19-3283; Rev 3; 10/06
High-Performance, Single-Ended, Current-Mode
PWM Controllers
General Description
The MAX5070/MAX5071 BiCMOS, high-performance,
current-mode PWM controllers have all the features
required for wide input voltage range isolated/nonisolated
power supplies. These controllers are used for low- and
high-power universal input voltage and telecom power
supplies.
The MAX5070/MAX5071 contain a fast comparator with
only 60ns typical delay from current sense to the output
for overcurrent protection. The MAX5070A/MAX5070B
have an integrated error amplifier with the output at
COMP. Soft-start is achieved by controlling the COMP
voltage rise using external components.
The frequency is adjustable from 20kHz to 1MHz with
an external resistor and capacitor. The timing capacitor
discharge current is trimmed allowing for programma-
ble dead time and maximum duty cycle for a given fre-
quency. The available saw-toothed waveform at R
T
C
T
can be used for slope compensation when needed.
The MAX5071A/MAX5071B include a bidirectional syn-
chronization circuit allowing for multiple controllers to
run at the same frequency to avoid beat frequencies.
Synchronization is accomplished by simply connecting
the SYNC pins of all devices together. When synchro-
nizing with other devices, the MAX5071A/MAX5071B
with the highest frequency synchronizes the other
devices. Alternatively, the MAX5071A/MAX5071B can
be synchronized to an external clock with an open-
drain output stage running at a higher frequency.
The MAX5071C provides a clock output pulse
(ADV_CLK) that leads the driver output (OUT) by
110ns. The advanced clock signal is used to drive the
secondary-side synchronous rectifiers.
The MAX5070/MAX5071 are available in 8-pin µMAX
®
and SO packages and operate over the automotive tem-
perature range of -40°C to +125°C.
Features
♦
Pin-for-Pin Replacement for UC2842 (MAX5070A)
and UC2844 (MAX5070B)
♦
2A Drive Source and 1A Sink Capability
♦
Up to 1MHz Switching Frequency Operation
♦
Bidirectional Synchronization
(MAX5071A/MAX5071B)
♦
Advanced Output Drive for Secondary-Side
Synchronous Rectification (MAX5071C)
♦
Fast 60ns Cycle-by-Cycle Current Limit
♦
Trimmed Oscillator Capacitor Discharge Current
Sets Maximum Duty Cycle Accurately
♦
Accurate 5% Start and Stop Voltage with 6V
Hysteresis
♦
Low 32µA Startup Current
♦
5V Regulator Output (VREF) with 20mA Capability
♦
Overtemperature Shutdown
MAX5070/MAX5071
Ordering Information
PART
MAX5070AASA
MAX5070AAUA
MAX5070BASA
MAX5070BAUA
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
8 SO
8 µMAX
8 SO
8 µMAX
Specify lead-free by adding the + symbol at the end of the part
number when ordering.
Ordering Information continued at end of data sheet.
Selector Guide appears at end of data sheet.
Pin Configurations
TOP VIEW
Applications
Universal Input AC/DC Power Supplies
Isolated Telecom Power Supplies
Isolated Power-Supply Modules
Networking Systems
Computer Systems/Servers
Industrial Power Conversion
Isolated Keep-Alive Circuits
COMP
1
8
7
VREF
V
CC
OUT
GND
FB
2
CS
3
MAX5070A
MAX5070B
6
5
R
T
/C
T
4
µMAX/SO
µMAX is a registered trademark of Maxim Integrated Products, Inc.
Pin Configurations continued at end of data sheet.
1
________________________________________________________________
Maxim Integrated Products
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.
High-Performance, Single-Ended, Current-Mode
PWM Controllers
MAX5070/MAX5071
ABSOLUTE MAXIMUM RATINGS
V
CC
(Low-Impedance Source) to GND ..................-0.3V to +30V
V
CC
(I
CC
< 30mA).....................................................Self Limiting
OUT to GND ...............................................-0.3V to (V
CC
+ 0.3V)
OUT Current.............................................................±1A for 10µs
FB, SYNC, COMP, CS, R
T
/C
T
, VREF to GND ...........-0.3V to +6V
COMP Sink Current (MAX5070)..........................................10mA
Continuous Power Dissipation (T
A
= +70°C)
8-Pin µMAX (derate 4.5mW/°C above +70°C) .............362mW
8-Pin SO (derate 5.9mW/°C above +70°C)...............470.6mW
Operating Temperature Range (Automotive) ....-40°C to +125°C
Maximum Junction Temperature .....................................+150°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
CC
= +15V, R
T
= 10kΩ, C
T
= 3.3nF, V
VREF
= OPEN, C
VREF
= 0.1µF, COMP = OPEN, V
FB
= 2V, CS = GND,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 1)
PARAMETER
REFERENCE
Output Voltage
Line Regulation
Load Regulation
Total Output Variation
Reference Output-Noise Voltage
Reference Output Short Circuit
OSCILLATOR
Initial Accuracy
Voltage Stability
Temp Stability
R
T
/C
T
Voltage Ramp (
P-P
)
R
T
/C
T
Voltage Ramp Valley
Discharge Current
Frequency Range
FB Input Voltage
FB Input Bias Current
Open-Loop Voltage Gain
Unity-Gain Bandwidth
Power-Supply Rejection Ratio
COMP Sink Current
COMP Source Current
COMP Output High Voltage
COMP Output Low Voltage
CURRENT-SENSE AMPLIFIER
Gain
Maximum Current-Sense Signal
A
CS
V
CS_MAX
(Notes 3, 4)
MAX5070A/B (Note 3)
V
COMP
= 5V, MAX5071_
2.85
0.95
0.95
3
1
1
3.26
1.05
1.05
V/V
V
V
RAMP
V
RAMP_VALLEY
I
DIS
f
OSC
V
FB
I
B(FB)
A
VOL
f
GBW
PSRR
I
SINK
I
SOURCE
V
COMPH
V
COMPL
12V
≤
V
CC
≤
25V (Note 2)
V
FB
= 2.7V, V
COMP
= 1.1V
V
FB
= 2.3V, V
COMP
= 5V
V
FB
= 2.3V, R
COMP
= 15kΩ to GND
V
FB
= 2.7V, R
COMP
= 15kΩ to VREF
60
2
-0.5
5
2V
≤
V
COMP
≤
4V
FB shorted to COMP
V
RT/CT
= 2V, T
A
= +25°C
7.9
20
2.465
2.5
-0.01
100
1
80
6
-1.2
5.8
0.1
0.5
-1.8
T
A
= +25°C
12V < V
CC
< 25V
-40°C < T
A
< +85°C
51
54
0.2
0.5
1.7
1.1
8.3
8.7
1000
2.535
-0.1
57
0.5
kHz
%
%
V
V
mA
kHz
V
µA
dB
MHz
dB
mA
mA
V
V
V
VREF
∆V
LINE
∆V
LOAD
V
REFT
V
NOISE
I
S_SC
T
A
= +25°C, I
VREF
= 1mA
12V < V
CC
< 25V, I
VREF
= 1mA
1mA < I
VREF
< 20mA
1mA < I
VREF
< 20mA, 12V < V
CC
< 25V
10Hz < f < 10kHz, T
A
= +25°C
V
VREF
= 0V
-30
4.9
50
-100
-180
4.950
5.000
0.4
6
5.050
4
25
5.1
V
mV
mV
V
µV
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ERROR AMPLIFIER (MAX5070A/MAX5070B)
2
_______________________________________________________________________________________
High-Performance, Single-Ended, Current-Mode
PWM Controllers
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +15V, R
T
= 10kΩ, C
T
= 3.3nF, V
VREF
= OPEN, C
VREF
= 0.1µF, COMP = OPEN, V
FB
= 2V, CS = GND,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 1)
PARAMETER
Power-Supply Rejection Ratio
Input Bias Current
Delay From CS to OUT
MOSFET DRIVER
OUT Low-Side On-Resistance
OUT High-Side On-Resistance
I
SOURCE
(Peak)
I
SINK
(Peak)
Rise Time
Fall Time
UNDERVOLTAGE LOCKOUT/STARTUP
Startup Voltage Threshold
Minimum Operating Voltage After
Turn-On
Undervoltage-Lockout Hysteresis
PWM
Maximum Duty Cycle
Minimum Duty Cycle
SUPPLY CURRENT
Startup Supply Current
Operating Supply Current
Zener Bias Voltage at V
CC
THERMAL SHUTDOWN
Thermal Shutdown
Thermal-Shutdown Hysteresis
SYNC Frequency Range
SYNC Clock Input High
Threshold
SYNC Clock Input Low Threshold
SYNC Clock Input Minimum
Pulse Width
SYNC Clock Output High Level
SYNC Clock Output Low Level
SYNC Leakage Current
T
SHDN
T
HYST
f
SYNC
V
SYNCINH
V
SYNCINL
t
PW_SYNCIN
V
SYNCOH
V
SYNCOL
I
SYNC
1mA external pulldown
R
SYNC
= 5kΩ
V
SYNC
= 0V
200
4.0
4.7
0
0.01
0.1
0.1
20
3.5
0.8
+150
4
1000
°C
°C
kHz
V
V
ns
V
V
µA
I
START
I
CC
V
Z
V
FB
= V
CS
= 0V
I
CC
= 25mA
24
32
3
26.5
65
5
µA
mA
V
D
MAX
D
MIN
MAX5070A/MAX5071A
MAX5070B/MAX5071B/MAX5071C
94.5
48
96
49.8
97.5
50
0
%
%
V
CC_START
V
CC_MIN
UVLO
HYST
15.2
9.2
16
10
6
16.8
10.8
V
V
V
V
RDS_ONL
V
RDS_ONH
I
SOURCE
I
SINK
t
r
t
f
I
SINK
= 200mA
I
SOURCE
= 100mA
C
OUT
= 10nF
C
OUT
= 10nF
C
OUT
= 1nF
C
OUT
= 1nF
4.5
3.5
2
1
15
22
10
7
Ω
Ω
A
A
ns
ns
SYMBOL
PSRR
I
CS
t
CS_DELAY
V
COMP
= 0V
50mV overdrive
CONDITIONS
12V
≤
V
CC
≤
25V
MIN
TYP
70
-1
60
-2.5
MAX
UNITS
dB
µA
ns
MAX5070/MAX5071
SYNCHRONIZATION (MAX5071A/MAX5071B only) (Note 5)
_______________________________________________________________________________________
3
High-Performance, Single-Ended, Current-Mode
PWM Controllers
MAX5070/MAX5071
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +15V, R
T
= 10kΩ, C
T
= 3.3nF, V
VREF
= OPEN, C
VREF
= 0.1µF, COMP = OPEN, V
FB
= 2V, CS = GND,
T
A
= -40°C to +85°C,
unless otherwise noted.) (Note 1)
PARAMETER
ADV_CLK (MAX5071C only)
ADV_CLK High Voltage
ADV_CLK Low Voltage
ADV_CLK Output Pulse Width
ADV_CLK Rising Edge to OUT
Rising Edge
ADV_CLK Source and Sink
Current
V
ADV_CLKH
V
ADV_CLKL
t
PULSE
t
ADV_CLK
I
ADV_CLK
10
I
ADV_CLK
= 10mA source
I
ADV_CLK
= 10mA sink
85
110
2.4
3
0.4
V
V
ns
ns
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ELECTRICAL CHARACTERISTICS
(V
CC
= +15V, R
T
= 10kΩ, C
T
= 3.3nF, V
VREF
= OPEN, C
VREF
= 0.1µF, COMP = OPEN, V
FB
= 2V, CS = GND,
T
A
= -40°C to +125°C,
unless otherwise noted.) (Note 1)
PARAMETER
REFERENCE
Output Voltage
Line Regulation
Load Regulation
Total Output Variation
Reference Output Noise Voltage
Reference Output Short Circuit
OSCILLATOR
Initial Accuracy
Voltage Stability
Temp Stability
R
T
/C
T
Voltage Ramp (
P-P
)
R
T
/C
T
Voltage Ramp Valley
Discharge Current
Frequency Range
FB Input Voltage
FB Input Bias Current
Open-Loop Voltage Gain
Unity-Gain Bandwidth
Power-Supply Rejection Ratio
COMP Sink Current
COMP Source Current
COMP Output High Voltage
COMP Output Low Voltage
V
RAMP
V
RAMP_VALLEY
I
DIS
f
OSC
V
FB
I
B(FB)
A
VOL
f
GBW
PSRR
I
SINK
I
SOURCE
V
COMPH
V
COMPL
12V
≤
V
CC
≤
25V (Note 2)
V
FB
= 2.7V, V
COMP
= 1.1V
V
FB
= 2.3V, V
COMP
= 5V
V
FB
= 2.3V, R
COMP
=15kΩ to GND
V
FB
= 2.7V, R
COMP
= 15kΩ to VREF
60
2
-0.5
5
2V
≤
V
COMP
≤
4V
FB shorted to COMP
V
RT/CT
= 2V, T
A
= +25°C
7.9
20
2.465
2.5
-0.01
100
1
80
6
-1.2
5.8
0.1
0.5
-1.8
T
A
= +25°C
12V < V
CC
< 25V
-40°C < T
A
< +125°C
51
54
0.2
1
1.7
1.1
8.3
8.7
1000
2.535
-0.1
57
0.5
kHz
%
%
V
V
mA
kHz
V
µA
dB
MHz
dB
mA
mA
V
V
V
VREF
∆V
LINE
∆V
LOAD
V
REFT
V
NOISE
I
S_SC
T
A
= +25°C, I
VREF
= 1mA
12V < V
CC
< 25V, I
VREF
= 1mA
1mA < I
VREF
< 20mA
1mA < I
VREF
< 20mA, 12V < V
CC
< 25V
10Hz < f < 10kHz, T
A
= +25°C
V
VREF
= 0V
-30
4.9
50
-100
-180
4.950
5.000
0.4
6
5.050
4
25
5.1
V
mV
mV
V
µV
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
ERROR AMPLIFIER (MAX5070A/MAX5070B)
4
_______________________________________________________________________________________
High-Performance, Single-Ended, Current-Mode
PWM Controllers
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +15V, R
T
= 10kΩ, C
T
= 3.3nF, V
VREF
= OPEN, C
VREF
= 0.1µF, COMP = OPEN, V
FB
= 2V, CS = GND,
T
A
= -40°C to +125°C,
unless otherwise noted.) (Note 1)
PARAMETER
CURRENT-SENSE AMPLIFIER
Gain
Maximum Current-Sense Signal
Power-Supply Rejection Ratio
Input Bias Current
Delay From CS to OUT
MOSFET DRIVER
OUT Low-Side On-Resistance
OUT High-Side On-Resistance
I
SOURCE
(Peak)
I
SINK
(Peak)
Rise Time
Fall Time
UNDERVOLTAGE LOCKOUT/STARTUP
Startup Voltage Threshold
Minimum Operating Voltage After
Turn-On
Undervoltage-Lockout Hysteresis
PWM
Maximum Duty Cycle
Minimum Duty Cycle
SUPPLY CURRENT
Startup Supply Current
Operating Supply Current
Zener Bias Voltage at V
CC
THERMAL SHUTDOWN
Thermal Shutdown
Thermal-Shutdown Hysteresis
SYNC Frequency Range
SYNC Clock Input High
Threshold
SYNC Clock Input Low Threshold
SYNC Clock Input Minimum
Pulse Width
SYNC Clock Output High Level
SYNC Clock Output Low Level
T
SHDN
T
HYST
f
SYNC
V
SYNCINH
V
SYNCINL
t
PW_SYNCIN
V
SYNCOH
V
SYNCOL
1mA external pulldown
R
SYNC
= 5kΩ
200
4.0
4.7
0
0.1
20
3.5
0.8
+150
4
1000
°C
°C
kHz
V
V
ns
V
V
I
START
I
CC
V
Z
V
FB
= V
CS
= 0V
I
CC
= 25mA
24
32
3
26.5
65
5
µA
mA
V
D
MAX
D
MIN
MAX5070A/MAX5071A
MAX5070B/MAX5071B/MAX5071C
94.5
48
96
49.8
97.5
50
0
%
%
V
CC_START
V
CC_MIN
UVLO
HYST
15.2
9.2
16
10
6
16.8
10.8
V
V
V
V
RDS_ONL
V
RDS_ONH
I
SOURCE
I
SINK
t
r
t
f
I
SINK
= 200mA
I
SOURCE
= 100mA
C
OUT
= 10nF
C
OUT
= 10nF
C
OUT
= 1nF
C
OUT
= 1nF
4.5
3.5
2
1
15
22
12
9
Ω
Ω
A
A
ns
ns
A
CS
V
CS_MAX
PSRR
I
CS
t
CS_DELAY
50mV overdrive
(Notes 3, 4)
MAX5070A/B (Note 3)
V
COMP
= 5V, MAX5071_
12V
≤
V
CC
≤
25V
2.85
0.95
0.95
3
1
1
70
-1
60
-2.5
3.26
1.05
1.05
V/V
V
dB
µA
ns
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5070/MAX5071
SYNCHRONIZATION (MAX5071A/MAX5071B only, Note 5)
_______________________________________________________________________________________
5
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