EVALUATION KIT AVAILABLE
MAX20021/MAX20022
Automotive Quad, Low-Voltage
Step-Down DC-DC Converters
General Description
The MAX20021/ MAX20022 power-management ICs
(PMICs) integrate four low-voltage, high-efficiency, step-
down DC-DC converters. Each of the four outputs is
factory or resistor programmable between 1.0V to 4.0V
and can deliver up to 1.0A of current. The PMICs operate
from 3.0V to 5.5V, making them ideal for automotive point-
of-load and post-regulation applications.
The PMICs feature fixed-frequency PWM-mode operation
with a switching frequency of 2.2MHz or 3.2MHz. High-
frequency operation allows for an all-ceramic capacitor
design and small-size external components. The low-
resistance on-chip switches ensure high efficiency at
heavy loads while minimizing critical inductances, making
the layout a much simpler task with respect to discrete
solutions. Internal current sensing and loop compensation
reduce board space and system cost.
The PMICs offer a spread-spectrum option to reduce
radiated emissions. Two of the four buck converters oper-
ate 180º out-of-phase with the internal clock. This feature
reduces the necessary input capacitance and improves
EMI as well. All four buck converters operate in constant-
PWM mode outside the AM band. The PMICs offer a
SYNC input to synchronize to an external clock.
The PMICs provide individual enable inputs and power-
good/reset outputs, as well as factory-programmable
RESET
times.
The PMICs offer several important protection features
including: input overvoltage protection, input undervoltage
monitoring, input undervoltage lockout, cycle-by-cycle
current limiting, and overtemperature shutdown. The
input undervoltage monitor indicates a brownout condition
by driving PG_ low when the input falls below the UVM
threshold.
The MAX20021/MAX20022 PMICs are available in a
28-pin TQFN package with an exposed pad and are
specified for operation over the -40ºC to +125ºC automo-
tive temperature range.
Benefits and Features
● Quad Step-Down DC-DC Converters with Integrated
FETs
● Operate from 3.0V to 5.5V Supply Voltage
● 1.0V to 4.0V Fixed or Adjustable Output Voltage
● 2.2MHz (MAX20022) or 3.2MHz (MAX20021)
Switching Frequency
● Four Channels Capable of Delivering Up to 1A Each
● Designed to Improve Automotive EMI Performance
• Forced-PWM Operation
• Two Channels 180º Out-of-Phase
• SYNC Input
• Spread-Spectrum Option
● Soft-Start and Supply Sequencing Reduces Inrush
Current
● Individual Enable Inputs and Power-Good Outputs to
Simplify Sequencing
● OV/UV Input-Voltage Monitoring
● Overtemperature and Short-Circuit Protection
● 28-Pin (5mm x 5mm x 0.8mm) TQFN-EP Package
● -40ºC to +125ºC Operating Temperature Range
Simplified Block Diagram
V
OUT1
10kΩ
PG_
5V
V
A
1µF
SS OSC
GND
4 CHANNELS
PV_
2.2µF
5V
MAX20021
EN_
CONTROL
SEL
SYNC
STEP-DOWN
PWM OUT_
1.0V TO 4.0V
UP TO
0.5A OR 1A
LX_
1.5µH
V
OUT_
10µF
Applications
● Automotive
● Industrial
Ordering Information/Selector Guide
appear at end of data
sheet.
For related parts and recommended products to use with this part, refer
to
www.maximintegrated.com/MAX20021.related.
PGND_
EN
OUTS_
EP
19-6628; Rev 3; 8/14
MAX20021/MAX20022
Automotive Quad, Low-Voltage
Step-Down DC-DC Converters
Absolute Maximum Ratings
PV_ to PGND_ .....................................................-0.3V to +6.0V
V
A
to GND ............................................................-0.3V to +6.0V
OUTS_, EN_, PG_, SYNC, SEL to GND ......-0.3V to VA + 0.3V
PV_ to PV_ ...........................................................-0.3V to +0.3V
PGND_ to GND ....................................................-0.3V to +0.3V
LX_ to PGND...............................................-1.0V to PV_ + 0.3V
LX_ Continuous RMS Current..............................................2.0A
Output Short-Circuit Duration ....................................Continuous
Continuous Power Dissipation (TA = +70ºC)
TQFN (derate 28.6mW/ºC above +70ºC) ..................2285mW
ESD
HB
.................................................................................±2kV
ESD
MM
..............................................................................±200V
Operating Temperature Range ..........................-40ºC to +125ºC
Junction Temperature ...................................................... +150ºC
Storage Temperature Range .............................-65ºC to +150ºC
Lead Temperature (soldering, 10s) ................................. +300ºC
Soldering Temperature (reflow) ....................................... +260ºC
Package Thermal Characteristics
(Note 1)
TQFN
Junction-to-Ambient Thermal Resistance (θ
JA
) ..............35°C/W
Junction-to-Case Thermal Resistance (θ
JC
) .....................3°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.
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
A
= V
PV1
= V
PV2
= V
PV3
= V
PV4
= 5.0V; T
A
= T
J
= -40ºC to +125ºC, unless otherwise noted. Typical values are at T
A
= +25ºC under
normal conditions, unless otherwise noted.) (Note 2)
PARAMETER
GENERAL
Supply Voltage Range
Supply Current
Shut-Off Current
Overvoltage Threshold
Undervoltage Monitor Threshold
UVLO Threshold
V
PV_
I
PV0
I
VPSD
Fully operational
No load, no switching,
V
EN1
= V
EN2
= V
EN3
= V
EN4
= V
PV_
V
EN1
= V
EN2
= V
EN3
=
V
EN4
= V
GND
Rising
Hysteresis
UVM option enabled
V
PV_
falling
V
PV_
rising
f
SW
Switching frequency = 2.2MHz
(see the
Selector Guide
)
Switching frequency = 3.2MHz
(see the
Selector Guide)
Spread-spectrum option = enabled
(see the Selector Guide)
2.0
3.0
2.2
3.2
+3
V
PV_
falling
V
PV_
hysteresis
2.68
3.0
2.4
MHz
3.4
%
4.15
T
A
= +25°C
T
A
= +125°C
5.6
3.0
2.5
3.8
0.1
2
5.8
0.1
4.3
0.1
4.45
6
5.5
5
2
V
mA
µA
V
V
V
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNIT
PWM Switching Frequency
Spread Spectrum
Df/f
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Maxim Integrated │ 2
MAX20021/MAX20022
Automotive Quad, Low-Voltage
Step-Down DC-DC Converters
Electrical Characteristics (continued)
(V
A
= V
PV1
= V
PV2
= V
PV3
= V
PV4
= 5.0V; T
A
= T
J
= -40ºC to +125ºC, unless otherwise noted. Typical values are at T
A
= +25ºC under
normal conditions, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
PWM switching frequency = 2.2MHz
(see the
Selector Guide)
PWM switching frequency = 3.2MHz
(see the
Selector Guide)
I
LOAD
= 0mA
I
LOAD
= 0mA to I
MAX
V
SFB_
MAX20022
I
LOAD
= I
MAX
I
LOAD
= I
MAX
/2, V
PV_
= 4.5V to 5.5V
V
PV_
= 5.0V, I
LX_
= 0.2A
V
PV_
= 5.0V, I
LX_
= 0.2A
I
LIM
1.0A channel output
(see the
Selector Guide)
0.5A channel output
(see the
Selector Guide)
Externally adjustable output
V
PV_
= 5.0V, LX_ = V
PGND_
or V
PV_
1.4
0.8
I
LOAD
= 0mA
I
LOAD
= 0mA to I
MAX
970
-1.5
+0.3
125
100
1.65
1.1
3272
I
B_OUTS_
20
0.1
45
4
100
V
EN_
= V
GND
(Note 3)
(Note 3)
T
J
rising (Note 4)
(Note 4)
V
OUT
rising (percentage of nominal output)
V
OUT
falling (percentage of nominal output)
V
OUT
rising (percentage of nominal output)
106
92.5
93.5
35
0
180
+185
15
110
94
95
114
96
97
66
250
200
2
A
1.5
Cycles
nA
µA
ns
ns
%
Ω
Degrees
Degrees
ºC
ºC
%
%
-3
1015
1030
-2.5
MIN
1.7
2.8
TYP
MAX
2.5
MHz
3.5
UNIT
SYNC Input Frequency Range
f
SYNC
OUT1, OUT2, OUT3, OUT4—SYNCHRONOUS STEP-DOWN DC-DC CONVERTERS
Fixed DC Output Accuracy
FB DC Set-Point Accuracy
Load Regulation
Line Regulation
pMOS On-Resistance
nMOS On-Resistance
+1.5
+3
%
mV
%
%
mΩ
mΩ
pMOS Current-Limit Threshold
Soft-Start Ramp Time
OUTS Leakage Current
LX Leakage Current
Minimum On-Time
LX Rise/Fall Time
Duty Cycle Range
OUTS_ Discharge Resistance
OUT1, OUT2 Phasing
OUT3, OUT4 Phasing
THERMAL OVERLOAD
Thermal-Shutdown Temperature
Hysteresis
OUTPUT POWER-GOOD INDICATORS (PG_)
Output Overvoltage Threshold
Output Undervoltage Threshold
www.maximintegrated.com
Maxim Integrated │ 3
MAX20021/MAX20022
Automotive Quad, Low-Voltage
Step-Down DC-DC Converters
Electrical Characteristics (continued)
(V
A
= V
PV1
= V
PV2
= V
PV3
= V
PV4
= 5.0V; T
A
= T
J
= -40ºC to +125ºC, unless otherwise noted. Typical values are at T
A
= +25ºC under
normal conditions, unless otherwise noted.) (Note 2)
PARAMETER
UV/OV Propagation Delay
PG_ Output High Leakage
Current
PG_ Output Low Level
ENABLE INPUTS (EN_)
Input High Level
Hysteresis
Pulldown Resistance
DIGITAL INTERFACE (SYNC, SEL)
Input Voltage High
Input Voltage Low
Input Voltage Hysteresis
Pulldown Resistance
Note 2:
All units are 100% production tested at +25ºC. All temperature limits are guaranteed by design.
Note 3:
Phase measurement is in relation to the rising edge of V
LX_
.
Note 4:
Guaranteed by design. Not production tested.
V
INH
V
INL
70
100
1.5
0.5
V
V
mV
kΩ
V
PV_
= 5.0V, V
EN_
rising
V
PV_
= 5.0V, V
EN_
falling
0.7
1.0
50
100
1.3
V
mV
kΩ
V
PV_
= 3.0V, sinking 3mA
SYMBOL
CONDITIONS
MIN
TYP
15
0.1
0.22
MAX
UNIT
µs
µA
V
www.maximintegrated.com
Maxim Integrated │ 4
MAX20021/MAX20022
Automotive Quad, Low-Voltage
Step-Down DC-DC Converters
Typical Operating Characteristics
BUCK EFFICIENCY (3.2MHz)
vs. LOAD CURRENT
MAX20021 toc01
(V
A
= V
PV1
= V
PV2
= V
PV3
= V
PV4
= 5.0V; T
A
= +25ºC, unless otherwise noted.)
BUCK EFFICIENCY (2.2MHz)
vs. LOAD CURRENT
f
SW
= 2.2MHz, V
PV_
= 5V
V
OUT1
= 3.3V
MAX20021 toc02
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
f
SW
= 3.2MHz, V
PV_
= 5V
V
OUT1
= 3.3V
V
OUT3
= 2.65V
V
OUT4
= 1.8V
V
OUT2
= 1.2V
90
80
EFFICIENCY (%)
70
60
50
40
30
20
10
V
PV_
= V
A
= V
EN_
T
A
= +125ºC
25
SUPPLY CURRENT (mA)
20
T
A
= +25ºC
15
10
5
0
T
A
= -40ºC
V
OUT3
= 2.65V
V
OUT4
= 1.8V
V
OUT2
= 1.2V
0
0.0001
0.0010
0.0100
0.1000
1.0000
0
0.0001
0.0010
0.0100
0.1000
1.0000
2.7
3.2
3.7
4.2
4.7
5.2
5.7
LOAD CURRENT (A)
LOAD CURRENT (A)
SUPPLY VOLTAGE (V)
LX LEAKAGE CURRENT
vs. TEMPERATURE
MAX20021 toc04
700
LX LEAKAGE CURRENT (nA)
600
500
400
300
200
100
0
-100
-60 -40 -20 0
LX_ TO PV_
LX_ TO PGND_
3.34
3.32
V
OUT1
(V)
3.30
3.28
3.26
3.24
3.22
3.20
0
20 40 60 80 100 120 140
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
I
OUT1
(A)
TEMPERATURE (ºC)
100.8
V
OUT2
(% NOMINAL)
100.6
100.4
100.2
100.0
99.8
99.6
2.7
3.2
3.7
MAX20021 toc06
101.0
LINE REGULATION (BUCK 2)
STARTUP SEQUENCE
MAX20021 toc07
MAX20021 toc05
800
3.36
LOAD REGULATION (BUCK 1)
T
A
= +125ºC
V
OUT1
V
OUT2
T
A
= +25ºC
V
OUT3
T
A
= -40ºC
4.2
V
PV2
(V)
4.7
5.2
5.7
2ms/div
V
OUT4
www.maximintegrated.com
Maxim Integrated │ 5
MAX20021 toc03
100
100
30
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
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