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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.
Applications
Telecom Power Supplies
Industrial Power Supplies
Networking Power Supplies
Isolated Power Supplies
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
Current-Mode PWM Controllers with Integrated
Startup Circuit
________________________________________________________________ Maxim Integrated Products
1
GND
CS
1
2
8
7
V
CC
NDRV
V
DD
FB
V+
8-SO
TOP VIEW
3
4
6
5
MAX5019/
MAX5020
SS_SHDN
Pin Configuration
Ordering Information
NDRV
V
IN
V
OUT
V
DD
V
CC
CS
FB
MAX5020
V+
SS_SHDN
GND
Typical Operating Circuit
19-2115; Rev 0; 7/01
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.
PART
TEMP. RANGE
PIN-PACKAGE
MAX5019CSA*
0
C to +70C
8-SO
MAX5019ESA*
-40
C to +85C
8-SO
MAX5020CSA*
0
C to +70C
8-SO
MAX5020ESA*
-40
C to +85C
8-SO
*See Selector Guide at end of data sheet.
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup Circuit
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
DD
= 13V, a 10F capacitor connects V
CC
to GND, V
CS
= 0, V+ = 48V, 0.1F capacitor connected from SS_SHDN to GND, NDRV
= open circuit, V
FB
= 3V, T
A
= -40C to +85C, unless otherwise noted. Typical values are at T
A
= +25C.)
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
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 1s.....................................1A
Continuous Power Dissipation (T
A
= +70C)
8-Pin SO (derate 5.88mW/C above +70C) ..............471mW
Operating Temperature Range.......................-40C to +85C
Storage Temperature Range........................-65C to +150C
Lead Temperature (soldering, 10s) .................. .........+300C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
SUPPLY CURRENT
I
V+(NS)
V
DD
= 0, V+ = 110V, driver not switching
0.8
1.6
V+ Supply Current
I
V+(S)
V+ = 110V, V
DD
= 0, FB = GND,
driver switching
1.6
3.0
mA
V+ Supply Current After Startup
V+ = 110V, V
DD
= 13V, FB = GND
14
A
I
VDD(NS)
V
DD
= 36V, driver not switching
0.9
1.6
V
D D
S up p l y C ur r ent
I
VDD(S)
V
DD
= 36V, driver switching, FB = GND
2.1
3.0
mA
V+ Shutdown Current
V
SS_
SHDN
= 0, V+ = 110V
180
290
A
V
DD
Shutdown Current
V
SS_
SHDN
= 0
4
20
A
PREREGULATOR/STARTUP
V+ Input Voltage
18
110
V
V
DD
Supply Voltage
13
36
V
INTERNAL REGULATORS (V
CC
)
Powered from V+, I
CC
= 7.5mA, V
DD
= 0
7.5
9.8
12.0
V
V
CC
Output Voltage
Powered from V
DD
, I
CC
= 7.5mA
9.0
10.0
11.0
V
V
CC
Undervoltage Lockout
V
CC_UVLO
V
CC
falling
6.6
V
OUTPUT DRIVER
Peak Source Current
V
CC
= 11V (externally forced)
570
mA
Peak Sink Current
V
CC
= 11V (externally forced)
1000
mA
NRDV High-Side Driver
Resistance
R
OH
V
CC
= 11V, externally forced,
NDRV sourcing 50mA
4
12
NDRV Low-Side Driver
Resistance
R
OL
V
CC
= 11V, externally forced,
NDRV sinking 50mA
1.6
4
ERROR AMPLIFIER
FB Input Resistance
R
IN
50
k
FB Input Bias Current
I
FB
V
FB =
V
SS_
SHDN
1
A
Error Amplifier Gain (Inverting)
A
VCL
-20
V/V
Closed-Loop 3dB Bandwidth
200
kHz
FB Input Voltage Range
2
3
V
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup Circuit
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
DD
= 13V, a 10F capacitor connects V
CC
to GND, V
CS
= 0, V+ = 48V, 0.1F capacitor connected from SS_SHDN to GND, NDRV
= open circuit, V
FB
= 3V, T
A
= -40C to +85C, unless otherwise noted. Typical values are at T
A
= +25C.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
SLOPE COMPENSATION
Slope Compensation
(MAX5019 only)
V
SCOMP
26
mV/
s
THERMAL SHUTDOWN
Thermal Shutdown Temperature
150
C
Thermal Hysteresis
25
C
CURRENT LIMIT
CS Threshold Voltage
V
ILIM
FB = GND
419
465
510
mV
CS Input Bias Current
0
V
CS
2V, FB = GND
-1
1
A
Current Limit Comparator
Propagation Delay
50mV overdrive on CS, FB = GND
180
ns
CS Blanking Time
FB = GND, only PWM comparator is blanked
70
ns
OSCILLATOR
Clock Frequency Range
FB = GND
247
275
302
kHz
MAX5019, FB = GND
75
85
Max Duty Cycle
MAX5020, FB = GND
44
50
%
SOFT-START
SS Source Current
I
SSO
V
SS_
SHDN
= 0
2.0
4.5
6.5
A
SS Sink Current
1.0
mA
Steady State Reference Voltage
at SS_
SHDN
V
SS
_
SHDN
No external load
2.331
2.420
2.500
V
V
SS_
SHDN
falling
0.25
0.37
0.41
Shutdown Threshold
V
SS_
SHDN
rising
0.53
0.59
0.65
V
Typical Operating Characteristics
(V+ = 48V, V
DD
= 13V, CS = GND, NRDV is open circuit, T
A
= +25C, unless otherwise noted.)
0.999
1.000
1.001
1.002
1.003
-40
0
-20
20
40
60
80
V
SS_SHDN
vs. TEMPERATURE
(AT THE END OF SOFT-START)
MAX5019 toc01
TEMPERATURE (
C)
V
FB
= 4V
V
SS_SHDN
(V) (NORMALIZED TO V
REF
= 2.4V)
273
274
276
275
277
278
-40
0
-20
20
40
60
80
NDRV FREQUENCY
vs. TEMPERATURE
MAX5019 toc02
TEMPERATURE (
C)
NDRV FREQUENCY (kHz)
FB = GND
80.4
80.6
80.5
80.8
80.7
80.9
81.0
-40
20
40
-20
0
60
80
MAX5019
MAXIMUM DUTY CYCLE
vs. TEMPERATURE
MAX5019 toc03
TEMPERATURE (
C)
MAXIMUM DUTY CYCLE (%)
FB = GND
MAX5019/MAX5020
Current-Mode PWM Controllers with Integrated
Startup Circuit
4
_______________________________________________________________________________________
46.8
47.2
47.0
47.6
47.4
47.8
48.0
-40
20
40
-20
0
60
80
MAX5020
MAXIMUM DUTY CYCLE
vs. TEMPERATURE
MAX5019 toc04
TEMPERATURE (
C)
MAXIMUM DUTY CYCLE (%)
FB = GND
V+ SUPPLY CURRENT
vs. TEMPERATURE
MAX5019 toc05
1.55
1.56
1.58
1.57
1.62
1.63
1.61
1.60
1.59
1.64
V+ SUPPLY CURRENT (mA)
-40
0
20
-20
40
60
80
TEMPERATURE (
C)
FB = V
DD
= GND
4.40
4.43
4.42
4.41
4.45
4.44
4.49
4.48
4.47
4.46
4.50
-40
-20
0
20
40
60
80
SOFT-START SOURCE CURRENT
vs. TEMPERATURE
MAX5019 toc06
TEMPERATURE (
C)
SOFT-START SOURCE CURRENT (
A)
V
DD
= FB = SS_SHDN = GND
V+ = 110V
13.50
13.55
13.70
13.65
13.60
13.75
13.80
-40
0
-20
20
40
60
80
V+ INPUT CURRENT vs.
TEMPERATURE (AFTER STARTUP)
MAX5019 toc07
TEMPERATURE (
C)
V+ INPUT CURRENT (
A)
V+ = 110V, V
DD
= 13V, FB = GND
179.0
180.0
179.5
180.5
182.0
181.5
181.0
182.5
-40
-20
0
20
40
60
80
V+ SHUTDOWN CURRENT
vs. TEMPERATURE
MAX5019 toc08
TEMPERATURE (
C)
V+ SHUTDOWN CURRENT (
A)
V+ = 110V, FB = SS_SHDN = GND
0.483
0.484
0.486
0.485
0.487
0.488
-40
0
-20
20
40
60
80
CS THRESHOLD VOLTAGE
vs. TEMPERATURE
MAX5019 toc09
TEMPERATURE (
C)
CS THRESHOLD VOLTAGE (V)
FB = GND
NDRV RESISTANCE
vs. TEMPERATURE
MAX5019 toc10
1.0
1.5
2.5
2.0
4.0
4.5
3.5
3.0
5.0
NDRV RESISTANCE (
)
-40
0
20
-20
40
60
80
TEMPERATURE (
C)
HIGH-SIDE DRIVER
LOW-SIDE DRIVER
-40
-20
0
20
40
60
80
CURRENT-LIMIT DELAY
vs. TEMPERATURE
MAX5019 toc11
TEMPERATURE (
C)
CURRENT-LIMIT DELAY (ns)
188
190
192
194
196
198
200
202
204
206
208
210
FB = GND, 100mV OVERDRIVE ON CS
2.400
2.402
2.406
2.404
2.408
2.410
0
10
15
5
20
25
30
35
40
V
SS_SHDN
vs. V
DD
MAX5019
toc12
V
DD
(V)
V
SS_SHDN
(V)
Typical Operating Characteristics (continued)
(V+ = 48V, V
DD
= 13V, CS = GND, NRDV is open circuit, T
A
= +25C, unless otherwise noted.)
_______________________________________________________________________________________
5
MAX5019/MAX5020
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
= +25C, unless otherwise noted.)
267.0
268.0
267.5
269.0
268.5
269.5
270.0
270.5
271.0
0
10
15
5
20
25
30
35
40
NDRV FREQUENCY vs. V
DD
MAX5019 toc13
V
DD
(V)
NDRV FREQUENCY (kHz)
FB = GND
47.0
47.2
47.1
47.4
47.3
47.6
47.5
47.7
47.9
47.8
48.0
0
10
15
5
20
25
30
35
40
MAX5020
MAXIMUM DUTY CYCLE vs. V
DD
MAX5019 toc14
V
DD
(V)
MAXIMUM DUTY CYCLE (%)
V
FB
= 4V, CS = GND
DEVICE POWERED
FROM V+
DEVICE POWERED
FROM V
DD
9.5
9.6
9.8
9.7
10.0
10.1
9.9
10.2
0
10
15
5
20
25
30
35
40
V
CC
vs. V
DD
MAX5019 toc15
V
DD
(V)
V
CC
(V)
DEVICE POWERED FROM V
DD
DEVICE POWERED
FROM V+
FB = GND
1.51
1.53
1.52
1.56
1.55
1.54
1.59
1.58
1.57
1.60
0
40
20
60
80
100
V+ SUPPLY CURRENT vs.
V+ VOLTAGE
MAX5019 toc16
V+ VOLTAGE (V)
V+ SUPPLY CURRENT (mA)
V
FB
= V
DD
= GND
0
2
14
6
4
8
10
12
16
0
40
30
10 20
50 60 70 80 90
110
V+ SUPPLY CURRENT vs. V+ VOLTAGE
(AFTER STARTUP)
MAX5019 toc17
V+ VOLTAGE (V)
V+ LEAKAGE CURRENT (
A)
100
V
DD
= 13V, FB = GND
9.0
9.4
9.2
9.8
9.6
10.2
10.0
10.4
V
CC
VOLTAGE vs. V
CC
CURRENT
MAX5019 toc18
V
CC
CURRENT (mA)
V
CC
VOLTAGE (V)
0
5.0
10.0
15.0
20.0
V+ = 110V, V
FB
= 4V
V
DD
= 36V
V
DD
= 13V
9.0
9.3
9.2
9.1
9.4
9.5
9.6
9.7
9.8
9.9
10.0
0
5.0
10.0
15.0
20.0
V
CC
VOLTAGE vs. V
CC
CURRENT
MAX5019
toc19
V
CC
CURRENT (mA)
V
CC
VOLTAGE (V)
V
DD
= GND, V
FB
= 4V
V+ = 110V
V+ = 90V
V+ = 72V
V+ = 48V
V+ = 36V
V+ = 24V
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