High-Voltage, 2.2MHz, 2A Automotive Step-

Down Converter with Low Operating Current

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Detailed Description

The MAX16974 is a constant-frequency, current-mode,

automotive buck converter with an integrated high-side

switch. The device operates with 3.5V to 28V input volt-

ages and tolerates input transients up to 42V. During

undervoltage events, such as cold-crank conditions, the

internal pass device maintains up to 92% duty cycle.

An open-drain, active-low reset output helps monitor the

output voltage. The device offers an adjustable reset

threshold that helps keep microcontrollers alive down

to their lowest specified input voltage. A capacitor pro-

grammable reset timeout ensures proper startup.

The switching frequency is resistor programmable from

220kHz to 2.2MHz to allow optimization for efficiency,

noise, and board space. A clock input, FSYNC, allows

the device to synchronize to an external clock.

During light-load conditions, the device enters skip

mode that reduces the quiescent current down to 35FA.

The 5V fixed output voltage option eliminates the need

for external resistors and reduces the supply current by

up to 50FA. See Figure 2 for the internal block diagram.

Supply Voltage Range (SUP)

with the typical 3.5V to 28V automotive battery voltage

range and can tolerate transients up to 42V.

Figure 2. Internal Block Diagram

10µA

COMP

COMP

GND

B.G.

REF

SOFT-

START

UVLO

MUX

LDO

STANDBY

SUPPLY

REF

EA

LOGIC FOR

DROPOUT

RES

FB

RESETI

CRES

PWM

COMP

LEVEL

SHIFT

LOGIC

EN

OSC

SUM

FSYNC

FOSC

BIAS

SUP

OUT

COMP

DRV

LX

BST

SUPSW

MAX16974