MAX5051AUI+T ,Parallelable, Clamped Two-Switch Power-Supply Controller ICApplications*Contact factory for availability.● High-Eficiency, Isolated Telecom/Datacom **EP = Ex ..
MAX5052AEUA ,22 V, 50 W, current-mode PWM controller with an error amplifier for isolated/nonisolated power supplyMAX5052/MAX505319-2590; Rev 1; 11/03Current-Mode PWM Controllers with an ErrorAmplifier for Isolate ..
MAX5052BEUA ,22 V, 50 W, current-mode PWM controller with an error amplifier for isolated/nonisolated power supplyApplicationsUniversal Input AC Industrial PowerPin ConfigurationPower Supplies ConversionIsolated T ..
MAX5053AEUA ,10.8 V, 50 W, current-mode PWM controller with an error amplifier for isolated/nonisolated power supplyELECTRICAL CHARACTERISTICS(V = +12V (for MAX5052, V must first be brought up to 23.6V for startup), ..
MAX5053BEUA+ ,Current-Mode PWM Controllers with an Error Amplifier for Isolated/Nonisolated Power SuppliesFeaturesThe MAX5052/MAX5053 current-mode PWM controllers ♦ Available in a Tiny 8-Pin µMAX Packageco ..
MAX5053BEUA+T ,Current-Mode PWM Controllers with an Error Amplifier for Isolated/Nonisolated Power SuppliesELECTRICAL CHARACTERISTICS(V = +12V (for MAX5052, V must first be brought up to 23.6V for startup), ..
MAX924ESE ,Ultra Low-Power / Single/Dual-Supply ComparatorsELECTRICAL CHARACTERISTICS: 5V OPERATION (continued)(V+ = 5V, V- = GND = 0V, T = T to T , unless ot ..
MAX924ESE ,Ultra Low-Power / Single/Dual-Supply ComparatorsGeneral Description ________
MAX924ESE+ ,Ultra Low-Power, Single/Dual-Supply ComparatorsELECTRICAL CHARACTERISTICS: 5V OPERATION(V+ = 5V, V- = GND = 0V, T = T to T , unless otherwise note ..
MAX9260GCB/V+T ,Gigabit Multimedia Serial Link with Spread Spectrum and Full-Duplex Control ChannelApplications Circuit appears at end of data sheet.For pricing, delivery, and ordering information, ..
MAX9310EUP ,1:5 Clock Driver with Selectable LVPECL Inputs and LVDS OutputsApplicationsData and Clock Drivers and BuffersCentral-Office Backplane Clock DistributionDSLAMBase ..
MAX9311ECJ ,1:10 Differential LVPECL/LVECL/HSTL Clock and Data DriversFeaturesThe MAX9311/MAX9313 are low-skew, 1-to-10 differen- +2.25V to +3.8V Differential HSTL/LVPE ..
MAX5051AUI+-MAX5051AUI+T
Parallelable, Clamped Two-Switch Power-Supply Controller IC
General DescriptionThe MAX5051 is a clamped, two-switch power-supply
controller IC. This device can be used both in forward or
flyback configurations with input voltage ranges from 11V
to 76V. It provides comprehensive protection mechanisms
against possible faults, resulting in very high reliability
power supplies. When used in conjunction with secondary
side synchronous rectification, power-supply efficiencies
can easily reach 92% for a +3.3V output power supply
operated from a 48V bus. The integrated high- and low-
side gate drivers provide more than 2A of peak gate-drive
current to two external N-channel MOSFETs. Low startup
current reduces the power loss across the bootstrap
resistor. A feed-forward voltagemode topology provides
excellent line rejection while avoiding the pitfalls of tradi-
tional current-mode control.
The MAX5051 power-supply controller is primary as well
as secondary-side parallelable, allowing the design of
scaleable power systems when necessary. When paral-
leling the primary side, dedicated pins allow for simultane-
ous wakeup or shutdown of all paralleled units, thus pre-
venting current-hogging during startup or fault conditions.
The MAX5051 generates a lookahead signal for driving
secondary-side synchronous MOSFETs. Special primary-
side synchronization inputs/outputs allow two primaries to
be operated 180° out of phase for increased output power
and lower input ripple currents.
The MAX5051 is available in a 28-pin TSSOP-EP pack-
age and operates over a wide -40°C to +125°C tempera-
ture range.
Warning: The MAX5051 is designed to work with high
voltages. Exercise caution.
Applications●High-Eficiency, Isolated Telecom/Datacom
Power Supplies●48V and 12V Server Power Supplies●48V Power-Supply Modules●Industrial Power Supplies
Features●Wide Input Voltage Range, 11V to 76V●Voltage Mode with Input Voltage Feed-Forward●Ripple-Phased Parallel Topology for High Current/
Power Output●2A Integrated High- and Low-Side MOSFET Drivers●SYNCIN And SYNCOUT Pins Enable 180° Out-Of-
Phase Operation●Programmable Brownout and Bootstrap UVLOs●High-Side Driver Bootstrap Capacitor Precharge Driver●Low Current-Limit Threshold for High Efficiency●Programmable Switching Frequency●Reference Voltage Soft-Start for Startup Without
Overshoots●Startup Synchronization with Multiple Paralleled
Primaries●Programmable Integrating Current-Limit Fault
Protection●Look-Ahead PWM Signal for Secondary-Side Synchronous Rectifier Drivers●Look-Ahead Drivers for Either A High-Speed
Optocoupler or Pulse Transformer●Wide -40°C to +125°C Operating Range●Thermally Enhanced 28-Pin TSSOP Package
Pin Configuration appears at end of data sheet.*Contact factory for availability.
**EP = Exposed pad.
PARTTEMP RANGEPIN-PACKAGEMAX5051AUI*-40°C to +85°C28-TSSOP-EP**
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
Ordering Information
EVALUATION KIT AVAILABLE
AVIN, PVIN, XFRMRH to GND .............................-0.3V to +80VBST to GND ..........................................................-0.3V to +95VBST, DRVH to XFRMRH .......................................-0.3V to +12VREG9, DRVDD, DRVL to GND .............................-0.3V to +12VDRVB, LXVDD, LXL, LXH to GND ........................-0.3V to +12VUVLO, STT, COMP, CON to GND.........................-0.3V to +12VFLTINT, RCFF to GND ..........................................-0.3V to +12VREG5, CS, CSS, FB to GND ..................................-0.3V to +6VSTARTUP, SYNCIN to GND ....................................-0.3V to +6VSYNCOUT, RCOSC to GND ...................................-0.3V to +6VPGND to GND ......................................................-0.3V to +0.3V
LXL, LXH Current Continuous ..........................................±50mADRVL, DRVH Current Continuous .................................±100mA
DRVL, DRVH Peak Current (<500ns) ...................................±5A
PVIN, REG9 Continuous Current ...................................+120mA
REG5 Continuous Current ...............................................+80mADRVB, RCFF, RCOSC, CSS Continuous Current ...........±20mA
COMP, SYNCOUT Continuous Current ...........................±20mAREG9, REG5, and COMP Short to GND ..................ContinuousContinuous Power Dissipation (TA = +70°C) 28-Pin TSSOP (derate 23.8mW/°C above +70°C) ....1905mW
Operating Temperature Range .........................-40°C to +125°CMaximum Junction Temperature (TJ) ..............................+150°C
Storage Temperature Range ............................-65°C to +150°CLead Temperature (soldering, 10s) .................................+300°C
(Note 1)TSSOP Junction-to-Ambient Thermal Resistance (θJA) ..........42°C/W
(AVIN = 12V, PVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF,
CREG5 = 4.7μF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. All driver, voltage-regulator, and refer-ence outputs unconnected except for bypass capacitors.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
SUPPLY CURRENT (AVIN, PVIN)AVIN Standby CurrentIASTBYVAVIN = VPVIN = 11V to 76V;
VSTARTUP = VCS = 0V;
VBST = VXFRMRH = VDRVDD = VREG9; RCFF loating
300450µA
PVIN Standby CurrentIPSTBY400650µA
AVIN Supply CurrentIAVINVAVIN = VPVIN = 11V to 76V;
VCS = 0V; VBST = VDRVDD = VREG9;
VXFRMRH = 0V; STARTUP, RCFF loating
0.651mA
PVIN Supply CurrentIPVIN812mA
AVIN Input Voltage RangeInferred from AVIN supply current test1176V
+9V LDO (REG9)PVIN Input Voltage RangeVPVINInferred from PVIN supply current test1176V
REG9 Output-Voltage Set PointVREG9VPVIN = 11V8.39.0V
REG9 Line RegulationVPVIN = 11V to 76V0.1mV/V
REG9 Load RegulationIREG9 = 0 to 80mA250mV
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
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.
Electrical Characteristics
Package Thermal Characteristics
Note 1: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to www.maximintegrated.com/thermal-tutorial.
(AVIN = 12V, PVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF,
CREG5 = 4.7μF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. All driver, voltage-regulator, and refer-ence outputs unconnected except for bypass capacitors.)
REG9 Dropout VoltageIREG9 = 80mA0.5V
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSREG9 Undervoltage Lockout
ThresholdVREG9 falling5.76.7V
REG9 Undervoltage Lockout
Threshold Hysteresis750mV
+5V LDO (REG5)REG5 Output-Voltage Set PointVREG54.85.1V
REG5 Load RegulationIREG5 = 0 to 40mA50mV
REG5 Dropout VoltageIREG5 = 40mA, measured with respect
to VREG90.5V
SOFT-START/REFERENCE (CSS)Reference VoltageVCSS1.1251.2351.255V
Soft-Start Pullup CurrentICSS70µA
ERROR AMPLIFIER (CSS, FB, COMP)FB Input RangeVFBInferred from FB offset voltage test03V
FB Input CurrentIFBVFB = VREF±250nA
COMP Output RangeInferred from FB offset voltage test2.16.0V
COMP Output Sink CurrentVFB = 3V20mA
COMP Output Source CurrentVFB = 0V30mA
Open-Loop GainGA2.1V < VCOMP < 6V80dB
Unity-Gain BandwidthBWCCOMP = 50pF, ICOMP = ±5mA3MHz
FB Offset VoltageVOSVFB = 0 to 3V; VCOMP = 2.1V to 6V;
ICOMP = -5mA to +5mA-3+3mV
COMP Output Slew RateSRCCOMP = 50pF1v/µs
PVIN UNDERVOLTAGE LOCKOUT (STT)PVIN Undervoltage LockoutVPVIN rising2223.525V
STT ThresholdVSTTVSTT rising1.181.241.30V
STT Input ImpedanceRSTT100kΩ
INTEGRATING FAULT PROTECTION (FLTINT)FLTINT Source CurrentIFLTINTμA
FLTINT Shutdown ThresholdVFLTINTSDV
FLTINT Restart HysteresisVFLTINTHYV
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
Electrical Characteristics (continued)
(AVIN = 12V, PVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF,
CREG5 = 4.7μF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. All driver, voltage-regulator, and refer-ence outputs unconnected except for bypass capacitors.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
OSCILLATOR (RCOSC, SYNCIN, SYNCOUT)PWM PeriodtSRRCOSC = 24kΩ, CRCOSC = 100pF3.9μs
Maximum PWM Duty CycleDMAXRRCOSC = 24kΩ, CRCOSC = 100pF48%
Maximum RCOSC FrequencyfRCOSCMAX1MHz
Maximum SYNCIN FrequencyfSYNCIN50% duty cycle500kHz
SYNCIN High-Level VoltageVHSYNCINPulse rising2.1V
SYNCIN Low-Level VoltageVLSYNCINPulse falling0.8V
SYNCIN Pulldown Resistor100kΩ
SYNCIN Rising to SYNCOUT Falling Delay30ns
SYNCIN Falling to SYNCOUT Rising Delay70ns
SYNCOUT Voltage HighSourcing 1.2mA4.55.1V
SYNCOUT Voltage LowSinking 2.4mA0.3V
RCOSC Peak Trip LevelVTH2.5V
RCOSC Valley Trip Level0.2V
RCOSC Input Bias Current-0.3μA
RCOSC Discharge MOSFET
RDS(ON)Sinking 10mA50100Ω
RCOSC Discharge Pulse Width50ns
UNDERVOLTAGE LOCKOUT (UVLO)UVLO ThresholdVUVLOVUVLO rising1.181.241.30V
UVLO HysteresisVHYS130mV
UVLO Input Bias CurrentIBUVLOVUVLO = 2.5V-100+100nA
PWM COMPARATORRCFF Input Voltage Range03V
Feed-Forward Discharge
MOSFET RDS(ON)RDS(RCFF)Sinking 10mA50100Ω
CON Input Voltage Range06V
RCFF Level-Shift VoltageVCPWM2.22.4V
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
Electrical Characteristics (continued)
(AVIN = 12V, PVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF,
CREG5 = 4.7μF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. All driver, voltage-regulator, and refer-ence outputs unconnected except for bypass capacitors.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSCON Input Bias CurrentICON-2+2μA
Propagation Delay to OutputtdCPWMDRVH, DRVL = unconnected, overdrive = 50mV, measured from CON to DRVL90ns
SYNCHRONOUS RECTIFIER PULSE TRANSFORMER DRIVER (LXVDD, LXH, LXL)High-Side MOSFET R DS(ON)RDSLXHLXH sourcing 10mA, VLXVDD = VREG536.512Ω
Low-Side MOSFET RDS(ON)RDSLXLLXL sinking 10mA, VLXVDD = VREG52.0510Ω
LXH Rising to DRVL Rising Delay90ns
CURRENT-LIMIT COMPARATOR (CS)Current-Limit Threshold VoltageVILIM144154164mV
Current-Limit Input Bias CurrentIBILIM0 < VCS < 0.3V-2+2μA
Propagation Delay to OutputtdILIMDRVH, DRVL = unconnected, overdrive = 10mV, measured from CS to DRVL100ns
LOW-SIDE MOSFET DRIVER (DRVDD, DRVL, PGND)Peak Source CurrentVDRVL = 0V, pulse width < 100ns;
VDRVDD = VREG92A
Peak Sink CurrentVDRVL = VREG9, pulse width < 100ns;
VDRVDD = VREG93A
DRVL Resistance SourcingIDRVL = 50mA, VDRVDD = VREG91.73.5Ω
DRVL Resistance SinkingIDRVL = -50mA, VDRVDD = VREG90.61.4Ω
HIGH-SIDE MOSFET DRIVER (BST, DRVH, XFRMRH)Peak Source CurrentVDRVH = GND, pulse width < 100ns,
VBST = VREG9, VXFRMRH = 0V2A
Peak Sink CurrentVDRVH = VBST, pulse width < 100ns,
VBST = VREG9, VXFRMRH = 0V5A
DRVH Resistance SourcingIDRVH = 50mA, VBST = VREG9,
VXFRMRH = 0V1.73.5Ω
DRVH Resistance SinkingIDRVH = -50mA, VBST = VREG9,
VXFRMRH = 0V0.61.4Ω
Skew Between Low-Side and High-Side Drivers0ns
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
Electrical Characteristics (continued)
(AVIN = 12V, PVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF,
CREG5 = 4.7μF, TA = TMIN to TMAX, unless otherwise noted. Typical values are at TA = +25°C. All driver, voltage-regulator, and refer-ence outputs unconnected except for bypass capacitors.)
(VAVIN = VPVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF, CREG5 = 4.7μF, TA = +25°C, unless otherwise noted.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
BOOST CAPACITOR CHARGE MOSFET (DRVB)DRVB Resistance SourcingIDRVB = 50mA835Ω
DRVB Resistance SinkingIDRVB = 50mA535Ω
Delay from Clock Fall200ns
One-Shot Pulse Width300ns
STARTUP (STARTUP)Startup ThresholdVSTARTUPVSTARTUP rising1.42.1V
Startup Threshold Hysteresis330mV
Internal Pullup CurrentISTARTUP50100μA
STARTUP Pulldown MOSFET
RDS(ON)Sinking 10mAΩ
OVERTEMPERATURE SHUTDOWNShutdown Junction TemperatureTemperature rising150°C
Hysteresis10°C
AVIN STANDBY CURRENT
vs. TEMPERATUREMAX5051 toc02
TEMPERATURE (°C)
AVIN STANDBY CURRENT (µA)
VUVLO = 0V
PVIN STANDBY CURRENT
vs. SUPPLY VOLTAGEMAX5051 toc03
PVIN SUPPLY VOLTAGE (V)
PVIN STANDBY CURRENT (µA)6050403020
VUVLO = 0V
AVIN STANDBY CURRENT
vs. AVIN SUPPLY VOLTAGEMAX5051 toc01
AVIN SUPPLY VOLTAGE (V)
AVIN STANDBY CURRENT (6040503020
VUVLO = 0V
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
Electrical Characteristics (continued)
Typical Operating Characteristics
(VAVIN = VPVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF, CREG5 = 4.7μF, TA = +25°C, unless otherwise noted.)
PVIN STARTUP VOLTAGE
vs. TEMPERATUREMAX5051 toc05
TEMPERATURE (°C)
PVIN STARTUP VOLTAGE (V)
STT = FLOATING
REG9 OUTPUT VOLTAGE
vs. REG9 OUTPUT CURRENTMAX5051 toc08
REG9 OUTPUT CURRENT (mA)
REG9 OUTPUT VOLTAGE (V)
REG9 OUTPUT VOLTAGE
vs. PVIN VOLTAGE
MAX5051 toc06
PVIN VOLTAGE (V)
REG9 OUTPUT VOLTAGE (V)6050403020
REG5 OUTPUT VOLTAGE
vs. REG5 OUTPUT CURRENT
MAX5051 toc09
REG5 OUTPUT CURRENT (mA)
REG5 OUTPUT VOLTAGE (V)70605040302010
PVIN STANDBY CURRENT
vs. TEMPERATURE
MAX5051 toc04
TEMPERATURE (°C)
PVIN STANDBY CURRENT (µA)
VUVLO = 0V
REG9 OUTPUT VOLTAGE
vs. TEMPERATUREMAX5051 toc07
TEMPERATURE (°C)
REG9 OUTPUT VOLTAGE (V)
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
Typical Operating Characteristics (continued)
(VAVIN = VPVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF, CREG5 = 4.7μF, TA = +25°C, unless otherwise noted.)
AVIN SUPPLY CURRENT
vs. TEMPERATUREMAX5051 toc11
TEMPERATURE (°C)
AVIN SUPPLY CURRENT (µA)
VUVLO = 0V
CSS SOFT-START CURRENT
vs. TEMPERATUREMAX5051 toc14
TEMPERATURE (°C)
CSS SOFT-START CURRENT (µA)
FLTINT CURRENT vs. TEMPERATURE
MAX5051 toc17
FLTINT CURRENT (µA)
PVIN SUPPLY CURRENT
vs. TEMPERATURE
MAX5051 toc12
TEMPERATURE (°C)
PVIN SUPPLY CURRENT (mA)
VPVIN = 12V
UVLO THRESHOLD vs. TEMPERATUREMAX5051 toc15
TEMPERATURE (°C)
UVLO (V)
RCFF LEVEL-SHIFT VOLTAGE
vs. TEMPERATURE
MAX5051 toc18
RCFF LEVEL-SHIFT VOLTAGE (V)
REG5 OUTPUT VOLTAGE
vs. TEMPERATURE
MAX5051 toc10
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
SOFT-START/REFERENCE VOLTAGE
vs. TEMPERATURE
MAX5051 toc13
TEMPERATURE (°C)
SOFT-START/REFERENCE VOLTAGE (V)
1.225
STT STARTUP THRESHOLD
vs. TEMPERATURE
MAX5051 toc16
STT (V)
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
Typical Operating Characteristics (continued)
(VAVIN = VPVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF, CREG5 = 4.7μF, TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics (continued)OPEN-LOOP GAIN/PHASE
vs. FREQUENCY
FREQUENCY (kHz)
0.011010010000.1110,000
GAIN (dB)
PHASE (DEGREES)
MAX5051 toc20
GAIN
PHASE
LXL AND LXH RDSON
vs. TEMPERATUREMAX5051 toc23
TEMPERATURE (°C)
DSON60-151035
LXH SOURCING 10mA
LXH SINKING 10mA
SYNCIN TO SYNCOUT PROPAGATION
DELAY vs. TEMPERATUREMAX5051 toc26
PROPAGATION DELAY (ns)
SYNCIN FALL
TO SYNCOUT RISE
SYNCIN RISE TO SYNCOUT FALL
COMP OUTPUT VOLTAGE
vs. TEMPERATUREMAX5051 toc21
TEMPERATURE (°C)
COMP OUTPUT VOLTAGE (V)
ISOURCE = 5mA
ISINK = 5mA
SWITCHING PERIOD vs. RRCOSCMAX5051 toc24
RRCOSC (kΩ)
SWITCHING PERIOD (µs)
DRVH MAXIMUM DUTY CYCLE
vs. TEMPERATURE
MAX5051 toc27
DRVH DUTY CYCLE (%)
CURRENT-LIMIT THRESHOLD
vs. TEMPERATURE
MAX5051 toc19
TEMPERATURE (°C)
CS THRESHOLD VOLTAGE (mV)
DRVH AND DRVL RDSON
vs. TEMPERATURE
MAX5051 toc22
TEMPERATURE (°C)
DSON
DRVH AND DRVL SOURCING 50mA
DRVH AND DRVL SINKING 50mA
NORMALIZED SWITCHING FREQUENCY
vs. TEMPERATUREMAX5051 toc25
NORMALIZED SWITCHING FREQUENCY
SWITCHING
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
(VAVIN = VPVIN = 12V, VUVLO = VSTT = 3V, VCON = 3V, RRCOSC = 24kΩ, CCSS = 10nF, CRCOSC = 100pF, CREG9 = 4.7μF, CREG5 = 4.7μF, TA = +25°C, unless otherwise noted.)
PINNAMEFUNCTIONRCOSCReset Input. Drive RESET low to clear all latches and registers (all outputs are turned off). All OUT
pulldown currents are disabled when RESET = low.SYNCOUTSynchronization Output. Synchronization signal to drive SYNCIN of a second MAX5051, if used.RCFFFeed-Forward Input. Connect a resistor from RCFF to AVIN and a capacitor from RCFF to GND. This is
the PWM ramp.CONPWM Comparator Noninverting Input. Connect CON to the optocoupler output for isolated applications,
or to COMP for nonisolated applications.CSSSoft-Start and Reference. Connect a 0.01μF or greater capacitor from CSS to GND. The 1.24V
reference voltage appears across this capacitor.COMPInternal Error Ampliier Output.FBFeedback Input. Inverting input of the internal error ampliier. The soft-started reference is connected to the noninverting input of this ampliier.REG55V Linear Regulator Output. Bypass REG5 to GND with a 4.7μF ceramic capacitor.REG99V Linear Regulator Output. Bypass REG9 to GND with a 4.7μF ceramic capacitor.PVIN
Regulator Voltage Input. Voltage input to the internal 5V and 9V linear regulators. A high-value resistor
connected from the input supply to PVIN provides the necessary current to charge up the startup capacitor, and the 400μA standby current required by the MAX5051. After startup, the output of a tertiary
winding is used to provide continued bias to the controller.STTStartup Threshold Input. Leave STT loating for a default startup voltage of 24V at PVIN. STT can be modiied by connecting external resistors. For high accuracy, choose external resistors with 50kΩ or less
impedance looking back into the divider.LXVDDSupply Input for the Secondary-Side Synchronous Pulse Transformer or Optocoupler Driver. LXVDD is
normally connected to REG5.
CON TO DRVL PROPAGATION DELAY
vs. TEMPERATUREMAX5051 toc28
TEMPERATURE (°C)
PROPAGATION DELAY (ns)
50mV OVERDRIVE
CS CURRENT LIMIT TO DRVH
PROPAGATION DELAY vs. TEMPERATUREMAX5051 toc29
TEMPERATURE (°C)
PROPAGATION DELAY (ns)
50mV OVERDRIVE
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
Typical Operating Characteristics (continued)
Pin Description
PINNAMEFUNCTIONLXHSynchronous-Pulse Transformer Driver, PMOS Open Drain. LXH is the high-side driver for the
secondaryside synchronous-pulse transformer. LXH can also drive a high-speed switching optocoupler. If not used, connect LXH to LXVDD.LXLSynchronous-Pulse Transformer Driver, NMOS Open Drain. LXL is the low-side driver for the
secondaryside synchronous-pulse transformer. LXL can also drive a high-speed switching optocoupler. If not used, connect LXL to PGND.CSCurrent-Sense Input. The current-limit threshold is internally set to 156mV relative to PGND. The device has an internal noise ilter. If necessary, connect an additional external RC ilter.DRVLGate-Drive Output for Low-Side MOSFET. DRVL is capable of sourcing and sinking approximately 2A
peak current.PGNDPower Ground.DRVDDSupply Input for Low-Side MOSFET Driver. Bypass DRVDD locally with good quality 1μF || 0.1μF ceramic capacitors. DRVDD is normally connected to REG9.DRVBGate-Drive Output for Boost MOSFET. Connect the gate of a small high-voltage external FET to this pin
to enable charging of the high-side boost capacitor connected between pins 20 and 22. This FET may
be necessary to keep the boost capacitor charged at light loads.XFRMRHTransformer Input. Transformer primary high-side connection.DRVHGate-Drive Output for High-Side MOSFET.BST
Boost Input. Boost supply connection point for the high-side MOSFET driver. Connect at least a 1μF || 0.1μF ceramic capacitor from BST to XFRMRH with short and wide PC board traces. If the voltage across the boost capacitor falls below the high-side undervoltage lockout threshold, the DRVH output
stops switching.AVINSupply Voltage Input. Connect AVIN directly to the input supply line.GNDAnalog Signal GroundUVLO
Undervoltage Lockout Input. An external voltage-divider from the input supply sets the startup voltage;
the threshold is 1.24V with 130mV hysteresis. UVLO can also be used as a shutdown input. If unused,
connect UVLO to REG5STARTUP
Startup Input. STARTUP coordinates simultaneous startup of multiple units from faults, during initial
turnon, and UVLO recovery. When paralleling the secondaries of two MAX5051’s, the STARTUP inputs
of each device must be connected together.FLTINT
Fault Integration Input. During persistent current-limit faults, a capacitor connected to FLTINT is charged
with an internal 90µA current source. Switching is terminated when the voltage reaches 2.9V. An
external resistor connected in parallel discharges the capacitor. Switching resumes when the voltage
drops to 2V.SYNCIN
Synchronization Input. SYNCIN accepts the synchronization signal from SYNCOUT of another
MAX5051 and shifts the switching of the synchronized unit by 180° allowing the reduction of input
bypass capacitors. The MAX5051 switches at the same frequency at SYNCIN. SYNCIN must be 50% duty cycle. Leave SYNCIN loating if unused.
MAX5051Parallelable, Clamped Two-Switch
Power-Supply Controller IC
Pin Description (continued)
