MAX15002 Datasheet, PDF (12/30 Pages) Maxim Integrated Products – Dual-Output Buck Controller with Tracking/Sequencing

Dual-Output Buck Controller with
Tracking/Sequencing
Functional Diagrams (continued)
PWM CONTROLLER 2
EN/TRACK2
MAX15002
VREF
DOWN2
EN/
TRACK2
FB2
DIGITAL
SOFT-START
AND STOP
CLK2
VREF
VR2
COMP2
CLK2
RAMP
SEL_
E/A
LEVEL
SHIFT
SEQ_
EN
CONFIG
EN1 SHDN ^EN2
1.24VON
1.12VOFF
SEQ_
OVL
OVL_
CONFIG
OVL2 ^RES
OVERLOAD
IMAX2 _{MANAGEMENT CLK2}
CPWM
CLK2
0.925
x
V_REF
FB2
R
Q
SET
DOMINANT
S
PGPD2
CSP2
CSN2
CURRENT-
LIMIT
SET
ILIM2
BST2
DH2
LX2
DREG2
DL2
PGND2
PGOOD2
Detailed Description
The MAX15002 is a dual-output, pulse-width-modulat-
ed (PWM), step-down, DC-DC controller with tracking
and sequencing options. The device operates over the
input voltage range of 5.5V to 23V or 5V ±10%. Each
PWM controller provides an adjustable output down to
0.6V and delivers at least 15A of load current with
excellent load and line regulation.
Each of the MAX15002 PWM sections utilizes a volt-
age-mode control scheme for good noise immunity and
offers external compensation allowing for maximum
flexibility with a wide selection of inductor values and
capacitor types. The device operates at a fixed switch-
ing frequency that is programmable from 200kHz to
2.2MHz and can be synchronized to an external clock
signal using the SYNC input. Each converter, operating
at up to 2.2MHz with 180° out-of-phase, increases the
input capacitor ripple frequency up to 4.4MHz, reduc-
ing the RMS input ripple current and the size of the
input bypass capacitor requirement significantly.
The MAX15002 provides Coincident Tracking,
Ratiometric Tracking, and Sequencing. This allows tai-
loring of the power-up/power-down sequence depend-
ing on the system requirements.
The MAX15002 features lossless valley-mode current-
limit protection by monitoring the voltage drop across
the synchronous MOSFET’s on-resistance to sense the
inductor current. The MAX15002’s internal current
source exhibits a positive temperature coefficient to help
compensate for the MOSFET’s temperature coefficient.
Use an external voltage-divider when a more precise
current limit is desired. This divider along with a preci-
sion shunt resistor allows for more accurate current limit.
The MAX15002 includes internal undervoltage lockout
with hysteresis, digital soft-start/soft-stop for glitch-free
power-up and power-down of the converter. The
power-on reset (RESET) with adjustable timeout period
monitors both outputs and provides a RESET signal to
the processor indicating when the outputs are within
regulation. Protection features include lossless valley-
mode current limit and hiccup mode output short-cir-
cuit protection.
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