19-2335; Rev 1; 6/02
Tracking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
General Description
The MAX1917 provides a complete power-manage-
ment solution for DDR memory. It contains a synchro-
nous buck controller and an amplifier to generate
1/2V
DDR
voltage for VTT and VTTR. The VTT and VTTR
voltages are maintained within 1% of 1/2V
DDR
. The
controller operates in synchronous rectification mode to
ensure balanced current sourcing and sinking capabili-
ty of up to 25A. With a shutdown current of less than
5µA, the MAX1917 is the best choice for low-power
notebook applications, as well as servers and desktop
computers. An all N-FET design optimizes efficiency.
The MAX1917 can also be used for generating V
DDR
and as a general-purpose step-down controller with
variable switching frequency as high as 1MHz with few
additional components.
The MAX1917 uses Maxim’s proprietary Quick-PWM™
architecture for fast transient response up to 96% effi-
ciency, and the smallest external components. Output
current monitoring is achieved without sense resistors
by monitoring the bottom FET’s drain-to-source voltage.
The current-limit threshold is programmable through an
external resistor. The MAX1917 comes in a space-sav-
ing 16-pin QSOP package.
o
25A Sourcing and Sinking Current
o
Automatically Sets VTT to 1/2V
DDR
o
VTT and VTTR Within 1% of 1/2V
DDR
o
Smallest Output Capacitors
o
4.5V to 14V (or 28V with Resistor-Divider) Input
Voltage Range
o
1.5V to 3.6V Input DDR Range
o
200kHz/300kHz/400kHz/550kHz Preset Switching
Frequencies
o
Variable Switching Frequency of Up to 1MHz
o
Overcurrent Protection Without Current-Sense
Resistor
o
Internal Soft-Start
o
VTTR Reference Sources and Sinks Up to 25mA
o
Quick-PWM Control for Fastest Loop Response
o
Up to 96% Efficiency
o
16-Pin QSOP Package
Features
MAX1917
Applications
DDR Memory Power
Supply
Processor or DSP Core
Supply
AGTL Bus Termination
Supply
Notebook Computers
Desktop Computers
Storage
Networking Systems
Ordering Information
PART
MAX1917EEE
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
16 QSOP
Typical Operating Circuit
V
IN
(2.5V TO 15V)
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
Pin Configuration
POK
EN/HSD
POK
VDDR
DDR
(4.5V TO 14V)
V+
REF
ILIM
FSEL
GND
DH
VL
V
OUT
TOP VIEW
EN/HSD 1
DDR 2
POK 3
VTT 4
ILIM 5
FSEL 6
REF 7
GND 8
16 LX
15 DH
14 BST
MAX1917
BST
LX
DL
PGND
VTT
VTTR
VTTR
MAX1917EEE
13 PGND
12 DL
11 VL
10 V+
9
VTTR
VL
QSOP
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
