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MAX5083
User Manual
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Rainbow Electronics MAX5083 User Manual

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.
All devices include programmable undervoltage lock­out and soft-start. Protection features include cycle-by­cycle 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.
Applications
FireWire®Power Supplies Automotive
Distributed Power Industrial
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
1.5A, 40V, MAXPower Step-Down DC-DC Converters
________________________________________________________________ Maxim Integrated Products 1
19-3657; Rev 0; 5/05
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.
Ordering Information
Typical Operating Circuits
FireWire is a registered trademark of Apple Computer, Inc.
Typical Operating Circuits continued at end of data sheet.
*EP = Exposed pad.
Pin Configurations appear at end of data sheet.
PART TEMP RANGE PIN-PACKAGE
MAX5082ATE -40°C to +125°C 16 TQFN-EP*
MAX5083ATE -40°C to +125°C 16 TQFN-EP*
V
IN
4.5V TO 40V
IN
R1
C1
R2
C2
PGND
REG
ON/OFF
SYNC SGND PGND SS COMP
DVREG
C-
MAX5082
D1
C
F
C+
BST
C
SS
C
BST
LX
FB
L1
C6
D2
C8
R5
C5
C7
R3
R6
R4
V
OUT
PGND
MAX5082/MAX5083
1.5A, 40V, MAXPower Step-Down DC-DC Converters
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
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.
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
*
(TA= +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
ELECTRICAL CHARACTERISTICS
(VIN= V
ON/OFF
= 12V, V
REG
= V
DVREG
, V
SYNC
= PGND = SGND, TA= TJ= -40°C to +125°C, unless otherwise noted. Typical values
are at T
A
= + 25°C.) (Note 1)
*As per JEDEC 51 Standard.
Input Voltage Range V
Undervoltage Lockout Threshold UVLO
Undervoltage Lockout Hysteresis UVLO
Switching Supply Current (PWM Operation)
Efficiency
No-Load Supply Current (PFM Operation)
Shutdown Current I
ON/OFF CONTROL
Input Voltage Threshold V
Input Voltage Hysteresis 0.12 V
Input Bias Current V
ERROR AMPLIFIER/SOFT-START
Soft-Start Current I
Reference Voltage (Soft-Start) V
FB Regulation Voltage V
FB Input Range 0 1.5 V
FB Input Current -250 +250 nA
COMP Voltage Range I
Open-Loop Gain 80 dB
Unity-Gain Bandwidth 1.8 MHz
FB Offset Voltage I
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX5082 4.5 40
IN
MAX5083 7.5 40
VIN rising, MAX5082 3.9 4.2
rising, MAX5083 6.8 7.3
V
IN
MAX5082 0.4
HYST
MAX5083 0.7
I
SW
VFB = 0V, MAX5082 10.5
VFB = 0V, MAX5083 9.5
VIN = 12V, V
= 4.5V, V
V
IN
OUT
OUT
(MAX5082)
MAX5082 1.4 2.5
MAX5083 1.3 2.3
SS
FB
V
I
SHDN
ON/OFFVON/OFF
SS
= 0V, V
ON/OFF
rising 1.20 1.23 1.25 V
= 0 to 40V -250 +250 nA
ON/OFF
= -500µA to +500µA 1.215 1.228 1.240 V
COMP
= -500µA to +500µA 0.25 4.50 V
COMP
= -500µA to +500µA -5 +5 mV
COMP
= 3.3V, I
= 3.3V, I
= 40V 200 300 µA
IN
= 1.5A 84
OUT
= 1.5A
OUT
88
81524µA
1.215 1.228 1.240 V
V
V
V
mA
%
mA
MAX5082/MAX5083
1.5A, 40V, MAXPower Step-Down DC-DC Converters
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VIN= V
ON/OFF
= 12V, V
REG
= V
DVREG
, V
SYNC
= PGND = SGND, TA= TJ= -40°C to +125°C, unless otherwise noted. Typical values
are at T
A
= + 25°C.) (Note 1)
Note 1: 100% production tested at TA= +25°C and TA= +125°C. Limits at -40°C are guaranteed by design.
OSCILLATOR
Frequency f
SYNC High-Level Voltage 2.2 V
SYNC Low-Level Voltage 0.8 V
SYNC Frequency Range f
PWM Modulator Gain f
Ramp Level Shift (Valley) 0.3 V
POWER SWITCH
Switch On-Resistance V
Switch Gate Charge V
Switch Leakage Current VIN = 40V, V
BST Leakage Current V
CHARGE PUMP
C- Output Voltage Low MAX5082 only, sinking 10mA 0.1 V
C- Output Voltage High
DVREG to C+ On-Resistance MAX5082 only, sourcing 10mA 10 Ω LX to PGND On-Resistance Sinking 10mA 12 Ω
CURRENT-LIMIT COMPARATOR
Pulse-Skip Threshold I Cycle-by-Cycle Current Limit I
Number of Consecutive ILIM Events to Hiccup
Hiccup Timeout 512
INTERNAL VOLTAGE REGULATOR
Output Voltage V
Line Regulation
Load Regulation I
Dropout Voltage
THERMAL SHUTDOWN
Thermal Shutdown Temperature Temperature rising +160 °C Thermal Shutdown Hysteresis 20 °C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
SYNC
V
SW
MAX
PFM
ILIM
REG
= 0V 225 250 275 kHz
SYNC
V
= 0V, V
SYNC
V
= 0V, VIN = 7.5V, MAX5083 87Maximum Duty Cycle D
SYNC
V
= 0V, VIN ≤ 40V 87
SYNC
= 150kHz to 350kHz 10 V/V
SYNC
- VLX = 6V 0.3 0.6 Ω
BST
- VLX = 6V 6 nC
BST
= V
BST
MAX5082 only, relative to DVREG, sourcing 10mA
MAX5082 4.75 5 5.25
MAX5083 7.6 8 8.4 VIN = 5.5V to 40V, MAX5082 1 V
= 9.0V to 40V, MAX5083 1
IN
= 0 to 20mA 0.25 V
REG
VIN = 4.5V, I V
= 7.5V, I
IN
= 4.5V, MAX5082 87
IN
150 350 kHz
= V
= 0V 10 µA
BST
= 40V 10 µA
IN
100 200 300 mA
1.9 2.7 3.5 A
= 20mA, MAX5082 0.5 = 20mA, MAX5083 0.5
LX
LX
= V
REG
REG
0.1 V
4
periods
%
Clock
V
mV/V
V
MAX5082/MAX5083
1.5A, 40V, MAXPower Step-Down DC-DC Converters
4 _______________________________________________________________________________________
Typical Operating Characteristics
(VIN= 12V, see Figure 5 (MAX5082) and Figure 6 (MAX5083), TA= +25°C, unless otherwise noted.)
UNDERVOLTAGE LOCKOUT HYSTERESIS
vs. TEMPERATURE (MAX5082)
MAX5082/3 toc01
TEMPERATURE (°C )
UNDERVOLTAGE LOCKOUT HYSTERESIS (V)
1108535 6010-15
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
-40 135
UNDERVOLTAGE LOCKOUT HYSTERESIS
vs. TEMPERATURE (MAX5083)
MAX5082/3 toc02
TEMPERATURE (°C )
UNDERVOLTAGE LOCKOUT HYSTERESIS (V)
1108535 6010-15
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
0
-40 135
ON/OFF THRESHOLD HYSTERESIS
vs. TEMPERATURE
MAX5082/3 toc03
TEMPERATURE (°C )
ON/OFF THRESHOLD HSYSTERESIS (V)
11085603510-15
0.05
0.10
0.15
0.20
0
-40 135
SHUTDOWN SUPPLY CURRENT vs. INPUT VOLTAGE (MAX5082)
MAX5082/3 toc04
INPUT VOLTAGE (V)
SHUTDOWN SUPPLY CURRENT (µA)
353020 2510 155
25
50
75
100
125
150
175
200
225
250
0
040
TA = +135°C
TA = +25°C
TA = +85°C
TA = -40°C
V
ON/OFF
= 0V
SHUTDOWN SUPPLY CURRENT vs. INPUT VOLTAGE (MAX5083)
MAX5082/3 toc05
INPUT VOLTAGE (V)
SHUTDOWN SYPPLY CURRENT (µA)
353020 2510 155
25
50
75
100
125
150
175
200
225
250
275
300
0
040
TA = +135°C
TA = +25°C
TA = +85°C
TA = -40°C
V
ON/OFF
= 0V
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE (MAX5082)
MAX5082/3 toc06
INPUT VOLTAGE (V)
SUPPLY CURRENT (mA)
35305 10 15 20 25
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
0
040
TA = +135°C
TA = +25°C
TA = +85°C
TA = -40°C
OPERATING FREQUENCY
vs. TEMPERATURE
MAX5082/3 toc07
TEMPERATURE (°C)
OPERATING FREQUENCY (kHz)
1108535 6010-15
242
244
246
248
250
252
254
256
258
260
240
-40 135
VIN = 4.5V
VIN = 40V
MAXIMUM DUTY CYCLE
vs. INPUT VOLTAGE (MAX5082)
MAX5082/3 toc08a
INPUT VOLTAGE (V)
MAXIMUM DUTY CYCLE (%)
353020 2510 155
82
84
86
88
90
92
94
96
98
100
80
040
MAX5082/MAX5083
1.5A, 40V, MAXPower Step-Down DC-DC Converters
_______________________________________________________________________________________ 5
Typical Operating Characteristics (continued)
(VIN= 12V, see Figure 5 (MAX5082) and Figure 6 (MAX5083), TA= +25°C, unless otherwise noted.)
MAXIMUM DUTY CYCLE
vs. INPUT VOLTAGE (MAX5083)
MAX5080 toc08b
INPUT VOLTAGE (V)
MAXIMUM DUTY CYCLE (%)
353020 2510 155
82
84
86
88
90
92
94
96
98
100
80
040
OPEN-LOOP GAIN/PHASE vs. FREQUENCY
MAX5082 toc10
FREQUENCY (kHz)
GAIN (dB)
PHASE (DEGREES)
10001001010.10.010.001
0
20
40
60
80
100
-20
75
100
125
150
175
50
0 10,000
GAIN
PHASE
OUTPUT CURRENT LIMIT
vs. INPUT VOLTAGE
MAX5082/3 toc10
INPUT VOLTAGE (V)
OUTPUT CURRENT LIMIT (A)
353020 2510 155
2.1
2.2
2.3
2.4
2.5
2.6
2.7
2.8
2.9
3.0
2.0 040
MAX5082
TA = +135°C
TA = +25°C
TA = +85°C
TA = -40°C
OUTPUT IS PULSED WITH 3% DUTY CYCLE
TURN-ON/OFF WAVEFORM
MAX5082/3 toc11a
V
OUT
2V/div
2ms/div
I
LOAD
= 1A
V
ON/OFF
2V/div
TURN-ON/OFF WAVEFORM
MAX5082/3 toc11b
V
ON/OFF
2V/div
V
OUT
2V/div
2ms/div
I
LOAD
= 100mA
OUTPUT VOLTAGE vs. TEMPERATURE
MAX5082/3 toc12
TEMPERATURE (°C)
OUTPUT VOLTAGE (V)
1108535 6010-15
3.22
3.24
3.26
3.28
3.30
3.32
3.34
3.36
3.38
3.40
3.20
-40 135
MAX5082
I
LOAD
= 0A
I
LOAD
= 1A
EFFICIENCY vs. LOAD CURRENT
MAX5082/3 toc13a
LOAD CURRENT (A)
EFFICIENCY (%)
0.10.01
20
30
40
50
60
70
80
90
100
0
0.001 101
VIN = 40V, V
OUT
= 3.3V
MAX5082
VIN = 24V, V
OUT
= 3.3V
VIN = 12V, V
OUT
= 3.3V
VIN = 7.5V, V
OUT
= 3.3V
VIN = 4.5V,
V
OUT
= 3.3V
MAX5082/MAX5083
1.5A, 40V, MAXPower Step-Down DC-DC Converters
6 _______________________________________________________________________________________
Typical Operating Characteristics (continued)
(VIN= 12V, see Figure 5 (MAX5082) and Figure 6 (MAX5083), TA= +25°C, unless otherwise noted.)
EFFICIENCY vs. LOAD CURRENT
MAX5082/3 toc13b
LOAD CURRENT (A)
EFFICIENCY (%)
0.10.01
20
30
40
50
60
70
80
90
100
0
0.001 101
VIN = 40V, V
OUT
= 5V
MAX5083
VIN = 24V, V
OUT
= 5V
VIN = 12V, V
OUT
= 5V
VIN = 7.5V, V
OUT
= 5V
LOAD-TRANSIENT RESPONSE
MAX5082/3 toc14
V
OUT
AC-COUPLED 200m/V/div
I
LOAD
1A/div
200µs/div
VIN = 12V, I
OUT
= 0.5A TO 1.5A
MAX5082
0
LX VOLTAGE AND INDUCTOR CURRENT
MAX5082/3 toc15
I
LOAD
= 40mA
INDUCTOR CURRENT 200mA/div
V
LX
5V/div
2µs/div
LX VOLTAGE AND INDUCTOR CURRENT
MAX5082/3 toc16
V
LX
5V/div
INDUCTOR CURRENT 100mA/div
2µs/div
I
LOAD
= 140mA
0
LX VOLTAGE AND INDUCTOR CURRENT
MAX5082/3 toc17
V
LX
5V/div
INDUCTOR CURRENT 500mA/div
2µs/div
I
LOAD
= 1A
0
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