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68 Threads found on Adc Ref
I am trying to use 24 bit adc LTC2410. I am applying the below voltages to LTC2410. Vcc: 3.3V ref+: +3.3V, ref-: Ground IN- is connected to Ground Should the maximum voltage on IN+ is 1.65? Why is it so? 2^24 = 16777216 bits. 3.3V = 16777216 bits 1 bit = 0.19nV. Is it right?
I used AD8226 to amplify a signal, and use AD1581 as its output ref. AD1581 should output 1.25V, and it works normally. My original purpose is to output a positive signal for adc. But AD8226 sometimes output negative signal, and its ref is -1.25V. The gain resistor is 51 ohms for AD8226 so that I can get almost the max gain, 1000. Who (...)
hi, I have written following program to convert ten analog inputs to digital signals, and put appropriate output regarding to comparison with ref signal (not determined yet). we use pin Vref- and Vref+ (AN2 & AN3) as voltage reference and AN12 pin as external interrupt. when I use two dimensional signal "if state", the (...)
You can run the IA125P off 3.7 or battery directly. The Power Supply Rejection Ratio or PSRR is 100dB in the audio range, so no additional regulator is needed. The IA also has a precision 2.5 V ref builtin. For RF noise on cable to load cell, you may need ferrite choke around cable. If using 12V, you can scale output down to adc input range with
hello, What is the ref for adc , is it 5V as +Vref and -Vref=0 so, you get 205 points for 100 °C calculus becomes Temp= Readadc*100/205; if you can use +4.096V for +Vref you will get 250 points for 100°C so more easy Temp=Readadc* 100/250; or Temp= (...)
hello, you need to amplifie a very week signal or use an AD7715 16 bits differential adc or MCP3424 up to 18bits resolution example : 16384 points for a scla of 128mV or other ... to treat the signal without adding analog components
hi i am not familiar in pic. but generally, i will give some points, i hope you had correct initialization in adc code and no hard ware faults. first thing is, check the ref voltage of the micro-controller , second thing is, check the datatype of the ldr_val
Hello rvs, Your LM35 can measure -55C to +150C with accuracy +1.5C and output scale 10mV/C. Your adc has 8-bit resolution with a maximum of 256 (28) steps. So, for Vref/2=1.28 Volt, you will get a full scale value for Vin=2.56Volt=2560mV. Rem
You need to reduce input voltage and shift by 1V to avoid negative values. Shift input voltage by adding a DC source of 1V, so new range will be 0 - 4V and then add a divider with factor 2, so new range will be 0 - 2V; with these range value can go to MAX1415; in software code need to take account these operation (shift and scaling). ref+ and ref-
Hi 1) the reading on the adc is Vinput / Vreference * 1024. If Vreference changes, then you obtain different readings with the same Vinput, and this in most cases unacceptable. You then have various choices: - use a good quality AVCC - use a reference voltage source connected to Aref - use the internal (...)
hi i want to design sigma delta adc and start using delta sigma toolbox would you introduce me good document to start using this delsig toolbox ?If you would like to use Schreier's Toolbox, you need to read the following book at least.
You need to rectify the AC input to get a DC value that is going to be approx. the peak value of the AC input. As this value is very high, place a voltage divider to suit the range of the adc inputs of the micro controller. Take care with the voltages that you are handling. The peak voltage will be more than 560v. Standard resistors do not withsta
have a look at Microchip's code examples for the PIC18 and adc
It looks like you are using the internal Vref. Check the device specs for the adc.. WHat is the Sample HOld value 4 cycles? 8 cycles? INPUT_CHANNEL_A0, refERENCE_Vrefplus_AVss, SAMPLE_HOLD_8_CYCLES,
Hi diarmuid! So, why 1.024V, it's for 1LSB => good for standardization of adc. ;-) And normally, this is reference voltage, i think it should not be called bandgap ref voltage, because the typical bandgap voltage is between 1.2 - 1.3 V, it is based on the theoretical value for silicon is 1.22eV at 0K.
Hello..i am interfacing lm35 with pic18f452..and i have to give 2.5 ref adc of pic using lm336..i dnt knw how to connect the adj terminal of lm336...m uploading the images of the circuit..and lm images.
If you look at page 112 of the data sheet which can be downloaded from Microchip, You will see that to configure the A/D you write to register adcON1. for example adcON1 = 0x80; /* 10 bit Right justified result, all analog inputs, Vdd as +ref, Vss -ref */ Then on page 111 To configure the conversion clock, select (...)
Hello, I was asking about the reference voltage and how to choose its value in the design of adc supposing I have VDD and what is its relation with the full scale input in dBm and Does it relate in any way with the bias voltage of the adc?
unsigned int adcRead(unsigned char channel) { unsigned int result; unsigned char sample_time = 5U; adcON1 = 0x80U; /* 10 bit Right justified result, Vdd as ref */ adcON0 = 0x81U; /* Conversion clock Fosc/32 */ adcON0 |= (unsigned char)(channel << 2U); /* Select channel */ (...)
Hi,there Recently I have seen a folded-cascode amp with a different input stage than usual in a folding adc,as can be seen in fig attached. The Va and Vb are two signals from previous flash-like pre-amp stage which generate some cross zeros and amplify the different between input and ref. .I wonder what the effect of the input stage,for the conn
We successfully used 2 buffers with ??A of quiescent current, each (Rout≈2kΩ), and a few tenths of pF's at the ref inputs (filling otherwise unused space). Low current was more important than real estate consumption. BTW: the still existent mV spikes on the Vrefs didn't do any harm. It was an RSD adc, however, where (...)
I designed a 14-bit 50Msps pipelined adc, I used fully differential flip-around THA, and the virtual ground voltage set to Vcm as shown in the figure. If I vary Vcm, the whole accuracy of my adc varied accordingly. But ref to the thoery, the Vcm will not affect the conversion accuracy. So where's the problem ? The pipeline is a 3.5bit of (...)
How to design a pipeline adc without using negative ref voltages.Lets say for an 1.5b stage we have the residue signal 2Vin +/-Vref.if we dont use negative voltages then how can we subtract charge from residue?? My adc residue is like
hi i am reading adxl335 and idg500 sensor with mcp3208 adc, i am getting the following values for 7 channels AZ AY AX GVref GY GX ref Ch1 Ch2 Ch3 Ch4 Ch5 Ch6 Ch7 Data: 2403 958 6235 2366 375 0 8164 Data: 2423 0 6335 5396 1351 0 8160 Data: 2428 0 6350 5731 1482 0 8160 Data: 2427 0 6353 5845 1506 0 8160 Data: 242
As said its to expand the measurement range of the adc. A digital adc value of zero would be an analog input voltage equal to the voltage applied to the ref-, and a maximum adc value 1024 for 10 bit would be obtained from an analog input voltage equal to the voltage applied to the ref+ pin. The idea is (...)
/*--- Initialise A/D convertor ---*/ void init_ad(void) { adcON1 = 0x20U; /* Conversion clock Fosc/32 */ adcON0 = 0x80U; /* 10 bit Right justified result, Vdd as ref */ } /*--- Read A/D conversion ---*/ int read_ad(unsigned char channel) { int result; unsigned char acquisition_time = 3U; (...)
If I were to change the reference voltage which the adc uses in my code after each conversion, would it affect the accuracy of my conversion? yes, if your code doesn't factor that in. no, if your code does factor that in.
Hello I need to design a system to monitor current on approx 40 voltage rails. I will be using an Rsense + Current amplifier on each rail but I cannot send all outputs of Current amplifier directly to adc in uController as I am not aware of any part with 40 channels. What I am thinking is to use Analog mux and send o/p of CSA to AMUX and then o
Hi, there. I gonna use ADS 8317 analog-to-digital converter and have a problem during testing it. The problem is about input signal range that I need is 0~5V. It's so weird that according to datasheet, input range is -Vref ~ +Vref with common voltage so I used 2.5V for reference level and common voltage, too. however, input (...)
Hi Everybody, Am new to the forum and I need help from you working in LPC2129 but unable to view the output of adc.I executed the sample programs from Keil in Keil IDE but still am helpless. Do help me in how to read the register value of adc.:? Thanks in advance:D
hello guys i want to feed an analog bipolar signal (that has negative and positve values) into adc of a PIC whic only receives positive values! so i had an amplifier which bias the output signal into half of the supply voltage which means that if the supply voltage is 5v then the reference voltage will be 2.5v (instead of 0v) so that i can fee
Hello Im using PIC18F4220, 20MHz ceramic, C18 compiler. I have a running project where im taking temperature readings after every 300ms intervals and display on 16x2 LCD. Im using thermistor MCP9701A. I have 8bit adc enabled on my PIC and im only reading the high byte ADRESH. My V+ref == Vdd and V-ref == Vss. All seems to (...)
Hi, These adc has a "Uout=Uref 2x" modus too; if you have 2.5V ref, your Uout is at max 4.8V (theoretically 5V)... But can you not change the Vcc to 5.5 or 6V? These (modius x2 & >5.5V supply) are needed (maybe) for your supplying of Uref too... K.
Hello. I need some advice. I'm building a custom nimh battery charger and i'm doing the adc routines to detect the peak voltage of the nimh cell (independent cell charger). The problem is that the readings are not stable/accurate. I have tried Vref+ 1.800v but the reading are 20mv off, then with 4.5v i get the correct value sometimes, but it's n
Hello, I am New for adc I am working on adc CS5460 24 Bit SPI Based. I can communicate with adc very fine "Means Reading and writing Some Default Registers. But I am NOT able to see Stable reading which i actual want to measure on HYPER TERMINAL also see some Garbage values Randomly Not periodically. Why? Can any one sent me (...)
A scheme for the connection of a single-ended signal source is provided in the ADS7861 datasheet: Connect the - input to refout and the + input to the source, referenced to refout. With an instrumentation amplifier, connecting the ref pin also to refout would achieve this. As another point, you should limit (...)
Hi all, i need to design a board that is using adc 12 bit. I don't know how to calculate maximum level of noise on my board that is still acceptable for correct operational of my adc. Can anybody help me? Thx.
Hi Use a delay after enabling the adc and befor start sampling - for letting the system stabilized (the ref) All the best Bobi
I design a telescope cascode opamp for a ref buffer, which output is linked to switch cap of adc. ref's voltage change from a low voltage to ref=1.25v when switch cap work, my opamp output swing is lower. my question is if the low outputswing will affect ref's settling? THANKS~
connect the point where you need to measure the voltage, to the adc pin of the microcontroller. thats it. Rest of the job is done by the software.. you should be writing a small code to aquire the adc input value by configuring the ports,adcON registers etc etc..
Hello, Does anyone have any or know where to get reference to Digital Error Calibration / Correction for adc Pipeline? Any helps on where to locate good references and books are welcomed and greatly appreciated. Thank you. SW
Hi to all, i am using two xbee modules. one act as a remote another one is base. I've configured remote xbee as adc input on 20th pin, 14th pin as ref. ref volt=3.3v and two modules having below configuration. when i gave a analog input(adc INPUT0) i was able to see the variation of pwm output on base module D0 pin using a (...)
Hi S_51, adc: I usualy use VDD and VSS as reference voltage. PIC has 10bit adc, this means an unprecise measurement in term of number conversion of bits. So, I think that precise voltage reference, with 10bit adc doesn't have much sence. Internal/external osilator: Internal osilator is temperature (...)
I have a delta sigma adc (cs5532). I'm trying to convert the small signals i.e mVs into digital. It has a 5V supply and a 2.5V ref voltage which is at 2.490 or 2.495V and maintained by a low ppm low noise ref voltage ic. The adc is in unipolar mode. So the negative values should be measured as zero and that is the case (...)
as we all know, the dac output is just the input of comparator. my ref volt is 0~2.5V,so the mid-volt is 1.25V. 1. For example ,the 1st sampling point is 1.4 (p input) and 1.1 (n input), 0.3V differential, so the initial input of comparator should be 1.1(p input of comp) and 1.4 (n input of comp). but my value is ~1.09(just ok?!), and ~1.34 o
Any good reference / books for calibrartion techniques of SAR adc? IEEE papers are OK. But if any comprehensive reference is known to anyone (may be book/ review paper / thesis etc.) would help much. Thanks in advance. Sankudey
AC couple is a common skill to isolate signal's dc level. If you are using adc, you can set the ref level of the adc to the middle of the signal level
All these have diff meaning for diff situations.. wats ure ref situation, adc?
I have just studied ARM7 and using LPC2148. I have met some problems about it. That I have done following the direction about adc cell on user menu LPC214x for writing keil C code base on example on site keilC.but it doesn't do as I want. The result of conversation alway zero.Why it is? the result only display on AD1GDR but the result of it on
Hi! this is my first project using the adc of my mega8535. i want to measure the temperature through lm35 and display it on the lcd. i have connected the Aref=4.7V Vcc=4.7V,AVcc=4.7V. My analogue channel is adc3(PA3). The LM35 is connected to 4.7V and the signal pin is directly connected to adc3. As i have seen in (...)