Rainbow Electronics MAX15046B User Manual

General description, Features, Applications

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40V, High-Performance, Synchronous

Buck Controller MAX15046

General Description

The MAX15046 synchronous step-down controller oper-
ates from a 4.5V to 40V input voltage range and gener-
ates an adjustable output voltage from 85% of the input
voltage down to 0.6V, supporting loads up to 25A. The
device allows monotonic startup into a prebiased bus
without discharging the output and features adaptive
internal digital soft-start.
The MAX15046 offers the ability to adjust the switching
frequency from 100kHz to 1MHz with an external resis-
tor. The MAX15046’s adaptive synchronous rectifica-
tion eliminates the need for an external freewheeling
Schottky diode. The device also utilizes the external
low-side MOSFET’s on-resistance as a current-sense
element, eliminating the need for a current-sense resis-
tor. This protects the DC-DC components from damage
during output overloaded conditions or output short-
circuit faults without requiring a current-sense resistor.
Hiccup-mode current limit reduces power dissipation
during short-circuit conditions. The MAX15046 includes
a power-good output and an enable input with precise
turn-on/turn-off threshold, which can be used for input
supply monitoring and for power sequencing.
Additional protection features include sink-mode current
limit, and thermal shutdown. Sink-mode current limit pre-
vents reverse inductor current from reaching dangerous
levels when the device is sinking current from the output.

The MAX15046 is available in a 16-pin QSOP or 16-pin
QSOP-EP package and operates over the -40NC to +125NC
temperature range.

Features

Input Voltage Ranges from 4.5V to 40V or 5V

10%

Adjustable Outputs from 0.85 x V

Down to 0.6V

Adjustable Switching Frequency (100kHz to 1MHz)

with Q10% (1MHz) Accuracy

Adaptive Internal Digital Soft-Start

Up to 25A Output Capability

Cycle-by-Cycle Valley-Mode Current Limit with

Adjustable, Temperature-Compensated Threshold

(30mV to 300mV)

Monotonic Startup into Prebiased Output

1% Accurate Voltage Reference

3A-Peak Gate Drivers

Hiccup-Mode Short-Circuit Protection (Patent-

Pending Architecture)

Overtemperature Shutdown

Power-Good (PGOOD) Output and Enable Input

(EN) with Q5% Accurate Threshold

Thermally Enhanced 16-Pin QSOP Package

Applications

Industrial Power Supplies (PLC, Industrial

Computers, Fieldbus Components, Fieldbus

Couplers)
Telecom Power Supplies
Base Stations

19-4719; Rev 0; 7/09

Pin Configurations appear at end of data sheet.

Ordering Information

+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.

Typical Operating Circuit

MAX15046

CSP

BST

DRV

PGND

GND

PGOOD

LIM

COMP

0.6V TO 0.85V x V

OUT

4.5V TO 40V

OFF

PART

TEMP RANGE

PIN-PACKAGE

MAX15046AAEE+

-40

C to +125

16 QSOP

MAX15046BAEE+

-40

C to +125

16 QSOP-EP*