MAX1917 Datasheet, PDF (1/18 Pages) Maxim Integrated Products – Tracking, Sinking and Sourcing, Synchronous Buck Controller for DDR Memory and Termination Supplies

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.
Applications
DDR Memory Power
Supply
Processor or DSP Core
Supply
AGTL Bus Termination
Supply
Notebook Computers
Desktop Computers
Storage
Networking Systems
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
TOP VIEW
Pin Configuration
EN/HSD 1
DDR 2
POK 3
VTT 4
ILIM 5
FSEL 6
REF 7
GND 8
MAX1917EEE
16 LX
15 DH
14 BST
13 PGND
12 DL
11 VL
10 V+
9 VTTR
QSOP
Features
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
PART
MAX1917EEE
Ordering Information
TEMP RANGE
-40°C to +85°C
PIN-PACKAGE
16 QSOP
VIN (2.5V TO 15V)
Typical Operating Circuit
EN/HSD
DH
POK
POK
VL
VDDR
VOUT
DDR MAX1917 BST
(4.5V TO 14V)
V+
LX
REF
DL
ILIM
VL
PGND
FSEL
VTT
VTTR
GND
VTTR
________________________________________________________________ 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.