LM2623: LM2623A Minimum operating supply voltage Vin_op

Hi Yamashiro-san
The IC "detects" Vin through the FREQ pin: when the voltage is lower that that Vin_op, the oscillator stop operation.

Now back to your question of what is the Vin_op: according the the datasheet is it really 0.8V on the high side. It may still operating when Vin drops below that but it is not guaranteed. Also please pay attention to the footnote regarding the loading capability and also Figure 7 of the datasheet.

Hope this clarifies. If this answers your question, please reply by clicking "This resolved my issue" button.

Best Regards,
Youhao Xi, System and Applications Engineering, APP-BMC-BCS, TI

Hi, Thank you for your reply. We got additional questions. Could you help us?

- LM2621 is similor to LM2623A. If input voltage become less than Vin_op, how does the behavior of the IC? If the IC detects Vin_op and will be active the protection like UVLO, how does the IC detect input voltage that is less than Vin_op?

- Regarding Figure 7 in datasheet of LM2623A, why does the output voltage decrease as the input voltage decreases? They are attempting to design under the following condition. Is there any possibility the IC can't regurate the output voltage in the low input voltage condition?

Vin=0.8V to 3.2V
Vout=5.68V
Iout=100mA

Best Regards,
tateo

Please allow me some more time to look into this.

Hi, Thank you for your reply. I look forward to your feedback.

Best Regards,

tateo