Rainbow Electronics MAX15046B - Manual

_______________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
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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
S
Input Voltage Ranges from 4.5V to 40V or 5V
Q 10%
S
Adjustable Outputs from 0.85 x V IN Down to 0.6V
S
Adjustable Switching Frequency (100kHz to 1MHz)
with Q10% (1MHz) Accuracy
S
Adaptive Internal Digital Soft-Start
S
Up to 25A Output Capability
S
Cycle-by-Cycle Valley-Mode Current Limit with
Adjustable, Temperature-Compensated Threshold
(30mV to 300mV)
S
Monotonic Startup into Prebiased Output
S Q 1% Accurate Voltage Reference
S
3A-Peak Gate Drivers
S
Hiccup-Mode Short-Circuit Protection (Patent-
Pending Architecture)
S
Overtemperature Shutdown
S
Power-Good (PGOOD) Output and Enable Input
(EN) with Q5% Accurate Threshold
S
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
IN
V CC DH
CSP
LX
BST
DL
DRV
PGND
GND
C1
Q1
Q2
PGOOD
EN
LIM
COMP
FB
RT
L1 0.6V TO 0.85V x V IN
V OUT
D1
R5
C4
C3
C2
R2
R3
R3
C6
C5
R4
4.5V TO 40V
V IN
ON
OFF
C7
R1
PART TEMP RANGE PIN-PACKAGE
MAX15046AAEE+ -40 ° C to +125 ° C 16 QSOP
MAX15046BAEE+ -40 ° C to +125 ° C 16 QSOP-EP*