AN2937 datasheet(19/41 Pages) STMICROELECTRONICS

19 / 41 page

AN2937

Jumper settings

Doc ID 15418 Rev 1

19/41

9.6

LDO regulation (LDOREFIN)

9.7

External bypass connections for the linear regulator (BYP)

Table 8.

Jumper S6 LDOREFIN (connect LDOREFIN pin to S6)

Position

LDO regulation

GND

The LDO regulates 5 V.

VREF2

The LDO regulates a voltage equal to two times the voltage at LDOREFIN input.

VCC

The LDO regulates 3.3 V.

Table 9.

Jumper S7 BYP (connect LDO_SW pin to S7)

Position

External bypass connections for the linear regulator

GND

The internal linear regulator LDO is always on. It can provide an output peak current

of 100 mA.

OUT1.

If LDO regulates 5 V and BYP goes higher than 4.74 V, an internal P-channel

MOSFET switch connects the BYP pin to the LDO pin, shutting down the LDO

internal linear regulator. It can provide an output peak current of 200 mA.

OUT2

If LDO regulates 3.3 V and BYP goes higher than 3.17 V, an internal P-channel

MOSFET switch connects the BYP pin to the LDO pin, shutting down the LDO

internal linear regulator. It can provide an output peak current of 100 mA.

AN2937 Datasheet(PDF) 19 Page - STMicroelectronics