EVALUATION KIT AVAILABLE
MAX15014–MAX15017
1A, 4.5V to 40V Input Buck Converters with
50mA Auxiliary LDO Regulators
General Description
The MAX15014–MAX15017 combine a step-down DC-DC
converter and a 50mA, low-quiescent-current low-dropout
(LDO) regulator. The LDO regulator is ideal for powering
always-on circuitry. The DC-DC converter input voltage
range is 4.5V to 40V for the MAX15015/MAX15016, and
7.5V to 40V for the MAX15014/MAX15017.
The DC-DC converter output is adjustable from 1.26V
to 32V and can deliver up to 1A of load current. These
devices utilize a feed-forward voltage-mode-control
scheme for good noise immunity in the high-voltage
switching environment and offer external compensation
allowing for maximum flexibility with a wide selection
of inductor values and capacitor types. The switching
frequency is internally fixed at 135kHz and 500kHz,
depending on the version chosen. Moreover, the switch-
ing frequency 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. The soft-start time is adjustable with an external
capacitor. The DC-DC converter can be disabled inde-
pendent of the LDO, thus reducing the quiescent current
to 47μA (typ).
The LDO linear regulators operate from 5V to 40V and
deliver a guaranteed 50mA load current. The devices
feature a preset output voltage of 5V (MAX1501_A) or
3.3V (MAX1501_B). Alternatively, the output voltage
can be adjusted from 1.5V to 11V by using an external
resistive divider. The LDO section also features a
RESET
output with adjustable timeout period.
Protection features include cycle-by-cycle current limit,
hiccup-mode output short-circuit protection, and thermal
shutdown. All devices are available in a space-saving,
high-power (2.86W), 36-pin TQFN package and are rated
for operation over the -40°C to +125°C automotive tem-
perature range.
Features
●
Combined DC-DC Converters and Low-Quiescent-
Current LDO Regulators
●
1A DC-DC Converters Operate from 4.5V to 40V
(MAX15015/MAX15016) or 7.5V to 40V
(MAX15014/MAX15017)
●
Switching Frequency of 135kHz
(MAX15014/MAX15016) or 500kHz
(MAX15015/MAX15017)
●
50mA LDO Regulator Operates from 5V to 40V
Independent of the DC-DC Converter
● 47μA Quiescent Current with DC-DC Converter
Off and LDO On
● 6μA System Shutdown Current
●
Frequency Synchronization Input
●
Shutdown/Enable Inputs
●
Adjustable Soft-Start Time
●
Active-Low Open-Drain
RESET
Output with
Programmable Timeout Delay
●
Thermal Shutdown and Output Short-Circuit
Protection
●
Space-Saving (6mm x 6mm) Thermally Enhanced
36-Pin TQFN Package
Ordering Information
PART
MAX15014AATX+
MAX15014BATX+
MAX15015AATX+
MAX15015BATX+
MAX15016AATX+
MAX15016BATX+
MAX15017AATX+
MAX15017BATX+
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
36 TQFN-EP*
36 TQFN-EP*
36 TQFN-EP*
36 TQFN-EP*
36 TQFN-EP*
36 TQFN-EP*
36 TQFN-EP*
36 TQFN-EP*
Applications
●
Mobile Radios
●
Navigation Systems
+Denotes
a lead(Pb)-free/RoHS-compliant package.
*EP
= Exposed pad.
19-0734; Rev 1; 11/14
MAX15014–MAX15017
1A, 4.5V to 40V Input Buck Converters with
50mA Auxiliary LDO Regulators
Absolute Maximum Ratings
IN_SW, IN_LDO, DRAIN, EN_SYS, EN_SW
to SGND ............................................................-0.3V to +45V
IN_LDO to IN_SW ................................................-0.3V to +0.3V
LX to SGND.........................................-0.3V to (V
IN_SW
+ 0.3V)
LX to PGND.........................................-0.3V to (V
IN_SW
+ 0.3V)
BST to SGND .......................................-0.3V to (V
IN_SW
+ 12V)
BST to LX ..............................................................-0.3V to +12V
PGND to SGND....................................................-0.3V to +0.3V
REG, DVREG, SYNC,
RESET,
CT to SGND .......-0.3V to +12V
FB, COMP_SW, SS to SGND ................-0.3V to (V
REG
+ 0.3V)
SET_LDO, LDO_OUT to SGND............................-0.3V to +12V
C+ to PGND
(MAX15015/MAX15016 only) ............(V
DVREG
- 0.3V) to 12V
C- to PGND
(MAX15015/MAX15016 only) ........ -0.3V to (V
DVREG
+ 0.3V)
LDO_OUT Output Current................................Internally Limited
Switch DC Current (DRAIN and LX pins combined)
T
J
= +125°C .........................................................................1.9A
T
J
= +150°C .......................................................................1.25A
RESET
Sink Current ............................................................5mA
Continuous Power Dissipation (T
A
= +70°C)
36-Pin TQFN (derate 26.3mW/°C above +70°C)
Single-Layer Board ....................................................2105mW
36-Pin TQFN (derate 35.7mW/°C above +70°C)
Multilayer Board.........................................................2857mW
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
IN_SW
= V
IN_LDO
= V
DRAIN
= 14V, V
EN_SYS
= V
EN_SW
= 2.4V, V
REG
= V
DVREG
, V
SYNC
= V
SET_LDO
= V
SGND
= V
PGND
= 0V,
C
REG
= 1μF, C
IN_SW
= 0.1μF, C
IN_LDO
= 0.1μF, C
LDO_OUT
= 10μF, C
DRAIN
= 0.22μF, T
A
= T
J
= -40°C to +125°C, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
System Supply Current (Not
Switching)
SYMBOL
CONDITIONS
V
FB
= 1.3V,
MAX15014/MAX15017
V
FB
= 1.3V,
MAX15015/MAX15016
V
FB
= 0V, MAX15014/
MAX15017
V
FB
= 0V, MAX15015/
MAX15016
ILDO_OUT = 100µA
ILDO_OUT = 50mA
2.4
0.8
220
I
EN_SYS
V
EN_SYS
= 2.4V
V
EN_SYS
= 14V
MAX15014/MAX15017
MAX15015/MAX15016
7.5
4.5
0.5
0.6
2
2
40.0
40.0
MIN
TYP
0.7
0.85
5.6
mA
8.6
47
130
6
63
200
10
µA
µA
V
mV
µA
MAX
1.8
mA
1.8
UNITS
I
SYS
No load
Switching System Supply
Current
I
SW
No load
LDO Quiescent Current
System Shutdown Current
System Enable Voltage
System Enable Hysteresis
System Enable Input Current
BUCK CONVERTER
Input Voltage Range
I
LDO
I
SHDN
V
EN_SYSH
V
EN_SYSL
V
EN_SYS
= 14V,
V
EN_SW
= 0V
V
EN_SYS
= 0V, V
EN_SW
= 0V
EN_SYS = high, system on
EN_SYS = low, system off
V
IN_SW
V
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MAX15014–MAX15017
1A, 4.5V to 40V Input Buck Converters with
50mA Auxiliary LDO Regulators
Electrical Characteristics (continued)
(V
IN_SW
= V
IN_LDO
= V
DRAIN
= 14V, V
EN_SYS
= V
EN_SW
= 2.4V, V
REG
= V
DVREG
, V
SYNC
= V
SET_LDO
= V
SGND
= V
PGND
= 0V,
C
REG
= 1μF, C
IN_SW
= 0.1μF, C
IN_LDO
= 0.1μF, C
LDO_OUT
= 10μF, C
DRAIN
= 0.22μF, T
A
= T
J
= -40°C to +125°C, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Undervoltage Lockout
Threshold
Undervoltage Lockout
Hysteresis
Output Voltage Range
Output Current
EN_SW Input Voltage
Threshold
EN_SW Hysteresis
Switching Enable Input Current
I
EN_SW
V
EN_SW
= 2.4V
V
EN_SW
= 14V
MAX15014/MAX15017, V
IN_SW
= 9V to 40V
MAX15015/MAX15016, V
IN_SW
= 5.5V to 40V
V
IN_SW
= 9.0V to 40V, MAX15014/MAX15017
V
IN_SW
= 5.5V to 40V, MAX15015/MAX15016
I
REG
= 0 to 20mA
V
IN_SW
= 7.5V (MAX15014/MAX15017),
V
IN_SW
= 4.5V (MAX15015/MAX15016),
I
REG
= 20mA
V
SYNC
= 0V, MAX15014/MAX15016
V
SYNC
= 0V, MAX15015/MAX15017
V
SYNC
= 0V, V
IN_SW
= 7.5V, MAX15014
(135kHz)
Maximum Duty Cycle
D
MAX
V
SYNC
= 0V, V
IN_SW
= 4.5V, MAX15016
(135kHz)
V
SYNC
= 0V, V
IN_SW
= 4.5V, MAX15015
(500kHz)
V
SYNC
= 0V, V
IN_SW
= 7.5V, MAX15017
(500kHz)
Minimum LX Low Time
SYNC High-Level Voltage
SYNC Low-Level Voltage
V
SYNC
= 0V
122
425
90
90
90
90
94
2.2
0.8
136
500
7.6
4.75
1
1
0.25
0.5
SYMBOL
UVLO
TH
CONDITIONS
V
IN_SW
and IN_LDO rising, MAX15014/
MAX15017
V
IN_SW
and IN_LDO rising, MAX15015/
MAX15016
MAX15014/MAX15017
MAX15015/MAX15016
Minimum output
Maximum output
EN_SW = high, switching power supply is on
EN_SW = low, switching power supply is off
220
0.5
0.6
2
2
8.4
5.25
2.4
0.8
MIN
6.7
3.90
TYP
7.0
4.08
0.54
0.3
1.26
32
1
MAX
7.4
V
4.25
V
V
A
V
mV
µA
UNITS
UVLO
HYST
V
OUT
I
OUT
V
EN_SWH
V
EN_SWL
INTERNAL VOLTAGE REGULATOR
Output Voltage
Line Regulation
Load Regulation
Dropout Voltage
OSCILLATOR
Frequency Range
f
CLK
150
575
98
98
%
96
98
ns
V
kHz
V
REG
V
mV/V
V
V
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MAX15014–MAX15017
1A, 4.5V to 40V Input Buck Converters with
50mA Auxiliary LDO Regulators
Electrical Characteristics (continued)
(V
IN_SW
= V
IN_LDO
= V
DRAIN
= 14V, V
EN_SYS
= V
EN_SW
= 2.4V, V
REG
= V
DVREG
, V
SYNC
= V
SET_LDO
= V
SGND
= V
PGND
= 0V,
C
REG
= 1μF, C
IN_SW
= 0.1μF, C
IN_LDO
= 0.1μF, C
LDO_OUT
= 10μF, C
DRAIN
= 0.22μF, T
A
= T
J
= -40°C to +125°C, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYNC Frequency Range
Ramp Level Shift (Valley)
ERROR AMPLIFER
Soft-Start Reference Voltage
Soft-Start Current
FB Regulation Voltage
FB Input Range
FB Input Current
COMP Voltage Range
Open-Loop Gain
Unity-Gain Bandwidth
PWM Modulator Gain
CURRENT-LIMIT COMPARATOR
Pulse Skip Threshold
Cycle-by-Cycle Current Limit
Number of Consecutive ILIM
Events to Hiccup
Hiccup Timeout
POWER SWITCH
Switch On-Resistance
Switch Gate Charge
Switch Leakage Current
BST Quiescent Current
BST Leakage Current
CHARGE PUMP (MAX15015/MAX15016)
C- Output Voltage Low
C- Output Voltage High
DVREG to C+ On-Resistance
LX to PGND On-Resistance
LDO
Input Voltage Range
Undervoltage Lockout Threshold
V
IN_LDO
UVLO_LDO
TH
V
IN_LDO
rising
5
3.90
4.1
40
4.25
V
V
V
BST
- V
LX
= 6V
V
BST
- V
LX
= 6V
V
IN_SW
= V
IN_LDO
= V
LX
= V
DRAIN
=
40V, V
FB
= 0V
V
BST
= 40V, V
DRAIN
= 40V, V
FB
= 0V,
DVREG = 5V
V
BST
= V
DRAIN
= V
LX
= V
IN_SW
= V
IN_
LDO
= 40V, EN_SW = 0V
Sinking 10mA
Relative to DVREG, sourcing 10mA
Sourcing 10mA
Sinking 10mA
0.15
0.4
4
10
400
600
1
0.1
0.1
10
12
0.80
Ω
nC
µA
µA
µA
V
V
Ω
Ω
IPFM
I
ILIM
100
1.3
200
2
7
512
300
2.6
mA
A
—
Clock
periods
f
SYNC
= 500kHz, MAX15015/MAX15017
f
SYNC
= 135kHz, MAX15014/MAX15016
V
SS
I
SS
V
FB
V
FB
I
FB
V
FB
= 1.244V
I
COMP
= -500µA to +500µA
V
SS
= 0V
1.210
7
1.210
0
-250
0.25
80
1.8
10
10
1.235
12
1.235
1.260
17
1.260
1.5
+250
4.5
V
µA
V
V
nA
V
dB
MHz
V/V
SYMBOL
f
SYNC
CONDITIONS
MAX15014/MAX15016
MAX15015/MAX15017
MIN
100
400
0.3
TYP
MAX
200
600
UNITS
kHz
V
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Maxim Integrated
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4
MAX15014–MAX15017
1A, 4.5V to 40V Input Buck Converters with
50mA Auxiliary LDO Regulators
Electrical Characteristics (continued)
(V
IN_SW
= V
IN_LDO
= V
DRAIN
= 14V, V
EN_SYS
= V
EN_SW
= 2.4V, V
REG
= V
DVREG
, V
SYNC
= V
SET_LDO
= V
SGND
= V
PGND
= 0V,
C
REG
= 1μF, C
IN_SW
= 0.1μF, C
IN_LDO
= 0.1μF, C
LDO_OUT
= 10μF, C
DRAIN
= 0.22μF, T
A
= T
J
= -40°C to +125°C, unless otherwise
noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Undervoltage Lockout
Hysteresis
Output Current
SYMBOL
UVLO_
LDO
HYST
I
OUT
V
IN
= 6V (Note 2)
I
LDO_OUT
= 100µA
SET_LDO = SGND,
6V ≤ V
IN_LDO
≤ 40V,
MAX1501_A
I
LDO_OUT
= 1mA
Output Voltage
V
LDO_OUT
1mA ≤ I
OUT
≤ 50mA,
V
IN_LDO
= 14V
I
LDO_OUT
= 100µA
SET_LDO = SGND,
6V ≤ V
IN_LDO
≤ 40V,
MAX1501_B
I
LDO_OUT
= 1mA
1mA ≤ I
LDO_OUT
≤
50mA, V
IN_LDO
= 14V
Adjustable Output Voltage
Range
V
ADJ
V
SET_LDO
> 0.25V
V
IN_LDO
= 5V,
MAX1501_A
V
IN_LDO
= 4.0V,
MAX1501_B
I
OUT
= 10mA
I
OUT
= 50mA
I
OUT
= 10mA
I
OUT
= 50mA
400
1.220
(Note 3)
I
SET_LDO
V
SET_LDO
= 11V
I
OUT
= 10mA, f = 100Hz, 500mV
P-P
, V
LDO_
OUT
= 5V
I
OUT
= 10mA, f = 1MHz, 500mV
P-P
, V
LDO_
OUT
= 5V
125
1.241
185
0.5
78
dB
24
185
300
mA
100
1.265
I
LDO_OUT
= 1mA
I
LDO_OUT
= 1mA
65
4.90
4.90
4.85
4.85
3.22
3.22
3.2
3.2
1.5
5
5
5
5
3.3
3.3
3.3
3.3
CONDITIONS
MIN
TYP
0.3
200
5.06
5.06
5.15
5.15
3.35
3.35
3.4
3.4
11.0
0.6
0.82
0.1
0.4
µs
V
mV
nA
V
V
V
MAX
UNITS
V
mA
Dropout Voltage
ΔV
DO
Startup Response Time
SET_LDO Reference Voltage
Minimum SET_LDO Threshold
SET_LDO Input Leakage
Current
V
SET_LDO
From EN_SYS high to LDO_OUT rise,
R
L
= 500Ω, SET_LDO = SGND
Power-Supply Rejection Ratio
PSRR
Short-Circuit Current
I
SC
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