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LM22674MRX-ADJ - Some questions

Other Parts Discussed in Thread: LM22674, LM2267X-22680DESIGN-CALC, TINA-TI

Hi all,

Would you mind if we ask LM22674MRX-ADJ?

<Confirmation1>
When we use WEBENCH with LM22674MRX-ADJ(LM22674), it only shows output voltage which MAX range is 5.0V. 
Our customer would like to use output voltage 12V or 10V, so do we have to use LM2267X-22680DESIGN-CALC
for caluculation, don't we?


<Confirmation2>
Condition: Input DC24V, output DC12V, Max current 0.3A 

We sumilated the schematic of LM22674MRX-ADJ using LM2267X-22680DESIGN-CALC as following.
http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/196/1300.20140930_5F00_-LM22674_5F00_DC24V_2D00_OUT12V-calculator.xls
And then, there is no Bode plot(because of simple switcher).
So we could judge whether phase margin is enough or not, if you know it, could you let us know? 


<Confirmation3>
Condition: Input DC12V, output DC10V, Max current 0.3A 
http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/196/8561.20140930_5F00_-LM22674_5F00_DC12V_2D00_OUT10V-calculator.xls
Output will be no stability.
About "the maximum duty cycle before the output voltage will "dropout" of regulation" P8 on the datasheet,
we got the Vin(min)=11.21V. So, compared with Vin=DC12V, there is no margin.
Is our recognition correct?


<Confirmation4>
Condition: Input DC24V, output DC-12V(negative voltage), Max current 0.3A 
After LM22674 operate,  the ground leve of LM22674 will be -12V.
http://e2e.ti.com/cfs-file.ashx/__key/communityserver-discussions-components-files/196/3348.20141001_5F00_-LM22674_5F00_DC24V_2D00_OUT_2D00_12V-schematic.pdf
When LM22674 turns off, is EN pin only connected to GND, right?

We need your help.

Kind regards,

Hirotaka Matsumoto