MAX1937EEI ,Two-Phase Desktop CPU Core Supply Controllers with Controlled VID ChangeFeaturesThe MAX1937/MAX1938/MAX1939 comprise a family of ±0.75% Output Voltage Accuracysynchronou ..
MAX1937EEI ,Two-Phase Desktop CPU Core Supply Controllers with Controlled VID ChangeELECTRICAL CHARACTERISTICS(V = 12V, V = V = 5V, PGND = GNDS = GND = 0, VID_ = GND, C = 47pF, C = 0. ..
MAX1937EEI+ ,Two-Phase Desktop CPU Core Supply Controllers with Controlled VID ChangeFeaturesThe MAX1937/MAX1938/MAX1939 comprise a family of ♦ ±0.75% Output Voltage Accuracysynchronou ..
MAX1937EEI+T ,Two-Phase Desktop CPU Core Supply Controllers with Controlled VID ChangeApplicationsNotebook and Desktop ComputersPin ConfigurationServers and WorkstationsBlade ServersTOP ..
MAX1938EEI-T ,Two-Phase Desktop CPU Core Supply Controllers with Controlled VID ChangeELECTRICAL CHARACTERISTICS(V = 12V, V = V = 5V, PGND = GNDS = GND = 0, VID_ = GND, C = 47pF, C = 0. ..
MAX1939 ,Two-Phase Desktop CPU Core Supply Controllers with Controlled VID ChangeFeaturesThe MAX1937/MAX1938/MAX1939 comprise a family of ♦ ±0.75% Output Voltage Accuracysynchronou ..
MAX489ESD ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversApplications ______________Ordering InformationLow-Power RS-485 TransceiversPART TEMP. RANGE PIN-PA ..
MAX489ESD+ ,±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 TransceiversELECTRICAL CHARACTERISTICS(V = 5V ±5%, T = T to T , unless otherwise noted.) (Notes 1, 2)CC A MIN M ..
MAX489ESD+T ,±15kV ESD-Protected, Slew-Rate-Limited, Low-Power, RS-485/RS-422 TransceiversApplications:MAX491E, and MAX1487E are low-power transceivers forMAX3430: ±80V Fault-Protected, Fai ..
MAX489MJD ,Low-Power / Slew-Rate-Limited RS-485/RS-422 TransceiversApplicationsMAX481C/D 0°C to +70°C Dice*Industrial-Control Local Area NetworksOrdering Information ..
MAX490 ,Low-Power, Slew-Rate-Limited RS-485/RS-422 TransceiversMAX481/MAX483/MAX485/MAX487–MAX491/MAX1487Low-Power, Slew-Rate-LimitedRS-485/RS-422 Transceivers
MAX4901EBL+T ,Low-RON, Dual-SPST/Single-SPDT Clickless Switches with Negative Rail CapabilityApplicationsBBCell Phones Notebook ComputersCOM N.C. (CMPO) GNDV N.C. GNDCCPDAs and Handheld Device ..
MAX1937EEI-MAX1939EEI
Two-Phase Desktop CPU Core Supply Controllers with Controlled VID Change
General DescriptionThe 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
AMDHammer, 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.
ApplicationsNotebook and Desktop Computers
Servers and Workstations
Blade Servers
High-End Switches
High-End Routers
Macro Base Stations
Features±0.75% Output Voltage AccuracyInstant Load-Transient ResponseUp to 90% Efficiency Eliminates HeatsinksUp to 60A Output Current8V to 24V Input RangeUser-Programmable Voltage PositioningControlled VID Voltage Transition500kHz Effective Switching FrequencyMAX1937: AMD Hammer CompatibleMAX1938: Intel VRM 9.0/9.1 CompatibleMAX1939: AMD Athlon Mobile CompatibleSoft-StartPower-Good (PWRGD) OutputCycle-by-Cycle Current LimitOutput Overvoltage Protection (OVP)RDS(ON)or RSENSECurrent SensingRemote Voltage Sensing28-Pin QSOP Package
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
Pin Configuration
Ordering Information19-2498; Rev 1; 10/02
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.
Typical Application Circuits and Functional Diagram appear
at end of data sheet.
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
ABSOLUTE MAXIMUM RATINGSStresses 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.
VCCto GND............................................................-0.3V to +28V
VDD, PWRGD, ILIM, FB to GND...............................-0.3V to +6V
EN, GNDS, VPOS, REF, VID_,
TIME to GND............................................0.3V to VVDD + 0.3V
PGND to GND.......................................................-0.3V to +0.3V
CS1, CS2 to GND......................................................-2V to +28V
VLG to GND..............................................................-0.3V to +7V
BST1, BST2 to GND...............................................-0.3V to +35V
LX1 to BST1..............................................................-7V to +0.3V
LX2 to BST2..............................................................-7V to +0.3V
DH1 to LX1.................................................-0.3V to VBST1 + 0.3V
DH2 to LX2.................................................-0.3V to VBST2 + 0.3V
DL1, DL2 to PGND......................................-0.3V to VVLG + 0.3V
Continuous Power Dissipation (TA= +70°C)
28-Pin QSOP (derate 20.8mW/°C above +70°C)......860.2mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
ELECTRICAL CHARACTERISTICS(VCC= 12V, VEN= VVDD= 5V, PGND = GNDS = GND = 0, VID_ = GND, CVPOS= 47pF, CREF= 0.1µF, VILIM= 1V, TA
= 0°C to
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
ELECTRICAL CHARACTERISTICS (continued)
(VCC= 12V, VEN= VVDD= 5V, PGND = GNDS = GND = 0, VID_ = GND, CVPOS= 47pF, CREF= 0.1µF, VILIM= 1V, TA
= 0°C to
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
ELECTRICAL CHARACTERISTICS (continued)
(VCC= 12V, VEN= VVDD= 5V, PGND = GNDS = GND = 0, VID_ = GND, CVPOS= 47pF, CREF= 0.1µF, VILIM= 1V, TA
= 0°C to
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
ELECTRICAL CHARACTERISTICS
(VVCC= 12V, VEN= VVDD= 5V, PGND = GNDS = GND, VID_= GND, CVPOS = 47pF, CREF= 0.1µF, VILIM= 1V, TA= -40°C to +85°C,
unless otherwise noted.) (Note 1)
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
ELECTRICAL CHARACTERISTICS (continued)
(VVCC= 12V, VEN= VVDD= 5V, PGND = GNDS = GND, VID_= GND, CVPOS = 47pF, CREF= 0.1µF, VILIM= 1V, TA= -40°C to +85°C,
unless otherwise noted.) (Note 1)
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
EFFICIENCY vs. LOAD CURRENT
AT 1.45V OUTPUT
MAX1937 toc01
LOAD CURRENT (A)
EFFICIENCY (%)10010100
EFFICIENCY vs. LOAD CURRENT
AT 1.85V OUTPUT
MAX1937 toc02
LOAD CURRENT (A)
EFFICIENCY (%)
FREQUENCY vs. LOAD CURRENT
MAX1937 toc03
LOAD CURRENT (A)
FREQUENCY (kHz)40302010
FREQUENCY vs. INPUT VOLTAGEMAX1937 toc04
INPUT VOLTAGE (V)
FREQUENCY (kHz)1211109
FREQUENCY vs. TEMPERATURE
MAX1937 toc05
TEMPERATURE (°C)
FREQUENCY (kHz)60-2002040
VCC INPUT CURRENT
vs. INPUT VOLTAGE
MAX1937 toc06
INPUT VOLTAGE (V)
INPUT CURRENT (1211109
VDD CURRENT vs. VDD VOLTAGE
MAX1937 toc07
VDD VOLTAGE (V)
CURRENT (mA)
Typical Operating Characteristics
(VIN= 12V, VOUT= 1.45V, TA= +25°C, unless otherwise noted.)
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
Typical Operating Characteristics (continued)(VIN= 12V, VOUT= 1.45V, TA= +25°C, unless otherwise noted.)
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
CURRENT-SENSE THRESHOLD vs. VILIMMAX1937 toc19
VILIM (V)
CURRENT-SENSE THRESHOLD (mV)
0.51.5
ypical Operating Characteristics (continued)(VIN= 12V, VOUT= 1.45V, TA= +25°C, unless otherwise noted.)
ENABLE SIGNAL
OUTPUT VOLTAGE:
0.5V/div
POK SIGNAL
1ms/div
MAX1937 toc16
SOFT-START WAVEFORMS
WITH 40A LOADINDUCTOR CURRENT:
10A/div
ENABLE SIGNAL
OUTPUT VOLTAGE:
0.5V/div
POK SIGNAL
20ms/div
MAX1937 toc17
SHUTDOWN WAVEFORM
WITH NO LOADINDUCTOR CURRENT:
10A/div
40µs/div
MAX1937 toc14
LOAD TRANSIENT
1A TO 40A TO 1ATRANSIENT CONTROL
SIGNAL:
C6 = 47pF
R2 = 91.1kΩ
INDUCTOR CURRENTS:
10A/div
OUTPUT VOLTAGE:
50mV/div
ENABLE SIGNAL
OUTPUT VOLTAGE:
0.5V/div
POK SIGNAL
1ms/div
MAX1937 toc15
SOFT-START WAVEFORMS
WITH NO LOADINDUCTOR CURRENT:
10A/div
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
REFERENCE VOLTAGE vs. TEMPERATUREMAX1937 toc22
TEMPERATURE (°C)
REFERENCE VOLTAGE (V)6040200-20
FB VOLTAGE vs. TEMPERATURE
MAX1937 toc23
TEMPERATURE (°C)
FB VOLTAGE (V)3510-15
FB VOLTAGE vs. TEMPERATURE
MAX1937 toc24
TEMPERATURE (°C)
FB VOLTAGE (V)6040200-20
OUTPUT VOLTAGE:
200mV/div
POK SIGNAL
40µs/div
MAX1937 toc20
VID CODE CHANGE ON-THE-FLY WITH 40A
LOAD 1.2V TO 1.45V TO 1.2VVID CODE CHANGE
CONTROL SIGNAL
OUTPUT VOLTAGE:
200mV/div
POK SIGNAL
40µs/div
MAX1937 toc21
VID CODE CHANGE ON-THE-FLY WITH 1A
LOAD 1.2V TO 1.45V TO 1.2VVID CONTROL
SIGNAL
ypical Operating Characteristics (continued)(VIN= 12V, VOUT= 1.45V, TA= +25°C, unless otherwise noted.)
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID Change
MAX1937/MAX1938/MAX1939wo-Phase Desktop CPU Core Supply Controllers
with Controlled VID ChangeThe MAX1937/MAX1938/MAX1939 is a family of syn-
chronous, two-phase step-down controllers capable of
delivering load currents up to 60A. The controllers use
Quick-PWM control architecture in conjunction with
active load current voltage positioning. Quick-PWM
control provides instantaneous load-step response,
while programmable voltage positioning allows the con-
verter to utilize full transient regulation limits, reducing
the output capacitance requirement. Furthermore, the
two phases operate 180°out-of-phase with an effective
500kHz switching frequency, thus reducing input and
output current ripple, as well as reducing input filter
capacitor requirements.
The MAX1937/MAX1938/MAX1939 are compliant with
the AMD Hammer, Intel VRM 9.0/VRM 9.1, and AMD
Athlon Mobile VID code specifications (see Table 1 for
VID codes). The internal DAC provides ultra-high accu-
racy of ±0.75%. A controlled VID voltage transition is
implemented to minimize both undervoltage and over-
voltage overshoot during VID input change.
Remote sensing is available for high output-voltage
accuracy. The MOSFET switches are driven by with a
6V gate-drive circuit to minimize switching and
crossover conduction losses to achieve efficiency as
high as 90%. The MAX1937/MAX1938/ MAX1939 fea-
ture cycle-by-cycle current limit to ensure current limit
is not exceeded. Crowbar protection is available to pro-
tect against output overvoltage.
The heart of the Quick-PWM core is the one-shot that
sets the high-side switch on-time. This fast, low-jitter,
one-shot circuitry varies the on-time in response to the
input and output voltages. The high-side switch on-time
is inversely proportional to the voltage applied to VCC
and directly proportional to the output voltage. This
algorithm results in a nearly constant switching fre-
quency, despite the lack of a fixed-frequency clock
generator. The benefits of a constant switching fre-
quency are twofold: the frequency selected avoids
noise-sensitive regions, and the inductor ripple current
operating point remains relatively constant, resulting in
easy design methodology and predictable output volt-
age ripple:
where the constant K is 4µs and VDROPis the voltage
drop across the low-side MOSFET’s on-resistance plus
the drop across the current-sense resistor (VDROP≈
75mV), if used.
The on-time one-shot has good accuracy at the operat-
ing point specified in the Electrical Characteristics. On-
times at operating points far removed from the
conditions specified in the Electrical Characteristicscan
vary over a wide range. For example, the regulators run
slower with input voltages greater than 12V because of
the very short on-times required.
Pin Description (continued)
