19-2115; Rev 0; 7/01
Current-Mode PWM Controllers with Integrated
Startup Circuit
General Description
The 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 high
voltages. Exercise caution.
Features
o
Wide Input Range: (18V to 110V) or (13V to 36V)
o
Isolated (without optocoupler) or Nonisolated
Power Supply
o
Current-Mode Control
o
Leading-Edge Blanking
o
Internally Trimmed 275kHz ±10% Oscillator
o
Low External Component Count
o
Soft-Start
o
High-Voltage Startup Circuit
o
Pulse-by-Pulse Current Limiting
o
Thermal Shutdown
o
SO-8 Package
MAX5019/MAX5020
Ordering Information
PART
MAX5019CSA*
MAX5019ESA*
MAX5020CSA*
MAX5020ESA*
TEMP. RANGE
0°C to +70°C
-40°C to +85°C
0°C to +70°C
-40°C to +85°C
PIN-PACKAGE
8-SO
8-SO
8-SO
8-SO
Applications
Telecom Power Supplies
Industrial Power Supplies
Networking Power Supplies
Isolated Power Supplies
*See Selector Guide at end of data sheet.
Typical Operating Circuit
Pin Configuration
V
IN
V
OUT
V
DD
V+
TOP VIEW
MAX5020
V+
1
V
DD
2
FB
3
8
7
V
CC
NDRV
GND
V
CC
NDRV
CS
MAX5019/
MAX5020
6
5
SS_SHDN
GND
FB
SS_SHDN
4
CS
8-SO
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Current-Mode PWM Controllers with Integrated
Startup Circuit
MAX5019/MAX5020
ABSOLUTE MAXIMUM RATINGS
V+ to GND ……………………………………...……-0.3V to +120V
V
DD
to GND.………………………………….……….-0.3V to +40V
V
CC
to GND.………………….……………………-0.3V to +12.5V
FB, NDRV, SS_SHDN, CS to GND .……-0.3V to V
CC
+ 0.3V
V
DD
and V
CC
Current …………………...…………………..20mA
NDRV Current Continuous...………………………………….25mA
NDRV Current for Less than 1µs..………….…………….……±1A
Continuous Power Dissipation (T
A
= +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
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
(V
DD
= 13V, a 10µF capacitor connects V
CC
to GND, V
CS
= 0, V+ = 48V, 0.1µF capacitor connected from SS_SHDN to GND, NDRV
= open circuit, V
FB
= 3V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SUPPLY CURRENT
I
V+(NS)
V+ Supply Current
V+ Supply Current After Startup
V
DD
Supply Current
V+ Shutdown Current
V
DD
Shutdown Current
PREREGULATOR/STARTUP
V+ Input Voltage
V
DD
Supply Voltage
INTERNAL REGULATORS (V
CC
)
V
CC
Output Voltage
V
CC
Undervoltage Lockout
OUTPUT DRIVER
Peak Source Current
Peak Sink Current
NRDV High-Side Driver
Resistance
NDRV Low-Side Driver
Resistance
ERROR AMPLIFIER
FB Input Resistance
FB Input Bias Current
Error Amplifier Gain (Inverting)
Closed-Loop 3dB Bandwidth
FB Input Voltage Range
2
R
IN
I
FB
A
VCL
V
FB =
V
SS_SHDN
50
±1
-20
200
3
kΩ
µA
V/V
kHz
V
R
OH
R
OL
V
CC
= 11V (externally forced)
V
CC
= 11V (externally forced)
V
CC
= 11V, externally forced,
NDRV sourcing 50mA
V
CC
= 11V, externally forced,
NDRV sinking 50mA
570
1000
4
1.6
12
4
mA
mA
Ω
Ω
V
CC_UVLO
Powered from V+, I
CC
= 7.5mA, V
DD
= 0
Powered from V
DD
, I
CC
= 7.5mA
V
CC
falling
7.5
9.0
9.8
10.0
6.6
12.0
11.0
V
V
V
18
13
110
36
V
V
I
VDD(NS)
I
VDD(S)
I
V+(S)
V
DD
= 0, V+ = 110V, driver not switching
V+ = 110V, V
DD
= 0, FB = GND,
driver switching
V+ = 110V, V
DD
= 13V, FB = GND
V
DD
= 36V, driver not switching
V
DD
= 36V, driver switching, FB = GND
V
SS_SHDN
= 0, V+ = 110V
V
SS_SHDN
= 0
0.8
1.6
14
0.9
2.1
180
4
1.6
3.0
290
20
1.6
3.0
mA
µA
mA
µA
µA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
2
_______________________________________________________________________________________
Current-Mode PWM Controllers with Integrated
Startup Circuit
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 13V, a 10µF capacitor connects V
CC
to GND, V
CS
= 0, V+ = 48V, 0.1µF capacitor connected from SS_SHDN to GND, NDRV
= open circuit, V
FB
= 3V, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C.)
PARAMETER
SLOPE COMPENSATION
Slope Compensation
(MAX5019 only)
THERMAL SHUTDOWN
Thermal Shutdown Temperature
Thermal Hysteresis
CURRENT LIMIT
CS Threshold Voltage
CS Input Bias Current
Current Limit Comparator
Propagation Delay
CS Blanking Time
OSCILLATOR
Clock Frequency Range
Max Duty Cycle
SOFT-START
SS Source Current
SS Sink Current
Steady State Reference Voltage
at SS_SHDN
Shutdown Threshold
V
SS
_SHDN
No external load
V
SS_SHDN
falling
V
SS_SHDN
rising
I
SSO
V
SS_SHDN
= 0
2.0
1.0
2.331
0.25
0.53
2.420
0.37
0.59
2.500
0.41
0.65
4.5
6.5
µA
mA
V
V
FB = GND
MAX5019, FB = GND
MAX5020, FB = GND
247
75
44
275
302
85
50
kHz
%
V
ILIM
FB = GND
0
≤
V
CS
≤
2V, FB = GND
50mV overdrive on CS, FB = GND
FB = GND, only PWM comparator is blanked
419
-1
180
70
465
510
1
mV
µA
ns
ns
150
25
°C
°C
V
SCOMP
26
mV/µs
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5019/MAX5020
Typical Operating Characteristics
(V+ = 48V, V
DD
= 13V, CS = GND, NRDV is open circuit, T
A
= +25°C, unless otherwise noted.)
V
SS_SHDN
vs. TEMPERATURE
(AT THE END OF SOFT-START)
MAX5019 toc01
NDRV FREQUENCY
vs. TEMPERATURE
MAX5019 toc02
MAX5019
MAXIMUM DUTY CYCLE
vs. TEMPERATURE
MAX5019 toc03
1.003
V
SS_SHDN
(V) (NORMALIZED TO V
REF
= 2.4V)
V
FB
= 4V
1.002
278
81.0
80.9
80.8
80.7
80.6
80.5
80.4
FB = GND
FB = GND
276
1.001
275
1.000
274
0.999
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
273
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
MAXIMUM DUTY CYCLE (%)
277
NDRV FREQUENCY (kHz)
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
_______________________________________________________________________________________
3
Current-Mode PWM Controllers with Integrated
Startup Circuit
MAX5019/MAX5020
Typical Operating Characteristics (continued)
(V+ = 48V, V
DD
= 13V, CS = GND, NRDV is open circuit, T
A
= +25°C, unless otherwise noted.)
MAX5020
MAXIMUM DUTY CYCLE
vs. TEMPERATURE
MAX5019 toc04
V+ SUPPLY CURRENT
vs. TEMPERATURE
MAX5019 toc05
SOFT-START SOURCE CURRENT
vs. TEMPERATURE
SOFT-START SOURCE CURRENT (µA)
4.49
4.48
4.47
4.46
4.45
4.44
4.43
4.42
4.41
4.40
MAX5019 toc06
48.0
47.8
FB = GND
47.6
47.4
47.2
47.0
46.8
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
1.64
1.63
V+ SUPPLY CURRENT (mA)
1.62
1.61
1.60
1.59
1.58
1.57
1.56
1.55
-40
-20
40
TEMPERATURE (°C)
0
20
60
80
FB = V
DD
= GND
4.50
V
DD
= FB = SS_SHDN = GND
V+ = 110V
MAXIMUM DUTY CYCLE (%)
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
V+ INPUT CURRENT vs.
TEMPERATURE (AFTER STARTUP)
MAX5019 toc07
V+ SHUTDOWN CURRENT
vs. TEMPERATURE
MAX5019 toc08
CS THRESHOLD VOLTAGE
vs. TEMPERATURE
MAX5019 toc09
13.80
13.75
V+ INPUT CURRENT (µA)
13.70
13.65
13.60
13.55
13.50
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
V+ = 110V, V
DD
= 13V, FB = GND
182.5
V+ SHUTDOWN CURRENT (µA)
182.0
V+ = 110V, FB = SS_SHDN = GND
181.5
181.0
180.5
180.0
179.5
179.0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
0.488
CS THRESHOLD VOLTAGE (V)
0.487
FB = GND
0.486
0.485
0.484
0.483
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
NDRV RESISTANCE
vs. TEMPERATURE
MAX5019 toc10
CURRENT-LIMIT DELAY
vs. TEMPERATURE
208
CURRENT-LIMIT DELAY (ns)
206
204
202
200
198
196
194
192
190
188
2.400
-40
-20
0
20
40
60
80
0
5
10
2.402
FB = GND, 100mV OVERDRIVE ON CS
V
SS_SHDN
(V)
MAX5019 toc11
V
SS_SHDN
vs. V
DD
MAX5019 toc12
5.0
4.5
NDRV RESISTANCE (Ω)
4.0
HIGH-SIDE DRIVER
3.5
3.0
2.5
2.0
1.5
1.0
-40
-20
40
TEMPERATURE (°C)
0
20
60
80
LOW-SIDE DRIVER
210
2.410
2.408
2.406
2.404
15
20
V
DD
(V)
25
30
35
40
TEMPERATURE (°C)
4
_______________________________________________________________________________________
Current-Mode PWM Controllers with Integrated
Startup Circuit
Typical Operating Characteristics (continued)
(V+ = 48V, V
DD
= 13V, CS = GND, NRDV is open circuit, T
A
= +25°C, unless otherwise noted.)
MAX5020
MAXIMUM DUTY CYCLE vs. V
DD
MAX5019 toc13
MAX5019 toc14
MAX5019/MAX5020
NDRV FREQUENCY vs. V
DD
271.0
270.5
NDRV FREQUENCY (kHz)
270.0
269.5
269.0
268.5
FB = GND
268.0
267.5
267.0
0
5
10
15
20
V
DD
(V)
25
30
35
40
47.9
MAXIMUM DUTY CYCLE (%)
47.8
47.7
V
FB
= 4V, CS = GND
10.1
10.0
V
CC
(V)
9.9
DEVICE POWERED FROM V
DD
47.6
47.5
47.4
47.3
47.2
47.1
47.0
0
5
10
15
20
V
DD
(V)
25
30
35
40
DEVICE POWERED
FROM V+
DEVICE POWERED
FROM V
DD
FB = GND
9.8
9.7
9.6
9.5
0
5
10
15
20
V
DD
(V)
25
30
35
40
DEVICE POWERED
FROM V+
V+ SUPPLY CURRENT vs.
V+ VOLTAGE
1.59
V+ SUPPLY CURRENT (mA)
1.58
1.57
1.56
1.55
1.54
1.53
1.52
1.51
0
20
40
60
80
100
V+ VOLTAGE (V)
V
FB
= V
DD
= GND
MAX5019 toc16
V+ SUPPLY CURRENT vs. V+ VOLTAGE
(AFTER STARTUP)
14
V+ LEAKAGE CURRENT (µA)
12
10
8
6
4
2
0
0 10 20 30 40 50 60 70 80 90 100 110
V+ VOLTAGE (V)
V
DD
= 13V, FB = GND
MAX5019 toc17
1.60
16
V
CC
VOLTAGE vs. V
CC
CURRENT
MAX5019 toc18
V
CC
VOLTAGE vs. V
CC
CURRENT
9.9
9.8
V
CC
VOLTAGE (V)
9.7
9.6
9.5
9.4
9.3
9.2
V+ = 36V
V+ = 24V
V
DD
= GND, V
FB
= 4V
V+ = 110V
V+ = 90V
V+ = 72V
V+ = 48V
MAX5019 toc19
10.4
V+ = 110V, V
FB
= 4V
10.2
V
DD
= 36V
V
CC
VOLTAGE (V)
10.0
9.8
V
DD
= 13V
9.6
9.4
9.2
9.0
0
5.0
10.0
15.0
V
CC
CURRENT (mA)
10.0
9.1
9.0
20.0
0
5.0
10.0
V
CC
CURRENT (mA)
15.0
20.0
_______________________________________________________________________________________
MAX5019 toc15
48.0
V
CC
vs. V
DD
10.2
5
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