MAX5041AEAI ,Dual-Phase / Parallelable / Average-Current-Mode ControllersFeaturesThe MAX5038A/MAX5041A dual-phase, PWM controllers +4.75V to +5.5V or +8V to +28V Input Vol ..
MAX5041BEAI ,Dual-Phase, Parallelable, Average Current-Mode ControllersFeaturesThe MAX5038/MAX5041 dual-phase, PWM controllers♦ +4.75V to +5.5V or +8V to +28V Input Volta ..
MAX5041EAI ,Dual-Phase / Parallelable / Average Current-Mode ControllersFeaturesThe MAX5038/MAX5041 dual-phase, PWM controllers +4.75V to +5.5V or +8V to +28V Input Volta ..
MAX5041EAI ,Dual-Phase / Parallelable / Average Current-Mode ControllersELECTRICAL CHARACTERISTICS(V = +5V, circuit of Figure 1, T = -40°C to +85°C, unless otherwise noted ..
MAX5041EAI ,Dual-Phase / Parallelable / Average Current-Mode ControllersApplicationsServers and WorkstationsOrdering InformationPoint-Of-Load High-Current/High-DensityTele ..
MAX5041EAI+ ,Dual-Phase, Parallelable, Average Current-Mode ControllersApplications ♦ 28-Pin SSOP PackageServers and WorkstationsOrdering InformationPoint-Of-Load High-Cu ..
MAX9234EUM+TD ,Hot-Swappable, 21-Bit, DC-Balanced LVDS DeserializersApplicationsOrdering InformationAutomotive Navigation SystemsAutomotive DVD Entertainment SystemsPI ..
MAX923CPA ,Ultra Low-Power, Single/Dual-Supply ComparatorsMAX921–MAX92419-0115; Rev 3; 3/95Ultra Low-Power, Single/Dual-Supply Comparators_______________
MAX923CPA ,Ultra Low-Power, Single/Dual-Supply ComparatorsELECTRICAL CHARACTERISTICS: 5V OPERATION (continued)(V+ = 5V, V- = GND = 0V, T = T to T , unless ot ..
MAX923CSA ,Ultra Low-Power, Single/Dual-Supply ComparatorsMAX921–MAX92419-0115; Rev 3; 3/95Ultra Low-Power, Single/Dual-Supply Comparators_______________
MAX923CSA ,Ultra Low-Power, Single/Dual-Supply ComparatorsFeaturesThe MAX921–MAX924 single, dual, and quad micro-' µMAX Package—Smallest 8-Pin SOpower, low-v ..
MAX923CSA+ ,Ultra Low-Power, Single/Dual-Supply ComparatorsApplications5 HYSTBattery-Powered SystemsThreshold DetectorsMAX9216 REFWindow ComparatorsGNDV-Oscil ..
MAX5041AEAI
Dual-Phase / Parallelable / Average-Current-Mode Controllers
General DescriptionThe MAX5038A/MAX5041A dual-phase, PWM controllers
provide high-output-current capability in a compact
package with a minimum number of external compo-
nents. The MAX5038A/MAX5041A utilize a dual-phase,
average-current-mode control that enables optimal use
of low RDS(ON)MOSFETs, eliminating the need for exter-
nal heatsinks even when delivering high output currents.
Differential sensing enables accurate control of the out-
put voltage, while adaptive voltage positioning provides
optimum transient response. An internal regulator
enables operation with input voltage ranges of +4.75V to
+5.5V or +8V to +28V. The high switching frequency, up
to 500kHz per phase, and dual-phase operation allow
the use of low-output inductor values and input capacitor
values. This accommodates the use of PC board-
embedded planar magnetics achieving superior reliabili-
ty, current sharing, thermal management, compact size,
and low system cost.
The MAX5038A/MAX5041A also feature a clock input
(CLKIN) for synchronization to an external clock, and a
clock output (CLKOUT) with programmable phase delay
(relative to CLKIN) for paralleling multiple phases. The
MAX5038A/MAX5041A also limit the reverse current in
case the bus voltage becomes higher than the regulat-
ed output voltage. The MAX5038A offers a variety of fac-
tory-trimmed preset output voltages (see Selector Guide)
and the MAX5041A offers an adjustable output voltage
between +1.0V to +3.3V.
The MAX5038A/MAX5041A operate over the extended
temperature range (-40°C to +85°C) and are available
in a 28-pin SSOP package. Refer to the MAX5037A and
MAX5065/MAX5067 data sheets for a VRM 9.0/VRM 9.1-
compatible, VID-controlled, adjustable output voltage
controller in a 44-pin MQFP/thin QFN or 28-pin SSOP
package.
ApplicationsServers and Workstations
Point-of-Load High-Current/High-Density
Telecom DC-DC Regulators
Networking Systems
Large-Memory Arrays
RAID Systems
High-End Desktop Computers
Features+4.75V to +5.5V or +8V to +28V Input Voltage
RangeUp to 60A Output CurrentInternal Voltage Regulator for a +12V or +24V
Power BusTrue Differential Remote Output SensingTwo Out-Of-Phase Controllers Reduce Input
Capacitance Requirement and Distribute Power
DissipationAverage-Current-Mode Control
Superior Current Sharing Between Individual
Phases and Paralleled Modules
Accurate Current Limit Eliminates MOSFET and
Inductor DeratingLimits Reverse-Current Sinking in Paralleled
ModulesIntegrated 4A Gate DriversSelectable Fixed Frequency 250kHz or 500kHz per
Phase (Up to 1MHz for Two Phases)Fixed (MAX5038A) or Adjustable (MAX5041A)
Output VoltagesExternal Frequency Synchronization from 125kHz
to 600kHzInternal PLL with Clock Output for Paralleling
Multiple DC-DC ConvertersThermal Protection28-Pin SSOP Package
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers 19-3034; Rev 0; 10/03
Ordering Information
Pin Configuration appears at end of data sheet.
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICSStresses 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.
IN to SGND.............................................................-0.3V to +30V
BST_ to SGND........................................................-0.3V to +35V
DH_ to LX_................................-0.3V to [(VBST_ - VLX_) + 0.3V]
DL_ to PGND..............................................-0.3V to (VCC+ 0.3V)
BST_ to LX_..............................................................-0.3V to +6V
VCCto SGND............................................................-0.3V to +6V
VCCto PGND............................................................-0.3V to +6V
SGND to PGND.....................................................-0.3V to +0.3V
All Other Pins to SGND...............................-0.3V to (VCC+ 0.3V)
Continuous Power Dissipation (TA= +70°C)
28-Pin SSOP (derate 9.5mW/°C above +70°C)..........762mW
Operating Temperature Range...........................-40°C to +85°C
Maximum Junction Temperature.....................................+150°C
Storage Temperature Range.............................-60°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
ELECTRICAL CHARACTERISTICS (continued)(VCC= +5V, circuit of Figure 1, TA= -40°C to +85°C, unless otherwise noted. Typical specifications are at TA= +25°C.) (Note 1)
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
ELECTRICAL CHARACTERISTICS (continued)(VCC= +5V, circuit of Figure 1, TA= -40°C to +85°C, unless otherwise noted. Typical specifications are at TA= +25°C.) (Note 1)
Note 1:Specifications from -40°C to 0°C are guaranteed by characterization but not production tested.
Note 2:Guaranteed by design. Not production tested.
Note 3:See Peak-Current Comparator section.
Note 4:Does not include an error due to finite error amplifier gain (see the Voltage-Error Amplifiersection).
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
EFFICIENCY vs. OUTPUT CURRENT AND
INTERNAL OSCILLATOR FREQUENCYMAX5038A/41A toc01
IOUT (A)
(%)44403632282420161284
EFFICIENCY vs. OUTPUT CURRENT
AND INPUT VOLTAGE
MAX5038A/41A toc02
IOUT (A)
(%)44403632282420161284
EFFICIENCY vs. OUTPUT CURRENT
MAX5038A/41A toc03
IOUT (A)
(%)44403632282420161284
EFFICIENCY vs. OUTPUT CURRENT
AND OUTPUT VOLTAGE
MAX5038A/41A toc04
IOUT (A)
(%)44403632282420161284
EFFICIENCY vs. OUTPUT CURRENT
AND OUTPUT VOLTAGE
MAX5038A/41A toc05
IOUT (A)
(%)44403632282420161284
SUPPLY CURRENT
vs. FREQUENCY AND INPUT VOLTAGE
MAX5038A/41A toc06
FREQUENCY (kHz)
ICC
(mA)
SUPPLY CURRENT
vs. TEMPERATURE AND FREQUENCY
MAX5038A/41A toc07
TEMPERATURE (°C)
(mA)3510-15
SUPPLY CURRENT
vs. TEMPERATURE AND FREQUENCY
MAX5038A/41A toc08
TEMPERATURE (°C)
ICC
(mA)3510-15
SUPPLY CURRENT
vs. LOAD CAPACITANCE PER DRIVER
MAX5038A/41A toc09
CDRIVER (nF)
ICC
(mA)117953
Typical Operating Characteristics
(Circuit of Figure 1. TA= +25°C, unless otherwise noted.)
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
Typical Operating Characteristics (continued)(Circuit of Figure 1, TA= +25°C, unless otherwise noted.)
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers 100ns/div
HIGH-SIDE DRIVER (DH_)
SINK AND SOURCE CURRENTDH_
1.6A/div
MAX5038A/41A toc19
100ns/div
LOW-SIDE DRIVER (DL_)
SINK AND SOURCE CURRENTDL_
1.6A/div
MAX5038A/41A toc20
100µs/div
PLL LOCKING TIME
250kHz TO 350kHz AND
350kHz TO 250kHzCLKOUT
5V/div
MAX5038A/41A toc21
PLLCMP
200mV/div
100µs/div
PLL LOCKING TIME
250kHz TO 500kHz AND
500kHz TO 250kHzCLKOUT
5V/div
MAX5038A/41A toc22
PLLCMP
200mV/div
100µs/div
PLL LOCKING TIME
250kHz TO 150kHz AND
150kHz TO 250kHzCLKOUT
5V/div
MAX5038A/41A toc23
PLLCMP
200mV/div
40ns/div
HIGH-SIDE DRIVER (DH_)
RISE TIMEMAX5038A/41A toc24
DH_
2V/div
40ns/div
HIGH-SIDE DRIVER (DH_)
FALL TIMEMAX5038A/41A toc25
DH_
2V/div
40ns/div
LOW-SIDE DRIVER (DL_)
RISE TIMEMAX5038A/41A toc26
DL_
2V/div
40ns/div
LOW-SIDE DRIVER (DL_)
FALL TIMEMAX5038A/41A toc27
DL_
2V/div
Typical Operating Characteristics (continued)(Circuit of Figure 1, TA= +25°C, unless otherwise noted.)
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
Typical Operating Characteristics (continued)(Circuit of Figure 1, TA= +25°C, unless otherwise noted.)
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
Functional Diagram
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
Detailed DescriptionThe MAX5038A/MAX5041A (Figures 1 and 2) average-
current-mode PWM controllers drive two out-of-phase
buck converter channels. Average-current-mode con-
trol improves current sharing between the channels
while minimizing component derating and size. Parallel
multiple MAX5038A/MAX5041A regulators to increase
the output current capacity. For maximum ripple rejec-
tion at the input, set the phase shift between phases to
90°for two paralleled converters, or 60°for three paral-
leled converters. The paralleling capability of the
MAX5038A/MAX5041A improves design flexibility in
applications requiring upgrades (higher load).
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers Dual-phase converters with an out-of-phase locking
arrangement reduce the input and output capacitor
ripple current, effectively multiplying the switching fre-
quency by the number of phases. Each phase of the
MAX5038A/MAX5041A consists of an inner average
current loop controlled by a common outer-loop volt-
age-error amplifier (VEA). The combined action of the
two inner current loops and the outer voltage loop cor-
rects the output voltage errors and forces the phase
currents to be equal.
MAX5038A/MAX5041A
Dual-Phase, Parallelable, Average-Current-Mode
Controllers
VINand VCCThe MAX5038A/MAX5041A accept an input voltage
range of +4.75V to +5.5V or +8V to +28V. All internal
control circuitry operates from an internally regulated
nominal voltage of +5V (VCC). For input voltages of +8V
or greater, the internal VCCregulator steps the voltage
down to +5V. The VCCoutput voltage is a regulated +5V
output capable of sourcing up to 80mA. Bypass VCCto
SGND with 4.7µF and 0.1µF low-ESR ceramic capacitors
in parallel for high-frequency noise rejection and stable
operation (Figures 1 and 2).
Calculate power dissipation in the MAX5038A/
MAX5041A as a product of the input voltage and the
total VCCregulator output current (ICC). ICCincludes
quiescent current (IQ) and gate drive current (IDD):
PD = VIN x ICC
ICC= IQ+ fSWx (QG1+ QG2 + QG3+ QG4)
where QG1, QG2, QG3,and QG4are the total gate
charge of the low-side and high-side external
MOSFETs, IQis 4mA (typ), and fSWis the switching fre-
quency of each individual phase.
For applications utilizing a +5V input voltage, disable
the VCCregulator by connecting IN and VCCtogether.
Undervoltage Lockout (UVLO)/Soft-StartThe MAX5038A/MAX5041A include an undervoltage
lockout with hysteresis and a power-on reset circuit for
converter turn-on and monotonic rise of the output volt-
age. The UVLO threshold is internally set between
+4.0V and +4.5V with a 200mV hysteresis. Hysteresis
at UVLO eliminates “chattering” during startup.
Most of the internal circuitry, including the oscillator,
turns on when the input voltage reaches +4V. The
MAX5038A/MAX5041A draw up to 4mA of current before
the input voltage reaches the UVLO threshold.
The compensation network at the current-error ampli-
fiers (CLP1 and CLP2) provides an inherent soft-start of
the output voltage. It includes a parallel combination of
capacitors (C28, C30) and resistors (R5, R6) in series
with other capacitors (C27, C29) (see Figures 1 and 2).
The voltage at CLP_ limits the maximum current avail-
able to charge output capacitors. The capacitor on
CLP_ in conjunction with the finite output-drive current
of the current-error amplifier yields a finite rise time for
the output current and thus the output voltage.
Internal OscillatorThe internal oscillator generates the 180°out-of-phase
clock signals required by the pulse-width modulation
(PWM) circuits. The oscillator also generates the 2VP-P
voltage ramp signals necessary for the PWM compara-
tors. Connect CLKIN to SGND to set the internal oscillator
frequency to 250kHz or connect CLKIN to VCCto set the
internal oscillator to 500kHz.
CLKIN is a CMOS logic clock input for the phase-
locked loop (PLL). When driven externally, the internal
oscillator locks to the signal at CLKIN. A rising edge at
CLKIN starts the ON cycle of the PWM. Ensure that the
external clock pulse width is at least 200ns. CLKOUT
provides a phase-shifted output with respect to the ris-
ing edge of the signal at CLKIN. PHASE sets the
amount of phase shift at CLKOUT. Connect PHASE to
VCCfor 120°of phase shift, leave PHASE unconnected
for 90°of phase shift, or connect PHASE to SGND for
60°of phase shift with respect to CLKIN.
The MAX5038A/MAX5041A require compensation on
PLLCMP even when operating from the internal oscillator.
The device requires an active PLL in order to generate
the proper clock signal required for PWM operation.
Control LoopThe MAX5038A/MAX5041A use an average-current-
mode control scheme to regulate the output voltage
(Figures 3a and 3b). The main control loop consists of
an inner current loop and an outer voltage loop. The
inner loop controls the output currents (IPHASE1and
IPHASE2) while the outer loop controls the output volt-
age. The inner current loop absorbs the inductor pole
reducing the order of the outer voltage loop to that of a
single-pole system.
The current loop consists of a current-sense resistor
(RS), a current-sense amplifier (CA_), a current-error
amplifier (CEA_), an oscillator providing the carrier
ramp, and a PWM comparator (CPWM_). The precision
CA_ amplifies the sense voltage across RSby a factor
of 18. The inverting input to the CEA_ senses the CA_
output. The CEA_ output is the difference between the
voltage-error amplifier output (EAOUT) and the ampli-
fied voltage from the CA_. The RC compensation net-
work connected to CLP1 and CLP2 provides external
frequency compensation for the respective CEA_. The
start of every clock cycle enables the high-side drivers
and initiates a PWM ON cycle. Comparator CPWM_
compares the output voltage from the CEA_ with a 0 to
+2V ramp from the oscillator. The PWM ON cycle termi-
nates when the ramp voltage exceeds the error voltage.
(1)
(2)
