ST1S40 behavior if output current < 124mA

[amull.1]

Hello there,

Can you tell me how the ST1S40 behaves when the current drawn is below 124mA ?

Or could you recommend me an alternative solution ?

I need a DC/DC converter with the following spec.

• Input 6-9V
• Output 3V3
• Current 10mA - 1A
• Housing SOIC

[Peter BENSCH]

Welcome, @amull.1​, to the community!

The ST1S14 is a regulator for max 3A, whose efficiency decreases below 200mA.

It would be better if you design the buck regulator for the maximum load current, in your case 1A. For this there are e.g. the following components, which are not synchronous regulators, but classical asynchronous regulators:

• ST1S03
• L7987L

Good luck!

Regards

/Peter

[amull.1]

Hello Peter

Thanks for the quick reply. So the controller would still work properly, just the efficiency would decrease?

An asynchronous regulator would also work but the ones you refer to are all out of stock.... and not in a SOIC package.

[Peter BENSCH]

I can only simulate the behaviour of the ST1S40 for currents greater than 100mA and therefore cannot make a statement for smaller currents. Actually, it should also work at 10mA, the ripple would then have to be significantly larger.

Regards

/Peter

[Peter BENSCH]

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/Peter