controlling the BW pin on the AD8237

Document created by analog-archivist Employee on Feb 23, 2016Last modified by ScottH on Feb 23, 2016
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Q

Part Number: AD8237

 


Can the BW pin of AD8237 be controlled with a GPIO on a MCU?

 

 

 

 

 

A

We see no problem with this. Advisable to use a pull-up resistor of about
4.7k ohms to the BW pin and interface to a microprocessor to control this
pin. e.g. control and output high or low to simulate this Vs or -Vs (gnd)

 


The BW pin is one input of a comparator. It is high-Z, there are no current
driving requirements, and there are no minimum rise/fall time requirements. The
other input of the comparator is at a resistor divider from +Vs to –Vs, which
creates a half-supply voltage for comparison.

 

Threshold voltages: High is (+VS + (–VS))/2 + 60mV min, Low is (+VS + (–VS))/2
– 60mV max  (this takes into account worst-case process variation and also 30mV
of hysteresis)

 

Propagation delay: typically 10µs comparator propagation delay + the settling
time of AD8237 in the final configuration

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