Author Topic: pins Connection of Instrumentation Amplifier  (Read 309 times)

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Offline Moturki

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pins Connection of Instrumentation Amplifier
« on: October 05, 2018, 05:40:24 pm »
Hello...

The attached screenshot is from INA114 datasheet, which explains the basic connections of this instrumentation amplifier. 

My questions are:
1) Should I have to use two 0.1micro-F that connected to V+and V- ? 
2) What should be the value of load resistor (Load) that connected to pin 5&6 ? 
 

Offline rstofer

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Re: pins Connection of Instrumentation Amplifier
« Reply #1 on: October 05, 2018, 07:20:43 pm »
Hello...

The attached screenshot is from INA114 datasheet, which explains the basic connections of this instrumentation amplifier. 

My questions are:
1) Should I have to use two 0.1micro-F that connected to V+and V- ? 
Always!  See 1st paragraph, page 8 of the datasheet.
Quote
2) What should be the value of load resistor (Load) that connected to pin 5&6 ?
According to the datasheet, it should produce a current on the order of 5 mA with 15 mA as the maximum short circuit current.  So, 5 mA is a number.

At the very top of the table on page 2, it talks about 2k Ohms.  So, that's a number and it represent all of the devices the amp connects to.  You wouldn't ordinarily have a load resistor, you would have further circuitry that presents a load.

Notice that the product of the recommended resistor (2k) and current (5 mA) yields 10V.  This is a magic number,  the maximum + or - signal voltage usually associated with a device powered by a +- 15V supply.

An observation I made many years ago:  Every single number in the datasheet imposes a limit on how I can use the device.  I need to understand them all!

http://www.ti.com/lit/ds/symlink/ina114.pdf
« Last Edit: October 05, 2018, 07:24:47 pm by rstofer »
 

Offline David Hess

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Re: pins Connection of Instrumentation Amplifier
« Reply #2 on: October 07, 2018, 01:22:49 am »
The capacitors are for power supply decoupling and may or may not be required.  For instance they might be shared with some other nearby IC.

The resistor across the output just represents the load.  There is no requirement to place an actual resistor there.
 


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