EVALUATION KIT AVAILABLE
Click here for production status of specific part numbers.
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
General Description
MAX20019/MAX20020 are 2.2MHz and 3.2MHz dual
step-down converters with integrated high-side and lowside MOSFETs. The high-voltage step-down converter
is designed for continuous operation up to 17V input
voltages. The output voltage is factory preset. Buck 1 is
preset to 3.3V, 3.0V, or 2.8V. Buck 2 is preset to 1.8V,
1.5V, 1.2V, or 1V. Another option is Buck 1 preset to 5V
and Buck 2 preset to 3.3V.
The low-voltage buck features fixed-frequency PWMmode 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 while minimizing critical inductance. A
500mV enable hysteresis on the MAX20019 allows the
use of long, low-cost coax cables, even during slow startup situations. The MAX20020’s Buck 1 starts after VSUP
is greater than 5.5V and Buck 1 is driven by the EN input.
Protection features include overvoltage (OV) protection,
cycle-by-cycle current limit, and thermal shutdown with
automatic recovery. The buck converters operate 180°
out-of-phase from each other to minimize input-current
ripple.
Applications
● Surround-View Camera Power Supplies
● Automotive Point-of-Load
19-100040; Rev 9; 1/19
Benefits and Features
● Small Solution Size
• 2mm x 3mm x 0.75mm 10-pin TDFN with
an Exposed Pad
• 2.2MHz and 3.2MHz Operation Allows
Smaller System Size
• No External Components Needed for Soft-Start
● Cable Flexibility
• 500mV Enable Hysteresis Allows for Long,
Low-Cost Cables During Slow Starts
● EMI Solutions
• Optional Spread-Spectrum Frequency Modulation
• Pinout Placement Allows for Tight PCB Layout of
Switching Nodes
● Self-Protected
• Overvoltage Protection, Thermal Shutdown,
Short-Circuit Protection
● Automotive Ready
• Wide 3.5V to 17V Input Voltage Range
for Power-Over-Coax
• Automotive Temperature Range -40°C to +125°C
• AEC-Q100 Qualified
Ordering Information and Typical Operating Circuits appear
at end of data sheet.
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Absolute Maximum Ratings
SUP, EN, LX1 to PGND*........................................-0.3V to +18V
OUT2 to PGND........................................-0.3V to (VPV2 + 0.3)V
BST to LX1...............................................................-0.3V to +6V
PV2, LX2 to PGND*.................................................-0.3V to +6V
AGND to PGND.....................................................-0.3V to +0.3V
BIAS to AGND.......................................................-0.3V to +6.0V
LX1 Short-Circuit Duration.........................................Continuous
LX2 Short-Circuit Duration.........................................Continuous
Continuous Power Dissipation (TA = +70°C)
derate 15.7mW/°C above +70°C.............................1253.9mW
Operating Temperature Range.......................... -40°C to +125°C
Junction Temperature.......................................................+150°C
Storage Temperature Range............................. -65°C to +150°C
Soldering Temperature (reflow)........................................+260°C
Lead Temperature............................................................+300°C
*LX1 has internal clamp diodes to PGND/AGND and SUP. LX2 has internal
clamp diodes to PV2 and PGND. Applications that forward bias these diodes
should take care not to exceed the IC’s package power-dissipation limits.
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 Information
PACKAGE TYPE: 10 TDFN
Package Code
T1032+2C
Outline Number
21-100125
Land Pattern Number
90-100079
PACKAGE TYPE: 10 SWTDFN
Package Code
T1032Y+2C
Outline Number
21-100197
Land Pattern Number
90-100079
THERMAL RESISTANCE, SINGLE-LAYER BOARD
Junction to Ambient (θJA)
87.5°C/W
Junction to Case (θJC)
11.7°C/W
THERMAL RESISTANCE, FOUR-LAYER BOARD
Junction to Ambient (θJA)
63.8°C/W
Junction to Case (θJC)
11.7°C/W
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 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.
www.maximintegrated.com
Maxim Integrated │ 2
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Electrical Characteristics
(VSUP = 8V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C under normal conditions, unless
otherwise noted.) (Note 1)
PARAMETER
Supply Voltage
Supply Current
Shutdown Supply Current
BIAS Regulator Voltage
SYMBOL
VSUP
ISUP
ISUP_SHUTDOWN
VBIAS
BIAS Undervoltage Lockout
VUVBIAS
BIAS Undervoltage-Lockout
Hysteresis
VUVBIASHYS
CONDITIONS
MIN
TYP
MAX
UNITS
MAX20019
3.5
17
MAX20020 VSUP rising
5.5
17
V
MAX20020 VSUP falling
5
mA
EN = high, no switching,
VOUT1 = 3.3V, VOUT2 = 1.8V
2.5
3.5
VEN = 0V (MAX20019 only)
20
30
VEN = 0V, VSUP < 4V (MAX20020 only)
20
30
µA
VSUP = 6V to 16V, IBIAS = 0mA to 15mA,
CBIAS = 2.2µF
4.75
VBIAS falling
2.7
2.9
V
400
650
mV
V
Thermal-Shutdown
Threshold
175
°C
Thermal-ShutdownThreshold Hysteresis
15
°C
BUCK CONVERTER (OUT1)
Output Voltage
VOUT1
-3
fSW = 2.2MHz, 6V < VSUP < 9V,
IOUT1 = 0mA to 500mA,
VOUT1 = 3.3V, 3.0V, or 2.8V
-3
IMAX
+3
%
6V < VSUP < 17V
Line Regulation
DMOS Peak Current-Limit
Threshold
fSW = 3.2MHz, 6V < VSUP < 9V,
IOUT1 = 0mA to 500mA,
VOUT1 = 3.3V, 3.0V, 2.8V
+3
0.4
0.8
%/V
1
1.2
A
High-Side DMOS RDS(ON)
RON_HS1
ILX1 = 500mA, VBIAS = 5V
250
500
mΩ
Low-Side DMOS RDS(ON)
RON_LS1
ILX1 = 500mA, VBIAS = 5V
200
500
mΩ
fSW = 3.2MHz
1.3
fSW = 2.2MHz
1.8
Soft-Start Ramp Time
LX1 Rise Time
tSS1
ms
4
tRISE, LX1
ns
LX1 Leakage Current
TA = +25°C
1
μA
BST Leakage Current
TA = +25°C
1
μA
100
ns
Minimum On-Time
www.maximintegrated.com
tON
Maxim Integrated │ 3
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Electrical Characteristics (continued)
(VSUP = 8V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C under normal conditions, unless
otherwise noted.) (Note 1)
PARAMETER
PWM Switching
Frequency
SYMBOL
fSW
CONDITIONS
Contact factory
MIN
TYP
MAX
3
3.2
3.4
2
2.2
2.4
Spread Spectrum
±3
Maximum Duty Cycle
UNITS
MHz
%
96
%
OUT1 Pulldown Resistance
VOUT1 = 3.3V, internal feedback-divider
330
kΩ
VOUT1 Debounce Time
Debounce time on VOUT1 falling to 90%
before VOUT2 starts shutdown; restart
once VOUT1 > 95%
25
µs
BUCK CONVERTER (OUT2)
Voltage Accuracy
VOUT2
0A < IOUT2 < 500mA, VOUT2 = 1.0V
-3.5
+3.5
0A < IOUT2 < 500mA, VOUT2 = 1.8V,
1.5V or 1.2V
-3
+3
0A < IOUT2 < 160mA, VOUT2 = 1.82V
-3
+3
%
High-Side pMOS RDS(ON)
RON_HS2
ILX2 = 200mA, VPV2 = 2.8V
110
250
mΩ
Low-Side nMOS RDS(ON)
RON_LS2
ILX2 = 200mA, VPV2 = 2.8V
170
350
mΩ
1
1.2
A
Current-Limit Threshold
ILIM2
Soft-Start Ramp Time
tSS2
OUT2 Enable Time
tEN2
0.8
fSW = 3.2MHz
1.3
fSW = 2.2MHz
1.8
Time from OUT1
soft-start done until
OUT2 begins soft-starts
fSW = 2.2MHz
1.8
fSW = 3.2MHz
1.3
LX2 Leakage Current
VPV2 = 2.8V, VLX2 = VPGND or VPV2,
TA = +25°C
LX Rise/Fall Time
VPV2 = 2.8V, IOUT2 = 200mA
ms
1
4
Duty-Cycle Range
OUT2 Discharge
Resistance
ms
µA
ns
100
%
Turn on when EN is low, thermal
shutdown, or overvoltage
500
Ω
OUT2 Pulldown
Resistance
VOUT2 = 1.8V, internal feedback-divider
180
kΩ
OUT1, OUT2 Phasing
(Note 2)
180
°
Overvoltage-Protection
Threshold
VOUT2 rising
107
VOUT2 falling
105
www.maximintegrated.com
ROUT2_dis
%
Maxim Integrated │ 4
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Electrical Characteristics (continued)
(VSUP = 8V, TA = TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TA = +25°C under normal conditions, unless
otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
1.0
1.5
2.2
V
LOGIC LEVEL (EN)
Input Rising Threshold
VEN
MAX20019
Input Hysteresis
Falling hysteresis (MAX20019)
0.5
V
Input Rising Threshold
VSUP rising (MAX20020)
5
V
Input Falling Threshold
VSUP falling (MAX20020)
4.5
V
Input Current
Logic input only, TA = +25°C
EN Input High Threshold
EN Input Low Threshold
VEN
MAX20020, VSUP > 5V, VEN rising
MAX20020, VSUP > 5V, VEN falling
1
1
2.4
µA
V
0.6
V
Note 1: Limits are 100% production tested at TA = +25°C. Limits over the operating temperature range and relevant supply voltage
are guaranteed by design and characterization. Typical values are at TA = +25°C.
Note 2: Guaranteed by design; not production tested.
www.maximintegrated.com
Maxim Integrated │ 5
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Typical Operating Characteristics
BUCK1 3.2MHz EFFICIENCY
vs. LOAD CURRENT
VOUT1 vs. LOAD CURRENT
100
OUTPUT VOLTAGE ACCURACY (%)
EFFICIENCY (%)
80
VSUP = 12V
VSUP = 10V
VSUP = 8V
VSUP = 6V
70
60
50
40
MAX20020
3.2MHz
VOUT1 = 3.3V
VOUT2 = 0V
VEN = 0V
TA = +25°C
30
20
10
1.00
0.50
0.00
-0.50
0.1
0.2
0.3
LOAD CURRENT (A)
0.4
0.5
toc03
OUTPUT VOLTAGE ACCURACY (%)
70
60
50
MAX20019
3.2MHz
VOUT1 = 3.3V,
VOUT2 = 1.8V,
TA = +25°C
20
10
0.0
0.1
0.2
0.3
LOAD CURRENT (A)
0.1
0.2
0.3
0.4
0.4
BUCK1 LOAD TRANSINET
BUCK2 OUTPUT VOLTAGE
vs. LOAD CURRENT
1.5
80
30
0.0
MAX20020
3.2MHz
0.5
LOAD CURRENT (A)
BUCK2 3.2MHz EFFICIENCY
vs. LOAD CURRENT
40
VOUT1 = 3.3V
VOUT2 = 0V
VEN = 0V
TA = +25°C
-1.00
-1.50
90
EFFICIENCY (%)
1.50
-2.00
0.0
100
0
VSUP = 12V
VSUP = 10V
VSUP = 8V
VSUP = 6V
2.00
90
0
toc02
2.50
toc01
VSUP = 12V
VSUP = 10V
VSUP = 8V
VSUP = 6V
1.0
0.5
0.0
-0.5
-1.0
VOUT1 = 3.3V
VOUT2 = 1.8V
TA = +25°C
-1.5
0.5
toc04
-2.0
0.0
0.1
0.2
0.3
0.4
0.5
LOAD CURRENT (A)
BUCK2 LOAD TRANSINET
toc05
VSUP = 8V
VOUT1 = 3.3V
fSW = 3.2MHz
toc06
VSUP = 8V
VOUT2 = 1.8V
fSW = 3.2MHz
VOUT1
100mV/div
(ACCOUPLED)
VOUT2
50mV/div
(ACCOUPLED)
IOUT1
500mA/div
IOUT2
500mA/div
50µs/div
www.maximintegrated.com
50µs/div
Maxim Integrated │ 6
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Typical Operating Characteristics (continued)
MAX20019 STARTUP
MAX20020 EN BUCK2 STARTUP
toc07
VSUP
toc08
8V
VSUP
8V
3.3V
VOUT1
1V/div
VOUT1
1V/div
VOUT2
VEN
5V/div
fSW = 3.2MHz
1V/div
VOUT2
VEN
1ms/div
500µs/div
MAX20019 360mA OUTPUT1 RIPPLE
MAX20019 60mA OUTPUT1 RIPPLE
toc10
toc09
VSUP
5V/div
fSW = 3.2MHz
VSUP = 8V, IOUT1 = 60mA, fSW = 2.2MHz
VSUP
10mV/div
(ACCOUPLED)
VOUT1
VSUP = 8V, IOUT1= 360mA, fSW = 2.2MHz
10mV/div
(ACCOUPLED)
VOUT1
8V
8V
200mA/div
VOUT2
200mA/div
0A
0V
VLX2
VOUT2
VSUP
0V
VLX2
100ns/div
100ns/div
SLOW VSUP - RISING
0A
LINE TRANSIENT
toc12
toc11
9V
IOUT 1 = 500mA
5V/div
VSUP
6V
VOUT1
2V/div
VOUT1
200mV/div
20mV/div
VOUT2
2V/div
VOUT2
VLX1
5V/div
VLX1
100ns/div
www.maximintegrated.com
350mA
500mA/div
100ns/div
Maxim Integrated │ 7
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Pin Configuration
TOP VIEW
BST
10
+
1
EN AGND BIAS OUT2
9
8
7
MAX20019
MAX20020
2
3
6
EP
4
5
SUP LX1 PGND LX2 PV2
TDFN/SWTDFN
(3mm x 2mm)
*EP = EXPOSED PAD, CONNECTED TO GROUND
Pin Description
PIN
NAME
FUNCTION
1
SUP
Voltage-Supply Input and Internal High-Side Switch Supply Input. SUP powers the internal linear regulator
and power to the internal switches of Buck 1. Connect a 10µF capacitor to ground. See the
Input Capacitor section.
2
LX1
Inductor Switching Node for Buck 1. Shutdown-discharge resistance when part is disabled.
See the Inductor Selection section for component values.
3
PGND
Power Ground. Connect PGND and AGND together. Connect to the exposed pad.
Refer to the EV kit layout for details.
4
LX2
Inductor Switching Node for Buck 2. See the Inductor Selection section for details.
5
PV2
Buck 2 Voltage Input and Voltage-Feedback Sense of Switching-Regulator Output 1. Connect to the output
capacitor of Buck 1 with a very short and wide trace. See the PCB Layout Guidelines section.
6
OUT2
Voltage Feedback Sense of Switching Regulator Output 2. The discharge resistor is enabled when
EN = 0, overvoltage on Buck 2, or thermal shutdown occurs.
7
BIAS
Linear Regulator Output. BIAS powers up the internal circuitry. Bypass with a 2.2µF capacitor to ground.
8
AGND
9
EN
High-Voltage-Tolerant Enable Input with Hysteresis. Driving the MAX20019 EN high enables Buck 1
and Buck 2 based on the timing in the Electrical Characteristics table. Driving the MAX20020 EN high
enables Buck 2.
10
BST
High-Side Driver Supply. Connect a 0.1µF capacitor between LX1 and BST for proper operation.
—
EP
www.maximintegrated.com
Analog Ground. Connect PGND and AGND together at the input capacitor. See the PCB Layout
Guidelines section.
Exposed Pad. Must be connected to ground plane on PCB, but is not a current-carrying path,
only needed for thermal transfer.
Maxim Integrated │ 8
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Functional Diagrams
BIAS
BIAS
AGND
2.2µF
BST
MAX20019
EN
EN, 500mV
HYSTERSIS
SUP
HV
STEP-DOWN
PWM
BUCK1
LX1
5V, 3.3V, 3.0V, 2.8V
500mA
VSUP
10µF
3.3µH
3.3V/2.8V
OUT1
22µF
PGND
OUTS1
EN
PV2
LX2
LV
STEP-DOWN
PWM
BUCK2
3.3V, 1.8V, 1.5V,
1.2V, 1.0V
500mA
PV2
2.2µH
1.8V
OUT2
22µF
PGND
OUT2
EN
www.maximintegrated.com
Maxim Integrated │ 9
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Functional Diagrams (continued)
BIAS
BIAS
AGND
2.2µF
BST
MAX20020
SUP
HV
STEP-DOWN
PWM
BUCK1
LX1
PGND
PV2
www.maximintegrated.com
3.3V, 1.8V, 1.5V,
1.2V, 1.0V
500mA
PV2
LX2
LV
STEP-DOWN
PWM
BUCK2
EN2 BLOCK
3.3V/2.8V
OUT1
OUTS1
EN
SUP
EN2
3.3µH
22µF
5V, 3.3V, 3.0V, 2.8V
500mA
CONTROL LOGIC
VSUP
10µF
2.2µH
1.8V
OUT2
22µF
PGND
OUT2
EN2
Maxim Integrated │ 10
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Detailed Description
The MAX20019/MAX20020 are small, dual synchronous
step-down converters with integrated high-side and lowside MOSFETs. The low-side MOSFET enables fixedfrequency forced-PWM (FPWM) operation. The highvoltage step-down converters operate up to 17V input
voltages. The switching frequency is set to 3.2MHZ or
factory programmable to 2.2MHz allowing for small component size. The devices’ output voltage is factory preset
with Buck 1 set to 3.3V, 3.0V, or 2.8V, and Buck 2 preset
to 1.8V, 1.5V, 1.2V, or 1V. Buck 1 can be set to 5V with
Buck 2 set to 3.3V. The Buck 1 converter can run at 96%
duty cycle in dropout and the Buck 2 converter can run at
100% duty cycle in dropout.
The MAX20019 EN pin uses a 500mV hysteresis to
accommodate for long and high-impedance cables. The
MAX20020 Buck 1 starts when VSUP > 5.5V (rising), and
EN enables Buck 2. Protection features include cycleby-cycle current limit, Buck 2 overvoltage monitoring and
pulldown, and thermal shutdown with automatic recovery.
Spread spectrum improves EMI performance.
DC-DC Converter Control Architecture
The step-down converter uses a PWM peak currentmode-control scheme, with a load-line architecture.
Peak current-mode control provides several advantages
over voltage-mode control, including precise control of
the inductor current on a cycle-by-cycle basis, simpler
compensation.
The output voltage is positioned slightly positive at no
load (still within the tolerance window), to take advantage
of the fact that any load disturbance is a load step only.
This increases the amount of margin available to the
undershoot that occurs on a load step, allowing a
reduction in the required output capacitance. As the
load increases, a small but controlled amount of load
regulation (“load-line”) error occurs, so that at heavier
loads the voltage is positioned slightly below nominal.
This takes advantage of the fact that any load disturbance
is load released, increasing the amount of margin available to the overshoot that occurs.
www.maximintegrated.com
Maximum Duty-Cycle Operation
The Buck 1 converter has a maximum duty cycle of
96% (typ). The IC monitors the off-time (time for which
the low-side FET is on) in PWM every switching cycle.
Once the minimum off-time is reached, the low-side FET
is forced on for 150ns (typ) every 8µs (3.2MHz) and 12µs
(2.2MHz). The input voltage at which the devices enter
dropout changes depending on the input voltage, output
voltage, switching frequency, load current, and the efficiency of the design.
The Input voltage at which the devices enter dropout can
be approximated as:
VSUP = (VOUT1 + (IOUT1 x RON_HS))/0.96
Note: The equation above does not take into account the
efficiency and switching frequency, but is a god first-order
approximation. Use the RON_HS number from the Max
column in the Electrical Characteristics table.
The Buck 2 converter can operate at 100% duty cycle
since the high-side MOSFET is a p-channel.
Linear Regulator Output (BIAS)
The devices include a 5V linear regulator (VBIAS) that
provides power to the internal circuit blocks. Connect a
2.2μF ceramic capacitor from BIAS to AGND.
System Enable (EN)
The MAX20019 uses an enable control input (EN) to activate the devices from their low-power shutdown mode.
EN is high-voltage compatible and can be connected
to SUP. The MAX20020 EN only controls the Buck 2
converter and requires VSUP > 5.5V and VOUT1 to have
reached regulation before powering up Buck 2 (see the
Startup and Soft-Start section).
A logic-low at the MAX20019 EN shuts down the device.
During shutdown, the internal linear regulator and gate
drivers turn off. Shutdown is the lowest power state.
Driving the MAX20020 EN pin low while VSUP > 5V only
shuts down the OUT2 converter.
Startup and Soft-Start
The ICs feature an internal soft-start timer and delay
timer. Figure 1 and Figure 2 show startup timing, delay
timing between Buck 1, Buck 2, and EN effect on timing.
Maxim Integrated │ 11
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
MAX20019
EN
SOFT-SHORT
ON VOUT1
VOUT1
VOUT2
1.3ms
1.3ms
1.3ms
1.3ms
1.3ms
(1.8ms)
(1.8ms)
(1.8ms)
(1.8ms)
(1.8ms)
Figure 1. MAX20019 Soft-Start Timing for 3.2MHz (2.2MHz)
MAX20020
SUP
SOFT-SHORT
ON VOUT1
VOUT1
1.3ms
(1.8ms)
EN
td2
VOUT2
1.3ms
1.3ms
1.3ms
(1.8ms)
(1.8ms)
(1.8ms)
IF td2 < 1.3ms (1.8ms) THEN VOUT2 SOFT-START BEGINS 1.3ms (1.8ms) AFTER VOUT1 IS DONE
Figure 2. MAX20020 Soft-Start Timing for 3.2MHz (2.2MHz)
www.maximintegrated.com
Maxim Integrated │ 12
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Applications Information
Current Limit/ Short-Circuit Condition
The devices have fault protection designed to protect
them against abnormal conditions. If either output is
shorted, then that respective converter implements a
cycle-by-cycle current limit. If VOUT1 is below 90% of the
factory-preset voltage, VOUT2 is disabled. Buck 2 only
reenters soft-start if VOUT1 recovers above 95%.
Output-Voltage Selection
Output voltages are set at the factory. Available options
are shown in Table 1.
Inductor Selection
Three key inductor parameters must be specified for
operation with the device: inductance value (L), inductor
saturation current (ISAT), and DC resistance (RDC). To
select inductance value, the ratio of inductor peak-to-peak
AC current to DC average current (LIR) must be selected
first. A good compromise between size and loss is a 30%
peak-to-peak ripple current to average current ratio (LIR
= 0.3). The switching frequency, input voltage, output
voltage, and selected LIR then determine the inductor
value as follows:
The device also has overtemperature protection. If the die
temperature exceeds approximately 175°C, the device
stops switching until the die temperature drops by approximately 15°C and then resumes operation, going through
soft-start once again.
OUT2 Overvoltage Protection
OUT2 is monitored for overvoltage and responds by
turning off the high-side and low-side MOSFETs and
enabling the 500Ω pulldown resistor on OUT2. The
overvoltage rising and falling thresholds are provided in
the Electrical Characteristics table.
L1 = ((VSUP - VOUT1) x VOUT1)/(VSUP x
fSW x (IOUT1+IPV2) x LIR)
Internal Oscillator
and:
The switching frequency (fSW) is set at the factory to
2.2MHz or 3.2MHz for both converters. The higher 3.2MHZ
frequency allows designs with lower inductor values and
less output capacitance. Consequently, peak currents and
I2R losses are lower at higher switching frequencies, but
core losses, gate-charge currents, and switching losses
increase. If typical input voltage is expected over 10V, then
values of VIN, VOUT, IOUT, and DCR losses may require
the 2.2MHz switching frequency due to minimum on-time
constraints.
L2 = ((VPV2 - VOUT2) x VOUT2)/(VPV2 x
fSW x IOUT2 x LIR)
where VSUP, VOUT1, VOUT2, IOUT1, and IOUT2 are
typical values (so efficiency is optimum for typical
conditions). The switching frequency is set by factory
programming (see the Internal Oscillator section). Table 1
lists some of the inductor values for 300mA output current
and several output voltages.
Table 1. Output-Voltage Selections
VOLTAGE SELECTIONS (V)
OUTPUT
VOUT1
5*
3.3
3
2.8
VOUT2
3.3*
1.8
1.8
1.8
VOUT2
—
1.5
1.5
1.5
VOUT2
—
1.2
1.2
1.2
VOUT2
—
1.0
1.0
1.0
*Contact factory for availability.
Table 2. Inductor Values for Typical VIN, VOUT, and IOUT Requirements
8V
(3.3V)
7V
(3.3V)
7V
(2.8V)
Inductor (μH), ILOAD = 300mA
6.8
6.8
Inductor (μH), ILOAD = 500mA
4.7
3.3
VSUP/VOUT (V)
12V
(3.3V*)
3.3V
(1.8V)
2.8V
(1.8V)
6.8
10
2.2
2.2
3.3
8.2
—
—
*fSW = 2.2MHz.
www.maximintegrated.com
Maxim Integrated │ 13
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Input Capacitor
The recommended system input capacitor is 10µF with an
X5R rating or better. The input filter capacitor reduces peak
currents drawn from the power source and reduces noise
and voltage ripple on the input caused by the circuit’s
switching.
Output Capacitor
The minimum output capacitance should be 22µF
ceramic with an X7S or X7R rating. The value and quality
of this capacitor is critical, as it sets the dominant pole of
the loop.
PCB Layout Guidelines
Careful PCB layout is critical to achieve low switching
losses and clean, stable operation. Use a multilayer board
whenever possible for better noise immunity and power
dissipation. Follow these guidelines for good PCB layout:
The power and the Buck 1 feedback signal use the
same input pin, PV2. It is critical that this trace is short
as possible from the output of Buck 1 to the input PV2.
The width should be sufficient enough to carry the
current for PV2 while not causing enough drop to cause
regulation error in Buck 1.
2) Use a large contiguous copper plane under the device
package. Ensure that all heat-dissipating components
have adequate cooling. The bottom pad of the device must be soldered down to this copper plane for
effective heat dissipation and getting the full power out
of the device. Use multiple vias or a single large via in
this plane for heat dissipation.
3) Isolate the power components and high-current path
from the sensitive analog circuitry. This is essential to
prevent any noise coupling into the analog signals.
4) 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
input capacitor, high-side FET, inductor, and the output
capacitor, should be as short as possible.
5) The ground connection for the analog and power
section should be close to the IC. This keeps the
ground current loops to a minimum. In cases where
only one ground is used, adequate isolation between
analog return signals and high-power signals must be
maintained.
6) Place the BIAS capacitor next to the BIAS pin and
connect to AGND with a short and wide trace.
1) Place a 0.1µF ceramic capacitor next to SUP and
the IC.
www.maximintegrated.com
Maxim Integrated │ 14
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Simplified Typical Operating Circuits
REF
EN
HVLDO
MAX20019
OSC
BANDGAP
BST
BIAS
SUP
CLK
BUCK1
CURRENT SENSE
+
SLOPE COMP
BUCK1
SOFT-START
BUCK1
LOGIC
CONTROL
330kΩ
BIAS
PWM
EAMP
PV2
LX1
PG1
VGOOD
PGND
AGND
REF
EN
PG1
CLK
PV2
BUCK2
CURRENT SENSE
+
SLOPE COMP
BUCK2
SOFT-START
PWM
EAMP
OUT2
180kΩ
VOVTH
PV2
BUCK2
LOGIC
CONTROL
PGND
PV2
OV
AGND
www.maximintegrated.com
LX2
PGND
Maxim Integrated │ 15
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Simplified Typical Operating Circuits (continued)
REF
HVLDO
SUP
MAX20020
OSC
BANDGAP
BST
BIAS
SUP
CLK
BUCK1
CURRENT SENSE
+
SLOPE COMP
BUCK1
SOFT-START
BUCK1
LOGIC
CONTROL
330kΩ
BIAS
PWM
EAMP
PV2
LX1
PG1
VGOOD
PGND
EN2
AGND
REF
PG1
CLK
PV2
BUCK2
CURRENT SENSE
+
SLOPE COMP
BUCK2
SOFT-START
PWM
EAMP
OUT2
180kΩ
VOVTH
PV2
BUCK2
LOGIC
CONTROL
PGND
PV2
OV
AGND
www.maximintegrated.com
LX2
PGND
Maxim Integrated │ 16
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Ordering Information
PART
SEQUENCING
PIN-PACKAGE
OUT1 (V)
OUT2 (V)
fSW
(MHz)
SPREAD
SPECTRUM
MAX20019ATBA/V+
Off
10 TDFN-EP*
3.3
1.8
3.2
On
MAX20019ATBA/VY+
Off
10 SWTDFN-EP*
3.3
1.8
3.2
On
MAX20019ATBB/V+
Off
10 TDFN-EP*
2.8
1.8
3.2
On
MAX20019ATBC/V+
Off
10 TDFN-EP*
3.3
1.2
3.2
On
MAX20019ATBD/V+
Off
10 TDFN-EP*
2.8
1.2
3.2
On
MAX20019ATBE/V+**
Off
10 TDFN-EP*
3.3
1.8
3.2
Off
MAX20019ATBF/V+**
Off
10 TDFN-EP*
2.8
1.8
3.2
Off
MAX20019ATBG/V+
Off
10 TDFN-EP*
3.3
1.2
3.2
Off
MAX20019ATBH/V+**
Off
10 TDFN-EP*
2.8
1.2
3.2
Off
MAX20019ATBI/V+
Off
10 TDFN-EP*
3.3
1.0
3.2
On
MAX20019ATBJ/V+
Off
10 TDFN-EP*
3.3
1.8
2.2
On
MAX20020ATBA/V+
On
10 TDFN-EP*
3.3
1.8
3.2
On
MAX20020ATBB/V+
On
10 TDFN-EP*
2.8
1.8
3.2
On
MAX20020ATBC/V+
On
10 TDFN-EP*
3.3
1.2
3.2
On
MAX20020ATBD/V+
On
10 TDFN-EP*
2.8
1.2
3.2
On
MAX20020ATBK/VY+**
On
10 SWTDFN-EP*
3.3
1.82
3.2
On
Note: All devices operate over the -40°C to +125°C automotive
temperature range.
/V denotes an automotive qualified part.
+Denotes a lead(Pb)-free/RoHS-compliant package.
SW = Side-wettable TDFN package.
*EP = Exposed pad.
**Future product—contact factory for availability.
Contact factory for the following options:
• 2.2MHz or SS = Off
• OUT2: 1.5V or 1V
• OUT1 and OUT2: 5V and 3.3V
Chip Information
PROCESS: CMOS
www.maximintegrated.com
Maxim Integrated │ 17
MAX20019/MAX20020
3.2MHz, 500mA Dual Step-Down Converters
for Automotive Cameras
Revision History
REVISION
NUMBER
REVISION
DATE
0
6/17
Initial release
—
1
9/17
Updated Ordering Information and Package Information tables
16
2
1/18
Added new row for Voltage Accuracy in Electrical Characteristics and added
future product variant (MAX20020ATBK/V+) to Ordering Information tables
4, 16
3
1/18
Changed MAX20019ATBJ/V+ fSW value in Ordering Information table from
3.2MHz to 2.2MHz
16
4
2/18
Removed future product status from MAX20019ATBA/VY+ and added future
product status to MAX20020ATBA/V+ in Ordering Information table
16
Added future product status to MAX20019ATBC/V+, MAX20019ATBD/V+, and
MAX20019ATBJ/V+ in Ordering Information table
16
Updated Ordering Information table and removed future product status from MAX20019ATBC/V+, MAX20020ATBB/V+, MAX20020ATBC/V+, MAX20020ATBD/V+,
and MAX20020ATBK/VY+. Added future part designation to MAX20020ATBA/V+
16
Updated Ordering Information table and added future part designation to MAX20019ATBC/V+, MAX20020ATBB/V+, MAX20020ATBC/V+, MAX20020ATBD/V+,
and MAX20020ATBK/VY+
16
4.1
5
4/18
5.1
PAGES
CHANGED
DESCRIPTION
6
6/18
Updated Ordering Information table and removed future part designation from
MAX20019ATBC/V+, MAX20019ATBD/V+, MAX20020ATBA/V+, MAX20020ATBB/V+, MAX20020ATBC/V+, MAX20020ATBD/V+.
17
7
9/18
Updated Ordering Information table and removed future part designation from
MAX20019ATBG/V+ and MAX20019ATBJ/V+.
17
8
11/18
9
1/19
Updated Absolute Maximum Ratings section and Package Information table.
Updated Ordering Information table to remove future part designation from
MAX20019ATBI/V+
2
17
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. │ 18
工商网监
湘ICP备2023018690号
