Connect the AD5412/AD5422's Iout and Vout pins directly together

Document created by analog-archivist Employee on Feb 23, 2016
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Is it possible to connect the AD5412/AD5422's Iout and Vout pins together, as
is possible with the AD5755?

 

The AD5422's Iout and Vout can be connected together but to prevent additional
errors in Iout mode there are some pre-requisites.

1. A buffer amplifier must be placed between Vout and +Vsense.

2. An external Rset must be used. If an internal Rset is used there will be an
additional current leakage path through the Vout Pin resulting in approx. 0.5%
error in Iout mode.

In Vout mode the Iout pin is in a high impedance state, effectively
disconnected.

A suitable opamp is OP184.


An alternative part to the AD5422 is the AD5751 and the AD5750, the Iout and
Vout pins of these devices can be directly connected together without
additional external circuitry.

However, please note that the AD5750 requires a dual power supply.

Their respective Product Pages on the ADI webpage are below:

http://www.analog.com/en/amplifiers-and-comparators/instrumentation-amplifiers/a
d5750/products/product.html

http://www.analog.com/en/amplifiers-and-comparators/instrumentation-amplifiers/a
d5751/products/product.html

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