Questions tagged [voltage-reference]

Anything related to the design and implementation of voltage references, i.e. circuits behaving like fixed (constant-value) voltage sources whose output voltage can be deemed very precise, accurate and stable. Voltage references are not meant to provide significant current to external circuits.

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3
votes
2answers
6k views

What is the function of this circuit?

Just wondering if someone can give me an explanation for this capacitor layout - what is it's function? The chip to the right is an ADC. Circled in blue. I'm guessing it is well known but i don't ...
16
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3answers
7k views

Why is there a 0R resistor linking GND and AGND in analog voltage reference circuit?

This is related to another question I've just posted (What's the purpose of a ferrite bead inductor on this circuit?), regarding the battery charger described in the AVR450 Application Note - ...
2
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2answers
1k views

Which is the correct voltage reference for a single supply instrumentation amplifier?

I'm working on using the TI INA333 in a single 3v supply configuration. I need to create a "mid supply" (half V+) for the REF pin. I have thought of 3 ways to do this: Voltage divider with ...
19
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1answer
6k views

AVR 1.1V Internal ADC Reference Over-Voltage

If I use the internal 1.1V reference for the ADC, and my Analog input exceeds 1.1V, lets say 2.5V, is that harmful to my microcontroller? Or will ADC value simply clip (to 0x3FF) at 1.1V? For ...
7
votes
2answers
21k views

How to calculate minimum zener current if it is not explicitly specified in the datasheet?

simulate this circuit – Schematic created using CircuitLab I'm going to use 1N4740A as a voltage reference in a similar way you see in the schematics above. In textbooks, a zener property ...
-2
votes
1answer
140 views

In HLW8012 where should I connect the reference voltage (GND)

In the datasheet of HLW8012, the both 33nF capacitors , 1K resistor and 0.1uF capacitor are connected to GND. I'm not sure where should I connect those ends of components marked with GND symbol, (To ...
24
votes
6answers
10k views

Voltage regulator vs. voltage reference

I need a cheap, somewhat accurate (~0.5%) voltage reference for some DACs. At first I was going to use a LDO voltage regulator (a TC1223 specifically) for this, it seems to fit the bill looking at the ...
13
votes
1answer
3k views

Can I use differential I/O pins of FPGA as high speed comparator?

High speed comparators are rather expensive and speed is what FPGAs are very good at. On the other hand, FPGAs (in my case: XC3S400) have paired differential pins in each bank that their voltages are ...
9
votes
1answer
6k views

Using a Zener diode as voltage reference

I want to use a zener diode as a voltage reference to the the PIC18F2550, as the analog V+ reference. I am planning to use this zener diode, but I am not sure how to calculate its values. I am ...
8
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2answers
9k views

What's the purpose of a ferrite bead inductor on this circuit?

I'm studying the analog voltage reference circuit described in the AVR450 Application Note - Battery Charger for SLA, NiCd, NiMH and Li-Ion Batteries, which schematic is below (copied from page 38). ...
4
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2answers
310 views

Learning about voltage references

I want to study the bandgap voltage reference and use it in somewhere. But first I would like to learn more about the basics of generating and using voltage references (mostly for operational ...
3
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2answers
2k views

ratiometric ADC, is it feasible to separate reference voltage and excitation voltage by an amplifier

I have a variety of bridge transducers (pressure, strain gage) with sensitivity of 1mV/V. Also, most 24-bit ADCs and analog frontend chips have a PGA with programmable gain between 1-128. This means ...
1
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3answers
747 views

Set a reference voltage: using a zener diode vs using a buffer

Given the following hysteresis comparator circuit: simulate this circuit – Schematic created using CircuitLab R1, R2 and OA1 are used to set a reference voltage for the comparator with ...
6
votes
3answers
3k views

Why do we need many complex voltage references when a zener can do the job

There is a huge variety of Zeners that exist. They have varying breakdown pd among other things. Why then do we need voltage references that are more complex and made up of many components?
3
votes
2answers
972 views

Flip a Schmitt-Trigger when current flows through a Zener diode

I am trying to design a circuit using an intermitent power source (a bicycle hub generator), which is rectified and filtered, and regulated at 6,8V. Now I want to "detect" when the power source is ON ...
3
votes
2answers
515 views

MCP1501 Voltage Reference has very noisy output

I want to use the MCP1501 precision voltage reference in an ADC circuit and have the issue that the reference produces a very noisy output. Much worse than an average LDO. I have a VPP of 200mV when ...
2
votes
2answers
328 views

How improve temperature sensitivity of HP 721A DC Power Supply voltage reference?

I have a sentimental affection for my HP 721A DC Power Supply: http://hpmemoryproject.org/pict/wall_a/anim/721a_q90/viewer.htm Rugged, dependable, and roughly as old as I am, it is also pretty ...
2
votes
1answer
271 views

Using positive voltage reference on a negative supply

Got a 9V,0,-9V power supply and want to get two stabilised voltage references at 2.5V and -2.5V. Is it possible to use a +2.5V reference chip "upside down" to supply the -2.5V?
2
votes
2answers
5k views

Long term effect of over-voltage on clamping diodes and ADC reference voltage

I am contemplating building a small voltage/current monitoring circuit that needs to monitor a wide range of voltages and currents. Currents will just be a single low-side shunt. Monitoring will be ...
0
votes
1answer
435 views

MCP6N11 voltage reference and output problem

I am currently trying to setup an instrumentation amplifier and I used MCP6N11. Basically I'm just trying to test the instruamp to output a certain voltage gain before I connect it to my actual ...
0
votes
4answers
269 views

Can anyone explain me how the voltage divider network works?

Can anyone explain me why the voltage of the red circle is 1.85V? I know how the 25k-25k divider works but just don't know how the +5V-200k network affects the result.
0
votes
3answers
581 views

Do the temperature coefficients of the resistors in the LM399/LM199 “Portable Calibrator” significantly effect the output stability?

I'd like to know how voltage reference stability is obtained in products like 6.5 digit multimeters that use LM399 as a voltage reference in spite of using two gain resistors. Let's assume an ideal ...
0
votes
2answers
359 views

Precision Shunt Regulator Increasing Voltage overtime

I want to have a stable voltage of 2.47V using TLV431AC which is a precision voltage-adjustable shunt regulator. http://www.ti.com/lit/ds/symlink/tlv431b.pdf I am able to get it by putting a 5k ...