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Evaluates: MAX17543 in

5V Output-Voltage Application

MAX17543 5V Output Evaluation Kit

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Regulator Enable/Undervoltage-Lockout

Level (EN/UVLO)

The device offers an adjustable input undervoltage-

lockout level. For normal operation, a shunt should be

installedacrosspins1-2onjumperJU1.Todisablethe

output,installashuntacrosspins2-3onJU1andtheEN/

UVLOpinispulledtoGND.SeeTable1forJU1settings.

Setthevoltageatwhichthedeviceturnsonwiththeresis-

tivevoltage-dividerR1/R2connectedfromVIN_toSGND.

ConnectthecenternodeofthedividertoEN/UVLO.

ChooseR1tobe3.32MΩandthencalculateR2asfollows:

INU

R1 1.215

R2

(V

1.215)

×

=

−

to turn on.

MODE Selection (MODE)

The device’s MODE pin can be used to select among

PWM,PFM,orDCMmodesofoperation.Thelogicstate

oftheMODEpinislatchedwhenVCCandEN/UVLOvolt-

agesexceedtherespectiveUVLOrisingthresholdsand

allinternalvoltagesarereadytoallowLXswitching.State

changes on the MODE pin are ignored during normal

operation.RefertotheMAX17543ICdatasheetformore

informationonPWM,PFM,andDCMmodesofoperation.

Table 2 shows EV kit jumper settings that can be used to

configure the desired mode of operation.

External Clock Synchronization (SYNC)

The internal oscillator of the device can be synchronized

toanexternalclocksignalontheSYNCpin.Theexternal

setbyR5.Theminimumexternalclockhighpulsewidth

should be greater than 50ns and the minimum external

clocklowpulsewidthshouldbegreaterthan160ns.

*Default position.

*Default position.

*Default position.

Table 1. Regulator Enable (EN/UVLO)

Description (JU1)

Table 2. MODE Description (JU2)

Table 3. SYNC Description (JU3)

SHUNT

POSITION

EN/UVLO PIN

MAX17543_ OUTPUT

1-2*

ConnectedtoVIN

Enabled

Not

installed

Connected to the

center node of

resistor-dividerR1

andR2

Enabled,UVLOlevel

setthroughtheR1and

R2resistors

2-3

ConnectedtoSGND

Disabled

SHUNT

POSITION

MODE PIN

MAX17543_ MODE

Not installed*

Unconnected

PFMmodeof

operation

1-2

Connected to

SGND

PWMmodeof

operation

2-3

Connected to

VCC

DCM mode of

operation

SHUNT

POSITION

SYNC PIN

MAX17543_ SYNC

1-2

Connected to

testlooponPCB

Frequencycanbe

synchronized with an

external clock

2-3*

Connected to

SGND

SYNCfeatureunused