19-3312; Rev 0; 7/04
AVAILABLE
ALUATION KIT
EV
Power IC with Integrated MOSFETs for Isolated IEEE
802.3af PD and Telecom Power-Supply Applications
General Description
The MAX5074 isolated PWM power IC features integrated
switching power MOSFETs connected in a voltage-
clamped, two-transistor, power-circuit configuration. This
device can be used in both forward and flyback configu-
rations with a wide input voltage range from 11V to 76V
and up to 15W of output power.
The voltage-clamped power topology enables full
recovery of stored magnetizing and leakage inductive
energy for enhanced efficiency and reliability. A look-
ahead signal for driving secondary-side synchronous
rectifiers can be used to increase efficiency.
A wide array of protection features includes UVLO,
overtemperature shutdown, and short-circuit protection
with hiccup current limit for enhanced performance and
reliability. Operation up to 500kHz allows smaller exter-
nal magnetics and capacitors.
The MAX5074 is rated for operation over the -40°C to
+125°C temperature range and is available in a 20-pin
TSSOP package.
Warning: The MAX5074 is designed to work with
high voltages. Exercise caution.
♦
No Reset Winding Required
♦
Up to 15W Output Power
♦
Bias Voltage Regulator with Automatic High-
Voltage Supply Turn-Off
♦
11V to 76V Wide Input Voltage Range
♦
Integrated High-Voltage 0.4Ω Power MOSFETs
♦
Feed-Forward Voltage-Mode Control For Fast
Input Transient Rejection
♦
Programmable Brownout Undervoltage Lockout
♦
Internal Overtemperature Shutdown
♦
Indefinite Short-Circuit Protection With
Programmable Fault Integration
♦
Integrated Look-Ahead Signal for Secondary-Side
Synchronous Rectification
♦
>90% Efficiency with Synchronous Rectification
♦
Up to 500kHz Switching Frequency
♦
High-Power (1.74W), Small-Footprint 20-Pin
Thermally Enhanced TSSOP Package
Features
♦
Clamped, Two-Switch Power IC for High Efficiency
MAX5074
Applications
IEEE 802.3af PD Power Supplies
Isolated IP Phone Power Supplies
High-Efficiency Telecom/Datacom Power Supplies
48V Input, Isolated Power-Supply Modules
WLAN Access-Point Power Supplies
ADSL Line Cards
ADSL Line-Driver Power Supplies
Distributed Power Systems with 48V Bus
Ordering Information
PART
MAX5074AUP
TEMP RANGE
-40°C to +125°C
PIN-PACKAGE
20-TSSOP-EP*
*EP
= Exposed pad.
Pin Configuration
TOP VIEW
REGOUT 1
RTCT 2
FLTINT 3
RCFF 4
RAMP 5
OPTO 6
CSS 7
PPWM 8
GND 9
CS 10
20 INBIAS
19 HVIN
18 UVLO
17 BST
Simplified Application Circuit
V
IN
C
IN
DRNH
D1
T1
XFRMRH
D3
V
OUT
C
OUT
DRVH
QH
MAX5074
16 DRNH
15 XFRMRH
14 DRVIN
13 XFRMRL
12 SRC
11 PGND
DRVL
MAX5074
XFRMRL
QL
D2
SRC
TSSOP
________________________________________________________________
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.
Power IC with Integrated MOSFETs for Isolated IEEE
802.3af PD and Telecom Power-Supply Applications
MAX5074
ABSOLUTE MAXIMUM RATINGS
HVIN, INBIAS, DRNH, XFRMRH,
XFRMRL to GND.................................................-0.3V to +80V
BST to GND ............................................................-0.3V to +95V
BST to XFRMRH .....................................................-0.3V to +12V
PGND to GND .......................................................-0.3V to +0.3V
UVLO, RAMP, CSS, OPTO, FLTINT, RCFF,
RTCT to GND......................................................-0.3V to +12V
SRC, CS to GND.......................................................-0.3V to +6V
REGOUT, DRVIN to GND .......................................-0.3V to +12V
REGOUT to HVIN ...................................................-80V to +0.3V
REGOUT to INBIAS ................................................-80V to +0.3V
REGOUT Current ................................................................50mA
PPWM to GND....................................-0.3V to (REGOUT + 0.3V)
PPWM Current .................................................................±20mA
DRNH, XFRMRH, XRFMRL, SRC Continuous Current (Average)
T
J
= +125°C......................................................................0.9A
T
J
= +150°C......................................................................0.6A
Continuous Power Dissipation (T
A
= +70°C)
20-Pin TSSOP-EP (derate 21.7mW/°C above +70°C) ....1.739W
20-Pin TSSOP-EP (θ
JA
) ................................................46°C/W
Operating Temperature Range .........................-40°C to +125°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-60°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
HVIN
= 12V, C
INBIAS
= 1µF, C
REGOUT
= 2.2µF, R
RTCT
= 25kΩ, C
RTCT
= 100pF, C
BST
= 0.22µF, V
CSS
= V
CS
= 0V, V
RAMP
= V
UVLO
= 3V,
T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Input Supply Range
OSCILLATOR (RTCT)
PWM Frequency
Maximum PWM Duty Cycle
Maximum RTCT Frequency
RTCT Peak Trip Level
RTCT Valley Trip Level
RTCT Input Bias Current
RTCT Discharge MOSFET
R
DS(ON)
RTCT Discharge Pulse Width
LOOK-AHEAD LOGIC (PPWM)
PPWM to XFRMRL Output
Propagation Delay
PPWM Output High
PPWM Output Low
Common-Mode Range
Input Offset Voltage
Input Bias Current
RAMP to XFRMRL Propagation
Delay
Minimum OPTO Voltage
Minimum RCFF Voltage
From RAMP (50mV overdrive) rising to
XFRMRL rising
V
CSS
= 0V, OPTO sinking 2mA
RCFF sinking 2mA
-2
100
1.47
2.18
t
PPWM
V
OH
V
OL
V
CM-PWM
PPWM rising to XFRMRL falling
Sourcing 2mA
Sinking 2mA
0
10
+2
7.0
110
11.0
0.4
5.5
ns
V
V
V
mV
µA
ns
V
V
Sinking 20mA
f
S
D
MAX
f
RTCTMAX
V
TH
R
RTCT
= 25kΩ, C
RTCT
= 100pF
R
RTCT
= 25kΩ, C
RTCT
= 100pF
(Note 2)
256
47
1
0.51 x
V
REGOUT
0.04 x
V
REGOUT
±1
30
50
60
kHz
%
MHz
V
V
µA
Ω
ns
SYMBOL
V
HVIN
CONDITIONS
MIN
11
TYP
MAX
76
UNITS
V
PWM COMPARATOR (OPTO, RAMP, RCFF)
2
_______________________________________________________________________________________
Power IC with Integrated MOSFETs for Isolated IEEE
802.3af PD and Telecom Power-Supply Applications
ELECTRICAL CHARACTERISTICS (continued)
(V
HVIN
= 12V, C
INBIAS
= 1µF, C
REGOUT
= 2.2µF, R
RTCT
= 25kΩ, C
RTCT
= 100pF, C
BST
= 0.22µF, V
CSS
= V
CS
= 0V, V
RAMP
= V
UVLO
= 3V,
T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
REGOUT LDO (REGOUT)
REGOUT Voltage Set Point
V
REGOUT
INBIAS floating, V
HVIN
= 11V to 76V
V
INBIAS
= V
HVIN
= 11V to 76V
INBIAS floating, V
HVIN
= 15V, I
REGOUT
= 0
to 30mA
REGOUT Load Regulation
V
INBIAS
= V
HVIN
= 15V, I
REGOUT
= 0 to
30mA
REGOUT Dropout Voltage
REGOUT Undervoltage Lockout
Threshold
REGOUT Undervoltage Lockout
Threshold Hysteresis
SOFT-START (CSS)
Soft-Start Current
FLTINT Source Current
FLTINT Trip Point
FLTINT Hysteresis
INTERNAL POWER MOSFETs
(See Figure 1, QH and QL)
On-Resistance
Off-State Leakage Current
Total Gate Charge Per FET
HIGH-SIDE DRIVER
Low-to-High Delay
High-to-Low Delay
Driver Output Voltage
LOW-SIDE DRIVER
Low-to-High Delay
High-to-Low Delay
CURRENT-LIMIT COMPARATOR (CS)
Current-Limit Threshold Voltage
Current-Limit Input Bias Current
V
ILIM
I
BILIM
0 < V
CS
< 0.3V
140
-2
156
172
+2
mV
µA
Driver delay until FET V
GS
reaches 0.9 x
V
DRVIN
and is fully on
Driver delay until FET V
GS
reaches 0.1 x
V
DRVIN
and is fully off
80
40
ns
ns
Driver delay until FET V
GS
reaches 0.9 x
(V
BST
- V
XFRMRH
) and is fully on
Driver delay until FET V
GS
reaches 0.1 x
(V
BST
- V
XFRMRH
) and is fully off
BST to XFRMRH with high side on
80
40
8
ns
ns
V
R
DS(ON)
V
DRVIN
= V
BST
= 9V,
V
XFRMRH
= V
SRC
= 0V, I
DS
= 50mA
-5
15
0.4
0.8
+5
Ω
µA
nC
I
CSS
I
FLTINT
FLTINT rising
33
80
2.7
0.8
µA
µA
V
V
INTEGRATING FAULT PROTECTION (FLTINT)
INBIAS floating, I
REGOUT
= 30mA
V
INBIAS
= V
HVIN
, I
REGOUT
= 30mA
REGOUT rising
REGOUT falling
6.6
0.7
0.25
1.25
1.25
7.4
V
V
V
8.3
9.5
9.2
11.0
0.25
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5074
_______________________________________________________________________________________
3
Power IC with Integrated MOSFETs for Isolated IEEE
802.3af PD and Telecom Power-Supply Applications
MAX5074
ELECTRICAL CHARACTERISTICS (continued)
(V
HVIN
= 12V, C
INBIAS
= 1µF, C
REGOUT
= 2.2µF, R
RTCT
= 25kΩ, C
RTCT
= 100pF, C
BST
= 0.22µF, V
CSS
= V
CS
= 0V, V
RAMP
= V
UVLO
= 3V,
T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless otherwise noted.) (Note 1)
PARAMETER
Propagation Delay to XFRMRL
SYMBOL
t
dILIM
CONDITIONS
From CS rising (10mV overdrive) to
XFRMRL rising
MIN
TYP
160
MAX
UNITS
ns
BOOST VOLTAGE CIRCUIT
(See Figure 1, QB)
Driver Output Delay
One-Shot Pulse Width
QB R
DS(ON)
THERMAL SHUTDOWN
Shutdown Temperature
Thermal Hysteresis
UVLO Threshold
UVLO Hysteresis
UVLO Input Bias Current
SUPPLY CURRENT
From V
HVIN
= 11V to 76V, V
CSS
= 0V,
V
INBIAS
= 11V
Supply Current
From V
INBIAS
= 11V to 76V, V
CSS
= 0V,
V
HVIN
= 76V
From V
HVIN
= 76V
Standby Supply Current
V
UVLO
= 0V
0.7
4.4
7
1
mA
2
6.0
mA
UNDERVOLTAGE LOCKOUT (UVLO)
V
UVLO
V
HYST
I
BUVLO
V
UVLO
= 3V
-100
V
UVLO
rising
1.14
140
+100
1.38
V
mV
nA
T
SH
T
HYST
Temperature rising
+160
15
°C
°C
t
PPWMD
t
PWQB
Sinking 20mA
200
300
30
60
ns
ns
Ω
Note 1:
All limits at -40°C are guaranteed by design and not production tested.
Note 2:
Output switching frequency is half of oscillator frequency.
Typical Operating Characteristics
(V
HVIN
= 48V, V
INBIAS
= 15V, C
INBIAS
= 1µF, C
REGOUT
= 2.2µF, R
RTCT
= 25kΩ, C
RTCT
= 100pF, C
BST
= 0.22µF, V
CSS
= V
CS
= 0V,
V
RAMP
= V
UVLO
= 3V, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless otherwise noted.)
UNDERVOLTAGE LOCKOUT THRESHOLD
vs. TEMPERATURE
MAX5074 toc01
STANDBY CURRENT vs. TEMPERATURE
MAX5074 toc02
HVIN INPUT CURRENT
vs. TEMPERATURE
4.7
4.6
I
HVIN
(mA)
4.5
4.4
4.3
4.2
4.1
4.0
V
HVIN
= 76V
INBIAS FLOATING
REGOUT = DRVIN
MAX5074 toc03
1.2600
UVLO RISING
1.2575
1.2550
V
UVLO
(V)
1.2525
1.2500
1.2475
1.2450
1.2425
1.2400
350
315
STANDBY CURRENT (µA)
280
245
210
175
140
105
70
35
0
I
HVIN
V
UVLO
= 0V
4.8
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
4
_______________________________________________________________________________________
Power IC with Integrated MOSFETs for Isolated IEEE
802.3af PD and Telecom Power-Supply Applications
Typical Operating Characteristics (continued)
(V
HVIN
= 48V, V
INBIAS
= 15V, C
INBIAS
= 1µF, C
REGOUT
= 2.2µF, R
RTCT
= 25kΩ, C
RTCT
= 100pF, C
BST
= 0.22µF, V
CSS
= V
CS
= 0V,
V
RAMP
= V
UVLO
= 3V, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C, unless otherwise noted.)
REGOUT VOLTAGE vs. TEMPERATURE
MAX5074 toc04
MAX5074
REGOUT VOLTAGE vs. INPUT VOLTAGE
MAX5074 toc05
REGOUT UVLO VOLTAGE
vs. TEMPERATURE
MAX5074 toc06
MAX5074 toc09
8.800
8.775
8.750
V
REGOUT
(V)
V
HVIN
= 76V
INBIAS FLOATING
8.75
INBIAS FLOATING
8.73
V
REGOUT
(V)
7.50
7.25
REGOUT UVLO VOLTAGE (V)
7.00
6.75
6.50
6.25
6.00
FALLING
RISING
8.725
8.700
8.675
8.650
8.625
8.600
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
8.71
8.69
8.67
8.65
11
24
37
50
63
76
V
HVIN
(V)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
REGOUT VOLTAGE vs. LOAD CURRENT
MAX5074 toc07
HVIN AND INBIAS INPUT CURRENT
vs. TEMPERATURE
MAX5074 toc08
REGOUT VOLTAGE vs. TEMPERATURE
10.60
10.59
10.58
10.57
V
REGOUT
(V)
10.56
10.55
10.54
10.53
10.52
10.51
10.50
V
HVIN
= V
INBIAS
= 76V
8.75
V
HVIN
= 15V
INBIAS FLOATING
8.70
V
REGOUT
(V)
5.0
4.5
4.0
3.5
I
HVIN
(mA)
3.0
2.5
2.0
1.5
1.0
0.5
I
HVIN
V
HVIN
= V
INBIAS
= 76V
I
INBIAS
V
HVIN
= V
INBIAS
= 76V
8.65
8.60
8.55
0
5
10
15
I
REGOUT
(mA)
20
25
30
0
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
REGOUT VOLTAGE vs. INPUT VOLTAGE
MAX5074 toc10
REGOUT VOLTAGE vs. LOAD CURRENT
V
HVIN
= V
INBIAS
= 15V
10.55
V
REGOUT
(V)
MAX5074 toc11
10.60
HVIN = INBIAS
10.58
V
REGOUT
(V)
10.60
10.56
10.50
10.54
10.52
10.45
10.50
11
24
37
50
63
76
V
HVIN
(V)
10.40
0
5
10
15
I
REGOUT
(mA)
20
25
30
_______________________________________________________________________________________
5
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