MAX17020 Datasheet, PDF (1/34 Pages) Maxim Integrated Products – Dual Quick-PWM Step-Down Controller with Low-Power LDO, RTC Regulator

19-4118; Rev 2; 2/09
EVAALVUAAILTAIOBNLEKIT
Dual Quick-PWM Step-Down Controller
with Low-Power LDO, RTC Regulator
General Description
The MAX17020 is a dual Quick-PWM™ step-down
power-supply (SMPS) controller with synchronous rec-
tification, intended for main 5V/3.3V or I/O 1.5V/1.05V
power generation in battery-powered systems. Low-
side MOSFET sensing provides a simple low-cost,
highly efficient current sense for valley current-limit
protection. Combined with the output overvoltage and
undervoltage protection features, this current limit
ensures robust output supplies.
The 5V/3.3V or 1.5V/1.05V SMPS outputs can save
power by operating in pulse-skipping mode or in ultra-
sonic mode to avoid audible noise. Ultrasonic mode
forces the controller to maintain switching frequencies
greater than 20kHz at light loads.
An internal 100mA linear regulator can be used to
either generate the 5V bias needed for power-up or
other lower power “always-on” suspend supplies. An
independent bypass input allows automatic bypassing
of the linear regulator when the SMPS is active.
This main controller also includes a secondary feed-
back input that triggers an ultrasonic pulse (DL1 turned
on) if the SECFB voltage drops below its threshold volt-
age. This refreshes an external charge pump driven by
DL1 without overcharging the output voltage.
The device includes independent shutdown controls to
simplify power-up and power-down sequencing. To
prevent current surges at startup, the internal voltage
target is slowly ramped up from zero to the final target
over a 1ms period. To prevent the output from ringing
below ground in shutdown, the internal voltage target
is ramped down from its previous value to zero over a
1ms period. Two independent power-good outputs
simplify the interface with external controllers.
The MAX17020 is a pin-for-pin replacement of the
MAX8778.
Applications
Notebook Computers
Main System Supply (5V and 3.3V Supplies)
I/O System Supply (1.5V and 1.05V Supplies)
Graphic Cards
DDR1, DDR2, DDR3 Power Supplies
Game Consoles
Low-Power I/O and Chipset Supplies
Two-to-Four Li+ Cell Battery-Powered Devices
PDAs and Mobile Communicators
Telecommunication
Features
o Dual Quick-PWM
o Internal 100mA 5V or Adjustable Linear Regulator
o Independent LDO Bypass Input
o Internal Boost Diodes
o Secondary Feedback Input Maintains Charge Pump
o 3.3V 5mA RTC Power (Always On)
o OUT1: 5V or 1.5V Fixed or 0.7V Adjustable
Feedback
o OUT2: 3.3V or 1.05V Fixed or Dynamic Adjustable
o Dynamic 0V to 2V REFIN2 Input on Second SMPS
o 2V ±1% 50µA Reference
o 6V to 24V Input Range (28V max)
o Ultrasonic Mode
o Independent SMPS and LDO Enable Controls
o Independent SMPS Power-Good Outputs
o Minimal Component Count
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX17020ETJ+
-40°C to +85°C
32 TQFN
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Pin Configuration
TOP VIEW
24 23 22 21 20 19 18 17
LX2 25
16 LX1
DH2 26
15 DH1
ON2 27
14 ON1
PGOOD2 28
SKIP 29
MAX17020
13 PGOOD1
12 ILIM1
OUT2 30
11 FB1
ILIM2 31
+ REFIN2 32
10 OUT1
9 BYP
1 2345678
THIN QFN (T3255-4)
5mm x 5mm
A "+" SIGN FIRST-PIN INDICATOR DENOTES A LEAD-FREE PACKAGE.
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products 1
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.