Pin Description (continued)

NAME

PIN

FUNCTION

10

EN/UVLO

Enable/Undervoltage Lockout Pin. Drive EN/UVLO high to enable the output. Connect to the

12

14

RESET

Open-Drain RESET Output. The RESET output is driven low if FB drops below 92% of its set

value. RESET goes high 1024 cycles after FB rises above 95% of its set value.

15

MODE/

SYNC

MODE pin configures the device to operate either in PWM, PFM, or DCM modes of operation.

Leave MODE unconnected for PFM operation (pulse-skipping at light loads). Connect MODE

operation. The device can be synchronized to an external clock using this pin. See the Mode

Selection (MODE) section and the External Frequency Synchronization section for more details.

16

SS

Soft-Start Input. Connect a capacitor from SS to SGND to set the soft-start time.

17

CF

At switching frequencies lower than 500kHz, connect a capacitor from CF to FB. Leave CF open

if switching frequency is equal or more than 500kHz.

18

FB

Feedback Input. Connect FB to the center tap of an external resistor-divider from the output to

SGND to set the output voltage. See the Adjusting Output Voltage section for more details

19

RT

Connect a resistor from RT to SGND to set the regulator’s switching frequency between 100kHz

and 2.2MHz. Leave RT open for the default 500kHz frequency. See the Setting the Switching

Frequency (RT) section for more details.

20

External Power Supply Input for the Internal LDO. Applying a voltage between 4.84V and 24V at

Also, add a local bypassing on this pin to SGND.

21

SGND

Analog Ground.

22

BST

Boost Flying Capacitor. Connect a 0.1μF ceramic capacitor between BST and LX.

—

EP

Exposed Pad. Connect to the GND pin of the IC. Connect to a large copper plane below the IC to

improve heat dissipation capability.

MAX17574

4.5V–60V, 3A, High-Efficiency,

Synchronous Step-Down DC-DC Converter

with Internal Compensation

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