Electrical Engineering Stack Exchange
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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.

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 over a wide range of environmental conditions, most commonly temperature and time.

Voltage references are usually not intended to be heavily loaded, i.e. they are not meant to provide significant current to external circuits. Where significant current is needed at a very precise voltage, a voltage reference can be used to drive a buffer circuit whose output is connected to the load.

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What do you need 1.018V for?

The Fluke 732A has among 10V and 1V references also a 1.018V reference (whereas the 10V is the "main" references and the others are formed by resistive voltage dividers). While having multiple reference voltages is surely convenient, why exactly…
PlasmaHH
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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 datasheet. Then I saw there is a separate…
GrixM
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Why use 2.048V and 4.096 as a reference?

On many voltage reference ICs (As an example a MAX610x) there seems to be various different reference voltages available (1.25, 1.8, 2.5, 3.3 etc). What strikes me as odd are the 2.048V and 4.096V references. Why do we use references at those…
MCG
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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 convenience, I am including an excerpt block diagram from…
vicatcu
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Why do they make traces to LTZ1000 in spiral shape?

I was browsing Google images of LTZ1000 voltage reference IC. I saw that in some of the PCBs, the traces that go to LTZ1000 are in spiral shape and cut out gaps are left between them. What is the reason behind this?
hkBattousai
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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 - Battery Charger for SLA, NiCd, NiMH and Li-Ion Batteries,…
Ricardo
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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 compared ( At least I think so !). They also…
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Need help understanding schematics in LT1019 datasheet

We are currently using AD7795 to get ratiometric reading of 4 load cells. It works, but the chip stocks are rather volatile. So, I am thinking on using much cheaper and easier to come by MCP3424/MCP3428, with added benefit of smaller PCB…
Maple
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ATMega328 External AREF Connection

From the ATMega328 datasheet, section 24.9.1: The internal voltage reference options may not be used if an external reference voltage is being applied to the AREF pin. From the Arduino reference pages: Alternatively, you can connect the…
vicatcu
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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 planning to have a 4.7V voltage reference, by just using…
mFeinstein
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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 called "minimum zener current \$(I_{z,min})\$" is thought,…
hkBattousai
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LEDs vs. Zeners: what is quiet?

LEDs can be, have been and are used as voltage references. Standard LEDs in various colors are cheap and hence sensible when wanting a low accuracy low voltage reference. Remember that low voltage Zeners have bad knee characteristics and poor…
Autistic
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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). On page 40, there's a schematic showing the MCU…
Ricardo
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Why can't a P-N junction diode be used as a voltage regulator or reference in forward bias?

Usually, a Zener or avalanche breakdown region for a suitably doped P-N junction is used for voltage regulation as a substantial variation in the current (due to minority carriers) requires a negligibly slight variation in reverse bias voltage. From…
ThePhysicist
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Buried zener voltage reference: noise vs temperature

Buried Zener voltage references like LTZ1000A are known for their low-noise. High stability of reference voltage is often improved by temperature stabilization at somewhat elevated temperature. I wonder, does it impact noise performance? Is there…
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