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1.5A, 40V, MAXPower Step-Down
DC-DC Converters
General Description
The MAX5082/MAX5083 are 250kHz PWM step-down
DC-DC converters with an on-chip, 0.3Ω high-side
switch. The input voltage range is 4.5V to 40V for the
MAX5082 and 7.5V to 40V for the MAX5083. The output
is adjustable from 1.23V to 32V and can deliver up to
1.5A of load current.
Both devices utilize a voltage-mode control scheme for
good noise immunity in the high-voltage switching envi-
ronment and offer external compensation allowing for
maximum flexibility with a wide selection of inductor val-
ues and capacitor types. The switching frequency is
internally fixed at 250kHz and can be synchronized to
an external clock signal through the SYNC input. Light
load efficiency is improved by automatically switching
to a pulse-skip mode.
All devices include programmable undervoltage lock-
out and soft-start. Protection features include cycle-by-
cycle current limit, hiccup-mode output short-circuit
protection, and thermal shutdown. Both devices are
available in a space-saving, high-power (2.7W), 16-pin
TQFN package and are rated for operation over the
-40°C to +125°C temperature range.
Features
♦
4.5V to 40V (MAX5082) or 7.5V to 40V (MAX5083)
Input Voltage Range
♦
1.5A Output Current
♦
V
OUT
Range From 1.23V to 32V
♦
Internal High-Side Switch
♦
Fixed 250kHz Internal Oscillator
♦
Automatic Switchover to Pulse-Skip Mode at
Light Loads
♦
External Frequency Synchronization
♦
Thermal Shutdown and Short-Circuit Protection
♦
Operates Over the -40°C to +125°C Temperature
Range
♦
Space-Saving (5mm x 5mm) High-Power 16-Pin
TQFN Package
MAX5082/MAX5083
Ordering Information
PART
MAX5082ATE
MAX5083ATE
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
16 TQFN-EP*
16 TQFN-EP*
Applications
FireWire
®
Power Supplies
Distributed Power
Automotive
Industrial
*EP
= Exposed pad.
Pin Configurations appear at end of data sheet.
FireWire is a registered trademark of Apple Computer, Inc.
Typical Operating Circuits
V
IN
4.5V TO 40V
C
F
D1
IN
R1
DVREG
C-
C+
BST
LX
C
BST
L1
V
OUT
C6
C1
REG
MAX5082
ON/OFF
SYNC SGND PGND
C2
PGND
SS
C
SS
FB
D2
C5
R6
R3
C8
R2
COMP
R5
C7
R4
PGND
Typical Operating Circuits continued at end of data sheet.
________________________________________________________________
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.
1.5A, 40V, MAXPower Step-Down
DC-DC Converters
MAX5082/MAX5083
ABSOLUTE MAXIMUM RATINGS
IN, ON/OFF to SGND..............................................-0.3V to +45V
LX to SGND .................................................-0.3V to (V
IN
+ 0.3V)
BST to SGND ................................................-0.3V to (V
IN
+ 12V)
BST to LX................................................................-0.3V to +12V
PGND to SGND .....................................................-0.3V to +0.3V
REG, DVREG, SYNC to SGND ...............................-0.3V to +12V
FB, COMP, SS to SGND ...........................-0.3V to (V
REG
+ 0.3V)
C+ to PGND (MAX5082 only)................(V
DVREG
- 0.3V) to +12V
C- to PGND (MAX5082 only) ................-0.3V to (V
DVREG
+ 0.3V)
Continuous current through internal power MOSFET (pins 11/12
connected together and pins 13/14 connected together)
T
J
= +125°C.........................................................................3A
T
J
= +150°C.........................................................................2A
Continuous Power Dissipation
*
(T
A
= +70°C)
16-Pin TQFN (derate 33.3mW/°C above +70°C) ...2666.7mW
16-Pin TQFN (θ
JA
)........................................................30°C/W
16-Pin TQFN (θ
JC
).......................................................1.7°C/W
Operating Temperature Range .........................-40
o
C to +125°C
Maximum Junction Temperature .....................................+150°C
Storage Temperature Range .............................-60°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
*As
per JEDEC 51 Standard.
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
IN
= V
ON/OFF
= 12V, V
REG
= V
DVREG
, V
SYNC
= PGND = SGND, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values
are at T
A
= + 25°C.) (Note 1)
PARAMETER
Input Voltage Range
Undervoltage Lockout Threshold
Undervoltage Lockout Hysteresis
Switching Supply Current (PWM
Operation)
Efficiency
No-Load Supply Current
(PFM Operation)
Shutdown Current
ON/OFF CONTROL
Input Voltage Threshold
Input Voltage Hysteresis
Input Bias Current
ERROR AMPLIFIER/SOFT-START
Soft-Start Current
Reference Voltage (Soft-Start)
FB Regulation Voltage
FB Input Range
FB Input Current
COMP Voltage Range
Open-Loop Gain
Unity-Gain Bandwidth
FB Offset Voltage
I
COMP
= -500µA to +500µA
-5
I
COMP
= -500µA to +500µA
I
SS
V
SS
V
FB
I
COMP
= -500µA to +500µA
8
1.215
1.215
0
-250
0.25
80
1.8
+5
15
1.228
1.228
24
1.240
1.240
1.5
+250
4.50
µA
V
V
V
nA
V
dB
MHz
mV
V
ON/OFF
= 0 to 40V
-250
V
ON/OFF
V
ON/OFF
rising
1.20
1.23
0.12
+250
1.25
V
V
nA
I
SHDN
SYMBOL
V
IN
UVLO
UVLO
HYST
I
SW
MAX5082
MAX5083
V
IN
rising, MAX5082
V
IN
rising, MAX5083
MAX5082
MAX5083
V
FB
= 0V, MAX5082
V
FB
= 0V, MAX5083
V
IN
= 12V, V
OUT
= 3.3V, I
OUT
= 1.5A
V
IN
= 4.5V, V
OUT
= 3.3V, I
OUT
= 1.5A
(MAX5082)
MAX5082
MAX5083
V
ON/OFF
= 0V, V
IN
= 40V
CONDITIONS
MIN
4.5
7.5
3.9
6.8
0.4
0.7
10.5
9.5
84
88
1.4
1.3
200
2.5
2.3
300
%
TYP
MAX
40
40
4.2
7.3
UNITS
V
V
V
mA
mA
µA
2
_______________________________________________________________________________________
1.5A, 40V, MAXPower Step-Down
DC-DC Converters
ELECTRICAL CHARACTERISTICS (continued)
(V
IN
= V
ON/OFF
= 12V, V
REG
= V
DVREG
, V
SYNC
= PGND = SGND, T
A
= T
J
= -40°C to +125°C, unless otherwise noted. Typical values
are at T
A
= + 25°C.) (Note 1)
PARAMETER
OSCILLATOR
Frequency
Maximum Duty Cycle
SYNC High-Level Voltage
SYNC Low-Level Voltage
SYNC Frequency Range
PWM Modulator Gain
Ramp Level Shift (Valley)
POWER SWITCH
Switch On-Resistance
Switch Gate Charge
Switch Leakage Current
BST Leakage Current
CHARGE PUMP
C- Output Voltage Low
C- Output Voltage High
DVREG to C+ On-Resistance
LX to PGND On-Resistance
CURRENT-LIMIT COMPARATOR
Pulse-Skip Threshold
Cycle-by-Cycle Current Limit
Number of Consecutive ILIM
Events to Hiccup
Hiccup Timeout
INTERNAL VOLTAGE REGULATOR
Output Voltage
Line Regulation
Load Regulation
Dropout Voltage
THERMAL SHUTDOWN
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
V
REG
MAX5082
MAX5083
V
IN
= 5.5V to 40V, MAX5082
V
IN
= 9.0V to 40V, MAX5083
I
REG
= 0 to 20mA
V
IN
= 4.5V, I
REG
= 20mA, MAX5082
V
IN
= 7.5V, I
REG
= 20mA, MAX5083
Temperature rising
4.75
7.6
5
8
5.25
8.4
1
1
0.25
0.5
0.5
V
mV/V
V
V
I
PFM
I
ILIM
MAX5082 only, sinking 10mA
MAX5082 only, relative to DVREG,
sourcing 10mA
MAX5082 only, sourcing 10mA
Sinking 10mA
100
1.9
200
2.7
4
512
Clock
periods
0.1
0.1
10
12
300
3.5
V
V
Ω
Ω
mA
A
V
BST
- V
LX
= 6V
V
BST
- V
LX
= 6V
V
IN
= 40V, V
LX
= V
BST
= 0V
V
BST
= V
LX
= V
IN
= 40V
0.3
6
10
10
0.6
Ω
nC
µA
µA
f
SYNC
f
SYNC
= 150kHz to 350kHz
150
10
0.3
f
SW
D
MAX
V
SYNC
= 0V
V
SYNC
= 0V, V
IN
= 4.5V, MAX5082
V
SYNC
= 0V, V
IN
= 7.5V, MAX5083
V
SYNC
= 0V, V
IN
≤
40V
225
87
87
87
2.2
0.8
350
V
V
kHz
V/V
V
%
250
275
kHz
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
MAX5082/MAX5083
+160
20
°C
°C
Note 1:
100% production tested at T
A
= +25°C and T
A
= +125°C. Limits at -40°C are guaranteed by design.
_______________________________________________________________________________________
3
1.5A, 40V, MAXPower Step-Down
DC-DC Converters
MAX5082/MAX5083
Typical Operating Characteristics
(V
IN
= 12V, see Figure 5 (MAX5082) and Figure 6 (MAX5083), T
A
= +25°C, unless otherwise noted.)
UNDERVOLTAGE LOCKOUT HYSTERESIS
vs. TEMPERATURE (MAX5082)
MAX5082/3 toc01
UNDERVOLTAGE LOCKOUT HYSTERESIS
vs. TEMPERATURE (MAX5083)
MAX5082/3 toc02
ON/OFF THRESHOLD HYSTERESIS
vs. TEMPERATURE
ON/OFF THRESHOLD HSYSTERESIS (V)
MAX5082/3 toc03
1.0
UNDERVOLTAGE LOCKOUT HYSTERESIS (V)
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
-40
-15
10
35
60
85
110
1.0
UNDERVOLTAGE LOCKOUT HYSTERESIS (V)
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
-40
-15
10
35
60
85
110
0.20
0.15
0.10
0.05
0
135
-40
-15
10
35
60
85
110
135
TEMPERATURE (°C )
TEMPERATURE (°C )
135
TEMPERATURE (°C )
SHUTDOWN SUPPLY CURRENT
vs. INPUT VOLTAGE (MAX5082)
MAX5082/3 toc04
SHUTDOWN SUPPLY CURRENT
vs. INPUT VOLTAGE (MAX5083)
MAX5082/3 toc05
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE (MAX5082)
3.5
SUPPLY CURRENT (mA)
3.0
2.5
2.0
1.5
1.0
T
A
= +25°C
T
A
= -40°C
T
A
= +85°C
T
A
= +135°C
MAX5082/3 toc06
250
SHUTDOWN SUPPLY CURRENT (µA)
225
200
175
150
125
100
75
50
25
0
0
5
10
15
20
25
30
35
V
ON/OFF
= 0V
T
A
= +25°C
T
A
= -40°C
T
A
= +135°C
T
A
= +85°C
SHUTDOWN SYPPLY CURRENT (µA)
300
275
250
225
200
175
150
125
100
75
50
25
0
0
4.0
T
A
= +135°C
T
A
= +85°C
T
A
= +25°C
T
A
= -40°C
V
ON/OFF
= 0V
5
10
15
20
25
30
35
40
0.5
0
0
5
10
15
20
25
30
35
40
40
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
INPUT VOLTAGE (V)
OPERATING FREQUENCY
vs. TEMPERATURE
MAX5082/3 toc07
MAXIMUM DUTY CYCLE
vs. INPUT VOLTAGE (MAX5082)
98
MAXIMUM DUTY CYCLE (%)
96
94
92
90
88
86
84
82
80
MAX5082/3 toc08a
260
258
OPERATING FREQUENCY (kHz)
256
254
252
250
248
246
244
242
240
-40
-15
10
35
60
85
110
V
IN
= 40V
V
IN
= 4.5V
100
135
0
5
10
15
20
25
30
35
40
TEMPERATURE (°C)
INPUT VOLTAGE (V)
4
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