MAX15021
Dual, 4A/2A, 4MHz, Step-Down
DC-DC Regulator withTracking/
Sequencing Capability
General Description
The MAX15021 is a dual-output, pulse-width-modulated
(PWM), step-down DC-DC regulator with tracking (coin-
cident and ratiometric) and sequencing options. The
device operates from 2.5V to 5.5V and each output can
be adjusted from 0.6V to the input supply (V
AVIN
). The
MAX15021 delivers up to 4A (regulator 1) and 2A (reg-
ulator 2) of output current. This device offers the ability
to adjust the switching frequency from 500kHz to 4MHz
and provides the capability of optimizing the design in
terms of size and performance.
The MAX15021 utilizes a voltage-mode control scheme
with external compensation to provide good noise
immunity and maximum flexibility in selecting inductor
values and capacitor types. The dual switching regula-
tors operate 180° out-of-phase, thereby reducing the
RMS input ripple current and thus the size of the input
bypass capacitor significantly.
The MAX15021 offers the ability to track (coincident or
ratiometric) or sequence during power-up and power-
down operation. When sequencing, it powers up glitch-
free into a prebiased output.
Additional features include an internal undervoltage
lockout with hysteresis and a digital soft-start/soft-stop
for glitch-free power-up and power-down. Protection
features include lossless cycle-by-cycle current limit,
hiccup-mode output short-circuit protection, and ther-
mal shutdown.
The MAX15021 is available in a space-saving, 5mm x
5mm, 28-pin TQFN-EP package and is specified for
operation from -40°C to +125°C temperature range.
Applications
RFID Reader Cards
Power-over-Ethernet (PoE) IP Phones
Automotive Multimedia
Multivoltage Supplies
Networking/Telecom
Benefits and Features
• Integration Reduces Power-Supply Footprint for Space-
Constrained Designs
• Dual-Output Synchronous Buck Regulators
• Integrated Switches for 4A and 2A Output Currents
• Programmable Switching Frequency from 500kHz
to 4MHz
• 28-Pin TQFN Package (5mm x 5mm)
• 180° Out-Of-Phase Operation Reduces Input
Ripple Current and Thus the Size of the Input
Bypass Capacitors
• Sophisticated Tracking/Sequencing Functions
Facilitate Reliable Processor Operation
• Digital Soft-Start and Soft-Stop for Tracking
Applications
• Digital Soft-Start into a Prebiased Load for
Sequencing Applications
• Sequencing or Coincident/Ratiometric Tracking
• Flexible Enough for Use in a Range of Designs
• 2.5V to 5.5V Input Voltage Range
• Output-Voltage Adjustable from 0.6V to V
AVIN
•
External Compensation for Maximum Flexibility
• 100% Maximum Duty Cycle
• Integrated Protection Features Save Space and
Increase Reliability
• Lossless, Cycle-by-Cycle Current Sensing
• Thermal Shutdown and Hiccup-Mode Short-Circuit
Protection
• 20µA Shutdown Current Extends Battery Life in
Portable Applications
N.C.
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N.C.
*EP = EXPOSED PAD.
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