Question about the maximum current allowed by the EN pin of the LDO power chip

xiaxingxing

Question about the maximum current allowed by the EN pin of the LDO power chip [Copy link]

The picture shows the maximum and minimum current of the EN enable pin of an LDO when EN = 0. My questions are as follows:

1) Is this maximum current and minimum current the maximum/minimum current consumed, or the maximum/minimum current allowed?

2) What is the maximum allowable current of the EN pin when EN=1? Because I saw some places saying that this pin should be connected to a resistor to limit the current first, and then connected to the input voltage Vin.

Attached is the datasheet of this LDO, thanks to all the experts!

maychang

Read the chip's datasheet carefully.

When reading, you cannot just look at one line, and you cannot just look at the values in that line, but you also have to look at where the line is located.

maychang

This is the ABSOLUTE MAXIMUM RATINGS of this chip. The EN pin current is not marked there. So the EN pin current value you posted is not the maximum allowable value.

maychang

The line you posted is here. The column is marked ELECTRICAL CHARACTERISTICS, which means electrical characteristics.

maychang

"What is the maximum allowable current of this EN pin when EN=1? Because I saw some places saying that this pin should be connected to a resistor to limit the current first, and then connected to the input voltage Vin. "

In the typical application circuit provided by this chip, the EN pin is directly connected to Vin without a resistor in series to limit the current.

The "some places" you see are not as authoritative as the typical application circuits given in the datasheet.

xiaxingxing

maychang posted on 2021-1-21 10:17 The line you posted is here. The column is marked with ELECTRICAL CHARACTERISTICS, which means electrical characteristics.

Sir, does "electrical characteristics" mean the current consumed by the pin when EN=0?

Aren't the maximum allowable current and the maximum consumed current both electrical characteristics? I never paid attention to this detail before. Thank you!

xiaxingxing

maychang posted on 2021-1-21 10:20 "What is the maximum allowable current of this EN pin when EN=1? Because I saw some places saying that this pin should be connected with a resistor to limit the current first, and then connected to...

"Because I saw some places saying that this pin needs to be connected with a resistor to limit the current first."

Senior, it is like this. I have seen some other power chips and some information on the Internet saying that the EN pin of some power chips should be connected to a resistor in series before connecting to Vin. It is not about this LDO.

maychang

xiaxingxing posted on 2021-1-21 10:34 Senior, does "electrical characteristics" mean the current consumed by the pin when EN=0? Aren't the maximum allowable current and the maximum consumed current both electrical...

"Does "electrical characteristics" mean the current consumed by the pin when EN=0?"

It is the current flowing into or out of the pin when the chip is in normal working state (these are marked in the column) and EN=0.

maychang

xiaxingxing posted on 2021-1-21 10:35 "Because I saw some places saying that this pin should be connected in series with a resistor to limit the current first." Senior, that's right. I saw other...

"I've seen some other power chips and some information online saying that the EN pin of some power chips should be connected to a resistor in series before connecting to Vin."

Obviously this chip is not included.

beyond_笑谈

maychang published on 2021-1-21 10:17 The line you posted is here. The column is marked ELECTRICAL CHARACTERISTICS, which means electrical characteristics.

EN＝0, this current refers to the dark current of this pin when EN＝0. If you are engaged in automotive electronics, you will know that the controller has dark current requirements.

The enable pin is an input type, and there is no maximum current unless the input voltage exceeds the range.