MAX5019ESA+T ,Current-Mode PWM Controllers with Integrated Startup CircuitELECTRICAL CHARACTERISTICS(V = 13V, a 10µF capacitor connects V to GND, V = 0, V+ = 48V, 0.1µF capa ..
MAX5020CSA ,Current-mode PWM controller with integrated startup circuitFeaturesThe MAX5019/MAX5020 integrate all the building Wide Input Range: (18V to 110V) or (13V to ..
MAX5020CSA+ ,Current-Mode PWM Controllers with Integrated Startup CircuitFeaturesThe MAX5019/MAX5020 integrate all the building♦ Wide Input Range: (18V to 110V) or (13V to ..
MAX5020ESA ,Current-Mode PWM Controllers with Integrated Startup CircuitFeaturesThe MAX5019/MAX5020 integrate all the building♦ Wide Input Range: (18V to 110V) or (13V to ..
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MAX5020ESA ,Current-Mode PWM Controllers with Integrated Startup CircuitFeaturesThe MAX5019/MAX5020 integrate all the building♦ Wide Input Range: (18V to 110V) or (13V to ..
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MAX5019CSA+-MAX5019ESA-MAX5019ESA+-MAX5019ESA+T-MAX5020CSA+-MAX5020ESA-MAX5020ESA+-MAX5020ESA+T
Current-Mode PWM Controllers with Integrated Startup Circuit
General DescriptionThe MAX5019/MAX5020 integrate all the building
blocks necessary for implementing DC-DC fixed-fre-
quency power supplies. Either primary- or secondary-
side regulation may be used to implement isolated or
nonisolated power supplies. These devices are current-
mode controllers with an integrated high-voltage start-
up circuit suitable for telecom/industrial voltage range
power supplies. Current-mode control with leading-
edge blanking simplifies control-loop design and inter-
nal ramp compensation circuitry stabilizes the current
loop when operating at duty cycles above 50%
(MAX5019). The MAX5019 allows 85% operating duty
cycle and can be used to implement flyback converters
whereas the MAX5020 limits the operating duty cycle to
less than 50% and can be used in single-ended for-
ward converters. A high-voltage startup circuit allows
these devices to draw power directly from the 18V to
110V input supply during startup. The switching fre-
quency is internally trimmed to 275kHz ±10%, thus
reducing magnetics and filter component costs.
The MAX5019/MAX5020 are available in 8-pin SO
packages.
Warning: The MAX5019/MAX5020 operate with highvoltages. Exercise caution.
ApplicationsTelecom Power Supplies
Industrial Power Supplies
Networking Power Supplies
Isolated Power Supplies
FeaturesWide Input Range: (18V to 110V) or (13V to 36V)Isolated (without optocoupler) or Nonisolated
Power SupplyCurrent-Mode ControlLeading-Edge BlankingInternally Trimmed 275kHz ±10% OscillatorLow External Component CountSoft-StartHigh-Voltage Startup CircuitPulse-by-Pulse Current LimitingThermal ShutdownSO-8 Package
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup CircuitGND
VCC
NDRVVDD
8-SOTOP VIEW
MAX5019/
MAX5020
SS_SHDN
Pin Configuration
Ordering InformationNDRV
VINVOUT
VDD
VCC
MAX5020
SS_SHDNGND
Typical Operating Circuit19-2115; Rev 0; 7/01
PARTTEMP. RANGEPIN-PACKAGE
MAX5019CSA* 0°C to +70°C8-SO
MAX5019ESA*-40°C to +85°C8-SO
MAX5020CSA* 0°C to +70°C8-SO
MAX5020ESA*-40°C to +85°C8-SO
*See Selector Guide at end of data sheet.
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup Circuit
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VDD= 13V, a 10µF capacitor connects VCCto GND, VCS= 0, V+ = 48V, 0.1µF capacitor connected from SS_SHDNto GND, NDRV
= open circuit, VFB= 3V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
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.
V+ to GND……………………………………...……-0.3V to +120V
VDDto GND.………………………………….……….-0.3V to +40V
VCCto GND.………………….……………………-0.3V to +12.5V
FB, NDRV, SS_SHDN, CS to GND .……-0.3V to VCC+ 0.3V
VDDand VCCCurrent …………………...…………………..20mA
NDRV Current Continuous...………………………………….25mA
NDRV Current for Less than 1µs..………….…………….……±1A
Continuous Power Dissipation (TA= +70°C)
8-Pin SO (derate 5.88mW/°C above +70°C).………....471mW
Operating Temperature Range…………..……...-40°C to +85°C
Storage Temperature Range……………..…….-65°C to +150°C
Lead Temperature (soldering, 10s) ………………………+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
SUPPLY CURRENTIV+(NS)VDD = 0, V+ = 110V, driver not switching0.81.6
V+ Supply CurrentIV+(S)V+ = 110V, VDD = 0, FB = GND,
driver switching1.63.0mA
V+ Supply Current After StartupV+ = 110V, VDD = 13V, FB = GND14μA
IVDD(NS)VDD = 36V, driver not switching0.91.6V D D S up p l y C ur r entIVDD(S)VDD = 36V, driver switching, FB = GND2.13.0mA
V+ Shutdown CurrentVSS_SHDN = 0, V+ = 110V180290μA
VDD Shutdown CurrentVSS_SHDN = 0420μA
PREREGULATOR/STARTUPV+ Input Voltage18110V
VDD Supply Voltage1336V
INTERNAL REGULATORS (VCC)Powered from V+, ICC = 7.5mA, VDD = 07.59.812.0VVCC Output VoltagePowered from VDD, ICC = 7.5mA9.010.011.0V
VCC Undervoltage LockoutVCC_UVLOVCC falling6.6V
OUTPUT DRIVERPeak Source CurrentVCC = 11V (externally forced)570mA
Peak Sink CurrentVCC = 11V (externally forced)1000mA
NRDV High-Side Driver
ResistanceROHVCC = 11V, externally forced,
NDRV sourcing 50mA412Ω
NDRV Low-Side Driver
ResistanceROLVCC = 11V, externally forced,
NDRV sinking 50mA1.64Ω
ERROR AMPLIFIERFB Input ResistanceRIN50kΩ
FB Input Bias CurrentIFBVFB = VSS_SHDN±1μA
Error Amplifier Gain (Inverting)AVCL-20V/V
Closed-Loop 3dB Bandwidth200kHz
FB Input Voltage Range23V
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup Circuit
ELECTRICAL CHARACTERISTICS (continued)(VDD= 13V, a 10µF capacitor connects VCCto GND, VCS= 0, V+ = 48V, 0.1µF capacitor connected from SS_SHDNto GND, NDRV
= open circuit, VFB= 3V, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
SLOPE COMPENSATIONSlope Compensation
(MAX5019 only)VSCOMP26mV/μs
THERMAL SHUTDOWNThermal Shutdown Temperature150°C
Thermal Hysteresis25°C
CURRENT LIMITCS Threshold VoltageVILIMFB = GND419465510mV
CS Input Bias Current0 ≤ VCS ≤ 2V, FB = GND-11μA
Current Limit Comparator
Propagation Delay50mV overdrive on CS, FB = GND180ns
CS Blanking TimeFB = GND, only PWM comparator is blanked70ns
OSCILLATORClock Frequency RangeFB = GND247275302kHz
MAX5019, FB = GND7585Max Duty CycleMAX5020, FB = GND4450%
SOFT-STARTSS Source CurrentISSOVSS_SHDN = 02.04.56.5μA
SS Sink Current1.0mA
Steady State Reference Voltage
at SS_SHDNVSS_SHDNNo external load2.3312.4202.500V
VSS_SHDN falling0.250.370.41Shutdown ThresholdVSS_SHDN rising0.530.590.65V
Typical Operating Characteristics(V+ = 48V, VDD= 13V, CS = GND, NRDV is open circuit, TA= +25°C, unless otherwise noted.)
VSS_SHDN vs. TEMPERATURE
(AT THE END OF SOFT-START)
MAX5019 toc01
VFB = 4V
SS_SHDN
(V) (NORMALIZED TO V
REF
= 2.4V)
NDRV FREQUENCY
vs. TEMPERATURE
MAX5019 toc02
NDRV FREQUENCY (kHz)
FB = GND
MAX5019
MAXIMUM DUTY CYCLE
vs. TEMPERATURE
MAX5019 toc03
MAXIMUM DUTY CYCLE (%)
FB = GND
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup CircuitMAX5020
MAXIMUM DUTY CYCLE
vs. TEMPERATURE
MAX5019 toc04
TEMPERATURE (°C)
MAXIMUM DUTY CYCLE (%)
FB = GND
V+ SUPPLY CURRENT
vs. TEMPERATUREMAX5019 toc05
V+ SUPPLY CURRENT (mA)
TEMPERATURE (°C)
FB = VDD = GND
SOFT-START SOURCE CURRENT
vs. TEMPERATURE
MAX5019 toc06
TEMPERATURE (°C)
SOFT-START SOURCE CURRENT (VDD = FB = SS_SHDN = GND
V+ = 110V
V+ INPUT CURRENT vs.
TEMPERATURE (AFTER STARTUP)
MAX5019 toc07
TEMPERATURE (°C)
V+ INPUT CURRENT (V+ = 110V, VDD = 13V, FB = GND
V+ SHUTDOWN CURRENT
vs. TEMPERATURE
MAX5019 toc08
TEMPERATURE (°C)
V+ SHUTDOWN CURRENT (V+ = 110V, FB = SS_SHDN = GND
CS THRESHOLD VOLTAGE
vs. TEMPERATURE
MAX5019 toc09
TEMPERATURE (°C)
CS THRESHOLD VOLTAGE (V)
FB = GND
NDRV RESISTANCE
vs. TEMPERATUREMAX5019 toc10
NDRV RESISTANCE (
TEMPERATURE (°C)
HIGH-SIDE DRIVER
LOW-SIDE DRIVER
CURRENT-LIMIT DELAY
vs. TEMPERATURE
MAX5019 toc11
TEMPERATURE (°C)
CURRENT-LIMIT DELAY (ns)
FB = GND, 100mV OVERDRIVE ON CS
VSS_SHDN vs. VDD
MAX5019
toc12
VDD (V)
SS_SHDN
(V)
Typical Operating Characteristics (continued)(V+ = 48V, VDD= 13V, CS = GND, NRDV is open circuit, TA= +25°C, unless otherwise noted.)
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup Circuit
Typical Operating Characteristics (continued)(V+ = 48V, VDD= 13V, CS = GND, NRDV is open circuit, TA= +25°C, unless otherwise noted.)
NDRV FREQUENCY vs. VDD
MAX5019 toc13
VDD (V)
NDRV FREQUENCY (kHz)FB = GND
MAX5020
MAXIMUM DUTY CYCLE vs.VDD
MAX5019 toc14
VDD (V)
MAXIMUM DUTY CYCLE (%)
VFB = 4V, CS = GND
DEVICE POWERED
FROM V+
DEVICE POWERED
FROM VDD
VCC vs. VDD
MAX5019 toc15
VDD (V)
(V)
DEVICE POWERED FROM VDD
DEVICE POWERED
FROM V+
FB = GND
V+ SUPPLY CURRENT vs.
V+ VOLTAGE
MAX5019 toc16
V+ VOLTAGE (V)
V+ SUPPLY CURRENT (mA)
VFB = VDD = GND
V+ SUPPLY CURRENT vs. V+ VOLTAGE
(AFTER STARTUP)
MAX5019 toc17
V+ VOLTAGE (V)
V+ LEAKAGE CURRENT (
VDD = 13V, FB = GND
VCC VOLTAGE vs. VCC CURRENT
MAX5019 toc18
VCC CURRENT (mA)
VOLTAGE (V)5.010.015.020.0
V+ = 110V, VFB = 4V
VDD = 36V
VDD = 13V
VCC VOLTAGE vs. VCC CURRENT
MAX5019
toc19
VCC CURRENT (mA)
VOLTAGE (V)
VDD = GND, VFB = 4V
V+ = 110V
V+ = 90VV+ = 72V
V+ = 48V
V+ = 36V
V+ = 24V
MAX5019/MAX5020
Detailed DescriptionUse the MAX5019/MAX5020 PWM current-mode con-
trollers to design flyback- or forward-mode power sup-
plies. Current-mode operation simplifies control-loop
design while enhancing loop stability. An internal high-
voltage startup regulator allows the device to connect
directly to the input supply without an external startup
resistor. Current from the internal regulator starts the
controller. Once the tertiary winding voltage is estab-
lished the internal regulator is switched off and bias
current for running the IC is derived from the tertiary
winding. The internal oscillator is set to 275kHz and
trimmed to ±10%. This permits the use of small mag-
netic components to minimize board space. Both the
MAX5019 and MAX5020 can be used in power sup-
plies providing multiple output voltages. A functional
diagram of the IC is shown in Figure 1. Typical applica-
tions circuits for forward and flyback topologies are
shown in Figure 2 and Figure 3, respectively. For isolat-
ed flyback power supplies use the circuit of Figure 4.
Current-Mode ControlThe MAX5019/MAX5020 offer current-mode control
operation with added features such as leading-edge
blanking with dual internal path that only blanks the
sensed current signal applied to the input of the PWM
comparator. The current limit comparator monitors the
CS pin at all times and provides cycle-by-cycle current
limit without being blanked. The leading-edge blanking
of the CS signal prevents the PWM comparator from
prematurely terminating the on cycle. The CS signal
contains a leading-edge spike that is the result of the
MOSFET gate charge current, capacitive and diode
reverse recovery current of the power circuit. Since this
leading-edge spike is normally lower than the current
limit comparator threshold, current limiting is not
blanked and cycle-by-cycle current limiting is provided
under all conditions.
Use the MAX5019 in discontinuous flyback applications
where wide line voltage and load current variation is
expected. Use the MAX5020 for single transistor for-
ward converters where the maximum duty cycle must
be limited to less than 50%.
Under certain conditions it may be advantageous to
use a forward converter with greater than 50% duty
cycle. For those cases use the MAX5019. The large
duty cycle results in much lower operating primary
RMS currents through the MOSFET switch and in most
cases a smaller output filter inductor. The major disad-
Current-Mode PWM Controllers with Integrated
Startup Circuit
Pin Description
PINNAMEFUNCTION1V+High-Voltage Startup Input. Connect directly to an input voltage between 18V to 110V. Connects
internally to a high-voltage linear regulator that generates VCC during startup.
2VDD
VDD is the Input of the Linear Regulator that Generates VCC. For supply voltages less than 36V, VDD
and V+ can both be connected to the supply. For supply voltages greater than 36V, VDD receives
its power from the tertiary winding of the transformer and accepts voltages from 13V to 36V. Bypass
to GND with a 4.7µF capacitor.
3FBInput of the Fixed-Gain Inverting Amplifier. Connect a voltage-divider from the regulated output to
this pin. The noninverting input of the amplifier is referenced to 2.4V.SS_SHDN
Soft-Start Timing Capacitor Connection. Ramp time to full current limit is approximately 0.45ms/nF.
This pin is also the reference voltage output. Bypass with a minimum 10nF capacitor to GND. The
device goes into shutdown when SS_SHDN is pulled below 0.25V.
5CS
Current Sense Input. Turns power switch off if VCS rises above 465mV for cycle-by-cycle current
limiting. CS is also the feedback for the current-mode controller. CS is connected to the PWM
comparator through a leading-edge blanking circuit.GNDGroundNDRVGate Drive. Drives a high-voltage external N-channel power MOSFET.
8VCC
Regulated IC Supply. Provides power for the entire IC. VCC is regulated from VDD during normal
operation and from V+ during startup. Bypass VCC with a 10μF tantalum capacitor in parallel with
0.1µF ceramic capacitor to GND.
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup CircuitHIGH-
VOLTAGE
REGULATOROUT
BIAS
WINDING
REGULATOROUT
SLOPE
COMPENSATION
26mV/μs
275kHz
OSCILLATOR
70ns
BLANKING
80%/50%
DUTY CYCLE
CLAMP
ILIM
BUF
UVLO
GND
VDD
SS_SHDN
PWM
VDD-OK
VCC
NDRV
VCC
4μA
50kΩ
5kΩ
2.4V
6.6V
0.7V
125mV
0.25V
26mV/μs
1MΩ
MAX5019 ONLY
ERROR
AMP
VCC
Figure 1. Functional Diagram
