Electrical Engineering Stack Exchange
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Questions tagged [programmable-gain-amplifier]

An amplifier, usually based on an operational amplifier or instrumentation amplifier, which has a gain that can be controlled programmatically (e.g. using digital input pins, I2C, etc.)

An amplifier, usually based on an operational amplifier or instrumentation amplifier, which has a gain that can be controlled programmatically (e.g. using digital input pins, I2C, etc.)

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Amplifier with selectable inversion?

Two inputs: Signal: 0-5 volt analog voltage Direction: Standard TTL logic Output: A single analog voltage from -10 to +10 volts When Direction is low, the Signal is amplified and inverted, so that the original 0 to 5 volts becomes 0 to -10 volts…
James Newton
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Digitally tunable gain, low-noise instrumentation amplifier

I want to make a digitally-tunable gain (~1 to 1000x), low-noise instrumentation amplifier. There are integrated ones (e.g. AD8557) but the input noise is too high. My current plan is to use an ultra-low-noise in-amp (e.g. INA849) and make the…
Eric M.
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Why does an RTD sensor circuit use a reference resistor that is 4x the RTD value?

I'm using an Adafruit MAX31865 board to measure the resistance of a PT1000 RTD. The board comes with a 4300-Ohm resistor. I'm trying to model the amount of noise (in degC/sqrt(Hz)) that I expect out of this circuit. But in order to do that, I'm…
Jonathan Wheeler
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What is more precise: using an op-amp or internal PGA of an ADC to amplify a low-voltage signal?

I'm wanting to current sense a 10A load with high precision. I'm planning to use a current shunt resistor and then amplify/filter this signal before sending it to an ADC. Which design flow is typically more precise? Using a high precision…
ken
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Two-digipot (MCP4131) programmable gain amplifier showing negative resistance, not reaching correct amplification

For fun I'm trying to design an epic amplifier with programmable gains from ~1.4 to 256. The opamp being used is a TLV2452. The digipot A can reach a minimum of 390 Ω. The digipot B can reach a maximum of 100 kΩ. The voltage source, 3.3 V in the…
Mr Man
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Question about the Texas Instruments LMH6881 programmable gain amplifier

I want to use a PGA (programmable gain amplifier). I found the LMH6881 which I will be probably using. On page 5 of the datasheet you can see that the analog input voltage range should be between 0V and VCC (which is 5V). On page 6 of the datasheet…
Yoomo
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Designing a non-inverting programmable gain amplifier circuit using the LT6910-1

I'm trying to design a band pass filter with a programmable gain option to record varying levels of sound as defined from a microcontroller. I used LTspice to design my circuit, and the filter portion of my circuit works as expected. The signal…
Naive_tech
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ADS1115 PGA Questions

I have two similar questions regarding the PGA of the ADS1115. Datasheet Say I have the PGA set to 2, so the max voltage read is 2.048V. If I apply 3V to AIN0, I assume it will give me the max voltage reading. But will it fry my board? Also, say I…
Molorius
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About nonlinearity of PGA (Programmable Gain Amplifier)

I find there are at least two methods to specify the nonlinearity of a programmable gain amplifier (PGA). For PGA204, it is given as '% of FSR', but for PGA280, it was given as 'ppm'. It seems the latter are more common. Then why use '% of FSR'? Are…
diverger
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Digital GND of PGA204

I'm using TI's PGA chip PGA204. It has a DGND and an AGND. And it states: Digital ground can be connected to any potential from the V– power supply to 4V less than V+. Digital ground is normally connected to ground. The digital inputs interface…
diverger
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THS7001 PGA input voltage drop issue

I am having issues simulating the THS7001 programmable gain amplifier (PGA). I have the following setup: I added a voltage divider at the input R11/(R10+R11) = 0.5, and configured the pre-amp stage of the THS7001 as a voltage follower. When I apply…
Adriaan Sadie
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Using a PGA to scale input voltage ranges?

I have a current design of a circuit which works well, but I am needing to make a few extensions to it. I am working on a 4 channel oscilloscope. Each channel must be able to take various ranges of input and properly scale it to 0 - 3.3 V for a ADC…
Beshoy Hanna
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Shifting AC Signal for ADC

I have AC signal that varies from 50mV (pk-pk) to 420mV (pk-pk). I am trying to use a PGA (programmable gain amplifier) to amplifiy the signal so that it can be sent to the ADC in an ATmega328P. The signal sent to the ADC needs to be within 0-3.3V.…
tamilnewzealand
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pga gain formula

Background: I am dealing with reverse engineering a software. And trying to understand a formula in the code. I found a formula that reads: pga_gain = pow (10.0, agc / 20.0); In the above formula what are 10.0 and 20.0. 10 seems to be the log10…
user3919652
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Programmable gain instrumentation amplifier with R-2R ladder and analog multiplexer

I want to build a programmable gain instrumentation amplifier with power of two possible gains (1x, 2x, 4x, 8x...). Is there a way to use a R-2R resistor ladder and an analog multiplexer in order to tune the \$R_{\text{gain}}\$? On the web I found…
KBowser
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