Skip to main content

Questions tagged [reference]

The tag has no usage guidance.

Filter by
Sorted by
Tagged with
1 vote
2 answers
59 views

Should reference plane change its potential value if a track goes to another layer?

Assume you have a four layer board. Signal GND Dielectric VDD Signal And you having a track in the 4:th layer. Suddenly you're using a via to go through the 4:th layer to 1:st layer. Question The ...
euraad's user avatar
  • 1,320
-1 votes
1 answer
42 views

What is the recommended reference for modules on the schematics?

In my schematics I often use external modules like NFC readers, USB/TTL converters, MP3 players, and so on. They are physically connected to the PCB with a connector (for example a standard 2,54 mm ...
Mark's user avatar
  • 1,223
0 votes
1 answer
38 views

DDR3 U-DIMM Signal Reference Plain

I am doing the PCB layout of a DDR3 U-DIMM and I have run into a perceived gap in the JEDEC DDR3 DIMM standards and am hoping to get some input from a DDR3 SME who could clarify the Address/Control ...
joel reindel's user avatar
0 votes
3 answers
266 views

Buck converter with external reference voltage?

I would like to have a buck converter that takes in a reference voltage, and outputs the same voltage. This is assuming that I'm giving it a Vin that's high enough to support the output voltage that I ...
user3338049's user avatar
3 votes
0 answers
60 views

Are there industry standards for incorporating a 10 MHz reference signal input into a design?

Are there any industry standards for accepting 10 MHz reference input signals into PCB designs? I've read about standard power levels (as in, 13 dBm at 50 ohm input impedance) in a few forums, but I'm ...
matt.han's user avatar
4 votes
3 answers
467 views

Unstable voltage reference after changing DAC

I have developed a DAC-based signal generator board that I want to use to generate sine waves of different amplitudes and frequencies. The board was working but unfortunately, the digital-to-analog ...
Mau5's user avatar
  • 314
0 votes
0 answers
43 views

Constellation diagram of an 8-PSK modulator with \$\cos(\omega _ct)\$ as reference oscillator [duplicate]

For the figure and problem below, is my 000 input plotted correctly and has the correct phase angle in my constellation diagram? The cos(ωct) is located on the positive x-axis since according to my ...
Wolfram's user avatar
  • 19
0 votes
0 answers
539 views

Constellation diagram of an 8 PSK with a \$\cos(\omega _ct)\$ reference oscillator

Please help me with this problem in Tomasi's book for digital modulation. After getting the summer output, I got confused about what to draw in the constellation diagram. According to my prof, since ...
Wolfram's user avatar
  • 19
0 votes
1 answer
115 views

Reference switch: which position and NC or NO?

I have a small linear axis, which is operated with a stepper motor. I need a reference switch to determine the position. My question is, do I run this switch as normally closed or normally open? Also, ...
Interpreter67's user avatar
0 votes
1 answer
64 views

RDS - PLC wires

I'm an American but I'm changing some of my drawings to RDS (Reference Designation System) to make these drawings more similar to the drawings of equipment that keep coming in. What is the proper ...
Jamie Marshall's user avatar
1 vote
2 answers
3k views

VREF pin of STM32F303

I am designing a custom-made board with STM32F303 MCU and some ADC chips. I have a question regarding VREF pin of the microcontroller. As far as I understood, its main function is to provide a ...
Valeriya's user avatar
  • 167
3 votes
1 answer
186 views

Is there sufficient 'ambient hum' to obtain a 60/120 Hz reference wirelessly?

In a typical urban (USA etc) setting, we seem to be awash in 'powerline hum'. Has it been done, or could it be practical, to recover this to get a wireless reference for a battery-powered system, like ...
Jim Mack's user avatar
  • 213
3 votes
3 answers
209 views

Should ADC reference pin also be a kelvin connection?

Reasking this question with a proper schematic: I am doing a ratiometric measurement of a Thermistor. The thermistor is located over 5 metres away from the ADC and all other components. This is going ...
AQUAMAN's user avatar
  • 361
-1 votes
3 answers
206 views

CMOS active crystal oscillator output voltage uncertainty

I want to use SG7050CAN CMOS active crystal oscillator as reference input to ADF4106 PLL. The input voltage level is 0.8/AVDD Vp-p min/max. Now, the SG7050CAN datasheet says, it's low voltage is 0.4 V ...
shafik's user avatar
  • 59
0 votes
2 answers
456 views

CMOS active crystal oscillator load capacitance, to be used for PLL reference

I do not have a clear idea of what load capacitance is. I am looking forward to use the ADF4106 PLL with a ~580 MHz VCO to synthesize the frequency. For the reference input to the PLL, I wanted to ...
shafik's user avatar
  • 59
1 vote
2 answers
2k views

Can I mass-delete REFs from components in KiCad?

I have a PCB, and it can't nearly fit all of the REF markings on F.SilkS and B.SilkS. I want to just make my own for a few components, e.g. I would write "R1-R16", rather than "R1",...
CATboardBETA's user avatar
4 votes
2 answers
2k views

Resistor in shunt regulator not following Ohm's law?

I was reverse engineering a power tool battery charger (21V SMPS) that derives its 5V rail from a simple shunt regulator, employing a TL431 programmable precision reference and a NPN transistor, as ...
parkside's user avatar
  • 847
0 votes
1 answer
119 views

Driving 18 Thermistors in parallel

I am designing a circuit that needs to have 18 thermistors to measure the temperature at various points. The thermistors are 2metres+ away from the ADC Usually when I power a thermistors I use a Vref ...
AQUAMAN's user avatar
  • 361
0 votes
1 answer
278 views

TP4056 custom PCB battery reference voltage

I have a custom PCB where I implemented BMS system based on TP4056 from a 5V regulated solar power source. Everything works as expected regarding battery charging and output but I am encountering a ...
Amogh Jain's user avatar
0 votes
1 answer
77 views

Driving Delta-Sigma ADC with reference clock output from MCU

I am sending out the PB clock (32MHz which is PLL multiplied) generated from the internal FRC on a pin to feed into an ADC as a master clock after probing it at 32MHz. This is what I see. It doesn't ...
Charlieduru's user avatar
0 votes
2 answers
320 views

Which is better for an adjustable stable reference voltage output?

I have two methods of achieving this and am trying to decide which one will be a better option for a stable output. The supply voltage is a linear regulator output, so it is pretty much constant. ...
kris123Berkeley's user avatar
1 vote
1 answer
161 views

Reference clock in FM receiver chips (si4735)

The datasheet is mentioning a 32678 Hz "reference clock" (RCLK) input. It appears to be a well known thing in this type of ICs because it's highlighted in the list of features. I guess ...
axk's user avatar
  • 825
1 vote
0 answers
66 views

How to connect a ENC28J60 or ENC424J600 to a KSZ8091 PHY and from PHY to an unmanged strapped configuration to a KSZ8863 or other switch

How would one go about connecting MAC chip to a PHY and then to a switch for dual ports for daisy chaining? Rather be a strapped configuration for use in unmanaged mode so no need for MCU software ...
blackedpi's user avatar
1 vote
2 answers
141 views

[op amp - Gain current source - current reference]

I have a question about the formula to consider for calculation of the gain for the electronic bellow. Thanks for your support.
geek225's user avatar
  • 197
2 votes
2 answers
711 views

How to solve a LED-resistor parallel with a resistor?

Hi there I am curious as to how you would solve this circuit to know voltage drops and currents. It came about from a previous question I had asked which showed my understanding was not quite what I ...
Ciribear's user avatar
0 votes
3 answers
77 views

Is there an equivalent EE term for "homeostasis"?

In biology, homeostasis is the state of steady internal physical and chemical conditions maintained by living systems. Is there an equivalent term for a circuit or electronic device? So that would ...
Paul Uszak's user avatar
  • 7,537
0 votes
0 answers
93 views

Current mirror not depending on power supply (BANDGAP design)

is there any topology that allows a current to stay constant on a current mirror when the power supply of the transistor is varied? I simulated a bandgap and the PTAT varies a lot when I the power ...
electricalEN's user avatar
0 votes
2 answers
395 views

Opamp Current Sink + FET circuit help

I've been trying to figure out a design someone made for controlling a precision high current LED, and it's got me in a bit of a pickle. For the life of me, I can't figure out this exact op amp ...
Audiomodder's user avatar
0 votes
1 answer
594 views

Reference manual & Datasheet

I am new in the world of microcontrollers and I want to know the main differences between a Datasheet and a Reference Manual of a microcontroller and when do I use one and when the other.
turddisturb's user avatar
1 vote
1 answer
133 views

Question about feedback in a current reference

I'm studying the following Vbe-based current reference: The author of my book says: Observe that the circuit has two feedback paths around the gain stage. One positive, the other negative. ...
Stefanino's user avatar
  • 616
3 votes
3 answers
2k views

Self Biased Current Reference

I'm studying this circuit: The author of my book says that the purpose of this circuit, called "Self Biased Current Reference", is to generate a current almost independently of the supply voltage. He ...
Stefanino's user avatar
  • 616
0 votes
1 answer
179 views

STM32F429ZI reference voltage

I want to use the full output resolution of DACs (12bit) in the range of 0-1 Volt (and not in the range 0-3.3 Volt). I see there is a pin VDD in this board (STM32F429ZI), please help me to understand ...
Michele M.'s user avatar
0 votes
1 answer
67 views

Series voltage reference output voltage

What is output voltage of series voltage reference IC (for example MAX6100) when input voltage is below minimum input voltage? Is it zero volts, or something else? Didn't find answer to this from ...
tipo1000's user avatar
0 votes
1 answer
156 views

Wheel heading using PWM

I have a general question which im not sure how to implement. Suppose that a car is driving on a straight road and it starts doing some maneuver. Due to this maneuver the driver moves the wheel ...
Ben's user avatar
  • 137
2 votes
1 answer
585 views

Selecting the equipment with the optimal 10 MHz reference

In a larger testbench I have 5 synchronized instruments (signal generators, ARBs, VSAs etc). I am trying to decide which instrument to take as "master". I rule out the older/cheaper parts (Tektronix ...
divB's user avatar
  • 1,316
2 votes
2 answers
2k views

10 MHz reference distribution (daisy chaining vs. BNC tees vs something else)

10 MHz is the quasi-standard for reference clock in measurement equipment. Most boxes have "REF in" and "REF out" or "10 MHz in"/"10 MHz out". In my case, I have a measurement setup consisting of an ...
divB's user avatar
  • 1,316
2 votes
3 answers
359 views

Create small variations in voltage for opamp reference pin

Hello and thanks beforehand. I'm designing a circuit to measure 4 wheatstone bridges using 4 Analog Devices AD8422 in-amps. Now, i'm feeding the AD8422 output to a 3.3V ADC, so i'm offsetting the ...
GuzLightyear's user avatar
0 votes
1 answer
264 views

AREF Voltage same as VDD but through a reference IC

My project has 9V and 3.3V on the board. I would like to use a precision voltage reference IC for the analog reference on the MCU (MCU powered by 3.3V). The precision of the voltage reference IC is 0....
zme's user avatar
  • 337
13 votes
3 answers
2k views

Copyright of reference designs?

I have been reading a design guide by TI which provides full schematics for their reference design seen Here. There is copyright stamped all over this document as seen below. I don't plan on using ...
user avatar
0 votes
2 answers
1k views

the voltage output and resistance of a potato

For an undergrad lab experiment on noise analysis in various electric power suppliers, I constructed a battery from a potato with Cu/Zn electrodes and measured the outgoing voltage. Now I want an ...
proton's user avatar
  • 117
1 vote
3 answers
646 views

How an op-amp determines its output without a reference point? [duplicate]

I was struggling to understand how an op-amp determines its output without a reference point. The output of an op-amp is A * (Vni - Vi) Then let's say we have an inverting op-amp with a gain of 1000,...
Faruk Eroglu's user avatar
0 votes
1 answer
71 views

Measuring PSR of a current reference chip

Some Background: I'm designing a test board to characterize noise and PSR of a multiple voltages(1V) and currents(1uA) reference IC. The chip has a single voltage source. I use ultra low noise MUX ...
sandvilly's user avatar
2 votes
1 answer
85 views

A mechano-electro-magnetical control circuit

I came up with the following mechano-electro-magnetical control circuit. The system as depicted here is in equilibrium, i.e. the upper spring s1 is relaxed , the upper circuit is closed (C1 producing ...
Hans-Peter Stricker's user avatar
5 votes
1 answer
752 views

What do decimal/alphanumeric suffixes after a slash mean in a schematic cross-reference?

I'm looking at a circuit diagram for the ChipWhisperer, which is a tool for power analysis and glitch attacks. You can grab the full circuit schematic as a PDF, but here's an excerpt: What do those ...
Polynomial's user avatar
  • 10.7k
5 votes
4 answers
3k views

Capacitor after Voltage Reference "for stability"

I've got a lot of experience with rather "low-level" electronics (resistor networks, passive filters, basic op-amp circuits) and some experience with higher-level stuff like micro-controllers, but I ...
Magic_Matt_Man's user avatar
3 votes
1 answer
579 views

How to connect a diy audio signal to my "expensive" audio interface

I'm a hobbyist and after some experimentation (around 4 years) I want to connect my signals I create on the breadboard to my expensive audio interface. Until now I was using the "mic" input on my ...
John Am's user avatar
  • 759
5 votes
1 answer
6k views

MOSFET Temperature coefficient

I'm reading a paper by Guillermo Serrano and Paul Hasler, A Precision Low-TC Wide-range CMOS Current Reference, IEEE JSSC Vol 43, no 2, Feb 2008. Link to paper - requires subscription to IEEE Xplore ...
Joren Vaes's user avatar
  • 12.6k
1 vote
6 answers
469 views

LM385Z-2.5 in series with voltage divider - voltage reference problem

I'm doing a simple circuit using LM385. In THEORY voltage measured on cathode of D2 should be 5V. And it is so, if R2 and R3 are not present in the circuit. So voltage divider from R2 and R3 across ...
Em Ka's user avatar
  • 167
0 votes
1 answer
164 views

Reference of component

I´m trying to repair my lock control in my car. And this board seems like the problem, so I want create a new board (exactly the same) based on this. But I facing a challenge: I cant determine what ...
Orlando's user avatar
  • 101
1 vote
1 answer
197 views

How to learn designing electronic cicuits? [closed]

This is a soft question. I have completed my engineering in electronics discipline and unfortunately I still don't have proper idea of designing electronic circuits. But anyhow I want to clear this ...
user3559780's user avatar