MAX17541G
42V, 500mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converter
General Description
The MAX17541G high-efficiency, high-voltage, synchronous
step-down DC-DC converter with integrated MOSFETs
operates over 4.5V to 42V input. The converter can
deliver up to 500mA and generates output voltages from
0.9V up to 0.92 x V
IN
. The feedback (FB) voltage is accurate
to within ±1.7% over -40°C to +125°C.
The MAX17541G uses peak-current-mode control with
pulse-width modulation (PWM) and operates with fixed
600kHz switching frequency at any load. The device
is available in a 10-pin (3mm x 2mm) TDFN package.
Simulation models are available.
Benefits and Features
● Reduces External Components and Total Cost
• No Schottky-Synchronous Operation
• All-Ceramic Capacitors, Ultra-Compact Layout
● Reduces Number of DC-DC Regulators to Stock
• Wide 4.5V to 42V Input
• Adjustable 0.9V to 92%V
IN
Output
• Delivers up to 500mA
● Reduces Power Dissipation
• Peak Efficiency > 90%
•
Shutdown Current = 0.9μA (typ)
● Operates Reliably in Adverse Industrial Environments
•
Hiccup-Mode Current Limit, Sink Current Limit,
and Autoretry Startup
• Built-In Output-Voltage Monitoring (RESET Pin)
•
Programmable EN/UVLO Threshold
• Adjustable Soft-Start and Prebiased Power-Up
• High Industrial -40°C to +125°C Ambient Operating
Temperature Range/-40°C to +150°C Junction
Temperature Range
Ordering Information
appears at end of data sheet.
Applications
●
●
●
●
●
●
Industrial Process Control
HVAC and Building Control
Base Station, VOIP, Telecom
Home Theatre
Battery-Powered Equipment
General-Purpose Point of Load
MAX17541G Application Circuit (5V Output, 500mA Maximum Load Current)
V
IN
C1
1µF
R1
3.32MΩ
EN/UVLO
R2
681k
V
CC
PGND
R4
82.5kΩ
V
IN
LX
L1
47µH
C4
10µF
V
OUT
5V, 500mA
1
JU1 2
3
MAX17541G
GND
C2
1µF
C3
3300pF
SS
FB/VO
R5
18.2kΩ
RESET
RESET
COMP
C9
22pF
R3
21.5kΩ
C5
3300pF
L1 = 74404054470 OR
XFL6060-473
19-7672 Rev 1; 7/16
MAX17541G
42V, 500mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Absolute Maximum Ratings
V
IN
to GND.............................................................-0.3V to +48V
EN/UVLO to GND.......................................-0.3V
to (V
IN
+ 0.3V)
LX to PGND................................................-0.3V
to (V
IN
+ 0.3V)
FB,
RESET,
COMP, SS to GND .............................-0.3V to +6V
V
CC
to GND..............................................................-0.3V to +6V
GND to PGND.......................................................-0.3V to +0.3V
LX Total RMS Current......................................................... ±1.6A
Output Short-Circuit Duration.....................................Continuous
Junction Temperature......................................................+150°C
Storage Temperature Range............................. -65°C to +160°C
Lead Temperature (soldering, 10s).................................+300°C
Soldering Temperature (reflow).......................................+260°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. Junction temperature greater than +125°C degrades operating lifetimes.
Package Thermal Characteristics
(Note 1)
10 TDFN
Continuous Power Dissipation (T
A
= +70°C)
(derate 14.9mW/°C above +70°C) (multilayer board) .1188.7mW
Junction-to-Ambient Thermal Resistance (θ
JA
) ...........67.3°C/W
Junction-to-Case Thermal Resistance (θ
JC
) ................18.2°C/W
Note 1:
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer
board. For detailed information on package thermal considerations, refer to
www.maximintegrated.com/thermal-tutorial.
Electrical Characteristics
(V
IN
= 24V, V
GND
= V
PGND
= 0V, C
VIN
= 1μF, C
VCC
= 1μF, V
EN
= 1.5V, C
SS
= 3300pF, V
FB
= 0.98 x V
OUT
, LX = unconnected, RESET
= unconnected. T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C. All voltages are referenced to GND,
unless otherwise noted.) (Note 2)
PARAMETER
INPUT SUPPLY (V
IN
)
Input Voltage Range
Input Supply Current
ENABLE/UVLO (EN/UVLO)
V
ENR
EN Threshold
EN Input Leakage Current
LDO
V
CC
Output Voltage Range
V
CC
Current Limit
V
CC
Dropout
V
CC
UVLO
V
CC
I
VCC-MAX
V
CC-DO
V
CC-UVR
V
CC-UVF
6V < V
IN
< 12V, 0mA < I
VCC
< 10mA,
12V < V
IN
< 42V, 0mA < I
VCC
< 2mA
V
CC
= 4.3V, V
IN
= 12V
V
IN
= 4.5V, I
VCC
= 5mA
V
CC
rising
V
CC
falling
4.65
15
4.1
3.85
3.55
4
3.7
4.15
3.85
5
40
5.35
80
V
mA
V
V
V
ENF
V
EN-TRUESD
I
EN
V
EN
rising
V
EN
falling
V
EN
falling, true shutdown
V
EN
= V
IN
= 42V, T
A
= +25°C
1.194
1.114
1.218
1.135
0.7
8
200
nA
1.236
1.156
V
V
IN
I
IN-SH
I
IN-SW
V
EN
= 0V, shutdown mode
Normal switching mode, no load
4.5
0.9
4.75
42
3.5
6.75
V
µA
mA
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
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Maxim Integrated
│
2
MAX17541G
42V, 500mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Electrical Characteristics (continued)
(V
IN
= 24V, V
GND
= V
PGND
= 0V, C
VIN
= 1μF, C
VCC
= 1μF, V
EN
= 1.5V, C
SS
= 3300pF, V
FB
= 0.98 x V
OUT
, LX = unconnected, RESET
= unconnected. T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C. All voltages are referenced to GND,
unless otherwise noted.) (Note 2)
PARAMETER
POWER MOSFETs
High-Side pMOS On-Resistance
R
DS-ONH
I
LX
= 0.5A
(sourcing)
I
LX
= 0.5A
(sinking)
T
A
= +25°C
0.55
0.85
1.2
0.2
0.35
0.47
1
Ω
Ω
T
A
= T
J
= +125°C
(Note 3)
T
A
= +25°C
T
A
= T
J
= +125°C
(Note 3)
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Low-Side nMOS On-Resistance
R
DS-ONL
LX Leakage Current
SOFT-START (SS)
Charging Current
FEEDBACK (FB/VO)
FB Regulation Voltage
FB Input Bias Current
OUTPUT VOLTAGE (V
OUT
)
Output Voltage Range
I
LX_LKG
I
SS
V
FB_REG
I
FB
V
OUT
G
M
I
COMP_SRC
I
COMP_SINK
R
CS
I
PEAK-LIMIT
I
RUNAWAY-
LIMIT
V
EN
= 0V, T
A
= +25°C,
V
LX
= (V
PGND
+ 1V) to (V
IN
- 1V)
V
SS
= 0.5V
4.7
0.884
V
FB
= 0.9V
0.9
5
0.9
µA
5.3
0.916
100
0.92 x
V
IN
µA
V
nA
V
TRANSCONDUCTANCE AMPLIFIER (COMP)
Transconductance
COMP Source Current
COMP Sink Current
Current-Sense Transresistance
CURRENT LIMIT
Peak Current-Limit Threshold
Runaway Current-Limit Threshold
Sink Current-Limit Threshold
TIMINGS
Switching Frequency
Events to Hiccup after Crossing
Runaway Current Limit
V
OUT
Undervoltage Trip Level to
Cause Hiccup
HICCUP Timeout
Minimum On-Time
Maximum Duty Cycle
LX Dead Time
t
ON_MIN
D
MAX
V
FB
= 0.98 x V
FB-REG
92
V
OUT-HICF
V
SS
> 0.95V (soft-start is done)
69.14
f
SW
V
FB
> V
OUT-HICF
V
FB
< V
OUT-HICF
560
280
600
300
1
71.14
32,768
75
94
5
120
96
73.14
640
320
kHz
Event
%
Cycles
ns
%
ns
0.64
0.65
0.3
0.76
0.78
0.35
0.86
0.905
0.4
A
A
A
I
COMP
= ±2.5µA
510
19
19
0.9
590
32
32
1
650
55
55
1.1
µS
µA
µA
V/A
I
SINK-LIMIT
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Maxim Integrated
│
3
MAX17541G
42V, 500mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Electrical Characteristics (continued)
(V
IN
= 24V, V
GND
= V
PGND
= 0V, C
VIN
= 1μF, C
VCC
= 1μF, V
EN
= 1.5V, C
SS
= 3300pF, V
FB
= 0.98 x V
OUT
, LX = unconnected, RESET
= unconnected. T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C. All voltages are referenced to GND,
unless otherwise noted.) (Note 2)
PARAMETER
RESET
RESET Output Level Low
RESET Output Leakage
Current High
V
OUT
Threshold for
RESET
Falling
V
OUT
Threshold for
RESET Rising
RESET Delay After FB Reaches
95% Regulation
THERMAL SHUTDOWN
Thermal-Shutdown Threshold
Thermal-Shutdown Hysteresis
Temperature rising
165
10
°C
°C
V
OUT-OKF
V
OUT-OKR
I
RESET
= 1mA
V
FB
= 1.01 x V
FB-REG
, T
A
= +25°C
V
FB
falling
V
FB
rising
V
FB
rising
90.5
93.5
92.5
95.5
1024
0.02
0.45
94.5
97.5
V
µA
%
%
Cycles
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Note 2:
All limits are 100% tested at +25°C. Limits over the operating temperature range and relevant supply voltage range are
guaranteed by design and characterization.
Note 3:
Guaranteed by design, not production tested.
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Maxim Integrated
│
4
MAX17541G
42V, 500mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converter
Typical Operating Characteristics
(V
IN
= 24V, V
GND
= V
PGND
= 0V, C
VIN
= 1μF, C
VCC
= 1μF, V
EN
= 1.5V, C
SS
= 3300pF, V
FB
= 0.98 x V
OUT
, LX = unconnected,
RESET
= unconnected, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at T
A
= +25°C. All voltages are referenced to
GND, unless otherwise noted.)
3.3V OUTPUT
EFFICIENCY vs. LOAD CURRENT
FIGURE 5 CIRCUIT
5V OUTPUT
EFFICIENCY vs. LOAD CURRENT
FIGURE 6 CIRCUIT
5V OUTPUT
EFFICIENCY vs. LOAD CURRENT
FIGURE 6 CIRCUIT
100
90
EFFICIENCY (%)
100
90
EFFICIENCY (%)
100
90
EFFICIENCY (%)
80
70
60
50
80
70
60
50
40
V
IN
= 12V
80
70
60
50
L1 = 74404054470
40
V
IN
= 24V
V
IN
= 36V
V
IN
= 24V
V
IN
= 36V
V
IN
= 12V
V
IN
= 12V
V
IN
= 24V
V
IN
= 36V
L1 = XFL6060-473
40
50
100 150 200 250 300 350 400 450 500
LOAD CURRENT (mA)
50
100 150 200 250 300 350 400 450 500
LOAD CURRENT (mA)
50
100 150 200 250 300 350 400 450 500
LOAD CURRENT (mA)
3.55
3.50
3.45
OUTPUT VOLTAGE (V)
3.40
3.35
3.30
3.25
3.20
3.15
3.10
3.05
0
5.03
SHUTDOWN CURRENT (µA)
5.01
V
IN
= 24V
OUTPUT VOLTAGE (V)
4.99
4.97
4.95
4.93
4.91
4.89
4.87
100
200
300
400
500
0
100
200
300
400
500
V
IN
= 12V
V
IN
= 36V
V
IN
= 24V
1.05
1.00
0.95
0.90
0.85
0.80
0.75
LOAD CURRENT (mA)
V
IN
= 12V
V
IN
= 36V
0.70
LOAD CURRENT (mA)
-40 -20
0
20
40
60
80
100 120
TEMPERATURE (°C)
toc06
NO-LOAD SWITCHING CURRENT (mA)
EN/UVLO THRESHOLD VOLTAGE (V)
1.22
1.21
1.20
1.19
1.18
1.17
1.16
1.15
1.14
1.13
1.12
-40 -20
0
20
40
60
80
toc07
FEEDBACK VOLTAGE (V)
4.95
RISING
THRESHOLD
0.91
4.90
0.90
4.85
FALLING
THRESHOLD
0.89
4.80
-40 -20
0
20
40
60
80
100 120
100 120
0.88
-40 -20
0
TEMPERATURE (°C)
TEMPERATURE (°C)
20 40 60 80
TEMPERATURE (°C)
100 120
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Maxim Integrated
│
5
toc08
5.00
NO-LOAD SWITCHING CURRENT
vs. TEMPERATURE
1.23
EN/UVLO THRESHOLD
vs. TEMPERATURE
0.92
FEEDBACK VOLTAGE
vs. TEMPERATURE
toc05
3.3V OUTPUT
LOAD AND LINE REGULATION
FIGURE 5 CIRCUIT
5.05
5V OUTPUT
LOAD AND LINE REGULATION
FIGURE 6 CIRCUIT
1.10
SHUTDOWN CURRENT
vs. TEMPERATURE
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