AMC1300: AMC1300 four-pin shunt sensing

Jiandong Liu

Part Number: AMC1300

Hi expert,

In AMC1300 datasheet, there is a description: "If a four-pin shunt is used, the device inputs are connected to the inner leads, and GND1 is connected to one of the outer leads of the shunt."

My customer want to know, what' the advantage of this kind of connection? Can you give some detailed explanation? Thanks.

Regards,

Jared.

over 3 years ago

0 Alexander Smith over 3 years ago

TI__Guru 51471 points

Hi Jared,

This is called a kelvin connection and has the advantage of effectively eliminating the resistance and temperature coefficient of the shunt resistor terminals. This allows for a high accuracy measurement for very low ohmic value shunts without calibration. There are many external articles covering this subject, but please let me know if you have any additional questions!

0 Jiandong Liu over 3 years ago in reply to Alexander Smith

TI__Intellectual 1801 points

Hi Smith,

Thanks for your reply. Customer is wondering why place GND1 connected to the outer leads of the shunt, not the inner lead? That's perfect if you can share some articles which can explain how this kind of connection improve measurement accuracy. Thanks a lot.

Regards,

Jared

+1 Alexander Smith over 3 years ago in reply to Jiandong Liu

TI__Guru 51471 points

Hi Jared,

To increase common-mode noise immunity. If GND1 is connected to the inner lead instead of the outer kelvin lead, there may be a different noise profile coupling to the device compared to the input connections to the kelvin terminals.

https://training.ti.com/getting-started-current-sense-amplifiers-session-13-layout-considerations

https://www.ti.com/lit/eb/slyy154a/slyy154a.pdf

https://www.ti.com/lit/ug/tidud33a/tidud33a.pdf