MAX38650 [MAXIM]
Tiny 1.8V to 5.5V Input, 390nA IQ, 100mA nanoPower Buck Converter with 100% Duty Cycle Operation;
| 型号： | MAX38650 |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | Tiny 1.8V to 5.5V Input, 390nA IQ, 100mA nanoPower Buck Converter with 100% Duty Cycle Operation |
| 文件： | 总13页 (文件大小：936K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
General Description
Benefits and Features
The MAX38650 is a nanoPower, ultra-low 390nA
quiescent current, buck (step-down) DC-DC converter
operating from 1.8V to 5.5V input voltage and supporting
load currents of up to 100mA with peak efficiencies of
95%. While in shutdown, there is only 5nA of shutdown
current. The device offers ultra-low quiescent current,
small total solution size, and high efficiency throughout
the load range. The device is ideal for battery
applications where long battery life is a must. The
MAX38650 supports 100% duty cycle operation allowing
seamless transition as battery discharges and falls
below the target output voltage. The MAX38650 utilizes
a unique control scheme that allows ultra-low quiescent
current and high efficiency over a wide output current
range. The device is offered in a space-saving, 1.58mm
x 0.89mm, 6-pin wafer-level package (WLP) (2 x 3
bumps, 0.4mm pitch). The part is specified over the
-40°C to +125°C operating temperature range.
•
Extends Battery Life
• 390nA Ultra-Low Quiescent Supply Current
• 5nA Shutdown Current
• 95% Peak Efficiency and over 85% at 10µA
•
Easy to Use—Addresses Popular Operation
• 1.8V to 5.5V Input Range
• Single Resistor-Adjustable VOUT from 1.2V to
3.3V (MAX38650A)
• Preprogrammed VOUT from 1.2V to 5V
(MAX38650B) in steps of 50mV
• 100% Duty Cycle Mode for Low Dropout
Operation
• ±1.5% Output Voltage Accuracy
• 100mA Load Current
•
•
Protects System in Multiple Use Cases
• Reverse-Current Blocking in Shutdown
• Active Discharge Feature
Reduces Size and Increases Reliability
• -40°C to +125°C Operating Temperature Range
• 1.58mm x 0.89mm, 0.4mm Pitch, 6-Pin (2 x 3)
WLP
Applications
•
•
Portable Space-Constrained Consumer Products
Wearable Devices, Ultra-Low-Power IoT, NB IoT,
and Bluetooth Low Energy (BLE)
Ordering Information appears at end of data sheet.
•
•
•
Single Li-Ion and Coin Cell Battery Products
Wired, Wireless, Industrial Products
Low-Voltage Industrial Applications
Typical Operating Circuit
2.2µH
INPUT 1.8V TO 5.5V
OUTPUT 1.2V TO 3.3V
LX
IN
OUT
C
OUT
C
IN
22µF
10µF
MAX38650A
HIGH (ON)
EN
RSEL
LOW (OFF)
GND
R
SEL
19-100931; Rev 0; 1/21
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
Absolute Maximum Ratings
IN, EN, OUT to GND............................................. -0.3V to +6V
Operating Temperature Range....................... -40°C to +125°C
Maximum Junction Temperature...................................+150°C
Storage Temperature Range.......................... -65°C to +150°C
Lead Temperature (soldering, 10 seconds) ..................+300ºC
Soldering Temperature (reflow).....................................+260°C
RSEL to GND....................-0.3V to lower of +6V or +IN + 0.3V
LX RMS Current...................................-1.6A
to +1.6A
RMS
RMS
Continuous Power Dissipation—WLP (T = +70°C) (Derate
A
10.51mW/°C above +70°C) .......................................... 840mW
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
WLP
Package Code
N60R1+1
Outline Number
21-100464
Land Pattern Number
Refer to Application Note 1891
THERMAL RESISTANCE, FOUR-LAYER BOARD
Junction to Ambient (θ
)
JA
95.15°C/W
N/A
Junction to Case (θ
)
JC
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.
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Maxim Integrated | 2
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
Electrical Characteristics
(V = 3.3V, V
IN
= 1.8V, T = -40°C to +125°C, C = 10μF, C = 22μF, unless otherwise specified.) (Note 1)
OUT
J
IN
OUT
PARAMETER
SYMBOL
CONDITIONS
= 0V, T = +25°C
MIN
1.8
TYP
MAX
UNITS
Shutdown Current
I
V
0.005
0.1
µA
IN_SD
EN
J
Guaranteed by input undervoltage
lockout and output accuracy
specifications
Input Voltage Range
V
5.5
1.8
V
V
IN
V
V
V
V
rising
falling
rising
falling
1.75
1.7
IN
IN
IN
IN
R
R
> 60kΩ
< 60kΩ
SEL
1.65
Input Undervoltage
Lockout
V
UVLO
2.6
2.65
SEL
2.45
1.2
2.5
Guaranteed by output accuracy
specification (MAX38650A)
Guaranteed by output accuracy
specification (MAX38650B)
3.3
5
Output Voltage Range
Output Accuracy
V
V
OUT
1.2
V
falling, when LX begins switching
OUT
ACC
above 300kHz, V > V
+ 0.3V,
-1.5
+1.5
+4
%
IN
OUT
Note 2
Hysteresis measured as a percent of
target output voltage;
Low-Power Mode Over-
Regulation Hysteresis
LPM_HYS
+1.3
+2.7
±2.5
390
%
%
V
= 2.5V
OUT_TARGET
DC Load Regulation
ACC
I
from 1mA to 80% of I
LOAD PEAK_LX
LD_REG
V
= V , not switching V
= 104% of
OUT
EN
IN
Quiescent Supply
Current into IN
I
target voltage, V
= 2.5V,
660
nA
Q_IN
OUT_TARGET
T = +25°C
J
Quiescent Supply
Current into IN in 100%
Mode
V
= V = 2.2V, V
= 2.5V,
OUT_TARGET
EN
IN
I
1050
15
1680
nA
nA
Q_IN_DO
I
= 0mA, T = +25°C
LOAD
J
V
= V , not switching V
= 104% of
OUT
EN
IN
Quiescent Supply
Current into OUT
I
target voltage, V
T = +25°C
J
= 2.5V,
OUT_TARGET
Q_OUT
Soft-Start Time
t
V
= 1.8V, I = 0mA
OUT
1
ms
nA
SS
OUT
V
= V = 5.5V, V = 0V,
OUT EN
LX
LX Leakage Current
I
4.5
100
0.31
525
250
LEAK_LX
PEAK_LX
T = +25°C
J
Inductor Peak Current
Limit
High-Side Channel
Resistance
Low-Side Channel
Resistance
I
Note 3
0.21
0.26
325
150
A
R
mΩ
mΩ
DS_H
R
DS_L
Zero-Crossing
Threshold
I
V
V
= 1.2V
OUT
Note 3
12.5
50
1
mA
ns
ZX_LX
Minimum Off-Time
t
OFF_MIN
LEAK_EN
Enable Input Leakage
Current
I
= 5.5V, T = +25°C
J
100
1.2
nA
EN
V
V
V
rising
falling
0.8
0.7
Enable Voltage
Threshold
IH
EN
EN
V
V
0.4
IL
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Maxim Integrated | 3
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
(V = 3.3V, V
IN
= 1.8V, T = -40°C to +125°C, C = 10μF, C = 22μF, unless otherwise specified.) (Note 1)
OUT
OUT
J
IN
PARAMETER
SYMBOL
CONDITIONS
= 0V (MAX38650A, MAX38650B)
EN
MIN
TYP
MAX
UNITS
Active Discharge
Resistance
R
V
50
85
200
Ω
OUT_DIS
Guaranteed by
output accuracy
Required Select
Resistor Accuracy
testing over R
SEL
ACC
MAX38650A
-1
+1
%
RSEL
range; use ±1%
resistor from
Table 1
Select Resistor
Detection Time
t
C
< 2pF
RSEL
MAX38650A
240
600
1320
µs
°C
RSEL
T rising when output turns off
J
165
150
Thermal Shutdown
Threshold
T
SHUT
T falling when output turns on
J
Note 1: Limits over the specified operating temperature and supply voltage range are guaranteed by design and characterization,
and production tested at room temperature only.
Note 2: Output accuracy in low-power mode (LPM) and does not include load, line, or ripple.
This is a static measurement. The actual peak current limit depends upon V , V
, and the inductor due to propagation
Note 3:
IN OUT
delays.
Typical Operating Characteristics
VIN = 3.6V, VOUT = 1.8V, CIN =10µF, COUT = 22µF, L = 2.2µH unless otherwise noted.
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Maxim Integrated | 4
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
www.maximintegrated.com
Maxim Integrated | 5
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
www.maximintegrated.com
Maxim Integrated | 6
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
Pin Configurations
TOP VIEW
2
1
3
A
IN
LX
GND
MAX38650
B
EN
OUT
RSEL/NC
WLP
Pin Descriptions
PIN
NAME
FUNCTION
Regulator Supply Input Pin. Connect to a voltage between 1.8V and 5.5V and bypass with a 10µF
capacitor from IN to GND.
A1
IN
A2
A3
LX
Switching Node Pin. Connect recommended inductor between LX and OUT.
GND
Ground Pin. Connect to application board GND.
MAX38650A: Connect a resistor from RSEL to GND to program the output voltage and IN undervoltage
B3
RSEL/NC threshold based on Table 1.
MAX38650B: The pin is no connect since the device is preprogrammed and should be left floating.
Output Voltage Pin. Connect to the load at a point where accurate regulation (output capacitor) is
required to eliminate voltage drops.
Enable Input Pin. Force this pin high to enable the buck converter. Force this pin low to disable the part
and enter shutdown.
B2
B1
OUT
EN
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Maxim Integrated | 7
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
Functional Diagram
MAX38650A/MAX38650B
IN
INPUT
C
IN
10µF
THERMAL
SHUTDOWN
EN
HIGH (ON)
STARTUP/
SHUTDOWN
EN
LOW (OFF)
REVERSE
BLOCKING
MAX38650A
ONLY
UVLO
THRESHOLD
TARGET
OUTPUT
SELECTOR
RSEL
CURRENT
SENSE
UVLO THRESHOLD
TARGET V
OUT
CONTROL LOGIC AND
MODULATOR
R
SEL
LX
2.2µH
OUTPUT
C
OUT
TARGET V
OUT
OUT
22µF
UVLO THRESHOLD
EN
ACTIVE
DISCHARGE
GND
Detailed Description
The MAX38650 is an ultra-low I (390nA) buck converter that steps-down from an input voltage range of 1.8V to 5.5V to
Q
a wide range of output voltages between 1.2V to 5V. The output voltage is either programmable (the MAX38650A) using
a single external resistor or fixed from the factory (the MAX38650B). The external R
resistor on the RSEL pin programs
SEL
the output voltage upon startup in the MAX38650A.
The buck converter automatically switches between low-power mode (LPM) and high-power mode (HPM) to better service
the load, depending on the load current. The buck converter overregulates in LPM to allow the output capacitor to handle
the transient load currents. The device supports 100% duty cycle operation.
The active discharge resistor in the MAX38650A/MAX38650B pulls OUT to ground when the part is in shutdown.
Enable Mode
When V is above the UVLO rising threshold and the EN pin is pulled high (V
> V ), the MAX38650 is enabled. For
IH
IN
EN
the MAX38650A, there is a delay in reading the RSEL pin after which the soft-start mechanism begins.
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Maxim Integrated | 8
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
Disable Mode
When the EN pin is pulled low (V
< V ), the MAX38650 goes into disable (shutdown) mode. While in shutdown, 5nA
IL
EN
of current is consumed from V Reverse-current blocking from the output is active only when the part is disabled.
IN.
Voltage Configuration
Select the RSEL resistor value by choosing the desired output voltage in Table 1.
The MAX38650A includes an RSEL pin to configure the output voltage and input UVLO threshold on startup. Resistors
with a tolerance of 1% (or better) should be chosen, with nominal values specified in Table 1.
At startup, the MAX38650 sources up to 200μA during the select resistor detection time, typically for 600μs (t
), to
RSEL
read the R
value.
SEL
Care must be taken that the total capacitance on this pin is less than 2pF. See the PCB Layout Guidelines for more
information.
The R
output voltage selection method has many benefits:
SEL
•
•
•
In conventional converters, current will be drawn from the output continuously through a feedback resistor-divider. In
the MAX38650, 200μA of current will be drawn only during startup, which helps to increase efficiency at light loads.
It provides lower cost and smaller size, since only one resistor is needed versus the two resistors in typical feedback
connections.
R
allows customers to stock just one part in their inventory system and use it in multiple projects with different
SEL
output voltages just by changing a single standard 1% resistor.
R allows much higher internal feedback resistors instead of lower impedance external feedback resistors, thus
•
SEL
enabling ultra-low power applications.
Table 1. MAX38650A RSEL Selection Table
TARGET OUTPUT VOLTAGE (V)
R
(kΩ)
INPUT UVLO THRESHOLD, RISING (V)
SEL
2.5
2
OPEN
909
768
634
536
452
383
56.2
47.5
40.2
34
1.75
1.75
1.75
1.75
1.75
1.75
1.75
2.6
1.8
1.5
1.3
1.25
1.2
3.3
3
2.6
2.8
2.75
2.5
2
2.6
2.6
28
2.6
23.7
20
2.6
1.8
1.5
1.25
1.2
2.6
16.9
14
2.6
2.6
11.8
2.6
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Maxim Integrated | 9
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
Note: The MAX38650B has an output voltage that is preprogrammed (no RSEL programming). Contact your Maxim
Integrated representative to order a part with an output voltage preprogrammed in the output voltage range from 1.2V to
5.0V in 50mV steps. The input UVLO threshold for a preprogrammed device is 1.75V (V rising) with 50mV hysteresis.
IN
100% Duty Cycle Operation
The MAX38650 features 100% duty cycle operation. When the input voltage approaches the output voltage, the
MAX38650 stops switching and enters 100% duty cycle operation. It connects the output to input through the high side
power switch and the inductor. Entry into 100% duty cycle mode depends on the voltage ripple at the IN and OUT pins;
refer to the Input and Output Capacitor Selection sections for recommended C and C
capacitors. When the input
IN
OUT
to the level 5% above its target level, the converter restarts regulation.
voltage is increased again where it pulls V
OUT
When the load is light, the device consumes only 1.05µA of current in 100% duty cycle mode while still protecting the
inductor current from exceeding current limit.
Active Discharge
The MAX38650 integrates a discharge resistor from the OUT pin to GND. This discharge resistor gets activated when
converter is disabled, which helps discharge the output capacitor quickly. The typical value of the discharge resistance is
85Ω.
Applications Information
Typical Application
L
2.2µH
INPUT 2.7V TO 5.5V
OUTPUT 1.8V
IN
LX
OUT
C
IN
C
OUT
10µF
22µF
MAX38650A
HIGH (ON)
EN
RSEL
LOW (OFF)
GND
R
SEL
20kΩ
Figure 1. 1.8V Buck Converter Using the MAX38650A
Inductor Selection
The inductor value for the MAX38650 affects the ripple current, the transition point from LPM to HPM and overall efficiency
performance. It is recommended to use an inductor value of 2.2μH.
Input Capacitor Selection
The input capacitor (C ) reduces the peak current drawn from battery or input power source and reduces the switching
IN
noise in the IC. The impedance of C at the switching frequency should be very low. Ceramic capacitors are
IN
recommended with their small size and low ESR. For most applications, it is recommended to use a 10µF ceramic
capacitor with X7R temperature characteristics. For operations where ambient temperature is less than +85°C, X5R can
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Maxim Integrated | 10
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
be used. In applications where the device will approach or go into 100% duty cycle operation, more capacitance at the
input pin is required; therefore, 10μF (5μF effective capacitance) at C is recommended.
IN
Output Capacitor Selection
The output capacitor (C
) is required to keep the output voltage ripple small and to ensure loop stability. C
must
OUT
OUT
have low impedance at the switching frequency. Ceramic capacitors are recommended due to their small size and low
ESR. Make sure the capacitor does not degrade its capacitance significantly over temperature and DC bias. For most
applications, it is recommended to use 22µF ceramic capacitor with X7R temperature characteristics. For operations
where ambient is less than +85°C, X5R can be used. A 22µF ceramic capacitor (10μF effective capacitance) is
recommended for applications.
PCB Layout and Routing
Careful PCB layout is especially important in nanoPower DC-DC converters. Poor layout can affect the IC performance
causing electromagnetic interference (EMI), electromagnetic compatibility (EMC) issues, ground bounce, voltage drops,
etc. Poor layout can also affect regulation and stability.
A good layout is implemented using the following rules:
•
Place the inductor, input capacitor, and output capacitor close to the IC using short traces and/or copper pours. These
components carry high switching currents and long traces act like antennas. The input capacitor placement is the most
important in the PCB layout and should be placed directly next to the IC. The inductor and output capacitor placement
are secondary to the input capacitor’s placement but should remain close to the IC.
The connection from the bottom plate of the input capacitor and the ground pin of the device must be extremely short,
as should be that of the output capacitor.
•
•
•
•
•
Similarly, the top plate of input capacitor connection to the IN pin of the device must be short as well.
Minimize the surface area used for LX since this is the noisiest node.
Keep the main power path from IN, LX, OUT, and GND as tight and short as possible.
Route the output voltage sense away from the inductor and LX switching node to minimize noise and magnetic
interference.
•
Maximize the size of the ground metal on the component side to help with thermal dissipation. Use a ground plane
with several vias connecting to the component-side ground to further reduce noise interference on sensitive circuit
nodes.
•
The trace used for the RSEL signal should neither be too long nor should produce a capacitance of more than 2pF.
It is also recommended to consult the MAX38650 EV kit layout.
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Maxim Integrated | 11
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
Ordering Information
ACTIVE
DISCHARGE
PART NUMBER
FEATURES
PACKAGE
MAX38650AANT+
MAX38650BANT+*
Yes
Yes
1.2V to 3.3V output voltage selectable using RSEL
WLP
Preprogrammed output voltage from 1.2V to 5V
WLP
*Future product—contact factory for availability.
+ Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape-and-reel.
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Maxim Integrated | 12
MAX38650
Tiny 1.8V to 5.5V Input, 390nA IQ,
100mA nanoPower Buck Converter
with 100% Duty Cycle Operation
Revision History
REVISION
NUMBER
0
REVISION
DATE
PAGES
CHANGED
—
DESCRIPTION
1/21
Initial release
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.
© 2021 Maxim Integrated Products, Inc.
相关型号：
MAX38650AANT+
Tiny 1.8V to 5.5V Input, 390nA IQ, 100mA nanoPower Buck Converter with 100% Duty Cycle Operation
MAXIM
MAX38650BANT+
Tiny 1.8V to 5.5V Input, 390nA IQ, 100mA nanoPower Buck Converter with 100% Duty Cycle Operation
MAXIM
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