MAX15046_10 Datasheet, PDF (1/24 Pages) Maxim Integrated Products – 40V, High-Performance, Synchronous Buck Controller

19-4719; Rev 1; 2/10
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40V, High-Performance, Synchronous
Buck Controller
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.
Pin Configurations appear at end of data sheet.
Features
S Input Voltage Ranges from 4.5V to 40V or 5V
Q10%
S Adjustable Outputs from 0.85 x VIN 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 Q1% 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
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX15046AAEE+ -40^°C to +125^°C 16 QSOP
MAX15046BAEE+ -40^°C to +125^°C 16 QSOP-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Typical Operating Circuit
4.5V TO 40V
V_IN
ON
OFF
R4
C1
C5
R3
C6
C7
R1
R3
IN
CSP
V_CC ^MAX15046
DH
PGOOD
LX
EN
BST
LIM
DL
COMP
DRV
FB
PGND
RT
GND
R2
C2
D1
C4
R5
Q1
L1
Q2
0.6V TO 0.85V x V_IN
V_OUT
C3
________________________________________________________________ Maxim Integrated Products   1
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