LMR36006-Q1: Which inductance 22uH or 33uH are recommended @ Vout=5V and fsw=400kHz?

Hi Yoshiki,

33uH is target to cover wide Vin up to 60V, 22uH is targeted for nominal 12V--24V input. you can choice  proper value based on Vin condition.

B R

Andy

Hi Andy-san,

I have additional 2 questions referring to your answer. Could you please give your comment for them?

1.
In general, I think 12V battery become up to 40V and 24V battery become up tp 60V. So I wonder if nominal 24V input means Vin up to 60V. Then I am not clear the difference between "33uH for wide Vin up to 60V" and "22uH for nominal 12V--24V input" you said. 

2. 
I guess Table5 "List of Components for Design 1" refers to Table4 "Detailed Design Parameters". Table4 says input voltage is "12 V to 24 V steady state, 4.2 V to 60-V transients." So I am not clear which 22uH or 33uH is suitable for 24V and 60V transients condition yet. 

Regards,
Ochi

Hi Ochi,

The inductor is considered on below:

1. Kind round 20%--50% at nominal input

2. Kind >10% at lowest Vin

3. inductor current peak not trig current limit at Vin max and max load, and output ripple is acceptable

4. smaller inductor for compact solution size and low cost.

You can select proper inductor value for your actual application condition.

B R

Andy

Hi Andy-san, 

What do you mean for lower inductor consideration you said? Could you tell me more detail because I did not understand what they mean?

1. Kind round 20%--50% at nominal input

2. Kind >10% at lowest Vin

In addition, do you mean both of 22uH and 33uH are OK if inductor considerations are considered enough?

Regards,
Ochi

Hi Ochi,

LMR36006 uses peak current model control, the inductor current ripple should be high enough to compare the current peak for proper switching control, the current ripple is getting smaller when Vin close to Vout, so we normally suggest to have Kind>10% at lowest Vin condition.

both of 22uH and 33uH are OK if they meet the consideration items on data sheet and above thread.

B R

Andy 

Hi Andy-san, 

Could you explain what does "Kind" mean? I could not understand which parameter in datasheet you indicated as "Kind".

I would appreciate if you could use the parameters which are included in datasheet. I guess it i would be really clear for me.

Regards,
Ochi