19-2498; Rev 1; 10/02
Two-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
General Description
The MAX1937/MAX1938/MAX1939 comprise a family of
synchronous, two-phase, step-down controllers capable
of delivering load currents up to 60A. The controllers uti-
lize Quick-PWM™ control architecture in conjunction with
active load-current voltage positioning. Quick-PWM con-
trol provides instantaneous load-step response, while
programmable voltage positioning allows the converter
to utilize full transient regulation limits, reducing the out-
put capacitance requirement. The two phases operate
180° out-of-phase with an effective 500kHz switching fre-
quency, thus reducing input and output current ripple, as
well as reducing input filter capacitor requirements.
The MAX1937/MAX1938/MAX1939 are compliant with
AMD Hammer, Intel
‚ Voltage-Regulator Module (VRM)
9.0/9.1, and AMD Athlon™ Mobile VID code specifica-
tions (see Table 1 for VID codes). The internal DAC pro-
vides ultra-high accuracy of ±0.75%. A controlled VID
voltage transition is implemented to minimize both
undervoltage and overvoltage overshoot during VID
input change.
Remote sensing is available for high output-voltage
accuracy. The MOSFET switches are driven by a 6V
gate-drive circuit to minimize switching and crossover
conduction losses to achieve efficiency as high as
90%. The MAX1937/MAX1938/MAX1939 feature cycle-
by-cycle current limit to ensure that the current limit is
not exceeded. Crowbar protection is available to pro-
tect against output overvoltage.
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Features
±0.75% Output Voltage Accuracy
Instant Load-Transient Response
Up to 90% Efficiency Eliminates Heatsinks
Up to 60A Output Current
8V to 24V Input Range
User-Programmable Voltage Positioning
Controlled VID Voltage Transition
500kHz Effective Switching Frequency
MAX1937: AMD Hammer Compatible
MAX1938: Intel VRM 9.0/9.1 Compatible
MAX1939: AMD Athlon Mobile Compatible
Soft-Start
Power-Good (PWRGD) Output
Cycle-by-Cycle Current Limit
Output Overvoltage Protection (OVP)
R
DS(ON)
or R
SENSE
Current Sensing
Remote Voltage Sensing
28-Pin QSOP Package
MAX1937/MAX1938/MAX1939
Ordering Information
PART
MAX1937EEI
MAX1938EEI
MAX1939EEI
TEMP RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
28 QSOP
28 QSOP
28 QSOP
Applications
Notebook and Desktop Computers
Servers and Workstations
Blade Servers
High-End Switches
High-End Routers
Macro Base Stations
TOP VIEW
VID0 1
VID1 2
TIME 3
VID2 4
VID3 5
VID4 6
VPOS 7
V
DD
8
ILIM 9
28 V
CC
27 BST1
26 DH1
25 LX1
24 CS1
Pin Configuration
MAX1937
MAX1938
MAX1939
23 DL1
22 VLG
21 PGND
20 DL2
19 CS2
18 LX2
17 DH2
16 BST2
15 PWRGD
Typical Application Circuits and Functional Diagram appear
at end of data sheet.
GND 10
GNDS 11
REF 12
Quick-PWM is a trademark of Maxim Integrated Products, Inc.
Athlon is a trademark of Advanced Micro Devices, Inc.
Intel is a registered trademark of Intel Corp.
EN 13
FB 14
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 ]
