Reading Digital Data
Disclaimer: I am new to EE. Everything I have learned so far I have taught myself from reading online and posting questions like this while working on this project. I apologize if I do a poor job of ...
- 231
3
votes
1
answer
159
views
Reading Flow Meters from Mic Port
I am attempting to read two hall-effect flow meters through the audio-in (mic) port of an Android device. I want to be able to read both flow meters independently. The audio-in port is a standard ...
- 231
4
votes
1
answer
1k
views
Arduino audio output via R-2R DAC - biasing output for piezo speaker
I followed a tutorial on 8-bic DACs using an R-2R resistor ladder.
I am outputting a sine-wave using data from 0 to 255 on pins 0-7. This goes through the pins into the R-2R DAC producing an analogue ...
- 143
3
votes
1
answer
760
views
Weird samples from SAR ADC
I am playing around with some SAR (Successive Approximation) A/D-converters. I have made a test circuit where I have a 16-bit DAC from Texas Instruments (R2R-based) and an 16-bit SAR ADC from Analog ...
- 325
1
vote
1
answer
6k
views
Can I use ATmega328 TX/RX pins to drive an R2R network and still use the serial port to program the MCU?
Background
I wanted to make a simple function generator with an ATmega328 and an R2R resistor network, similar to Jesper Hansen's Mini DDS (Direct Digital Synthesis).
To make the function generation ...
- 6,154