LP3907 datasheet(27/57 Pages) TI1

Part #	LP3907

Description	Dual High-Current Step-Down DC/DC and Dual Linear Regulator with I2C-Compatible Interface

PDF	57 Pages

Scroll/Zoom	100%

Manufacturer	TI1 [Texas Instruments]

Direct Link	http://www.ti.com

Logo

27 / 57 page

EN1

nPOR

RDY1

EN2

RDY2

EN1

nPOR

RDY1

EN2

RDY2

Case1

Case2

EN1

nPOR

RDY1

EN2

RDY2

Case3

Counter

delay

Counter

delay

Counter

delay

LP3907

www.ti.com

SNVS511N – JUNE 2007 – REVISED AUGUST 2011

Figure 7. NPOR With Counter Delay

The above diagram shows the simplest application of the Power On Reset, where both switcher enables are tied

together. In Case 1, EN1 causes nPOR to transition LOW and triggers the nPOR delay counter. If the power

supply for Buck2 does not come on within that period, nPOR will stay LOW, indicating a power fail mode. Case 2

indicates the vice versa scenario if Buck1 supply did not come on. In both cases the nPOR remains LOW.

Case 3 shows a typical application of the Power On Reset, where both switcher enables are tied together. Even

if RDY1 ramps up slightly faster than RDY2 (or vice versa), then nPOR signal will trigger a programmable delay

before going HIGH, as explained below.

Submit Documentation Feedback

Product Folder Links: LP3907

LP3907 Datasheet(PDF) 27 Page - Texas Instruments