Differential Amplifiers

Q&A ad8211 GNDconnection

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ad8211 GNDconnection

jeh2017 on Jan 10, 2017

Where is mistake?

20 ohm Resistor between v+ and shunt or between V- and shunt could be damaged.

We are checking motor drive current by AD8211. Motor VCC 24V and GND (GND_Motor) is filtteres (Emifilter)

AD8211: V+ is connected 5V_CTRL (using cap 100nF / GND CTRL ) AD8211 GND is connected GND_CTRL.

Shunt resistor is 0.01ohm. Between Vin+ and Vin- line is Cap 1uF serial resitor foe both Vin+ and Vin- are 20ohm .

could GND of AD8211 be connected to the GND_Motor or GND_CTRL?

0 Emman.A

on Jun 27, 2017 4:17 AM over 3 years ago
Hi,

Can you confirm if the AD8211 gets damage or you are getting wrong output voltage?

The AD8211 ground should be connected to GND_CTRL.

We also do not recommend putting the 20 ohms in series with the AD8211 inputs because it will introduce gain error on your system.

Best regards,

Emman
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0 EZAdministrator

on Aug 2, 2018 3:41 PM over 2 years ago
This question has been assumed as answered either offline via email or with a multi-part answer. This question has now been closed out. If you have an inquiry related to this topic please post a new question in the applicable product forum.

Thank you,
EZ Admin
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0 jeh2017 on Sep 13, 2018 12:34 PM over 2 years ago in reply to EZAdministrator

Hi

Now i found same problem again and seems that AD8211 is damaged and output voltage is too much, close to 5v

Those 20 ohm resistors were damaged as well. I changed resistors but output voltage was still too high.Seems that New Ad8211 helps, Reference voltage ls 3.3V in controller.
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