MAX20029BATICV [MAXIM]
Automotive Quad/Triple Low-Voltage Step-Down DC-DC Converters;
| 型号： | MAX20029BATICV |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Automotive Quad/Triple Low-Voltage Step-Down DC-DC Converters |
| 文件： | 总17页 (文件大小：677K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
EVALUATION KIT AVAILABLE
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
General Description
Benefits and Features
● Quad Step-Down DC-DC Converters with Integrated
The MAX20029/MAX20029B/MAX20029C/MAX20029D
power-management ICs (PMICs) integrate four low-volt-
age, high-efficiency, step-down DC-DC converters. Each
of the four outputs is factory or resistor programmable
between 1V to 4.0V (MAX20029/MAX20029B) or 0.7V
to 3.8V (MAX20029C/MAX20029D). The MAX20029/
MAX20029C has two 0.5A/1A/1.5A channels and two
0.5A/1.5A channels, while the MAX20029B/MAX20029D
has two 0.5A/1.5A channels and by combining channels
1 and 2, a single 2A/3A channel. The PMICs operate from
3.0V to 5.5V, making them ideal for automotive point-of-
load and post-regulation applications.
FETs
● Operate from 3.0V to 5.5V Supply Voltage
● 0.7V to 4.0V Fixed or Adjustable Output Voltage
● 2.2MHz Switching Frequency
●ꢀ MAX20029/MAX20029C:ꢀUpꢀtoꢀFourꢀ1.5AꢀChannels
●ꢀ MAX20029B/MAX20029D:ꢀUpꢀtoꢀOneꢀ3Aꢀ+ꢀTwoꢀ1.5Aꢀ
Channels
● Designed to Improve Automotive EMI Performance
• Forced-PWM Operation
• Two Channels 180º Out-of-Phase
• SYNC Input
The PMICs feature fixed-frequency PWM-mode operation
with a switching frequency of 2.2MHz. 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.
• Spread-Spectrum Option
● Soft-Start and Supply Sequencing Reduces Inrush
Current
● Individual Enable Inputs and Power-Good Outputs to
Simplify Sequencing
● OV 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
The PMICs offer a spread-spectrum option to reduce
radiated emissions. Two of the four buck converters
operate 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.
Ordering Information appears at end of data sheet.
The PMICs provide individual enable inputs and power-good/
reset outputs, as well as factory-programmable PG times.
The PMICs offer several important protection
features including: input overvoltage protection, input
undervoltage lockout, cycle-by-cycle current limiting, and
overtemperature shutdown.
The MAX20029/MAX20029B/MAX20029C/MAX20029D
PMICs are available in a 28-pin TQFN package with an
exposed pad and are specified for operation over the
-40ºC to +125ºC automotive temperature range.
Applications
●ꢀ Automotive
●ꢀ Industrial
19-100083; Rev 11; 2/20
MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Simplified Block Diagram
V
OUT1
MAX20029
10kΩ
EN_
PG_
CONTROL
5V
V
A
SYNC
SS OSC
1µF
GND
5V
4 CHANNELS
PV_
2.2µF
1.5µH
LX_
STEP-DOWN
PWM OUT_
1.0V TO 4.0V
V
OUT_
22µF
UP TO 1.5A
PGND_
OUTS_
EN
EP
Maxim Integrated
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Absolute Maximum Ratings
PV_ to PGND_.....................................................-0.3V to +6.0V
Continuous Power Dissipation (T = +70ºC)
A
V
to GND............................................................-0.3V to +6.0V
28-pin TQFN (derate 28.6mW/ºC above +70ºC).......2285mW
Operating Temperature Range..........................-40ºC to +125ºC
Junction Temperature......................................................+150ºC
Storage Temperature Range.............................-65ºC to +150ºC
Lead Temperature (soldering, 10s) .................................+300ºC
Soldering Temperature (reflow).......................................+260ºC
A
OUTS_,ꢀEN_,ꢀPG_,ꢀSYNCꢀtoꢀGND...............-0.3V to V + 0.3V
A
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
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.
Package Thermal Characteristics (Note 1)
28 TQFN
Junction-to-AmbientꢀThermalꢀResistanceꢀ(θ ) ..........35°C/W
Junction-to-CaseꢀThermalꢀResistanceꢀ(θ ).....................3°C/W
JC
JA
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.
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.
PACKAGE TYPE
PACKAGE CODE
OUTLINE NO.
21-0140
LAND PATTERN NO.
90-0025
28 TQFN-EP
T2855+5
Electrical Characteristics
(V = V
= V
= V
= V
= 5.0V; T = T = -40°C to +125°C, unless otherwise noted. Typical values are at T = +25°C under
A
PV1
PV2
PV3
PV4 A J A
normal conditions, unless otherwise noted.) (Note 2)
PARAMETER
GENERAL
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNIT
Supply Voltage Range
V
Fully operational
No load, no switching,
3.0
2.5
5.5
5
V
PV_
Supply Current
I
3.8
mA
PV0
V
= V
= V
= V
= V
EN1
EN2
EN3
EN4 PV_
V
V
V
= V
= V
=
=
EN1
EN3
GND
EN2
EN4
T
T
= +25°C
0.1
2
2
6
A
A
Shut-OffꢀCurrent
I
µA
V
VPSD
= +125°C
Rising
Hysteresis
5.6
5.8
0.1
Overvoltage Threshold
V
V
V
falling
2.68
2.6
PV_
PV_
PV_
UVLOꢀThreshold
falling (MAX20029D)
rising
V
3.0
2.4
PWM Switching Frequency
f
2.0
2.2
MHz
SW
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Electrical Characteristics (continued)
(V = V
= V
= V
= V
= 5.0V; T = T = -40°C to +125°C, unless otherwise noted. Typical values are at T = +25°C under
A
PV1
PV2
PV3
PV4 A J A
normal conditions, unless otherwise noted.) (Note 2)
PARAMETER
Spread Spectrum
SYNC Input Frequency Range
SYNCHRONOUS STEP-DOWN DC-DC CONVERTERS (OUT1–OUT4) MAX20029D
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNIT
Spread-spectrum option = enabled
(see the Selector Guide)
Df/f
+3
%
f
1.7
2.5
MHz
SYNC
+1.5
I
I
I
= 0mA
LOAD
LOAD
LOAD
-3
-3
+3
+3
= 0mA to I
MAX
= 0mA to 1.0A (MAX20029C/
MAX20029D)
Fixed DC Output Accuracy
%
I
= 0mA to 1.0A at 125°C
LOAD
-3
+3.2
+3
(MAX20029C/MAX20029D)
I
= 0mA to 1.5A (MAX20029C/
LOAD
-3.75
-3.75
MAX20029D)
I
= 0mA to 1.5A at 125°C
LOAD
+3.2
(MAX20029C)
I
= 0mA (MAX20029/
LOAD
1015
-1.5
MAX20029B)
FB DC Set-Point Accuracy
V
mV
SFB_
I
= 0mA to IMAX (MAX20029/
LOAD
970
1030
MAX20029B)
MAX20029
MAX20029B/
MAX20029D
(OUT3,ꢀOUT4)
MAX20029C
Per 1A of load
Per 2A of load
Load Regulation
Line Regulation
%
%
MAX20029B/
MAX20029D
(OUT1)
-1.5
+0.3
I
= IMAX/2, V
= 4.5V to 5.5V
LOAD
PV_
pMOS On-Resistance
nMOS On-Resistance
125
100
250
200
mΩ
mΩ
V
V
= 5.0V, I
= 5.0V, I
= 0.2A
= 0.2A
PV_
LX_
PV_
LX_
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Electrical Characteristics (continued)
(V = V
= V
= V
= V
= 5.0V; T = T = -40°C to +125°C, unless otherwise noted. Typical values are at T = +25°C under
A
PV1
PV2
PV3
PV4 A J A
normal conditions, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
OUT1/OUT2,ꢀOptꢀ1ꢀ
MIN
TYP
MAX
UNIT
0.8
1.1
1.5
(0.5A channel)
MAX20029
MAX20029C
OUT1/OUT2,ꢀOpt 2
(1A channel)
1.4
1.65
2.2
2
OUT1/OUT2,ꢀOptꢀ3ꢀ
(1.5A channel)
1.85
2.75
MAX20029B/
MAX20029D
(OUT1,ꢀ2Aꢀ
channel, per
LX_ pin)
1.4
1.65
2.2
2
A
pMOS Current-Limit Threshold
(see Selector Guide)
MAX20029B/
MAX20029D
(OUT1,ꢀ3Aꢀ
channel, per
LX_) pin
1.85
2.75
OUT3/OUT4
(0.5A channel)
0.8
1.1
2.2
1.5
(see Selector Guide)
OUT3/OUT4
(1.5A channel)
1.85
2.75
Soft-Start Ramp Time
OUTSꢀLeakageꢀCurrent
LX Leakage Current
3272
20
Cycles
nA
I
Externally adjustable output
B_OUTS_
V
= 5.0V, LX_ = V
or V
PV_
0.1
µA
PV_
EN_
PGND_
Minimum On-Time
45
4
66
ns
ns
LX Rise/Fall Time
Duty-Cycle Range
100
%
OUTS_ꢀDischargeꢀResistance
OUT1,ꢀOUT2ꢀPhasing
OUT3,ꢀOUT4ꢀPhasing
THERMAL OVERLOAD
Thermal-Shutdown Temperature
Hysteresis
V
= V
35
0
Ω
GND
(Note 3)
(Note 3)
Degrees
Degrees
180
T rising (Note 4)
J
+185
15
ºC
ºC
(Note 4)
OUTPUT POWER-GOOD INDICATORS (PG1–PG4)
V
rising (percentage of nominal
OUT
Output Overvoltage Threshold
106
110
114
%
output)
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Electrical Characteristics (continued)
(V = V
= V
= V
= V
= 5.0V; T = T = -40°C to +125°C, unless otherwise noted. Typical values are at T = +25°C under
A
PV1
PV2
PV3
PV4 A J A
normal conditions, unless otherwise noted.) (Note 2)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNIT
V
falling (percentage of nominal
OUTꢀ
92.5
94
96
output)
V
rising (percentage of nominal
OUTꢀ
93.5
90
95
94
97
96
output)
OutputꢀUndervoltageꢀThreshold
UV/OVꢀPropagationꢀDelay
%
V
falling (percentage of nominal
OUTꢀ
output), MAX20029C/MAX20029D
V
rising (percentage of nominal
OUTꢀ
90.5
95
15
96.5
output), MAX20029C/MAX20029D
µs
PG_ Output High Leakage
Current
0.1
µA
PG_ Output Low Level
V
= 3.0V, sinking 3mA
0.22
1.3
V
PV_
Option 1
Option 2
256
Cycles
Cycles
Active Timeout Period
20480
ENABLE INPUTS (EN1–EN4)
Input High Level
V
V
= 5.0V, V
= 5.0V, V
rising
falling
0.7
1.5
1.0
50
V
PV_
EN_
Hysteresis
mV
kΩ
PV_
EN_
Pulldown Resistance
DIGITAL INTERFACE (SYNC)
Input Voltage High
100
V
V
V
INH
Input Voltage Low
V
0.5
INL
Input Voltage Hysteresis
Pulldown Resistance
70
mV
kΩ
100
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
Note 4: Guaranteed by design. Not production tested.
.
LX_
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Typical Operating Characteristics
(V = V
= V
= V
= V
= 5.0V; T = +25°C, unless otherwise noted.)
A
PV1
PV2
PV3
PV4 A
SUPPLY CURRENT
EFFICIENCY CURVE
toc02
toc01
35
30
25
20
15
10
5
100
VOUT = 3.3V
V
PV_ = VA = VEN_
NO LOAD
90
80
70
60
50
40
30
20
10
0
VOUT = 1.8V
VOUT = 1.2V
0
2.7
3.2
3.7
4.2
4.7
5.2
5.7
0.001
0.01
0.1
1
SUPPLY VOLTAGE (V)
LOAD CURRENT (A)
LOAD REGULATION
LINE REGULATION
toc03
toc04
3.36
3.34
3.32
3.30
3.28
3.26
3.24
3.22
3.20
3.18
100.8
100.6
100.4
100.2
100.0
99.8
VOUT = 3.3V
VOUT1 = 1.8V
99.6
0
0.2 0.4 0.6 0.8
1
1.2 1.4
2.7
3.2
3.7
4.2
4.7
5.2
5.7
LOAD CURRENT (A)
SUPPLY VOLTAGE (V)
SWITCHING FREQUENCY
vs. TEMPERATURE
P-CHANNEL SWITCH RESISTANCE
vs. SUPPLY VOLTAGE
103
102
101
100
99
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
T
= +125ºC
A
T
= +25ºC
A
T
= -40ºC
A
98
97
-60 -40 -20
0
20 40 60 80 100 120 140
2.7
3.2
3.7
4.2
4.7
(V)
5.2
5.7
TEMPERATURE (°C)
V
PV_
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Pin Configuration
TOP VIEW
21 20 19 18 17 16 15
14
13
OUTS4 22
PG4 23
OUTS3
EN3
12 PG3
24
25
26
27
28
GND
MAX20029
MAX20029B
GND
PG2
11
10
9
SYNC
V
A
EP = GND
EN2
PG1
+
8
OUTS2
OUTS1
1
2
3
4
5
6
7
TQFN
5mm x 5mm
Pin Description
PIN
NAME
FUNCTION
1
EN1
Active-High Digital Enable Input for Buck 1. Driving EN1 high enables Buck 1.
Buck 1 Voltage Input. Connect a 2.2µF or larger ceramic capacitor from PV1 to PGND1 as close
as possible to the device.
2
PV1
3
4
5
LX1
Buckꢀ1ꢀSwitchingꢀNode.ꢀLX1ꢀisꢀhighꢀimpedanceꢀwhenꢀtheꢀdeviceꢀisꢀoff.
Power Ground for Buck 1
PGND1
PGND2
Power Ground for Buck 2
Buckꢀ2ꢀSwitchingꢀNode.ꢀLX2ꢀisꢀhighꢀimpedanceꢀwhenꢀtheꢀdeviceꢀisꢀoff.ꢀConnectꢀtoꢀLX1ꢀforꢀtheꢀ
MAX20029B/MAX20029D.
6
7
LX2
PV2
Buck 2 Voltage Input. Connect a 2.2µF or larger ceramic capacitor from PV2 to PGND2 as close
as possible to the device.
Buck 2 Voltage-Sense Input. Connect to output capacitor. Connect to ground for the
MAX20029B/MAX20029D.
8
9
OUTS2
Active-High Digital Enable Input for Buck 2. Driving EN2 high enables Buck 2. Connect to ground
for the MAX20029B/MAX20029D.
EN2
Open-Drain, Active-High, Power-Good Output for Buck 2. To obtain a logic signal, pull up PG2
with an external resistor connected to a positive voltage equal to or lower than VA. Connect to
ground for the MAX20029B/MAX20029D.
10
PG2
11
12
13
GND
PG3
EN3
Ground
Open-Drain, Active-High, Power-Good Output for Buck 3. To obtain a logic signal, pull up PG3
with an external resistor connected to a positive voltage equal to or lower than VA.
Active-High Digital Enable Input for Buck 3. Driving EN3 high enables Buck 3.
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Pin Description (continued)
PIN
NAME
FUNCTION
14
OUTS3
Buck 3 Voltage Sense Input
Buck 3 Voltage Input. Connect a 2.2µF or larger ceramic capacitor from PV3 to PGND3 as close
as possible to the device.
15
PV3
16
17
18
19
LX3
PGND3
PGND4
LX4
Buckꢀ3ꢀSwitchingꢀNode.ꢀLX3ꢀisꢀhighꢀimpedanceꢀwhenꢀtheꢀdeviceꢀisꢀoff.
Power Ground for Buck 3
Power Ground for Buck 4
Buckꢀ4ꢀSwitchingꢀNode.ꢀLX4ꢀisꢀhighꢀimpedanceꢀwhenꢀtheꢀdeviceꢀisꢀoff.
Buck 4 Voltage Input. Connect a 2.2µF or larger ceramic capacitor from PV4 to PGND4 as close
as possible to the device.
20
PV4
21
22
EN4
Active-High Digital Enable Input for Buck 4. Driving EN4 high enables Buck 4.
Buck 4 Voltage Sense Input
OUTS4
Open-Drain, Active-High, Power-Good Output for Buck 4. To obtain a logic signal, pull up PG4
with an external resistor connected to a positive voltage equal to or lower than VA.
23
24
25
PG4
GND
Analog Ground
SYNC Input. Supply an external clock to control the switching frequency. Connect SYNC to
PGND_ to use the default switching frequency.
SYNC
Analog Voltage Supply. Connect a 1µF or larger ceramic capacitor from VA to GND as close as
possible to the device. Connect to the same supply as PV_ inputs.
26
VA
Open-Drain, Active-High, Power-Good Output for Buck 1. To obtain a logic signal, pull up PG1
with an external resistor connected to a positive voltage equal to or lower than VA.
27
28
PG1
OUTS1
Buck 1 Voltage Sense Input
Exposed Pad. Connect the exposed pad to ground. Connecting the exposed pad to ground does
not remove the requirement for proper ground connections to PGND1–PGND4 and GND. The
exposed pad is attached with epoxy to the substrate of the die, making it an excellent path to
remove heat from the IC.
—
EP
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
ꢀUꢁꢁENTꢄSENSE
AꢃP
PV1ꢅPV4
V
ꢁEF
PEAꢂ
ꢀUꢁꢁENT
ꢀOꢃP
PV1
ꢁAꢃP
GENEꢁATOꢁ
∑
PGND1
PV1
ꢀONTꢁOL
LOGIꢀ
LX1ꢅLX4
Pꢇꢃ
ꢀOꢃP
V
ꢁEF
PGND1
PGND1
ꢅPGND4
VALLEꢆ
ꢀUꢁꢁENT
LIꢃ ꢀOꢃP
SOFTꢄSTAꢁT
GENEꢁATOꢁ
ꢀLꢂ180 ꢀLꢂ
OUTS1ꢅ
OUTS4
P1ꢄOꢂ
FEEDꢈAꢀꢂ
SELEꢀT
SEL
V
ꢁEF
OTP
ꢀLꢂ
TꢁIꢃꢈITS
SꢆNꢀ
OSꢀ
ꢀLꢂ180
V
VOLTAGE
ꢁEFEꢁENꢀE
A
UVLO
V
ꢁEF
PꢄOꢂꢉ1ꢊ4ꢋ
V
A
MAX20029
MAX20029B
MAX20029C
PG1
PG2
PG3
PG4
EN1
EN2
EN3
EN4
ꢃAIN
ꢀONTꢁOL
LOGIꢀ
GND
Figure 1. Internal Block Diagram
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
supply returns to within the operating range of 5.7V
(typ) or less during the timeout period, the power-good
indicators go high.
Detailed Description
The MAX20029/MAX20029B/MAX20029C/MAX20029D
PMICs offer four high-efficiency, synchronous step-down
converters that operate with a 3.0V to 5.5V input voltage
range and provide a 0.7V to 4.0V output voltage range.
The PMICs deliver up to 1.5A of load current per output,
and achieve ±3% output error over load, line, and tem-
perature ranges.
Input Undervoltage Lockout (UVLO)
The PMICs feature an undervoltage lockout on the PV_
inputs set at 2.77V (typ) falling. This prevents loss of
control of the device by shutting down all outputs. This
circuit is only active when at least one buck converter is
enabled.
The PMICs feature fixed-frequency PWM-mode operation
with a 2.2MHz switching frequency. An optional spread-
spectrum frequency modulation minimizes radiated
electromagnetic emissions due to the switching frequency,
while a factory-programmable synchronization input (SYNC)
allows the device to synchronize to an external clock.
Power-Good Outputs (PG_)
The PMICs feature an open-drain power-good output for
each of the four buck regulators. PG_ asserts low when
the output voltage drops 6% below the regulated voltage
or 10% above the regulated voltage for approximately
15µs. PG_ remains asserted for a fixed number of
switching cycles after the output returns to its regulated
voltage. See the Selector Guide for available options.
PG_ asserts low during soft-start and in shutdown. PG_
becomes high impedance when Buck_ is in regulation.
ConnectꢀPG_ꢀtoꢀaꢀlogicꢀsupplyꢀwithꢀaꢀ10kΩꢀresistor.
Integrated low R
switches help minimize efficiency
DS(ON)
losses at heavy loads and reduce critical/parasitic
inductance, making the layout a much simpler task with
respect to discrete solutions.
The PMICs are offered in factory-preset output voltages to
allow customers to achieve ±3% output-voltage accuracy,
without using expensive 0.1% resistors. In addition,
adjustable output-voltage versions can be set to any
desired values between 1.0V and 4.0V using an external
resistive divider. See the Selector Guide for available
options.
Soft-Start
The soft-start time limits startup inrush current by forc-
ing the output voltage to ramp up towards its regulation
point. During soft-start, the converters operate in skip
mode to prevent the outputs from discharging. Expected
soft-start time for MAX20029 and MAX20029B is approxi-
mately 1.5ms, and approximately 1ms for MAX20029C/
MAX20029D (scaling factor is applied due to internal volt-
age reference difference).
Additionally, each converter features soft-start, PG_
output, overcurrent, and overtemperature protections
(see Figure 1).
Control Scheme
The PMICs use peak current-mode control, and feature
internal slope compensation and loop compensation, both
of which reduce board space and allow a very compact
solution.
+5.0%
+1.5%
0%
Hybrid Load-Line Architecture
-1.0%
The PMICs feature hybrid load-line architecture to reduce
the output capacitance needed, potentially saving system
cost and size. This results in a measurable load-transient
response.
-3.5%
4µs
4µs
1.0A
0A
Input Overvoltage Monitoring (OV)
1µs
1µs
The PMICs feature an input overvoltage-monitoring circuit
on the input supply. When the input exceeds 5.8V (typ)
all power-good indicators (PG_) go low. When the input
Figure 2. Load-Transient Response
Maxim Integrated
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
cools by 15°C. The IC goes through a standard power-up
sequence as defined in the Soft-Start section.
Spread-Spectrum Option
The PMICs feature a linear spread-spectrum (SS)
operation, which varies the internal operating frequency
Applications Information
between f
and (f
+ 3%). The internal oscillator is
SW
SW
frequency modulated at a rate of 1.5kHz with a frequency
deviation of 3% (see Figure 3). This function does
not apply to an oscillation frequency applied externally
through the SYNC pin. Spread spectrum is a factory-
selectable option. See the Selector Guide for available
options.
Adjustable Output-Voltage Option
The MAX20029/MAX20029B PMICs feature adjustable
output voltages (see the Selector Guide for more details),
which allows the customer to set the outputs to any volt-
age between 1.0V and V
a resistive divider from output (V
- 0.5V (up to 4.0V). Connect
)ꢀtoꢀOUTS_ꢀtoꢀGNDꢀ
to set the output voltage (see Figure 4).ꢀSelectꢀR2ꢀ(OUTS_ꢀ
PV_
OUT_
Synchronization (SYNC)
toꢀtheꢀGNDꢀresistor)ꢀ≤ꢀ100kΩ.ꢀCalculateꢀR1ꢀ(V
OUTS_ꢀresistor)ꢀwithꢀtheꢀfollowingꢀequation:
to the
OUT_
The PMICs feature a SYNC input to allow the internal
oscillator to synchronize with an external clock. SYNC
accepts signal frequencies in the range of 1.7MHz <
f
< 2.5MHz. Connect to PGND_ if the SYNC feature
V
SYNC
OUT_
−1
R1= R2
is not used.
V
OUTS_
Current-Limit/Short-Circuit Protection
The PMICs offer a current-limit feature that protects the
devices against short-circuit and overload conditions on
each output. In the event of a short-circuit or overload
condition at an output, the high-side MOSFET remains on
until the inductor current reaches the high-side MOSFET’s
current-limit threshold. The converter then turns on the
low-side MOSFET and the inductor current ramps down.
The converter allows the high-side MOSFET to turn on
only when the inductor current ramps down to the low-
side MOSFET’s current threshold. This cycle repeats until
the short or overload condition is removed.
where
V
= 1.0V (see the Electrical Characteristics
OUTS_
table). The output voltage is nominal at 50% load current.
The external feedback resistive divider must be frequency
compensated for proper operation. Place a capacitor
acrossꢀ R1ꢀ inꢀ theꢀ resistiveꢀ dividerꢀ network.ꢀ Useꢀ theꢀ
following equation to determine the value of the capacitor:
R2
R1
R2
R1
I f
> 1, C1 = C
else C1= C, where C = 15pF
Overtemperature Protection
Thermal-overload protection limits the total power dissipa-
tion in the PMICs. When the junction temperature exceeds
185°C (typ), an internal thermal sensor shuts down the
step-down converters, allowing the IC to cool. The thermal
sensor turns on the IC again after the junction temperature
V
OUT_
R1
R2
C1
MAX20029
MAX20029B
OUTS_
f
+ 3%
SW
INTERNAL
OSCILLATOR
FREQUENCY
f
SW
Figure 4. Adjustable Output-Voltage Configuration
t
t + 667µs
TIME
t + 1.334ms
ConnectꢀOUTS_ꢀtoꢀV
for a fixed 1.0V output voltage.
OUT_
Figure 3. Effect of Spread Spectrum on Internal Oscillator
Maxim Integrated
│ 12
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
junction temperature at high power dissipation in some
PMIC applications. Furthermore, the solder mask around
the IC area on both top and bottom layers can be removed
to radiate the heat directly into the air. The maximum
allowable power dissipation in the IC is as follows:
Inductor Selection
The PMICs are optimized for use with a 1.5µH inductor
on outputs configured for 0.5A, 1A, or 1.5A, and a 1.0µH
inductor for an output configured for 2A or 3A. For output
voltagesꢀlessꢀthanꢀ0.9V,ꢀ0.47μHꢀisꢀrecommended.
T
− T
(
)
J(MAX)
A
Input Capacitor
P
=
MAX
θ
+ θ
CA
The PMICs are designed to operate with a single 2.2µF
ceramic bypass capacitor on each PV_ input. Phase
interleaving of the four buck converters contributes to
a lower required input capacitance by canceling input
ripple currents. Place the bypass capacitors as close as
possible to their corresponding PV_ input to ensure the
best EMI and jitter performance.
JC
where T
is the maximum junction temperature
J(MAX)
(+150°C), T ꢀisꢀtheꢀambientꢀairꢀtemperature,ꢀθ (3°C/W
A
JC
for the 28-pin TQFN) is the thermal resistance from the
junctionꢀtoꢀtheꢀcase,ꢀandꢀθ is the thermal resistance from
CA
the case to the surrounding air through the PCB, copper
traces,ꢀandꢀtheꢀpackageꢀmaterials.ꢀθ
is directly related
CA
to system-level variables and can be modified to increase
the maximum power dissipation.
Output Capacitor
All outputs of the PMICs are optimized for use with ceramic
capacitors.
The TQFN package has an exposed thermal pad on its
underside. This pad provides a low thermal-resistance path
for heat transfer into the PCB. This low thermally resistive
path carries a majority of the heat away from the IC. The
PCB is effectively a heatsink for the IC. The exposed pad
should be connected to a large ground plane for proper
thermal and electrical performance. The minimum size
of the ground plane is dependent upon many system
variables. To create an efficient path, the exposed pad
should be soldered to a thermal landing, which is connected
to the ground plane by thermal vias. The thermal landing
should be at least as large as the exposed pad and can be
made larger depending on the amount of free space from
the exposed pad to the other pin landings. A sample layout
is available on the evaluation kit to speed designs.
For
V
V
> 0.2:
OUT/ IN
20
C
C
=
µF
OUT_MIN
V
OUT
33
=
µF
OUT_NOM
V
OUT
For
V
V
ꢀꢀ≤ꢀ0.2:
OUT/ IN
40
C
C
=
µF
OUT_MIN
V
OUT
60
=
µF
OUT_NOM
PCB Layout Guidelines
V
OUT
Careful PCB layout is critical to achieve low switching
lossesꢀandꢀclean,ꢀstableꢀoperation.ꢀUseꢀaꢀmultilayerꢀboardꢀ
whenever possible for better noise immunity and power
dissipation. Follow these guidelines for good PCB layout:
Additional output capacitance can be used if better volt-
age ripple or load-transient response is required (see
Figure 2). To guarantee stability, it is recommended that
the phase margin be measured under the worst-case
deration of the output capacitor(s). Due to the soft-start
sequence, the PMICs are unable to drive arbitrarily large
output capacitors.
1)ꢀ UseꢀaꢀlargeꢀcontiguousꢀcopperꢀplaneꢀunderꢀtheꢀPMICꢀ
packages. Ensure that all heat-dissipating components
have adequate cooling.
2) Keep the high-current paths short, especially at the
ground terminals. This practice is essential for stable,
jitter-free operation. The high current path comprising
of input capacitor, inductor, and the output capacitor
should be as short as possible.
Thermal Considerations
How much power the package can dissipate strongly
depends on the mounting method of the IC to the PCB
andꢀ theꢀ copperꢀ areaꢀ forꢀ cooling.ꢀ Usingꢀ theꢀ JEDECꢀ testꢀ
standard, the maximum power dissipation allowed is
2285mW in the TQFN package. More power dissipation
can be handled by the package if great attention is given
during PCB layout. For example, using the top and bottom
copper as a heatsink and connecting the thermal vias to
one of the middle layers (GND) transfers the heat from the
package into the board more efficiently, resulting in lower
3) Keep the power traces and load connections short. This
practiceꢀisꢀessentialꢀforꢀhighꢀefficiency.ꢀUseꢀthickꢀcopperꢀ
PCBs (2oz vs. 1oz) to enhance full-load efficiency.
4)ꢀ Useꢀ aꢀ singleꢀ groundꢀ planeꢀ toꢀ reduceꢀ theꢀ chanceꢀ ofꢀ
ground potential differences. With a single ground
plane, enough isolation between analog return signals
and high-power signals must be maintained.
Maxim Integrated
│ 13
www.maximintegrated.com
MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Typical Operating Circuits
VIN
/4
PV1–PV4
OUTS1
4x2.2µF
MAX20029/
MAX20029C
1.5µH
1.5µH
LX1
PGND1
OUTS2
VOUT1
22µF
VIN
/4
EN1–EN4
20kΩ
PG1–PG4
VA
VIN
LX2
VOUT2
22µF
PGND2
GND
OUTS4
OUTS3
1.5µH
1.5µH
VOUT4
22µF
LX4
LX3
VOUT3
22µF
PGND4
PGND3
EP
Maxim Integrated
│ 14
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Typical Operating Circuits (continued)
VIN
/4
PV1–PV4
OUTS1
4x2.2µF
VIN
1µH
MAX20029B
MAX20029D
LX1
LX2
VOUT1
47µF
/3
EN1, 3, 4
PGND1
PGND2
20kΩ
/3
PG1, 3, 4
VA
PG2
EN2
OUTS2
VIN
GND
OUTS4
OUTS3
1.5µH
1.5µH
VOUT4
22µF
LX4
LX3
VOUT3
22µF
PGND4
PGND3
EP
Maxim Integrated
│ 15
www.maximintegrated.com
MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Selector Guide
I
V
OUT
(V)
OUT
(A)
SPREAD
SPECTRUM
PG_ TIMEOUT
(CYCLES)
PART
CH1
CH2
CH3
CH4
CH1
CH2
CH3
CH4
MAX20029
MAX20029ATIA/V+
MAX20029ATIB/V+
MAX20029ATIC/V+
MAX20029ATID/V+
MAX20029ATIF/V+
MAX20029B
1.5
1.0
1.0
1.0
1.5
1.5
1.0
1.0
1.0
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
0.5
1.5
ADJ
1.5
1.8
1.0
1.0
ADJ
1.8
ADJ
1.15
3.3
ADJ
1.4
1.2
3.3
3.3
Off
256
256
256
+3%
+3%
+3%
+3%
1.35
1.8
ADJ
ADJ
256
256
1.8
MAX20029BATIA/V+
MAX20029BATIB/V+
MAX20029BATIC/V+
MAX20029BATID/V+
MAX20029BATIE/V+**
MAX20029C
3.0
3.0
3.0
3.0
3.0
―
―
―
―
—
1.5
1.5
1.5
1.5
1.5
1.5
1.5
1.5
0.5
1.5
ADJ
1
―
―
―
―
—
ADJ
1.8
1.8
1.8
1.8
ADJ
1.5
1.0
1.2
3.3
Off
+3%
Off
20,480
20,480
256
1.1
1.0
1.5
+3%
+3%
256
256
MAX20029CATIA/V+
MAX20029CATIB/V+
1.5
1.0
1.5
1.0
1.5
1.5
0.5
1.5
1.5
1.5
1.5
3.3
1.5
1.8
1.8
0.9
3.3
1.0
1.1
0.7
0.7
1.8
Off
256
256
256
+3%
+3%
MAX20029CATIC/V+** 1.5
0.85
MAX20029D
3.0
—
1.5
1.5
1.1
—
0.7
1.8
Off
20,480
MAX20029DATIA/V+
Note: Contact factory for custom configuration. Factory-selectable features include:
CH1/CH2 Current Configuration: 0.5A, 1.0A, or 1.5A (both channels have the same current level)
CH3, CH4 Current Configuration: 0.5A or 1.5A
DC-DC Voltages:
• (MAX20029/MAX20029B) Adjustable, or a fixed voltage between 1.0V and 4.0V in 50mV steps
• (MAX20029C) Fixed voltages between 0.7V and 3.8V in 50mV steps
Spread Spectrum: Off, +3%, or +6%
PG_ Active Timeout Period: 256 or 20,480 clock cycles
CH1 Current Configuration: 2.0A or 3.0A
**Future product—contact factory for availability
See the Ordering Information table for other options.
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
MAX20029ATI_/V+
MAX20029BATI_/V+
MAX20029CATI_/V+
MAX20029DATI_/V+
-40°C to +125°C 28 TQFN-EP*
-40°C to +125°C 28 TQFN-EP*
-40°C to +125°C 28 TQFN-EP*
-40°C to +125°C 28 TQFN-EP*
Note: Insert the desired suffix letter (from the Selector Guide)
into the blank area "_" to indicate factory-selectable features.
/V denotes an automotive qualified part that conforms to
AEC-Q100.
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
**Future part—contact factory for availability.
Maxim Integrated
│ 16
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MAX20029/MAX20029B/
MAX20029C/MAX20029D
Automotive Quad/Triple Low-Voltage
Step-Down DC-DC Converters
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
0
6/17
Initial release
—
Replaced TOCs 1, 2, 3, 4 deleted TOCs 6–9, and renumbered TOC10 to TOC05 and
TOC12 to TOC06; added MAX20029ATIC/V+ (as a future product) and
MAX20029BATIB/V+ to the Selector Guide
1
2
9/17
6, 7, 16
15
Removed future product status from MAX20029ATIC/V+ and added future product
status on MAX20029BATIB/V+ in the Selector Guide
10/17
Updatedꢀtitle,ꢀGeneral Description, Benefits and Features, and Detailed Description;
updated Electrical Characteristic table, Figure 1, Typical Operating Circuits; added
MAX20029BATIC/V+ and MAX20029CATIA/V+ to the Selector Guide and Ordering
Information tables as future parts
3
4
7/18
1–16
UpdatedꢀGeneral Description, Electrical Characteristics table, Soft-Start, and Output
Capacitor. Added MAX20029ATID/V+**, MAX20029BATID/V+**, MAX20029CATIB/
V+** with the accompanying ordering information to the Selector Guide
1, 4, 5, 10, 12,
15
9/18
9/18
5
UpdatedꢀElectrical Characteristics table
4
Replaced missing rows from bottom of Electrical Characteristics table and
future product and Ordering Information footnotes under the Selector Guide, which
were omitted in error
5.1
5, 16
Added MAX20029BATIE/V+** with the accompanying ordering information and
removed future product status from MAX20029CATIA/V+ in the Selector Guide
6
7
10/18
1/19
16
16
Removed future product status from MAX20029BATID/V+ and MAX20029CATIB/V+,
updated CH1 for MAX20029CATIB/V+, and corrected DC-DC Voltages note in the
Selector Guide
Removed future product status from MAX20029ATID/V+, MAX20029BATIB/V+ and
MAX20029BATIC/V+ in the Selector Guide
8
9
2/19
3/19
16
16
Added MAX20029ATIF/V+ in the Selector Guide
Added MAX20029D in the General Description and Benefits and Features, updated
Electrical Characteristics table, added MAX20029D in the Pin Description table,
Detailed Description and Soft-Start section, updated Inductor Selection, added
MAX20029D in the Typical Operating Circuitsꢀdiagram,ꢀUpdatedꢀSelector Guide and
Ordering Information tables by adding new row for MAX20029D
1, 3–6, 8, 11,
13, 15-16
10
11
12/19
2/20
Added MAX20029CATIC/V+** and updated MAX20029DATIA/V+ in Ordering
Information
16
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
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.
2019 Maxim Integrated Products, Inc.
│ 17
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