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MAX1917EEE+

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18
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
Features
♦ 25A Sourcing and Sinking Current
♦ Automatically Sets VTT to 1/2V
DDR
♦ VTT and VTTR Within 1% of 1/2V
DDR
♦ Smallest Output Capacitors
♦ 4.5V to 14V (or 28V with Resistor-Divider) Input
Voltage Range
♦ 1.5V to 3.6V Input DDR Range
♦ 200kHz/300kHz/400kHz/550kHz Preset Switching
Frequencies
♦ Variable Switching Frequency of Up to 1MHz
♦ Overcurrent Protection Without Current-Sense
Resistor
♦ Internal Soft-Start
♦ VTTR Reference Sources and Sinks Up to 25mA
♦ Quick-PWM Control for Fastest Loop Response
♦ Up to 96% Efficiency
♦ 16-Pin QSOP Package
MAX1917
Tracking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
MAX1917
V
IN
(2.5V TO 15V)
POK
VDDR
EN/HSD
POK
DDR
V+
REF
ILIM
FSEL
GND
DH
VL
BST
DL
LX
PGND
VTT
VTTR
V
OUT
VTTR
(4.5V TO 14V)
VL
Typical Operating Circuit
19-2335; Rev 1; 6/02
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.
PART TEMP RANGE PIN-PACKAGE
MAX1917EEE -40°C to +85°C 16 QSOP
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
EN/HSD LX
DH
BST
PGND
DL
VL
V+
VTTR
TOP VIEW
MAX1917EEE
QSOP
DDR
POK
FSEL
VTT
ILIM
REF
GND
Pin Configuration
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
DDR Memory Power
Supply
Processor or DSP Core
Supply
AGTL Bus Termination
Supply
Notebook Computers
Desktop Computers
Storage
Networking Systems
MAX1917
Tracking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V+ = 12V, V
EN/HSD
= V
DDR
= 2.5V, C
VL
= 4.7µF, C
VTTR
= 1µF, C
REF
= 0.22µF, V
FSEL
= 0, ILIM = VL, PGND = LX = POK = GND,
BST = VL. Specifications are for T
A
= 0°C to +85°C. Typical values are at T
A
= +25°C, unless otherwise specified.)
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
V+ to GND ..............................................................-0.3V to +15V
EN/HSD to GND .....................................................-0.3V to +16V
VL to GND ................................................................-0.3V to +6V
PGND to GND .......................................................-0.3V to +0.3V
VTT, DDR, POK to GND ...........................................-0.3V to +6V
REF, VTTR, DL, ILIM, FSEL to GND ................-0.3V to VL + 0.3V
LX to PGND ............................................................-0.3V to +30V
BST to GND ............................................................-0.3V to +36V
DH to LX ......................................................-0.3V to V
BST
+ 0.3V
LX to BST..................................................................-6V to +0.3V
REF Short Circuit to GND ...........................................Continuous
Continuous Power Dissipation (T
A
= +70°C)
16-Pin QSOP (derate up to +70°C)..............................667mW
16-Pin QSOP (derating above +70°C).....................8.3mW/°C
Operating Temperature Range
Extended .........................................................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering 10s.) .................................+300°C
PARAMETER CONDITIONS MIN TYP MAX UNITS
5.5 14.0
V+ Input Voltage Range
VL = V+ 4.5 5.5
V
EN/HSD Input Voltage Range Enabled 1.5 15.0 V
DDR Input Voltage Range 0 3.6 V
V+ Supply Current VTT = 2.0V 0.8 1.2 mA
DDR Supply Current 115 250 µA
EN/HSD Supply Current 510µA
VL Supply Current VL = V+ = 5.5V, VTT = 2.0V 0.8 1.2 mA
V+ Shutdown Supply Current EN/HSD = 0V 3 5 µA
DDR Shutdown Supply Current EN/HSD = 0V 1 µA
VL Shutdown Supply Current VL = V+ = 5.5V 3 5 µA
VL Undervoltage Lockout
Threshold
Rising edge, hysteresis = 40mV 4.05 4.25 4.40 V
VTT
VTT Input Bias Current V
VTT
= 2.5V -0.1 0 µA
VTT Feedback Voltage Range 0 1.8 V
Overload range, V
DDR
= 1.8V 49.5 50 50.5
VTT Feedback Voltage
Accuracy
Overload range, V
DDR
= 3.6V 49.5 50 50.5
%V
DDR
REFERENCE
Reference Output Voltage V+ = VL = 4.5V to 5.5V, I
REF
= 0 1.98 2.00 2.02 V
Reference Load Regulation V+ = VL = 5V, I
REF
= 0 to 50µA 10 mV
Reference UVLO V+ = VL = 5V 1.5 1.6 1.7 V
VTTR
VTTR Output Voltage Range 0 1.8 V
I
VTTR
= -5mA to +5mA 49.5 50 50.5
I
VTTR
= -25mA to +25mA, V
DDR
= 1.8V 49 50 51
VTTR Output Accuracy
I
VTTR
= -25mA to +25mA, V
DDR
= 3.6V 49.5 50 50.5
%V
DDR
MAX1917
Tracking, Sinking and Sourcing, Synchronous Buck
Controller for DDR Memory and Termination Supplies
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(V+ = 12V, V
EN/HSD
= V
DDR
= 2.5V, C
VL
= 4.7µF, C
VTTR
= 1µF, C
REF
= 0.22µF, V
FSEL
= 0, ILIM = VL, PGND = LX = POK = GND,
BST = VL. Specifications are for T
A
= 0°C to +85°C. Typical values are at T
A
= +25°C, unless otherwise specified.)
PARAMETER CONDITIONS MIN TYP MAX UNITS
Thermal Shutdown Rising temperature, typical hysteresis = 15°C +160 °C
SOFT-START
ILIM Ramp Period
Ramps the ILIM trip threshold from 20% to 100%
in 20% increments
1.7 ms
OSCILLATOR
FSEL = VL 200
FSEL = unconnected 300
FSEL = REF 400
Oscillator Frequency
FSEL = GND 550
kHz
FSEL = VL 2.18 2.5 2.83
FSEL not connected 1.45 1.67 1.89
FSEL = REF 1.09 1.25 1.41
On Time (Note 1)
FSEL = GND 0.82 0.91 1.00
µs
Minimum Off Time (Note 1) 350 400 ns
CURRENT LIMIT
LX to PGND, ILIM = VL 90 100 110
LX to PGND, R
ILIM
= 100kΩ 40 50 60
Current-Limit Threshold
(Positive Direction)
LX to PGND, R
ILIM
= 400kΩ 170 200 230
mV
Current-Limit Threshold
(Negative Direction)
LX to PGND, ILIM = VL, with percentage of positive
current-limit threshold
-90 -110 -130 %
ILIM Input Current 5µA
V
L
REGULATOR
Output Voltage
5.5V < V+ < 14V
1mA < I
VL
< 35mA
4.8 5.0 5.2 V
Line Regulation 5.5V < V+ < 14V, I
VL
= 10mA 0.2 %
RMS Output Current 35 mA
Bypass Capacitor ESR < 100mΩ 2.2 µF
DRIVER
DH Gate-Driver On-Resistance V
BST
- V
LX
= 5V 1.4 2.5 Ω
DL Gate-Driver On-Resistance
(Source)
DL high state 1.6 3 Ω
DL Gate-Driver On-Resistance
(Sink)
DL low state 0.75 1.25 Ω
DL rising 32
Dead Time
DL falling 30
ns
FSEL LOGIC
Logic Input Current -3 3 µA
Logic GND Level 0.5 V
Logic REF Level FSEL = VREF 1.65 2.35 V
Logic Float Level FSEL floating 3.15 3.85 V
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18

MAX1917EEE+

Mfr. #:
Buy MAX1917EEE+
Manufacturer:
Maxim Integrated
Description:
Switching Controllers Track/Sink/Source Synchronous Buck
Lifecycle:
New from this manufacturer.
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