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Evaluates: MAX14571–MAX14573

MAX14571 Evaluation Kit

Undervoltage Lockout (UVLO)

Jumper JU3 (shunted by default) connects the UVLO pin

to GND and configures the device to have the internal

19.2V preset UVLO. To configure a user-defined UVLO,

disconnect JU3 and connect a shunt on JU5. This allows

the device to monitor the IN voltage. Connect a resistor

on R10 to set the user-defined UVLO threshold. Use the

following equation to set the UVLO threshold:

9

1

10

UVLO

BG

R

V

Vx

R





=

+









where:

R9 is 2.2MΩ

External LED2 indicates that an UVLO fault has occurred.

Enable (J1)

To enable the device, connect a USB connector from the

computer to the USB connector, J1. This provides 5V to

VBUS and to the EN pin (JU8 connects VBUS to IN by

default). If no cable is available, connect a 5V DC power

supply between test point TP3 and the corresponding

GND test point, TP4.

Negative Input Test

test should be performed when the output capacitors are

fully discharged and VBUS should not be supplied.

Table 1. Default Jumper Settings (JU1–JU11, JU13)

JUMPER

SHUNT POSITION

DESCRIPTION

JU1

1-2*

Sets current threshold to 0.709A.

3-4

Sets current threshold to 2.304A.

5-6

Sets current threshold to 4.197A.

7-8

Adjustable current limit using a potentiometer.

JU2

1-2

Connects the SETI pin to GND, asserts the FLAG output, and sets the current limit to 0A.

Open*

Allows the user to connect JU1 shunts to configure the current limit.

JU3

1-2*

Connects the UVLO pin to GND and enables the internal UVLO threshold.

Open

Allows the user to connect an external resistor-divider to set a user-defined UVLO

threshold.

Note: JU5 should also be connected.

JU4

1-2*

Connects the OVLO pin to GND and enables the internal OVLO threshold.

Open

Allows the user to connect an external resistor-divider to set a user-defined OVLO thresh-

old.

Note: JU5 should also be connected.

JU5

1-2

Allows the user to connect an external resistor-divider to set a user-defined OVLO and

UVLO threshold.

Open*

Connect JU3 and JU4 or connect an external resistor-divider for normal UVLO/OVLO

operation.