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Hi,
We are using P/N: CAT4240TD-GT3 for 24V (80mA) Vout for LCD backlight application. How can we use the same part for 9.3 Vout at 120 mA application. We are not able to get data on this. There is no info available in datasheet.
Regards
Yogesh
DC transfer for Duty cycle: D=Vout-Vin/Vout
Maximum duty cycle is 92% at Vin=3V. (CAT4240TD-GT3 datasheet)
To calculate duty cycle and inductance you need to know the worst input voltage condition which you have not mentioned.
For instance if your Vin is 5V duty cycle will be 46%.
D=(Vout – Vin)/Vout =9.3-5/9.3 =0.46
Inductor current
IL=I out/1-D = 0.22 Amp,
Inductor peak current
I pk= IL (1 + (ripple ratio/2)) = 0.264 Amp (I used ripple 0.4)
Inductance
L = Von *D/ripple *IL*f = 26uH
Current sense resistor Rs=0.3/0.120 = 2.5Ohm.
Details regarding passive components are described in our application section of our datasheet at: http://www.onsemi.com/pub_link/Collateral/CAT4240-D.PDF
Answered by: ON Semiconductor
2013-01-22 15:45:27.864