MAX15462 [MAXIM]
42V, 300mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converters;
| 型号： | MAX15462 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | 42V, 300mA, Ultra-Small, High-Efficiency Synchronous Step-Down DC-DC Converters |
| 文件： | 总23页 (文件大小：2478K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EVALUATION KIT AVAILABLE
MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
General Description
Benefits and Features
● Eliminates External Components and Reduces
The MAX15462 high-efficiency, high-voltage, synchronous
step-down DC-DC converter with integrated MOSFETs
operates over a 4.5V to 42V input voltage range. The
converter delivers output current up to 300mA at 3.3V
(MAX15462A), 5V (MAX15462B), and adjustable output
voltages (MAX15462C). The device operates over the
-40°C to +125°C temperature range and is available in a
compact 8-pin (2mm x 2mm) TDFN package. Simulation
models are available.
Total Cost
• No Schottky—Synchronous Operation for High
Efficiency and Reduced Cost
• Internal Compensation
• Internal Feedback Divider for Fixed 3.3V, 5V
Output Voltages
• Internal Soft-Start
• All-Ceramic Capacitors, Ultra-Compact Layout
● Reduces Number of DC-DC Regulators to Stock
• Wide 4.5V to 42V Input Voltage Range
• Fixed 3.3V and 5V Output Voltage Options
The device employs a peak-current-mode control
architecture with a MODE pin that can be used to
operate the device in the pulse-width modulation (PWM)
or pulse-frequency modulation (PFM) control schemes.
PWM operation provides constant frequency operation at
all loads and is useful in applications sensitive to variable
switching frequency. PFM operation disables negative induc-
tor current and additionally skips pulses at light loads for high
efficiency. The low-resistance on-chip MOSFETs ensure high
efficiency at full load and simplify the PCB layout.
• Adjustable 0.9V to 0.89 x V Output Voltage Option
IN
• Delivers Up to 300mA Load Current
• Configurable Between PFM and Forced-PWM
Modes
● Reduces Power Dissipation
• Peak Efficiency = 92%
• PFM Feature for High Light-Load Efficiency
• Shutdown Current = 2.2µA (typ)
● Operates Reliably in Adverse Industrial Environments
• Hiccup-Mode Current Limit and Autoretry Startup
• Built-In Output Voltage Monitoring with Open-Drain
RESET Pin
To reduce input inrush current, the device offers an
internal soft-start. The device also incorporates an EN/
UVLO pin that allows the user to turn on the part at the
desired input-voltage level. An open-drain RESET pin can
be used for output-voltage monitoring.
• Programmable EN/UVLO Threshold
• Monotonic Startup into Prebiased Output
• Overtemperature Protection
Applications
● Process Control
● Industrial Sensors
● 4–20mA Current Loops
● HVAC and Building Control
● High-Voltage LDO Replacement
● General-Purpose Point of Load
• 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.
Typical Operating Circuit
L1
V
OUT
33µH
V
IN
3.3V,
300mA
4.5V TO
42V
V
LX
IN
C
1µF
IN
C
10µF
OUT
EN/UVLO
GND
MAX15462A
V
CC
RESET
C
VCC
1µF
V
MODE
OUT
19-7552; Rev 1; 2/17
MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Absolute Maximum Ratings
V
to GND............................................................-0.3V to +48V
Continuous Power Dissipation (T = +70°C)
IN
A
EN/UVLO to GND..................................................-0.3V to +48V
LX to GND....................................................-0.3V to V + 0.3V
8-Pin TDFN (derate 6.2mW/°C above +70°C) ............496mW
Junction Temperature......................................................+150°C
Storage Temperature Range............................ -65°C to +150°C
Soldering Temperature (reflow).......................................+260°C
Lead Temperature (soldering, 10s) .................................+300°C
IN
V
, FB/V
, RESET to GND .............................-0.3V to +6V
CC
OUT
MODE to GND.............................................-0.3V to V
+ 0.3V
CC
LX total RMS Current.....................................................±800mA
Output Short-Circuit Duration....................................Continuous
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.
(Note 1)
Package Thermal Characteristics
TDFN
Junction-to-Ambient Thermal Resistance (θ ) ......+162°C/W
JA
Junction-to-Case Thermal Resistance (θ ).............+20°C/W
JC
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 = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, LX = MODE = RESET = unconnected; T = -40°C to +125°C, unless
EN/UVLO A
IN
GND
IN
VCC
otherwise noted. Typical values are at T = +25°C. All voltages are referenced to GND, unless otherwise noted.) (Note 2)
A
PARAMETER
INPUT SUPPLY (V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
)
IN
Input Voltage Range
V
4.5
42
4
V
IN
Input Shutdown Current
Input Supply Current
I
V
= 0V, shutdown mode
2.2
95
µA
IN-SH
EN/UVLO
MODE = unconnected,
FB/V = 1.03 x FB/V
I
160
4
µA
Q-PFM
OUT
OUT-REG
I
Normal switching mode, V = 24V
2.5
mA
Q-PWM
IN
ENABLE/UVLO (EN/UVLO)
V
V
V
V
V
rising
1.19
1.06
1.215
1.09
0.75
1.24
1.15
ENR
EN/UVLO
EN/UVLO
EN/UVLO
EN/UVLO
EN/UVLO Threshold
V
falling
V
ENF
V
falling, true shutdown
EN-TRUESD
EN/UVLO Input Leakage Current
I
= 42V, T = +25°C
-100
+100
nA
EN/UVLO
A
LDO (V
)
CC
V
V
V
Output Voltage Range
Current Limit
V
6V < V < 42V, 0mA < I < 10mA
VCC
4.75
5
5.25
50
V
mA
V
CC
CC
CC
CC
IN
I
V
V
V
V
= 4.3V, V = 12V
13
30
VCC-MAX
CC
IN
Dropout
V
= 4.5V, I = 5mA
VCC
0.15
4.18
3.8
0.3
CC-DO
IN
V
rising
falling
4.05
4.3
CC-UVR
CC
CC
V
UVLO
V
CC
V
3.7
3.95
CC-UVF
Maxim Integrated
│ 2
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Electrical Characteristics (continued)
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, LX = MODE = RESET = unconnected; T = -40°C to +125°C, unless
IN
GND
IN
VCC
EN/UVLO
A
otherwise noted. Typical values are at T = +25°C. All voltages are referenced to GND, unless otherwise noted.) (Note 2)
A
PARAMETER
POWER MOSFETs
SYMBOL
CONDITIONS
MIN
TYP
1.35
0.45
MAX
UNITS
T
T
T
T
= +25°C
1.75
2.7
A
A
A
A
I
= 0.3A
LX
High-Side pMOS On-Resistance
R
Ω
DS-ONH
(sourcing)
= T = +125°C
J
= +25°C
0.55
0.9
I
= 0.3A
LX
Low-Side nMOS On-Resistance
LX Leakage Current
R
Ω
DS-ONL
(sinking)
= T = +125°C
J
V
V
= 0V, V = 42V, T = +25°C,
IN A
EN/UVLO
I
-1
+1
µA
LX-LKG
= (V
+ 1V) to (V - 1V)
LX
GND
IN
SOFT-START (SS)
Soft-Start Time
t
3.8
4.1
4.4
ms
SS
FEEDBACK (FB)
MODE = GND, MAX15462C
MODE = unconnected, MAX15462C
MAX15462C
0.887
0.887
-100
0.9
0.915
-25
0.913
0.936
FB Regulation Voltage
FB Leakage Current
V
V
FB-REG
I
nA
FB
OUTPUT VOLTAGE (V
)
OUT
MODE = GND, MAX15462A
3.25
3.25
4.93
4.93
3.3
3.35
5
3.35
3.42
5.07
5.18
MODE = unconnected, MAX15462A
MODE = GND, MAX15462B
V
Regulation Voltage
V
V
OUT
OUT-REG
MODE = unconnected, MAX15462B
5.08
CURRENT LIMIT
Peak Current-Limit Threshold
I
0.49
0.58
0.25
0.56
0.66
0.62
0.73
0.35
A
A
PEAK-LIMIT
I
RUNAWAY-
LIMIT
Runaway Current-Limit Threshold
MODE = GND
0.3
A
mA
A
Negative Current-Limit
Threshold
I
SINK-LIMIT
0.01
0.13
PFM Current Level
TIMING
I
PFM
Switching Frequency
f
465
500
1
535
kHz
SW
Events to Hiccup After Crossing
Runaway Current Limit
Cycles
FB/V
to Cause Hiccup
Undervoltage Trip Level
OUT
62.5
64.5
66.5
%
Hiccup Timeout
131
90
ms
ns
%
Minimum On-Time
Maximum Duty Cycle
t
130
94
ON-MIN
D
MAX
FB/V
= 0.98 x FB/V
OUT-REG
89
91.5
OUT
Maxim Integrated
│ 3
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Electrical Characteristics (continued)
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, LX = MODE = RESET = unconnected; T = -40°C to +125°C, unless
IN
GND
IN
VCC
EN/UVLO
A
otherwise noted. Typical values are at T = +25°C. All voltages are referenced to GND, unless otherwise noted.) (Note 2)
A
PARAMETER
LX Dead Time
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
5
ns
RESET
FB/V
Rising
Threshold for RESET
Threshold for RESET
OUT
FB/V
FB/V
rising
93.5
90
95.5
92
2
97.5
%
%
OUT
FB/V
OUT
falling
94
OUT
Falling
RESET Delay After FB/V
OUT
ms
Reaches 95% Regulation
RESET Output Level Low
RESET Output Leakage Current
MODE
I
= 5mA
0.2
0.1
V
RESET
V
= 5.5V, T = +25°C
µA
RESET
A
MODE Internal Pullup Resistor
THERMAL SHUTDOWN
Thermal-Shutdown Threshold
Thermal-Shutdown Hysteresis
500
kΩ
Temperature rising
166
10
°C
°C
Note 2: Limits are 100% tested at T = +25°C. Limits over the operating temperature range and relevant supply voltage range are
A
guaranteed by design and characterization.
Maxim Integrated
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Typical Operating Characteristics
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, T = +25°C, unless otherwise noted.)
IN
GND
IN
VCC
EN/UVLO
A
EFFICIENCY vs. LOAD CURRENT
toc02a
EFFICIENCY vs. LOAD CURRENT
EFFICIENCY vs. LOAD CURRENT toc02
toc01
100
100
90
80
70
60
50
40
30
20
100
90
80
70
60
50
40
30
20
90
80
70
VIN = 6V
VIN = 12V
VIN = 12V
VIN = 24V
VIN = 12V
60
VIN = 24V
VIN = 24V
50
VIN = 36V
VIN = 36V
40
FIGURE 7 APPLICATION
CIRCUIT, PFM MODE
FIGURE 5 APPLICATION
CIRCUIT, PFM MODE
FIGURE 6 APPLICATION
CIRCUIT, PFM MODE
VIN = 36V
30
20
VOUT = 2.5V
VOUT = 3.3V
VOUT = 5V
1
10
100
1
10
100
1
10
100
LOAD CURRENT (mA)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
EFFICIENCY vs. LOAD CURRENTtoc04
EFFICIENCY vs. LOAD CURRENT toc02b
EFFICIENCY vs. LOAD CURRENTtoc03
100
90
80
70
60
50
40
100.00
90.00
80.00
70.00
60.00
50.00
40.00
30.00
20.00
10.00
0.00
100
90
80
70
60
50
40
30
20
10
0
VIN = 12V
VIN = 24V
VIN = 12V
VIN = 24V
VIN = 36V
VIN = 24V
VIN = 18V
VIN = 36V
VIN = 36V
FIGURE 5 APPLICATION
CIRCUIT, PWM MODE
FIGURE 6 APPLICATION
CIRCUIT, PWM MODE
FIGURE 8 APPLICATION
CIRCUIT, PFM MODE
V
OUT = 3.3V
V
OUT = 5V
VOUT = 12V
1
10
100
0
50
100
150
200
250
300
0
50
100
150
200
250
300
LOAD CURRENT (mA)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
OUTPUT VOLTAGE
vs. LOAD CURRENT
EFFICIENCY vs. LOAD CURRENTtoc04a
EFFICIENCY VS. LOAD CURRENT
toc04b
toc05
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
3.37
3.36
3.35
3.34
3.33
3.32
3.31
3.3
FIGURE 5 APPLICATION
CIRCUIT, PFM MODE
VOUT = 3.3V
VIN = 18V
VIN = 24V
VIN = 24V
VIN = 6V
VIN = 12V
VIN = 12V
VIN = 36V
VIN = 24V
VIN = 36V
VIN = 36V
FIGURE 8 APPLICATION
CIRCUIT, PWM MODE
FIGURE 7 APPLICATION
CIRCUIT, PWM MODE
VOUT = 12V
V
OUT = 2.5V
3.29
0
50
100
150
200
250
300
0
50
100
150
200
250
300
0
50
100
150
200
250
300
LOAD CURRENT (mA)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
Maxim Integrated
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Typical Operating Characteristics (continued)
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, T = +25°C, unless otherwise noted.)
IN
GND
IN
VCC
EN/UVLO
A
OUTPUT VOLTAGE
vs. LOAD CURRENT
OUTPUT VOLTAGE
vs. LOAD CURRENT
OUTPUT VOLTAGE
vs. LOAD CURRENT
toc06
toc06a
toc06b
5.1
5.08
5.06
5.04
5.02
5
2.54
2.53
2.52
2.51
2.5
12.35
FIGURE 6 APPLICATION
CIRCUIT, PFM MODE
FIGURE 7 APPLICATION
CIRCUIT, PFM MODE
FIGURE 8 APPLICATION
CIRCUIT, PFM MODE
12.3
VOUT = 5V
VOUT = 2.5V
VOUT = 12V
VIN = 24V
12.25
VIN = 18V
VIN = 12V
12.2
VIN = 24V
VIN = 36V
VIN = 6V,24V
VIN = 12V
VIN = 36V
VIN = 36V
12.15
12.1
12.05
12
2.49
4.98
2.48
0
0
50
100
150
200
250
300
50
100
150
200
250
300
0
50
100
150
200
250
300
LOAD CURRENT (mA)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
FEEDBACK VOLTAGE
vs. LOAD CURRENT
OUTPUT VOLTAGE
vs. LOAD CURRENT
OUTPUT VOLTAGE
vs. LOAD CURRENT
toc06c
toc07
toc08
0.92
0.915
0.91
3.303
3.302
3.301
3.3
5.003
5.002
5.001
5
PFM MODE
FIGURE 5 APPLICATION
CIRCUIT, PWM MODE
OUT = 3.3V
FIGURE 5 APPLICATION
CIRCUIT, PWM MODE
V
V
OUT = 5V
VIN = 12V
VIN = 24V
VIN = 36V
VIN = 6V,24V
4.999
4.998
4.997
4.996
0.905
0.9
VIN = 36V
3.299
3.298
3.297
VIN = 12V
50
VIN = 12V
VIN = 24V
150
VIN = 36V
0.895
0
50
100
150
200
250
300
0
100
200
250
300
0
50
100
150
200
250
300
LOAD CURRENT (mA)
LOAD CURRENT (mA)
LOAD CURRENT (mA)
OUTPUT VOLTAGE
vs. TEMPERATURE
OUTPUT VOLTAGE vs. TEMPERATURE
5.04
5.02
5.00
4.98
4.96
4.94
3.32
3.31
3.30
3.29
3.28
3.27
FIGURE 6 APPLICATION
CIRCUIT, LOAD = 300mA
FIGURE 5 APPLICATION
CIRCUIT, LOAD = 300mA
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
Maxim Integrated
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Typical Operating Characteristics (continued)
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, T = +25°C, unless otherwise noted.)
IN
GND
IN
VCC
EN/UVLO A
NO-LOAD SUPPLY CURRENT
vs. INPUT VOLTAGE
FEEDBACK VOLTAGE
VS. TEMPERATURE
100
98
96
94
92
90
toc10a
0.908
0.904
0.900
0.896
0.892
0.888
0.884
0.880
PFM MODE
45 55
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
5
15
25
35
INPUT VOLTAGE (V)
NO-LOAD SUPPLY CURRENT
vs. TEMPERATURE
SHUTDOWN CURRENT
vs. INPUT VOLTAGE
140
6
130
120
110
100
90
5
4
3
2
1
0
80
70
PFM MODE
60
5
15
25
35
45
55
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
INPUT VOLTAGE (V)
SHUTDOWN CURRENT
vs. TEMPERATURE
SWITCH CURRENT LIMIT
vs. INPUT VOLTAGE
600
550
500
450
400
350
300
250
200
2.40
2.25
2.10
1.95
1.80
1.65
1.50
SWITCH PEAK CURRENT LIMIT
SWITCH NEGATIVE CURRENT LIMIT
5
15
25
35
45
55
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
INPUT VOLTAGE (V)
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Typical Operating Characteristics (continued)
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, T = +25°C, unless otherwise noted.)
IN
GND
IN
VCC
EN/UVLO A
EN/UVLO THRESHOLD
vs. TEMPERATURE
SWITCH CURRENT LIMIT
vs. TEMPERATURE
600
550
500
450
400
350
300
250
200
1.24
1.22
1.20
1.18
1.16
1.14
1.12
1.10
1.08
RISING
SWITCH PEAK CURRENT LIMIT
SWITCH NEGATIVE CURRENT LIMIT
FALLING
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
SWITCHING FREQUENCY
vs. TEMPERATURE
RESET THRESHOLD
vs. TEMPERATURE
560
540
520
500
480
460
98
97
96
95
94
93
92
91
90
RISING
FALLING
440
0
10
20
30
40
50
60
-40 -20
0
20 40 60 80 100 120
TEMPERATURE (°C)
TEMPERATURE (°C)
LOAD TRANSIENT RESPONSE,
PFM MODE (LOAD CURRENT STEPPED
LOAD TRANSIENT RESPONSE,
PFM MODE (LOAD CURRENT STEPPED
FROM 5mA TO 150mA)
FROM 5mA TO 150mA)
MAX15462 toc20
MAX15462 toc21
V
OUT
(AC)
100mV/div
V
OUT
(AC)
100mV/div
FIGURE 5
FIGURE 6
APPLICATION CIRCUIT
APPLICATION CIRCUIT
V
OUT
= 3.3V
V
= 5V
OUT
I
I
OUT
OUT
100mA/div
100mA/div
100µs/div
100µs/div
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│ 8
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Typical Operating Characteristics (continued)
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, T = +25°C, unless otherwise noted.)
IN
GND
IN
VCC
EN/UVLO A
LOAD TRANSIENT RESPONSE
LOAD TRANSIENT RESPONSE,
PFM MODE (LOAD CURRENT STEPPED
FROM 5mA TO 150mA)
PFM MODE (LOAD CURRENT STEPPED
FROM 5mA TO 150mA)
toc21b
toc21a
VOUT (AC)
VOUT (AC)
100mV/div
200mV/div
FIGURE 8
APPLICATION CIRCUIT
FIGURE 7
APPLICATION CIRCUIT
VOUT = 2.5V
V
= 12V
OUT
IOUT
IOUT
100mA/div
100mA/div
100µs/div
100µs/div
LOAD TRANSIENT RESPONSE,
LOAD TRANSIENT RESPONSE,
PFM OR PWM MODE (LOAD CURRENT
PFM OR PWM MODE (LOAD CURRENT
STEPPED FROM 150mA TO 300mA)
STEPPED FROM 150mA TO 300mA)
MAX15062 toc22
MAX15062 toc23
V
(AC)
V
(AC)
OUT
100mV/div
OUT
100mV/div
I
OUT
I
OUT
100mA/div
100mA/div
FIGURE 5
FIGURE 6
APPLICATION CIRCUIT
APPLICATION CIRCUIT
V
OUT
= 3.3V
V
= 5V
OUT
40µs/div
40µs/div
LOAD TRANSIENT RESPONSE
PFM OR PWM MODE (LOAD CURRENT
STEPPED FROM 150mA TO 300mA)
LOAD TRANSIENT RESPONSE
PFM OR PWM MODE (LOAD CURRENT
STEPPED FROM 150mA TO 300mA)
toc23b
toc23a
VOUT (AC)
50mV/div
VOUT (AC)
200mV/div
IOUT
100mA/div
IOUT
FIGURE 8
APPLICATION CIRCUIT
FIGURE 7
APPLICATION CIRCUIT
100mA/div
V
= 12V
V
= 2.5V
OUT
OUT
40µs/div
40µs/div
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Typical Operating Characteristics (continued)
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, T = +25°C, unless otherwise noted.)
IN
GND
IN
VCC
EN/UVLO A
LOAD TRANSIENT RESPONSE,
PWM MODE (LOAD CURRENT
LOAD TRANSIENT RESPONSE,
PWM MODE PWM mode (LOAD CURRENT
STEPPED FROM NO LOAD TO 150mA)
STEPPED FROM NO LOAD TO 150mA)
MAX15062 toc24
MAX15062 toc25
V
(AC)
V
(AC)
OUT
OUT
100mV/div
100mV/div
FIGURE 5
FIGURE 6
APPLICATION CIRCUIT
APPLICATION CIRCUIT
V
OUT
= 5V
V
= 3.3V
OUT
I
OUT
I
OUT
100mA/div
100mA/div
40µs/div
40µs/div
LOAD TRANSIENT RESPONSE
LOAD TRANSIENT RESPONSE
PWM MODE (LOAD CURRENT STEPPED
PWM MODE (LOAD CURRENT STEPPED
FROM NO LOAD TO 150mA)
FROM NO LOAD TO 150mA)
toc25a
toc25b
VOUT (AC)
VOUT (AC)
50mV/div
200mV/div
FIGURE 8
APPLICATION CIRCUIT
FIGURE 7
APPLICATION CIRCUIT
V = 12V
OUT
V
= 2.5V
OUT
IOUT
IOUT
100mA/div
100mA/div
40µs/div
40µs/div
FULL-LOAD SWITCHING WAVEFORMS
SWITCHING WAVEFORMS
(PFM MODE)
(PWM OR PFM MODE)
MAX15062 toc27
MAX15062 toc26
FIGURE 6 APPLICATION CIRCUIT
= 5V, LOAD = 20mA
V
= 5V,
OUT
V
OUT
LOAD = 300mA
V (AC)
OUT
20mV/div
V
(AC)
OUT
100mV/div
V
LX
V
LX
10V/div
10V/div
I
I
OUT
OUT
100mA/div
200mA/div
10µs/div
2µs/div
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Typical Operating Characteristics (continued)
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, T = +25°C, unless otherwise noted.)
IN
GND
IN
VCC
EN/UVLO A
NO-LOAD SWITCHING WAVEFORMS
SOFT-START
(PWM MODE)
MAX15062 toc29
MAX15062 toc28
V
OUT
= 5V
V
EN/UVLO
5V/div
V (AC)
OUT
20mV/div
V
OUT
1V/div
V
LX
10V/div
FIGURE 5
APPLICATION CIRCUIT
= 3.3V
V
OUT
I
OUT
100mA/div
I
OUT
100mA/div
V
RESET
5V/div
1ms/div
2µs/div
SOFT-START
SOFT-START
MAX15062 toc30
toc30a
VEN/UVLO
5V/div
V
EN/UVLO
5V/div
VOUT
1V/div
IOUT
V
OUT
1V/div
100mA/div
FIGURE 6
FIGURE 7
APPLICATION CIRCUIT
APPLICATION CIRCUIT
= 5V
V
= 2.5V
V
OUT
OUT
I
OUT
100mA/div
VRESET
5V/div
V
RESET
5V/div
1ms/div
1ms/div
SHUTDOWN WITH ENABLE
SOFT-START
MAX15062 toc31
toc30b
VEN/UVLO
5V/div
V
EN/UVLO
5V/div
V
OUT
1V/div
VOUT
5V/div
I
OUT
100mA/div
IOUT
100mA/div
FIGURE 8
APPLICATION CIRCUIT
= 12V
V
OUT
V
RESET
5V/div
VRESET
5V/div
400µs/div
1ms/div
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Typical Operating Characteristics (continued)
(V = 24V, V
= 0V, C = C
= 1µF, V
= 1.5V, T = +25°C, unless otherwise noted.)
IN
GND
IN
VCC
EN/UVLO
A
SOFT-START WITH 3V PREBIAS
OVERLOAD PROTECTION
BODE PLOT
MAX15062 toc32
MAX15062 toc33
MAX15062 toc34
50
180
144
108
72
40
30
20
10
0
V
V
EN/UVLO
5V/div
IN
20V/div
GAIN
PHASE
V
OUT
36
V
OUT
2V/div
1V/div
0
FIGURE 6
APPLICATION CIRCUIT
NO LOAD
f
= 47kHz,
PHASE MARGIN = 59°
CR
-10
-20
-30
-40
-50
-36
-72
-108
-144
-180
PWM MODE
FIGURE 5 APPLICATION CIRCUIT
= 3.3V
I
V
OUT
200mA/div
OUT
V
RESET
5V/div
2
4
6 8 1
10k
2
4
6 8 1
100k
2
1k
FREQUENCY (Hz)
1ms/div
20ms/div
BODE PLOT
BODE PLOT
MAX15062 toc35
MAX15062 toc35a
50
40
180
144
108
72
50
40
180
GAIN
144
108
GAIN
30
30
PHASE
20
20
72
PHASE
10
36
10
36
0
0
0
0
f
= 43kHz,
PHASE MARGIN = 60°
CR
f
= 47kHz,
CR
PHASE MARGIN = 60°
-10
-20
-30
-40
-50
-36
-72
-108
-144
-180
-10
-20
-30
-40
-50
-36
-72
FIGURE 7 APPLICATION CIRCUIT
V
FIGURE 6 APPLICATION CIRCUIT
= 5V
-108
-144
-180
= 2.5V
V
OUT
OUT
2
4
6 8 1
10k
2
4
6 8 1
100k
2
1k
1k
10k
100k
FREQUENCY (Hz)
FREQUENCY (Hz)
MAX15462, 5V OUTPUT, 0.3A LOAD CURRENT
,
CONDUCTED EMI CURVE
BODE PLOT
toc36
MAX15062 toc35b
50
40
180
144
108
72
70
GAIN
30
QUASI-PEAK LIMIT
AVERAGE LIMIT
60
50
40
30
20
10
20
PHASE
10
36
0
0
f
= 36kHz,
CR
PHASE MARGIN = 66°
-10
-20
-30
-40
-50
-36
-72
-108
-144
-180
PEAK
EMISSIONS
FIGURE 8 APPLICATION CIRCUIT
AVERAGE
EMISSIONS
V
= 12V
OUT
30
1
10
0.15
1k
10k
100k
FREQUENCY (MHz)
FREQUENCY (Hz)
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Pin Configuration
TOP VIEW
LX
8
GND RESET MODE
5
7
6
MAX15462
1
2
3
4
FB/V
+
V
IN
EN/UVLO
V
CC
OUT
TDFN
(2mm x 2mm)
Pin Description
PIN
NAME
FUNCTION
1
V
Switching Regulator Power Input. Connect a X7R 1µF ceramic capacitor from V to GND for bypassing.
IN
IN
Active-High, Enable/Undervoltage-Detection Input. Pull EN/UVLO to GND to disable the regulator
2
3
4
EN/UVLO
output. Connect EN/UVLO to V for always-on operation. Connect a resistor-divider between V and
EN/UVLO to GND to program the input voltage at which the device is enabled and turns on.
IN
IN
V
Internal LDO Power Output. Bypass V
to GND with a minimum 1µF capacitor.
CC
CC
Feedback Input. For fixed-output voltage versions, connect FB/V
directly to the output. For the
OUT
FB/V
adjustable output voltage version, connect FB/V
to a resistor-divider between V
and GND to
OUT
OUT
OUT
adjust the output voltage from 0.9V to 0.89 x V
.
IN
PFM/PWM Mode Selection Input. Connect MODE to GND to enable the fixed-frequency PWM
operation. Leave unconnected for light-load PFM operation.
5
6
MODE
Open-Drain Reset Output. Pull up RESET to an external power supply with an external resistor.
RESET goes low when the output voltage drops below 92% of the set nominal regulated voltage.
RESET goes high impedance 2ms after the output voltage rises above 95% of its regulation value. See
the Electrical Characteristics table for threshold values.
RESET
Ground. Connect GND to the power ground plane. Connect all the circuit ground connections together at
a single point. See the PCB Layout Guidelines section.
7
GND
LX
Inductor Connection. Connect LX to the switching-side of the inductor. LX is high impedance when the
device is in shutdown.
8
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Block Diagram
V
IN
LDO
REGULATOR
PEAK-LIMIT
RUNAWAY-
LIMIT
CURRENT-
SENSE
CURRENT-
SENSE
V
CC
CS
LOGIC
AMPLIFIER
PFM
MAX15462
POK
EN/UVLO
DH
HIGH-SIDE
DRIVER
CHIPEN
CLK
1.215V
THERMAL
SHUTDOWN
LX
V
CC
OSCILLATOR
SLOPE
500kΩ
MODE
DL
PFM/PWM
CONTROL
LOGIC
LOW-SIDE
DRIVER
MODE SELECT
0.55V
CC
SLOPE
CS
R1
*
LOW-SIDE
CURRENT
SENSE
SINK-LIMIT
PWM
FB/V
OUT
NEGATIVE
CURRENT
REF
ERROR
AMPLIFIER
GND
R2
3.135V FOR MAX15462A
4.75V FOR MAX15462B
0.859V FOR MAX15462C
CLK
RESET
REFERENCE
SOFT-START
2ms
DELAY
FB/V
OUT
*RESISTOR-DIVIDER ONLY FOR MAX15462A, MAX15462B
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
loads. However, the PWM mode of operation gives lower
efficiency at light loads compared to PFM mode of operation.
Detailed Description
The MAX15462 high-efficiency, high-voltage, synchronous
step-down DC-DC converter with integrated MOSFETs
operates over a wide 4.5V to 42V input voltage range.
The converter delivers output current up to 300mA at
3.3V (MAX15462A), 5V (MAX15462B), and adjustable
output voltages (MAX15462C). When EN/UVLO and
PFM Mode Operation
PFM mode operation disables negative inductor current
and skips pulses at light loads for high efficiency. In
PFM mode, the inductor current is forced to a fixed
peak of 130mA every clock cycle until the output rises to
102.3% of the nominal voltage. Once the output reaches
102.3% of the nominal voltage, both high-side and low-
side FETs are turned off and the part enters hibernate
operation until the load discharges the output to 101.1%
of the nominal voltage. Most of the internal blocks are
turned off in hibernate operation to save quiescent cur-
rent. After the output falls below 101.1% of the nominal
voltage, the device comes out of hibernate operation,
turns on all internal blocks, and again commences the
process of delivering pulses of energy to the output until
it reaches 102.3% of the nominal output voltage. The device
naturally exits PFM mode when the load current exceeds
55mA (typ). The advantage of the PFM mode is higher
efficiency at light loads because of lower quiescent
current drawn from supply.
V
CC
UVLO are satisfied, an internal power-up sequence
soft-starts the error-amplifier reference, resulting in a
clean monotonic output-voltage soft-start independent of
the load current. The FB/V
pin monitors the output
OUT
voltage through a resistor-divider. RESET transitions
to a high-impedance state 2ms after the output voltage
reaches 95% of regulation. The device selects either
PFM or forced-PWM mode depending on the state of the
MODE pin at power-up. By pulling the EN/UVLO pin low,
the device enters the shutdown mode and consumes only
2.2µA (typ) of standby current.
DC-DC Switching Regulator
The device uses an internally compensated, fixed-frequency,
current-mode control scheme (see the Block Diagram).
On the rising-edge of an internal clock, the high-side
pMOSFET turns on. An internal error amplifier compares
the feedback voltage to a fixed internal reference voltage
and generates an error voltage. The error voltage is com-
pared to a sum of the current-sense voltage and a slope-
compensation voltage by a PWM comparator to set the
on-time. During the on-time of the pMOSFET, the induc-
tor current ramps up. For the remainder of the switching
period (off-time), the pMOSFET is kept off and the low-
side nMOSFET turns on. During the off-time, the inductor
releases the stored energy as the inductor current ramps
down, providing current to the output. Under overload
conditions, the cycle-by-cycle current-limit feature limits
the inductor peak current by turning off the high-side
pMOSFET and turning on the low-side nMOSFET.
Internal 5V Linear Regulator
An internal regulator provides a 5V nominal supply to
power the internal functions and to drive the power
MOSFETs. The output of the linear regulator (V ) should
CC
be bypassed with a 1µF capacitor to GND. The V
CC
regulator dropout voltage is typically 150mV. An undervolt-
age-lockout circuit that disables the regulator when V
CC
UVLO hysteresis
falls below 3.8V (typ). The 400mV V
CC
prevents chattering on power-up and power-down.
Enable Input (EN/UVLO), Soft-Start
When EN/UVLO voltage is above 1.21V (typ), the device’s
internal error-amplifier reference voltage starts to ramp up.
The duration of the soft-start ramp is 4.1ms, allowing a
smooth increase of the output voltage. Driving EN/UVLO
low disables both power MOSFETs, as well as other internal
Mode Selection (MODE)
The logic state of the MODE pin is latched after V
CC
circuitry, and reduces V quiescent current to below 2.2µA.
IN
and EN/UVLO voltages exceed respective UVLO rising
thresholds and all internal voltages are ready to allow
LX switching. If the MODE pin is unconnected at power-
up, the part operates in PFM mode at light loads. If the
MODE pin is grounded at power-up, the part operates in
constant-frequency PWM mode at all loads. State changes
on the MODE pin are ignored during normal operation.
EN/UVLO can be used as an input-voltage UVLO adjustment
input. An external voltage-divider between V and EN/UVLO
IN
to GND adjusts the input voltage at which the device turns
on or turns off. If input UVLO programming is not desired,
connect EN/UVLO to V (see the Electrical Characteristics
IN
table for EN/UVLO rising and falling threshold voltages).
PWM Mode Operation
In PWM mode, the inductor current is allowed to go
negative. PWM operation is useful in frequency-sensitive
applications, providing fixed switching frequency at all
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
a fault condition, the output voltage drops to 65% (typ)
of its nominal value any time after soft-start is complete,
Reset Output (RESET)
The device includes an open-drain RESET output to
monitor the output voltage. RESET goes high impedance
2ms after the output rises above 95% of its nominal set
value and pulls low when the output voltage falls below
92% of the set nominal regulated voltage. RESET asserts
low during the hiccup timeout period.
hiccup mode is triggered. In hiccup mode, the converter
is protected by suspending switching for a hiccup timeout
period of 131ms. Once the hiccup timeout period expires,
soft-start is attempted again. Hiccup mode of operation
ensures low power dissipation under output short-circuit
conditions.
Startup into a Prebiased Output
Care should be taken in board layout and system wiring
to prevent violation of the absolute maximum rating of the
The device is capable of soft-start into a prebiased
output, without discharging the output capacitor in both the
PFM and forced-PWM modes. Such a feature is useful in
applications where digital integrated circuits with multiple
rails are powered.
FB/V
pin under short-circuit conditions. Under such
OUT
conditions, it is possible for the ceramic output capacitor
to oscillate with the board or wiring inductance between
the output capacitor or short-circuited load, thereby causing
the absolute maximum rating of FB/V
(-0.3V) to be
OUT
Operating Input Voltage Range
exceeded. The parasitic board or wiring inductance should
be minimized, and the output voltage waveform under
short-circuit operation should be verified, to ensure the
The maximum operating input voltage is determined
by the minimum controllable on-time and the minimum
operating input voltage is determined by the maximum
duty cycle and circuit voltage drops. The minimum and
maximum operating input voltages for a given output
voltage should be calculated as follows:
absolute maximum rating of FB/V
is not exceeded.
OUT
Thermal Overload Protection
Thermal overload protection limits the total power
dissipation in the device. When the junction temperature
exceeds +166°C, an on-chip thermal sensor shuts down
the device, turns off the internal power MOSFETs, allowing
the device to cool down. The thermal sensor turns the
device on after the junction temperature cools by 10°C.
V
+ (I
×(R
+ 0.5))
DCR
OUT
OUT
D
V
=
+ (I
×1.0)
OUT
INMIN
MAX
V
OUT
V
=
INMAX
t
× f
ONMIN SW
Applications Information
where V
the maximum load current, R
the inductor, f
is maximum duty cycle (0.9), and t
is the steady-state output voltage, I
is
OUT
OUT
is the DC resistance of
DCR
Inductor Selection
A low-loss inductor having the lowest possible DC
resistance that fits in the allotted dimensions should be
is the switching frequency (max), D
SW
MAX
is the worst-
ONMIN
case minimum controllable switch on-time (130ns).
selected. The saturation current (I
) must be high
SAT
enough to ensure that saturation cannot occur below the
Overcurrent Protection/Hiccup Mode
maximum current-limit value (I ) of 0.56A (typ).
PEAK-LIMIT
The device is provided with a robust overcurrent protec-
tion scheme that protects the device under overload and
output short-circuit conditions. A cycle-by-cycle peak
current limit turns off the high-side MOSFET whenever
the high-side switch current exceeds an internal limit
of 0.56A (typ). A runaway current limit on the high-side
switch current at 0.66A (typ) protects the device under
high input voltage, and short-circuit conditions when
there is insufficient output voltage available to restore the
inductor current that was built up during the on period of
the step-down converter. One occurrence of the runaway
current limit triggers a hiccup mode. In addition, if, due to
The required inductance for a given application can be
determined from the following equation:
L = 9.3 x V
OUT
where L is inductance in µH and V
is output voltage.
OUT
Once the L value is known, the next step is to select the
right core material. Ferrite and powdered iron are com-
monly available core materials. Ferrite cores have low
core losses and are preferred for high-efficiency designs.
Powdered iron cores have more core losses and are rela-
tively cheaper than ferrite cores. See Table 1 to select the
inductors for typical applications.
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Table 1. Inductor Selection
INPUT VOLTAGE
RANGE V (V)
IN
V
(V)
I
(mA)
OUT
L (µH)
RECOMMENDED PART NO.
Coilcraft LPS4018-333ML
OUT
4.5 to 42
6 to 42
3.3
300
33
47
5
300
300
300
300
Coilcraft LPS4018-473ML
Coilcraft LPS4018-223ML
Wurth 74408943101
4.5 to 42
14 to 42
17 to 42
1.8 or 2.5
22
12
15
100
150
TDK VLC6045T-151M
Table 2. Output Capacitor Selection
INPUT VOLTAGE
RANGE V (V)
IN
V
(V)
I
(mA)
OUT
COUT (µF)
RECOMMENDED PART NO.
OUT
4.5 to 42
6 to 42
3.3
300
10µF/1206/X7R/6.3V Murata GRM31CR70J106K
10µF/1206/X7R/6.3V Murata GRM31CR70J106K
22µF/1206/X7R/6.3V Murata GRM31CR70J226K
4.7µF/1206/X7R/16V Murata GRM31CR71C475K
4.7µF/1206/X7R/25V Murata GRM31CR71E475K
5
300
300
300
300
4.5 to 42
14 to 42
17 to 42
1.8 or 2.5
12
15
application, such that the output-voltage deviation is less
than 3%. Required output capacitance can be calculated
from the following equation:
V
IN
V
IN
R1
R2
MAX15462
EN/UVLO
30
C
=
OUT
V
OUT
where C
is the output capacitance in µF and V
OUT
OUT
is the output voltage. See Table 2 to select the output
capacitor for typical applications. It should be noted that
dielectric materials used in ceramic capacitors exhibit
capacitance loss due to DC bias levels and should be
appropriately derated to ensure the required output
capacitance is obtained in the application.
Figure 1. Adjustable EN/UVLO Network
Input Capacitor
Small ceramic capacitors are recommended for the
device. The input capacitor reduces peak current drawn
from the power source and reduces noise and voltage
ripple on the input caused by the switching circuitry. A
minimum of 1µF, X7R-grade capacitor is recommended
for the input capacitor of the device to keep the input
voltage ripple under 2% of the minimum input voltage,
and to meet the maximum ripple-current requirements.
Setting the Input Undervoltage-Lockout Level
The devices offer an adjustable input undervoltage-
lockout level. Set the voltage at which the device turns
on with a resistive voltage-divider connected from V
IN
to GND (see Figure 1). Connect the center node of the
divider to EN/UVLO.
Choose R1 to be 3.3MΩ max, and then calculate R2 as follows:
R1×1.215
R2 =
Output Capacitor
Small ceramic X7R-grade capacitors are sufficient and
recommended for the device. The output capacitor has
two functions. It filters the square wave generated by the
device along with the output inductor. It stores sufficient
energy to support the output voltage under load transient
conditions and stabilizes the device’s internal control
loop. Usually, the output capacitor is sized to support a
step load of 50% of the maximum output current in the
(V
-1.215)
INU
where V
is the voltage at which the device is required
INU
to turn on. If the EN/UVLO pin is driven from an external
signal source, a series resistance of minimum 1kΩ is
recommended to be placed between the signal source
output and the EN/UVLO pin, to reduce voltage ringing
on the line.
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Adjusting the Output Voltage
PCB Layout Guidelines
The MAX15462C output voltage can be programmed from
Careful PCB layout is critical to achieve clean and stable
operation. The switching power stage requires particular
attention. Follow the guidelines below for good PCB layout.
0.9V to 0.89 x V . Set the output voltage by connecting a
IN
resistor-divider from output to FB to GND (see Figure 2).
For output voltages less than 6V, choose R2 in the 50kΩ
to 150kΩ range. For the output voltages greater than 6V,
choose R2 in the 25kΩ to 75kΩ range and calculate R1
with the following equation:
● Place the input ceramic capacitor as close as possible
to the V and GND pins.
IN
● Connect the negative terminal of the V
bypass
CC
capacitor to the GND pin with shortest possible trace or
ground plane.
V
OUT
● Minimize the area formed by the LX pin and the inductor
R1 = R2 ×
− 1
0.9
connection to reduce the radiated EMI.
● Place the V decoupling capacitor as close as possible
CC
Power Dissipation
to the V
pin.
CC
At a particular operating condition, the power losses that
lead to temperature rise of the part are estimated as fol-
lows:
● Ensure that all feedback connections are short and
direct.
● Route the high-speed switching node (LX) away from
1
the FB/V , RESET, and MODE pins.
OUT
2
P
= P
×
- 1 - (I
×R
)
DCR
LOSS
OUT
OUT
η
For a sample PCB layout that ensures the first-pass
success, refer to the MAX15462 evaluation kit layouts
available at www.maximintegrated.com.
P
= V
×I
OUT OUT
OUT
where P
is the output power, η is the efficiency of
OUT
power conversion, and R
is the DC resistance of the
DCR
output inductor. See the Typical Operating Characteristics
for the power-conversion efficiency or measure the
efficiency to determine the total power dissipation.
V
OUT
R1
R2
The junction temperature (T ) of the device can be
J
FB
MAX15462C
GND
estimated at any ambient temperature (T ) from the
A
following equation:
T = T + θ ×P
LOSS
(
)
J
A
JA
where θ is the junction-to-ambient thermal impedance
JA
of the package. Junction temperature greater than +125°C
degrades operating lifetimes.
Figure 2. Setting the Output Voltage
Maxim Integrated
│ 18
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
L1
V
V
IN
V
OUT
LX
IN
C
IN
C
OUT
R1
R2
GND
EN/UVLO
MAX15462A/B
V
OUT
V
CC
V
CC
RESET
C
VCC
R3
MODE
V
CC
V
PLANE
IN
C
IN
U1
L1
LX
R1
V
IN
EN/UVLO
GND
RESET
C
OUT
V
CC
R2
V
OUT
C
MODE
VCC
V
OUT
PLANE
GND
PLANE
R3
VIAS TO V
VIAS TO V
VIAS TO BOTTOM-SIDE GROUND PLANE
OUT
CC
Figure 3. Layout Guidelines for MAX15462A and MAX15462B
Maxim Integrated
│ 19
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
L1
V
V
IN
V
OUT
LX
IN
C
IN
C
OUT
R1
R2
GND
EN/UVLO
R4
R5
MAX15462C
FB
V
CC
V
CC
RESET
C
VCC
R3
MODE
V
CC
V
PLANE
IN
C
IN
U1
L1
LX
R1
V
IN
EN/UVLO
GND
RESET
C
OUT
V
CC
R2
FB
C
MODE
VCC
V
OUT
PLANE
R5
R4
GND
PLANE
R3
VIAS TO V
VIAS TO V
VIAS TO BOTTOM-SIDE GROUND PLANE
OUT
CC
Figure 4. Layout Guidelines for MAX15462C
Maxim Integrated
│ 20
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
L1
L1
V
OUT
V
OUT
33µH
47µH
V
IN
V
IN
3.3V,
300mA
5V,
300mA
4.5V TO
6V TO
42V
V
LX
V
LX
IN
IN
C
1µF
C
IN
1µF
IN
C
10µF
C
OUT
10µF
42V
OUT
EN/UVLO
GND
EN/UVLO
GND
MAX15462A
MAX15462B
V
CC
V
CC
RESET
RESET
C
VCC
1µF
C
VCC
1µF
V
V
MODE
MODE
OUT
OUT
MODE = GND FOR PWM
MODE = OPEN FOR PFM
MODE = GND FOR PWM
MODE = OPEN FOR PFM
L1: COILCRAFT LPS4018-333ML
L1: COILCRAFT LPS4018-473ML
C
C
: MURATA 10µF/X7R/6.3V/1206 GRM31CR70J106K
: MURATA 1μF/X7R/50V/1206 GRM31CR71H105K
C
: MURATA 10µF/X7R/6.3V/1206 GRM31CR70J106K
OUT
OUT
C : MURATA 1μF/X7R/50V/1206 GRM31CR71H105K
IN
IN
Figure 5. 3.3V, 300mA Step-Down Regulator
Figure 6. 5V, 300mA Step-Down Regulator
L1
L1
V
OUT
V
OUT
22µH
100µH
V
IN
V
IN
2.5V,
300mA
12V,
300mA
4.5V TO
42V
14V TO
42V
V
LX
V
LX
IN
IN
C
1µF
C
IN
1µF
IN
C
22µF
C
4.7µF
OUT
OUT
EN/UVLO
GND
EN/UVLO
GND
R1
133kΩ
R1
499kΩ
MAX15462C
MAX15462C
V
CC
FB
V
CC
FB
C
VCC
1µF
C
VCC
1µF
R2
75kΩ
R2
40.2kΩ
MODE
MODE
RESET
RESET
MODE = GND FOR PWM
MODE = OPEN FOR PFM
MODE = GND FOR PWM
MODE = OPEN FOR PFM
L1: COILCRAFT LPS4018-223ML
L1: Wurth 74408943101
C
C
: MURATA 22µF/X7R/6.3V/1206 (GRM31CR70J226K)
: M URATA 1μF/X7R/50V/1206 (GRM31CR71H105K)
C
: MURATA 4.7µF/X7R/16V/1206 (GRM31CR71C475K)
OUT
OUT
C : M URATA 1μF/X7R/50V/1206 (GRM31CR71H105K)
IN
IN
Figure 7. 2.5V, 300mA Step-Down Regulator
Figure 8. 12V, 300mA Step-Down Regulator
Maxim Integrated
│ 21
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
L1
L1
V
OUT
V
OUT
22µH
150µH
V
IN
V
IN
1.8V,
300mA
15V,
300mA
4.5V TO
17V TO
42V
V
LX
V
LX
IN
IN
C
1µF
C
IN
1µF
IN
C
22µF
C
OUT
4.7µF
42V
OUT
EN/UVLO
GND
EN/UVLO
GND
R1
75kΩ
R1
499kΩ
MAX15462C
MAX15462C
V
CC
FB
V
CC
FB
C
VCC
1µF
C
VCC
1µF
R2
75kΩ
R2
31.6kΩ
MODE
MODE
RESET
RESET
MODE = GND FOR PWM
MODE = OPEN FOR PFM
MODE = GND FOR PWM
MODE = OPEN FOR PFM
L1: COILCRAFT LPS4018-223ML
L1: TDK VLC6045T-151M
C
C
: MURATA 22µF/X7R/6.3V/1206 (GRM31CR70J226K)
: MURATA 1μF/X7R/50V/1206 (GRM31CR71H105K)
C
: MURATA 4.7µF/X7R/25V/1206 (GRM31CR71E475K)
OUT
OUT
C : MURATA 1μF/X7R/50V/1206 (GRM31CR71H105K)
IN
IN
Figure 9. 1.8V, 300mA Step-Down Regulator
Figure 10. 15V, 300mA Step-Down Regulator
Ordering Information
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PIN-
PACKAGE
PART
TEMP RANGE
V
OUT
MAX15462AATA+ -40°C to +125°C
MAX15462BATA+ -40°C to +125°C
MAX15462CATA+ -40°C to +125°C
8 TDFN
3.3V
5V
8 TDFN
8 TDFN
Adj
PACKAGE
PACKAGE
OUTLINE
NO.
LAND
PATTERN NO.
TYPE
CODE
+Denotes a lead(Pb)-free/RoHS-compliant package.
8 TDFN
T822CN+1
21-0487
90-0349
Chip Information
PROCESS: BiCMOS
Maxim Integrated
│ 22
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MAX15462
42V, 300mA, Ultra-Small, High-Efficiency,
Synchronous Step-Down DC-DC Converters
Revision History
REVISION REVISION
PAGES
DESCRIPTION
CHANGED
NUMBER
DATE
0
1
3/15
Initial release
Updated junction temperature and added text TOC36
—
2/17
1–4, 12, 17, 18
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
2017 Maxim Integrated Products, Inc.
│ 23
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