LM25118-Q1: [LM25118-Q1/LM5118-Q1 ] the part can cover Vin = 3V ?

Paul Kim

Intellectual 1430 points

Part Number: LM25118-Q1
Other Parts Discussed in Thread: LM5118-Q1, , LM5118, LM25118

hi team

LM25118-Q1 and LM5118-Q1 has Vin = Min 3V spec in D/S,

but there is one condition that "Vin >= 5V is required to initially start the controller" as below.

my question is if Vin is below 5V, LM25118-Q1 and LM5118-Q1 cannot start to run ?

I cannot absolutely use LM25118-Q1 and LM5118-Q1 if Vin is below 5V ?

because custormer worst Vin scenario is 3V.

it is confused.

over 7 years ago

0 Terry Allinder over 7 years ago

TI__Expert 3535 points

Paul, yes the LM25118 and LM5118 require 5V to start-up. If you refer to Figure 4 in the LM25118 data sheet you will see that with VIN =3V, the VCC regulator output will not exceed the VCCUVLO lockout (3.86Vmax). To be sure that the VCC regulator is above the VCCUVLO lockout, VIN needs to be 5V, refer to page 22 in the data sheet.

Terry

0 Paul Kim over 7 years ago in reply to Terry Allinder

TI__Intellectual 1430 points

Hi Terry

once LM25118 finishes the startup with VIn = 5V, can we reduce VIn down to 3V ?

still LM25118 can run properly, right ?

0 Terry Allinder over 7 years ago in reply to Paul Kim

TI__Expert 3535 points

Paul,

Yes after start-up the LM25118 can operate down to 3V.

Terry

Power management

Power management forum

LM25118-Q1: [LM25118-Q1/LM5118-Q1 ] the part can cover Vin = 3V ?