LSF0102: Question about Figure 8-1

Kazuhiko Hirano

Part Number: LSF0102

Tool/software:

Hello,

My customer is suggesting the datasheet Figure 8-1 is wrong.
The datasheet 7.3.2 recommends the EN pin to be driven by an open-drain driver.
So, they are mentioning the Figure 8-1 should be the following by right. What does TI think about this?

Best regards,

K.Hirano

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 326910 points

The voltage at the EN pin must be lower than 3.3 V; this is usually ensured by the voltage drop over the 200 kΩ resistor. If you were to drive the EN pin high with a push/pull driver, then the voltage indeed would be too high.

The arrows are wrong. When driving the top end of the 200 kΩ resistor to 3.3 V, then the EN pin is at the correct voltage.

0 Kazuhiko Hirano over 1 year ago in reply to Clemens Ladisch

TI__Genius 16408 points

Clemens,

Thank you for your response.
Let me ask some more.
Do you mean the 3.3V enable signal in Figure 8-1 is driven from a push/pull driver, not open drain driver?
And the Vref_B is also supplied by the same push/pull driver through 200kohms resister?

Best regards,

K.Hirano

0 Clemens Ladisch over 1 year ago in reply to Kazuhiko Hirano

Guru 326910 points

Yes; the external enable signal is connected only to the top of the resistor, i.e., it replaces the 3.3 V supply for the LSF.

Logic

Logic forum

LSF0102: Question about Figure 8-1