Rainbow Electronics MAX15023 - Manual

General Description
The MAX15023 dual, synchronous step-down controller
operates from a 5.5V to 28V or 5V ±10% input voltage
range and generates two independent output voltages.
Each output is adjustable from 85% of the input voltage
down to 0.6V and supports loads of 12A or higher. Input
voltage ripple and total RMS input ripple current are
reduced by interleaved 180° out-of-phase operation.
The MAX15023 offers the ability to adjust the switching
frequency from 200kHz to 1MHz with an external resistor.
The MAX15023’s adaptive synchronous rectification elimi-
nates the need for external freewheeling Schottky diodes.
The device also utilizes the external low-side MOSFET’s
on-resistance as a current-sense element, eliminating the
need for a current-sense resistor. 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
MAX15023 includes two independent power-good out-
puts and two independent enable inputs with precise
turn-on/turn-off thresholds, which can be used for supply
monitoring and for power sequencing.
Additional protection features include cycle-by-cycle,
low-side, sink peak current limit, and thermal shutdown.
Cycle-by-cycle, low-side, sink peak current limit prevents
reverse inductor current from reaching dangerous levels
when the device is sinking current from the output. The
MAX15023 also allows prebiased startup without dis-
charging the output and features adaptive internal digital
soft-start. This new proprietary feature enables monoton-
ic charging of externally large output capacitors at start-
up, and achieves good control of the peak inductor
current during hiccup-mode short-circuit protection.
The MAX15023 is available in a space-saving and ther-
mally enhanced 4mm x 4mm, 24-pin TQFN-EP pack-
age. The device operates over the -40°C to +85°C
extended temperature range.
Applications
Point-of-Load Regulators
Set-Top Boxes
LCD TV Secondary Supplies
Switches/Routers
Power Modules
DSP Power Supplies
Features
♦ 5.5V to 28V or 5V ±10% Input Supply Range
♦ 0.6V to (0.85 x V
IN ) Adjustable Outputs
♦ Adjustable 200kHz to 1MHz Switching Frequency
♦ Guaranteed Monotonic Startup into a Prebiased
Load
♦ Lossless, Cycle-by-Cycle, Low-Side, Source Peak
Current Limit with Adjustable, Temperature-
Compensated Threshold
♦ Cycle-by-Cycle, Low-Side, Sink Peak Current-
Limit Protection
♦ Proprietary Adaptive Internal Digital Soft-Start
♦ ±1% Accurate Voltage Reference
♦ Internal Boost Diodes
♦ Adaptive Synchronous Rectification Eliminates
External Freewheeling Schottky Diodes
♦ Hiccup-Mode Short-Circuit Protection and
Thermal Shutdown
♦ Power-Good Outputs and Analog Enable Inputs
for Power Sequencing
MAX15023
Wide 4.5V to 28V Input, Dual-Output
Synchronous Buck Controller
________________________________________________________________ Maxim Integrated Products 1
23
24
22
21
*EP
*EXPOSED PAD (CONNECT TO GROUND).
8
7
9
EN1
PGOOD1
DL1
PGND1
10
FB1
FB2 PGOOD2 DL2 COMP2 PGND2
1 2
LIM2
4 5 6
17 18 16 14 13
LIM1
COMP1
DH2
DH1
BST1
LX1
MAX15023
EN2
V
CC
3
15
IN
20
+
11 BST2 SGND
19 12 LX2 RT
TQFN
TOP VIEW
Pin Configuration
Ordering Information
19-4219; Rev 0; 7/08
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
EVALUATION KIT
AVAILABLE
PART TEMP RANGE PIN-PACKAGE
MAX15023ETG+ -40°C to +85°C 24 TQFN-EP*
+ Denotes a lead-free/RoHS-compliant package.
* EP = Exposed pad.