MAX15066EWE+T ,High-Efficiency, 4A, Step-Down DC-DC Regulator with Internal Power SwitchesApplicationsCOMPPGOOD● Distributed Power SystemsSS● Preregulators for Linear RegulatorsGND● Home En ..
MAX1507ETA+ ,Linear Li+ Battery Charger with Integrated Pass FET and Thermal Regulation in 3mm x 3mm Thin DFNApplications MAX1507ETA-T -40°C to +85°C 8 Thin DFN-EP* AGWMAX1507ETA+T -40°C to +85°C 8 Thin DFN-E ..
MAX1508ETA ,Linear Li Battery Charger with Integrated Pass FET / Thermal Regulation / and ACOKin 3mm x 3mm TDFNFeaturesThe MAX1508 is an intelligent, stand-alone constant-cur- Stand-Alone Linear 1-Cell Li+ Ba ..
MAX1508ETA+ ,Linear Li+ Battery Charger with Integrated Pass FET, Thermal Regulation, and ACOK Flag in 3mm x 3mm TDFNApplications +Denotes lead-free package.Cellular and Cordless PhonesOrdering Information continued ..
MAX1508ETA+T ,Linear Li+ Battery Charger with Integrated Pass FET, Thermal Regulation, and ACOK Flag in 3mm x 3mm TDFNMAX1508/MAX1508Y/MAX1508Z19-2890; Rev 2; 8/05Linear Li+ Battery Charger with Integrated Pass FET,Th ..
MAX1508ZETA+T ,Linear Li+ Battery Charger with Integrated Pass FET, Thermal Regulation, and ACOK Flag in 3mm x 3mm TDFNELECTRICAL CHARACTERISTICS(V = 5V, V = 4.0V, ACOK = EN = CHG = unconnected (for the MAX1508 and MAX ..
MAX4145ESD ,High-Speed / Low-Distortion / Differential Line ReceiversFeaturesThe MAX4144/MAX4145/MAX4146 differential lineMAX4144:receivers offer unparalleled high-spee ..
MAX4146ESD ,High-Speed / Low-Distortion / Differential Line ReceiversELECTRICAL CHARACTERISTICS (continued)(V = +5V, V = -5V, SHDN = 0V, R = ∞, T = T to T , unless othe ..
MAX4147 ESD ,300MHz / Low-Power / High-Output-Current / Differential Line DriverELECTRICAL CHARACTERISTICS(V = +5V, V = -5V, T = T to T , unless otherwise noted. Typical values ar ..
MAX4147ESD ,300MHz / Low-Power / High-Output-Current / Differential Line DriverFeaturesThe MAX4147 differential line driver offers high-speed' 2V/V Fixed Gainperformance while co ..
MAX4147ESD ,300MHz / Low-Power / High-Output-Current / Differential Line DriverApplicationsVDSL, ADSL, HDSLV 14 VEE 1 CC13Video Twisted-Pair Driver IN+ 2 OUT+RfN.C. 12 SENSE+3Dif ..
MAX4147ESD+T ,300MHz, Low-Power, High-Output Current, Differential Line DriverApplicationsVDSL, ADSL, HDSLV 14 VEE 1 CC13Video Twisted-Pair Driver IN+ 2 OUT+RfN.C. 12 SENSE+3Dif ..
MAX15066EWE+T
High-Efficiency, 4A, Step-Down DC-DC Regulator with Internal Power Switches
General DescriptionThe MAX15066/MAX15166 current-mode, synchronous,
DC-DC buck converters deliver an output current up
to 4A with high efficiency. The devices operate from
an input voltage of 4.5V to 16V and provides an
adjustable output voltage from 0.606V to 90% of the
input voltage. The devices are ideal for distributed power
systems, notebook computers, nonportable consumer
applications, and preregulation applications.
The devices feature a PWM mode operation with
an internally fixed switching frequency of 500kHz
(MAX15066) and 350kHz (MAX15166) capable of 90%
maximum duty cycle. The devices automatically enter
skip mode at light loads. The current-mode control
architecture simplifies compensation design and ensures
a cycle-by-cycle current limit and fast response to line
and load transients. A high gain transconductance
error amplifier allows flexibility in setting the external
compensation, simplifying the design and allowing for an
all-ceramic design.
The synchronous buck regulators feature inter-
nal MOSFETs that provide better efficiency than
asynchronous solutions, while simplifying the design
relative to discrete controller solutions. In addition to
simplifying the design, the integrated MOSFETs mini-
mize EMI, reduce board space, and provide higher reli-
ability by minimizing the number of external components.
Additional features include an externally adjustable
soft-start, independent enable input and power-good
output for power sequencing, and thermal shutdown
protection. The devices offer overcurrent protection
(high-side sourcing) with hiccup mode during an output
short-circuit condition. The devices ensure safe startup
when powering into a prebiased output.
The MAX15066/MAX15166 are available in a 2mm x
2mm, 16-bump (4 x 4 array), 0.5mm pitch wafer-level
package (WLP) and are fully specified from -40NC to
+85NC.
Applications●Distributed Power Systems●Preregulators for Linear Regulators●Home Entertainment (TV and Set-Top Boxes)●Network and Datacom●Servers, Workstations, and Storage
Beneits and Features●Feature Integration Shrinks Solution SizeIntegrated 40mΩ (High-Side) and 18.5mΩ (Low-
Side) RDS-ON Power MOSFETsStable with Low-ESR Ceramic Output CapacitorsEnable Input and Power-Good OutputCycle-by-Cycle Overcurrent ProtectionFully Protected Against Overcurrent
(Hiccup Protection) and Overtemperature●High Efficiency Conserves PowerUp to 96% Eficiency (5V Input and 3.3V Output)Up to 93% Eficiency (12V Input and 3.3V Output)Automatic Skip Mode During Light Loads●Safe, Reliable, Accurate OperationContinuous 4A Output Current±1% Output Accuracy Over Load, Line, and
TemperatureSafe Startup Into Prebiased OutputProgrammable Soft-StartVDD LDO Undervoltage Lockout●Well Suited to Distributed Power, Networking, and
Computing Applications4.5V to 16V Input Voltage RangeAdjustable Output Voltage Range from 0.606V to (0.9 x VIN)●Available in EE-Sim® Design and Simulation Tool to
Slash Design Time
Typical Application Circuit
Ordering Information appears at end of data sheet.EE-Sim is a registered trademark of Maxim Integrated
COMP
BST
GND
VDD
PGOOD
MAX15066
MAX15166
INPUT
4.5V TO 16V
1.8V/4A
OUTPUT
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
EVALUATION KIT AVAILABLE
Absolute Maximum RatingsNote 1: LX has internal clamp diodes to GND and IN. Applications that forward bias these diodes should take care not to exceed
the device’s package power dissipation.
Note 2: Package thermal resistances were obtained based on the MAX15066/MAX15166 evaluation kit.
Note 3: Continuous operation at full current beyond +105NC can degrade product life.
IN to GND ..............................................................-0.3V to +18V
EN to GND ..................................................-0.3V to (VIN + 0.3V)
LX to GND .............-0.3V to the lower of +18V and (VIN + 0.3V)
LX to GND (for 50ns) ....-1V to the lower of +18V and (VIN + 0.3V)
PGOOD to GND ......................................................-0.3V to +6V
VDD to GND .............-0.3V to the lower of +6V and (VIN + 0.3V)
COMP, FB, SS to
GND ........................-0.3V to the lower of +6V and (VDD + 0.3V)
BST to LX ...............................................................-0.3V to +6V
BST to GND ..........................................................-0.3V to +24V
BST to VDD ...........................................................-0.3V to +18V
LX RMS Current (Note 1) ...............................................0 to 9A
Converter Output and VDD
Short-Circuit Duration .......................................... Continuous
Continuous Power Dissipation (TA = +70NC)
16-Bump WLP (derate 20.4mW/NC above +70NC)
Multilayer Board .......................................................1500mW
Thermal Resistance (θJA) (Note 2) ..............................23.6NC/W
Operating Temperature Range .........................-40NC to +85NC
Junction Temperature (Note 3) ......................................+150NC
Continuous Operating Temperature
at Full Current (Note 3) ................................................+105NC
Storage Temperature Range ..........................-65NC to +150NC
Soldering Temperature (reflow) .................................... +260NC
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.
Electrical Characteristics(VIN = 12V, CVDD = 1FF, CIN = 22FF, TA = TJ = -40NC to +85NC, typical values are at TA = TJ = +25NC, unless otherwise noted.)
(Note 4)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
STEP-DOWN CONVERTER
Input Voltage RangeVIN4.516V
Quiescent CurrentIINNot switching1.12mA
Shutdown Input Supply CurrentVEN = 0V26FA
ENABLE INPUT
EN Shutdown Threshold VoltageVEN_SHDNVEN rising0.7V
EN Shutdown Voltage
HysteresisVEN_HYST70mV
EN Lockout Threshold VoltageVEN_LOCKVEN rising1.71.92.1V
EN Lockout Threshold
Hysteresis
VEN_LOCK_
HYST200mV
EN Input CurrentIENVEN = 12V0.82.65FA
POWER-GOOD OUTPUT
PGOOD ThresholdVPGOOD_THVFB rising0.540.560.585V
PGOOD Threshold HysteresisVPGOOD_
HYST15mV
PGOOD Output Low VoltageVPGOOD_IPGOOD = 5mA, VFB = 0.5V35100mV
PGOOD Leakage CurrentIPGOODVPGOOD = 5V, VFB = 0.7V100nA
ERROR AMPLIFIER
Error-Amplifier gMV1.6mS
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
Electrical Characteristics (continued)(VIN = 12V, CVDD = 1FF, CIN = 22FF, TA = TJ = -40NC to +85NC, typical values are at TA = TJ = +25NC, unless otherwise noted.)
(Note 4)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
Error-Amplifier Voltage GainAVEA90dB
FB Set-Point AccuracyVFB600606612mV
FB Input Bias CurrentIFBVFB = 0.5V or 0.7V-100+100nA
SOFT-START
SS CurrentISSVSS = 0.45V, sourcing4.555.5FA
SS Discharge ResistanceRSSISS = 10mA, sinking6I
CURRENT SENSE
Current Sense to COMP
Transconductance gMC9S
COMP Clamp LowVFB = 0.7V0.68V
PWM CLOCK
Switching FrequencyfSWMAX15066450500550kHzMAX15166315350385
Maximum Duty CycleDMAX90%
Minimum Controllable On-Time150ns
Slope Compensation Ramp
Valley840mV
Slope Compensation Ramp
AmplitudeVSLOPEExtrapolated to 100% duty cycle667mV
INTERNAL LDO OUTPUT (VDD)
VDD Output VoltageVDD IVDD = 1mA, VIN = 6.5V to 16V4.755.15.45VIVDD = 1mA to 25mA, VIN = 6.5V4.755.15.45
VDD Short-Circuit CurrentVIN = 6.5V3090mA
VDD LDO Dropout VoltageIVDD = 5mA, VDD drops by 2%100mV
VDD Undervoltage Lockout
ThresholdVUVLO_THVDD rising, LX starts switching3.73.94.1V
VDD Undervoltage Lockout
Hysteresis
VUVLO_
HYST150mV
POWER SWITCH
LX On-ResistanceHigh-side switch, ILX = 0.4A40mILow-side switch, ILX = 0.4A18.5
High-Side Switch Source
Current-Limit ThresholdIHSCL5.57.7A
Low-Side Switch Zero-Crossing
Current-Limit Threshold0.21A
High-Side Switch Skip Sourcing
Current-Limit Threshold0.58A
LX Leakage CurrentVBST = 21V, VIN = VLX = 16V0.01FAVBST = 5V, VIN = 16V, VLX = 0V0.01
BST Leakage CurrentVBST = 21V, VIN = VLX = 16V0.01FA
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
Typical Operating Characteristics(VIN = 12V, VOUT = 1.8V, CVDD = 1FF, CIN = 22FF, COUT = 47FF, TA = +25NC (Figure 1, MAX15066), unless otherwise noted.)
Note 4: Specifications are 100% production tested at TA = +25NC. Limits over the operating temperature range are guaranteed by
design and characterization.
Electrical Characteristics (continued)(VIN = 12V, CVDD = 1FF, CIN = 22FF, TA = TJ = -40NC to +85NC, typical values are at TA = TJ = +25NC, unless otherwise noted.)
(Note 4)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
HICCUP PROTECTION
Blanking Time
21 x
Soft-Start
Time
THERMAL SHUTDOWN
Thermal Shutdown ThresholdRising160NC
Thermal Shutdown Hysteresis20NC
EFFICIENCY vs. LOAD CURRENT
(MAX15066)
MAX15066 toc01
ILOAD (A)
EFFICIENCY (%)
VOUT = 1.2V
VOUT = 1.8V
VOUT = 5.0VVOUT = 3.3V
VOUT = 2.5V
MAX15066 toc02
EFFICIENCY vs. LOAD CURRENT
(MAX15066)
EFFICIENCY (%)
ILOAD (A)
VOUT = 3.3V
VOUT = 2.5V
VOUT = 1.8V
VOUT = 5.0V
VOUT = 1.2V
MAX15066 toc03
EFFICIENCY vs. LOAD CURRENT
(MAX15066)
EFFICIENCY (%)
ILOAD (A)
VOUT = 1.2V
VOUT = 1.8V
VOUT = 2.5V
VIN = 5V
VOUT = 3.3V
EFFICIENCY vs. LOAD CURRENT
(MAX15066)
MAX15066 toc04
EFFICIENCY (%)
VOUT = 3.3V
VOUT = 2.5V
VOUT = 1.8V
VOUT = 1.2V
VIN = 5V
MAX15066 toc05
VOUT
100mV/div
AC-COUPLED
ILOAD
1A/div
100µs/div
LOAD-TRANSIENT RESPONSE
(MAX15066)
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
Typical Operating Characteristics (continued)(VIN = 12V, VOUT = 1.8V, CVDD = 1FF, CIN = 22FF, COUT = 47FF, TA = +25NC (Figure 1, MAX15066), unless otherwise noted.)
LOAD REGULATION
MAX15066 toc11
OUTPUT CHANGE (%)
LOAD-TRANSIENT RESPONSE
(MAX15166)
MAX15066 toc10
40µs/div
VIN = 12V
VOUT = 0.9V
dl/dt = 1A/µs
COUT = 4 x 47µF
(SEE FIGURE 2 FOR
OTHER VALUES)
EFFICIENCY (12V) vs. OUTPUT CURRENT
(MAX15166)
MAX15066 toc09
OUTPUT CURRENT (A)
EFFICIENACY (%) 21
VIN = 12.0V
VOUT = 0.9VVOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3V
VOUT = 1.2V
EFFICIENCY (5V) vs. OUTPUT CURRENT
(MAX15166)
MAX15066 toc08
OUTPUT CURRENT (A)
EFFICIENACY (%) 21
VOUT = 3.3V
VIN = 5.0V
VOUT = 2.5V
VOUT = 1.8V
VOUT = 0.9VVOUT = 1.2V
MAX15066 toc07
VOUT
100mV/div
AC-COUPLED
IOUT
2A/div
100µs/div
LOAD-TRANSIENT RESPONSE
(MAX15066)
MAX15066 toc06
VOUT
100mV/div
AC-COUPLED
IOUT
2A/div
100µs/div
LOAD-TRANSIENT RESPONSE
(MAX15066)
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
Typical Operating Characteristics (continued)(VIN = 12V, VOUT = 1.8V, CVDD = 1FF, CIN = 22FF, COUT = 47FF, TA = +25NC (Figure 1, MAX15066), unless otherwise noted.)
SHUTDOWN WAVEFORM
MAX15066 toc17VEN
10V/div
VOUT
1V/div
ILOAD
2A/div
VPGOOD
5V/div
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
SUPPLY CURRENT (µA)
MAX15066 toc16
SHUTDOWN SUPPLY CURRENT
vs. INPUT VOLTAGE
MAX15066 toc15
INPUT VOLTAGE (V)
SUPPLY CURRENT (µA)
EN = 0V
INPUT CURRENT vs. INPUT VOLTAGE
(MAX15066)
MAX15066 toc14
INPUT VOLTAGE (V)
INPUT CURRENT (mA)
L = 2.2µH
NO LOAD
SWITCHING FREQUENCY
vs. INPUT VOLTAGE (MAX15066)
MAX15066 toc13
INPUT VOLTAGE (V)
FREQUENCY (kHz)
TA = -40°C
TA = +25°C
TA = +85°C
1A LOAD
FB SET POINT vs. TEMPERATURE
MAX15066 toc12
TEMPERATURE (°C)
FB (mV)3510-15
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
Typical Operating Characteristics (continued)(VIN = 12V, VOUT = 1.8V, CVDD = 1FF, CIN = 22FF, COUT = 47FF, TA = +25NC (Figure 1, MAX15066), unless otherwise noted.)
STARTUP INTO PREBIAS (NO LOAD)
MAX15066 toc23
VOUT
1V/div
1V/div
ILOAD
2A/div
VEN
10V/div
SOFT-START TIME vs. CAPACITANCE
MAX15066 toc22
SOFT-START TIME (ms)
SKIP MODE WAVEFORM
(MAX15066)
MAX15066 toc21
VOUT
AC-COUPLED
20mV/div
VLX
10V/div
ILOAD
2A/div
40µs/div
SOFT-START WAVEFORM
MAX15066 toc20
2A/div
VOUT
1V/div
VPGOOD
5V/div
VEN
10V/div
400µs/div
SWITCHING BEHAVIOR
(MAX15066)
MAX15066 toc19
VLX
10V/div
VOUT
AC-COUPLED
10mV/div
2A/div
1µs/div
OUTPUT SHORT-CIRCUIT WAVEFORM
MAX15066 toc18
VOUT
2V/div
VSS
1V/div
IIN
0.5A/div
20ms/div
IOUT
10A/div
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
Typical Operating Characteristics (continued)(VIN = 12V, VOUT = 1.8V, CVDD = 1FF, CIN = 22FF, COUT = 47FF, TA = +25NC (Figure 1, MAX15066), unless otherwise noted.)
JUNCTION TEMPERATURE vs. AMBIENT TEMPERATURE
(VIN = 5V, L = 2.2µH, LOAD CURRENT = 4A)
(MAX15066)
MAX15066 toc28
JUNCTION TEMPERATURE (°C)
VOUT = 3.3V
VOUT = 1.8V
VOUT = 1.2V
VOUT = 2.5V
JUNCTION TEMPERATURE vs. AMBIENT TEMPERATURE
(VIN = 12V, L = 2.2uH, LOAD CURRENT = 4A)
(MAX15066)
MAX15066 toc27
AMBIENT TEMPERATURE (°C)
JUNCTION TEMPERATURE (°C)65354555
VOUT = 5V
VOUT = 3.3V
VOUT = 2.5V
VOUT = 1.8V
VOUT = 1.2V
MAXIMUM LOAD CURRENT
vs. TEMPERATURE (VIN = 5V)
(MAX15066)
MAX15066 toc26
MAXIMUM LOAD CURRENT (A)5
TEMPERATURE (°C)
MAXIMUM CURRENT IS LIMITED BY
THERMAL SHUTDOWN OR CURRENT LIMIT
L = 2.2µH
VOUT = 3.3V
VOUT = 2.5V
VOUT = 1.2V
VOUT = 1.8V
MAXIMUM LOAD CURRENT
vs. TEMPERATURE (VIN = 12V)
(MAX15066)
MAX15066 toc25
MAXIMUM LOAD CURRENT (A)5
TEMPERATURE (°C)
VOUT = 1.2V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 3.3VVOUT = 5.0V
L = 2.2µH
MAXIMUM CURRENT IS LIMITED BY
THERMAL SHUTDOWN OR CURRENT LIMIT
STARTUP INTO PREBIAS (4A LOAD)
MAX15066 toc24
VOUT
1V/div
5A/div
ILOAD
5A/div
VEN
10V/div
400µs/div
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
Pin Description
Pin ConigurationBUMPNAMEFUNCTION
A1, A2GNDGround. Connect A1 and A2 together as close as possible to the device.
A3, A4IN
Power-Supply Input. Input supply range is from 4.5V to 16V. Connect A3 and A4 together as close as
possible to the device. Bypass IN to GND with a minimum 22FF ceramic capacitor as close as
possible to the device.
B1–B3LX
Inductor Connection. Connect an inductor between LX and the regulator output. LX is high
impedance when the device is in shutdown mode. Connect all LX nodes together as close as possible
to the device.VDDInternal 5V LDO Output. VDD powers the internal analog core. Connect a minimum of 1FF ceramic
capacitor from VDD to GND.BSTHigh-Side MOSFET Driver Supply. Bypass BST to LX with a 0.01FF capacitor. BST is internally
connected to the VDD regulator through a pMOS switch.
C2, C3I.C.Internal Connection. Leave unconnected.ENEnable Input. Connect EN to GND to disable the device. Set EN to above 1.9V (typ) to enable the
device. EN can be shorted to IN for always-on operation.PGOOD
Power-Good Output. PGOOD is an open-drain output that goes high impedance when VFB exceeds
0.56V (typ). PGOOD is internally pulled low when VFB falls below 0.545V (typ). PGOOD is internally
pulled low when the device is in shutdown mode, VDD is below the UVLO threshold, or the device is in
thermal shutdown.FBFeedback Input. Connect FB to the center tap of an external resistor-divider from the output to GND to
set the output voltage from 0.606V to 90% of VIN. COMPVoltage-Error Amplifier Output. Connect the necessary compensation network from COMP to GND
(see the Compensation Design section). SSSoft-Start Timing Capacitor Connection. Connect a capacitor from SS to GND to set the startup time
WLP
TOP VIEW
(BUMPS ON BOTTOM)
I.C.BST
PGOOD
I.C.LXLX
GNDINGNDC3COMPD3B3
VDDA2
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
Block Diagram5V LDOENABLE CONTROL AND
THERMAL SHUTDOWN
COMP
VDD
BST
GND
BIAS GENERATOR
CONTROL
LOGIC
CURRENT-SENSE AMPLIFIER
AND CURRENT LIMIT
UVLO
COMPARATOR
3.9V/3.75V
VDD
OSCILLATOR
VOLTAGE REFERENCE
1.6V
CLAMP
5µA
ZERO-CROSSING
CURRENT LIMIT
ERROR
AMPLIFIER
PWM
COMPARATOR
PGOOD
POWER-GOOD
COMPARATOR0.560V RISING,
0.545V FALLING
VDD
MAX15066
MAX15166
MAX15066 (500kHz)
MAX15166 (350kHz)
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
Detailed DescriptionThe MAX15066/MAX15166 are high-efficiency, peak
current-mode, step-down DC-DC converters with
integrated high-side (40mI) and low-side (18.5mI)
power switches. The output voltage is set from 0.606V to
0.9 x VIN by using an external resistive divider and can
deliver up to 4A of load current. The input voltage range
is 4.5V to 16V, making these devices ideal for distrib-
uted power systems, notebook computers, nonportable
consumer applications, and preregulation applications.
The devices feature a PWM, internally fixed switching
frequency of 500kHz (MAX15066) and 350kHz
(MAX15166) with a 90% maximum duty cycle. PWM
current-mode control allows for an all-ceramic
capacitor solution. The devices include a high gain
transconductance error amplifier. The current-mode
control architecture simplifies compensation design, and
ensures a cycle-by-cycle current limit and fast reaction to
line and load transients. The low RDS-ON, internal MOSFET
switches ensure high efficiency at heavy loads and
minimize critical inductances, reducing layout sensitivity.
The devices feature thermal shutdown, overcurrent
protection (high-side sourcing and hiccup protection),
and an internal 5V (25mA) LDO with undervoltage
lockout. An externally adjustable voltage soft-start
gradually ramps up the output voltage and reduces
inrush current. At light loads, as soon as a low-side
MOSFET zero-crossing event is detected, the devices
automatically switch to pulse-skipping mode to keep the
quiescent supply current low and enhances the light load
efficiency. An independent enable input controls and the
power-good output allow for flexible power sequencing.
The devices also provide the ability to start up into a
prebiased output.
Controller Function—PWM Logic and Skip ModeThe devices employ PWM control with a constant
switching frequency of 500kHz (MAX15066) or 350kHz
(MAX15166) at medium and heavy loads, and skip mode
at light loads. When EN is high, after a brief settling time,
PWM operation starts when VSS exceeds the FB voltage,
at the beginning of soft-start.
The first operation is always a high-side turn-on at the
beginning of the clock cycle. The high side is turned off
when any of the following conditions occur:
1) COMP voltage exceeds the internal current-mode
ramp waveform, which is the sum of the slope com-
pensation ramp and the current-mode ramp derived
from the inductor current waveform (through the
current-sense block).
2) The high-side current limit is reached.
3) The maximum duty cycle of 90% is reached.
The low side turns off when the clock period ends or
when the zero-crossing current threshold is intercepted.
The devices monitor the inductor current during every
switch cycle and automatically enters discontinuous
mode when the inductor current valley intercepts the
zero-crossing threshold (under light loads); under very
light load conditions, skip mode is activated/deactivated
on a cycle-by-cycle basis.
Figure 1. Reference Circuit
COMP
22µF2.2µH
1µF
COUT270pF
CCOMP10nF
10nF
10kI
RCOMP
10kI
BST
GND
VDD
PGOOD
INPUT
4.5V TO 16V
OUTPUT
MAX15066
MAX15166COMPONENT
COUT
RCOMP
CCOMP
VOUT
MAX15066
1 x 47µF4 x 47µF
1.8V0.9V
2700pF2700pF
7.5kI7.5kI
20kI5.1kI
MAX15166
MAX15066/MAX15166High-Eficiency, 4A, Step-Down DC-DC Regulators with Internal Power Switches
