MAX38640AENT+ [MAXIM]
Switching Regulator,;型号: | MAX38640AENT+ |
厂家: | MAXIM INTEGRATED PRODUCTS |
描述: | Switching Regulator, 开关 |
文件: | 总15页 (文件大小:807K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
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MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
General Description
Benefits and Features
The MAX3864xA/B are nanoPower family of ultra-low
330nA quiescent current buck (step-down) DC-DC con-
verters operating from 1.8V to 5.5V input voltage and sup-
porting load currents of up to 175mA, 350mA, 700mA with
peak efficiencies of 96%. While in shutdown, there is only
5nA of shutdown current. The devices offer ultra-low qui-
escent current, small total solution size, and high efficien-
cy throughout the load range. The MAX3864xA/B are ide-
al for battery applications where long battery life is a must.
● Extends Battery Life
• 330nA Ultra-Low Quiescent Supply Current
• 5nA Shutdown Current
• 96% Peak Efficiency and Over 88% at 10µA
● Easy to Use – Addresses Popular Operation
• 1.8V to 5.5V Input Range
• Preprogrammed V
• Single Resistor Adjustable V
• ±1.75% Output Voltage Accuracy
from 0.5V to 5V
OUT
from 0.7V to 3.3V
OUT
The MAX3864xA/B family utilizes a unique control scheme
that allows ultra-low quiescent current and high efficiency
over a wide output current range. MAX38642 excludes ac-
tive discharge resistor in shutdown which allows the out-
put to be regulated or held high by another source or by
the charged output capacitor.
• Up to 175mA/350mA/700mA Load Current
● Protects System in Multiple Use Cases
• Reverse-Current Blocking in Shutdown
• Optional Active Discharge Feature
● Reduces Size and Increases Reliability
• -40°C to +85°C Temperature Range
The MAX3864xA/B devices are offered in a space-saving
1.42mm x 0.89mm 6-pin wafer-level package (WLP) (2
x 3 bumps, 0.4mm pitch), as well as a 2mm x 2mm,
6-pin µDFN package. All parts are specified from -40°C to
+85°C.
• 2mm x 2mm 6-pin µDFN Package
• 1.42mm x 0.89mm, 0.4mm Pitch 6-pin (2 x 3) WLP
Ordering Information appears at end of data sheet.
Applications
● Portable Space-Constrained Consumer Products
● Wearable devices, Ultra-Low-Power IoT, NB IoT, and
BLE
● Single Li-ion and Coin Cell Battery Products
● Wired, Wireless, Industrial Products
Typical Operating Circuit
2.2µH
INPUT 1.8V-5.5V
OUTPUT 1.8V
IN LX
OUT
CIN
COUT
10µF
22µ F
MAX38640A
RSEL
RSEL
EN
GND
768kΩ
19-100410; Rev 0; 10/18
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Absolute Maximum Ratings
IN, EN, RSEL, NC, OUT to GND.............................. -0.3V to +6V
4.5mW/°C above +70°C) ...............................................357.8mW
Operating Temperature Range.............................-40°C to +85°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
LX RMS Current WLP ............................. -1.6A
LX RMS Current µDFN.................................. -1A
to +1.6A
RMS
RMS
RMS
to +1A
RMS
Continuous Power Dissipation - WLP (T = +70°C) (Derate
A
10.5mW/°C above +70°C)................................................ 840mW
Continuous Power Dissipation – µDFN (T = +70°C) (Derate
A
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
6 µDFN
Package Code
L622+1C
21-0164
90-0004
Outline Number
Land Pattern Number
Thermal Resistance, Four Layer Board:
Junction-to-Ambient (θ
)
223.6°C/W
122°C/W
JA
Junction-to-Case Thermal Resistance (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.
6 WLP
Package Code
Outline Number
N60E1+2
21-100128
Land Pattern Number
Refer to Application Note 1891
Thermal Resistance, Four Layer Board:
Junction-to-Ambient (θ
)
JA
95.15°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.
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Maxim Integrated | 2
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Electrical Characteristics
(V = 3.3V, V
IN
= 1.8V, T = -40°C to +85°C, C = 4.7µF, C
= 10µF, unless otherwise specified. (Note 1))
OUT
OUT
A
IN
PARAMETER
Shutdown Current
Input Voltage Range
SYMBOL
CONDITIONS
= 0V, T = 25°C
MIN
TYP
MAX
0.1
UNITS
I
V
EN
0.005
µA
V
IN_SD
A
V
Guaranteed by Output Accuracy
1.8
5.5
IN_RANGE
V
R
> 50kΩ rising
V
IN
1.75
50
1.8
V
UVLO
UVLO
SEL
(MAX3864xA),
MAX3864xB
Hysteresis
rising
mV
Input Undervoltage
Lockout
V
V
IN
2.6
2.7
V
mV
V
R
SEL
< 50kΩ
(MAX3864xA)
Hysteresis
125
Output Voltage Range
Output Accuracy
V
Guaranteed by Output Accuracy
0.5
5
OUT_RANGE
OUT falling, when LX begins switching
V
above 1MHz, V
5.5V (Note 2)
= 0.7V to 3.3V, V =
IN
-1.75
+1.75
%
%
OUT_ACC
OUT
V
OUT
= 1.8V, V = 2.0V to 5.5V, I
=
OUT
IN
DC Line Regulation
V
LREG
I
Q_IN
±1.5
330
10mA to 160mA
= V , not switching V = 106% of
OUT
V
EN
IN
Quiescent Supply
Current Into IN
target voltage, V
= 25°C
= 2.5V, T
660
nA
OUT TARGET
A
V
= V , not switching V
= 106% of
OUT
EN
IN
Quiescent Supply
Current Into OUT
I
target voltage, V
= 2.5V,
10
nA
Q_OUT
OUT TARGET
T
A
= 25°C
Soft-Start Slew Rate
LX Leakage Current
dV
/dt
V
= 1.8V, no load
OUT
6.5
2
mV/µs
nA
OUT
I
V
LX
= V = 5.5V, T = 25°C
100
1200
600
LEAK_LX
IN
A
MAX38643
800
400
225
1000
500
250
95
Inductor Peak Current
Limit
I
MAX38641/MAX38642
MAX38640
mA
mΩ
PEAK_LX
300
MAX38643
150
MAX38641/
MAX38642
High-Side R
R
V
IN
= 3.3V
= 3.3V
170
320
DSON
DS_H
MAX38640
MAX38643
320
50
600
90
MAX38641/
MAX38642
Low-Side R
R
V
V
80
150
5
160
290
mΩ
DSON
DS_L
IN
MAX38640
Zero-Crossing
Threshold
I
= 1.2V, percent of I
PEAK_LX
%
ZX_LX
OUT
Enable Input Leakage
I
V
V
V
= 5.5V, T = +25°C
0.1
0.8
0.7
100
1.2
nA
LEAK_EN
EN
EN
EN
A
V
EN_R
rising
falling
Enable Voltage
Threshold
V
V
EN_F
0.4
50
Active Discharge
Resistance ( MAX3860/
MAX3861/MAX3863
Only)
V
EN
= 0V,
R
85
200
Ω
OUT_DIS
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Maxim Integrated | 3
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Electrical Characteristics (continued)
(V = 3.3V, V
IN
= 1.8V, T = -40°C to +85°C, C = 4.7µF, C
= 10µF, unless otherwise specified. (Note 1))
OUT
OUT
A
IN
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Required Select
Resistor Accuracy
(MAX3864xA only)
Use the nearest ±1% resistor from R
Selection Table
SEL
R
-1
+1
%
SEL
Select Resistor
Detection Time
(MAX3864xA Only)
t
C
SEL
< 2pF
240
600
1320
µs
RSEL
Thermal Shutdown
T
T
T rising when output turns off
165
150
°C
ºC
SHUT
J
Thermal Shutdown
Threshold
T falling when output turns on
J
SHUT
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.
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Maxim Integrated | 4
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Typical Operating Characteristics
(MAX38640AENT+, V = 3.6V, V
= 1.8V, L = 2.2μH, C = 10μF, C
= 22μF, T = 25°C, unless otherwise noted.)
OUT A
IN
OUT
IN
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Maxim Integrated | 5
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Typical Operating Characteristics (continued)
(MAX38640AENT+, V = 3.6V, V
= 1.8V, L = 2.2μH, C = 10μF, C
= 22μF, T = 25°C, unless otherwise noted.)
OUT A
IN
OUT
IN
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Maxim Integrated | 6
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Typical Operating Characteristics (continued)
(MAX38640AENT+, V = 3.6V, V
= 1.8V, L = 2.2μH, C = 10μF, C
= 22μF, T = 25°C, unless otherwise noted.)
OUT A
IN
OUT
IN
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Maxim Integrated | 7
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Pin Configurations
MAX3864__ELT+
IN
1
2
3
6
5
4
EN
MAX3864--ELT+
LX
OUT
GND
RSEL/NC
MAX3864__ENT+
1
2
3
A
B
IN
LX
MAX3864--ENT+
OUT
GND
RSEL
/NC
EN
Pin Description
PIN
NAME
FUNCTION
MAX3864 MAX3864
__ELT+
__ENT+
Regulator Supply Input. Connect to a voltage between 1.8V and 5.5V and bypass with a
10µF capacitor from IN to GND.
1
A1
IN
2
3
A2
A3
LX
Switching Node. Connect an inductor between LX and the regulator output.
Ground.
GND
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Maxim Integrated | 8
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Pin Description (continued)
PIN
NAME
FUNCTION
MAX3864 MAX3864
__ELT+
__ENT+
MAX3864__A: Output Voltage Select Input. Connect a resistor from RSEL to GND to
program the output voltage and IN undervoltage threshold based on the Table 1.
4
B3
RSEL/NC
MAX3864__B: No Connect. Leave floating.
Output Voltage Sense Input. Connect to the load at a point where accurate regulation
(output capacitor) is required to eliminate resistive metal drops.
5
6
B2
B1
OUT
EN
Enable Input. Force this pin high to enable the buck converter. Force this pin low to disable
the part and enter shutdown.
Functional Diagrams
MAX38640/1/2/3 A/B
INPUT
IN
REVERSE
BLOCKING
CIN
10µF
UVLO
CURRENT SENSE
EN
2.2µH
MODULATOR
OUTPUT
LX
COUT
THERMAL SHUTDOWN
22µF
OUT
REFERENCE
OPTIONAL ACTIVE
DISCHARGE
MAX3864xA ONLY
UVLO AND TARGET
OUTPUT SELECTOR
RSEL
RSEL
GND
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Maxim Integrated | 9
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Detailed Description
MAX38640/1/2/3 A/B are ultra-low IQ (330nA) buck converters that step-down from 1.8V to 5.5V to wide range of output
voltages between 0.5V to 5V. The output voltage is either programmable on MAX3864xA versions using an external
resistor or fixed for MAX3864xB versions. The external R
startup for MAX3864xA versions.
resistor on the RSEL pin programs the output voltage upon
SEL
The buck converter automatically switches between ultra-low-power mode (ULPM), low-power mode (LPM), and high-
power mode (HPM) to better service the load, depending on the load current. The buck converter overregulates in ultra-
low-power mode to allow the output capacitor to handle the transient load currents. The device has 90% duty cycle
limitation.
Active discharge resistor in MAX38640/MAX38641/MAX38643 pulls OUT to ground when the part is in shutdown. Active
discharge has been strategically omitted for MAX38642 to preserve the charge on the output capacitor in shutdown.
Harvesting applications where the output is connected to a super capacitor can take advantage of reverse-current
blocking feature to preserve the charge on the output capacitor even if the input were to fall below the output in shutdown.
Applications where two MAX38642 buck converters are connected in parallel to the drive the load can have the input of
one of the buck converters to go to 0V in shutdown without dragging the output down or loading the other buck.
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Maxim Integrated | 10
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Voltage Configuration
The MAX3864xA includes an RSEL pin to configure the output voltage and input UVLO threshold on startup. Resistors
with tolerance 1% (or better) should be chosen, with nominal values specified in Table 1.
Table 1. MAX3864xA 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
324
267
226
191
162
133
113
95.3
80.6
66.5
56.2
47.5
40.2
34
1.75
1.75
1.75
1.75
1.75
1.75
1.75
1.75
1.75
1.75
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
1.15
1.1
1.05
1
0.95
0.9
0.85
0.8
0.75
0.7
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
1.15
1.1
1
2.6
16.9
14
2.6
2.6
11.8
10
2.6
2.6
8.45
7.15
5.9
2.6
2.6
0.95
2.6
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Maxim Integrated | 11
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Table 1. MAX3864xA RSEL Selection Table (continued)
TARGET OUTPUT VOLTAGE (V)
R
(kΩ)
INPUT UVLO THRESHOLD, RISING (V)
SEL
0.9
0.8
4.99
SHORT TO GND
2.6
2.6
The MAX3864xB has a fixed output voltage that is preprogrammed (no RSEL programming). Contact Maxim to order a
part with an output voltage listed in Table 2. The input UVLO threshold for MAX3864xB is 1.75V (typ., V rising) with
IN
50mV hysteresis (typ.).
Table 2. MAX3864xB Preprogrammed Output Voltage Table
PART NUMBER
MAX3864xB-50
MAX3864xB-45
MAX3864xB-40
MAX3864xB-33
MAX3864xB-30
MAX3864xB-275
MAX3864xB-25
MAX3864xB-20
MAX3864xB-18
MAX3864xB-15
MAX3864xB-12
MAX3864xB-10
MAX3864xB-09
MAX3864xB-08
MAX3864xB-07
MAX3864xB-065
MAX3864xB-06
MAX3864xB-055
MAX3864xB-05
OUTPUT VOLTAGE (V)
5.0
4.5
4.0
3.3
3.0
2.75
2.5
2.0
1.8
1.5
1.2
1.0
0.9
0.8
0.7
0.65
0.6
0.55
0.5
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Maxim Integrated | 12
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Applications Information
Inductor Selection
The inductor value for MAX3864x affects the ripple current, the transition point from low power mode (LPM) to ultra-
low-power mode (ULPM), and the overall efficiency performance. Based on the peak current limit required for different
applications, it is recommended to select an inductor value based on Table 3.
Table 3. Inductor Selection
PEAK CURRENT, PART NUMBER
1.0A Peak Current, MAX38643
INDUCTANCE RANGE (µH)
1.0–1.5
2.2
500mA Peak Current, MAX38641/MAX38642
250mA Peak Current, MAX38640
2.2–4.7
Input Capacitor
The input capacitor (C ) reduces the peak current drawn from battery or input power source and reduces the
IN
switching 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, use 10µF ceramic capacitor with X5R or X7R
temperature characteristics.
Output Capacitor
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. Capacitors
with X5R or X7R temperature characteristics typically perform well. A 22µF ceramic capacitor is recommended for most
applications.
Enabling Device
The device has a dedicated EN pin. This pin can be driven by a digital signal. It is recommended that the digital signal
enables the device after V crosses the UVLO threshold. In applications where EN is tied to IN, the device is designed
IN
to be powered by fast V slew rates. If V slew rates are slower than 5V/ms, users must delay enabling the device after
IN
IN
V
IN
crosses the UVLO threshold. This can be done using a simple RC circuit, as shown in Figure 1.
IN
BAT54
REN
EN
CEN
Figure 1. RC Circuit at EN
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Maxim Integrated | 13
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
PCB Layout and Routing
High switching frequencies and large peak currents make PCB layout a very important part of the buck regulator design.
Good design minimizes excessive EMI (Electromagnetic Interference) on the feedback paths and voltage gradients in the
ground plane, to avoid instability and regulation errors. The input capacitor (C ) should be placed as close as possible
IN
to the IC pins IN and GND. Connect the inductor, input capacitor, and output capacitor (C
) as close together as
OUT
possible, and keep their traces short, direct, and wide.
Connect the two GND pins under the IC and directly to the ground of the output capacitor. Keep noisy traces, such as the
LX node, as short as possible. The OUT pin should be connected to the output capacitor and this trace should be routed
away from the main power path between the inductor and C
. The OUT trace should also be routed away from noisy
OUT
traces such as the LX line or other external noise sources. Refer to the MAX3864x evaluation kit for an example PCB
layout and routing scheme.
Ordering Information
PEAK
INDUCTOR
CURRENT
(A)
ACTIVE
DISCHARGE
PART NUMBER
PACKAGE
FEATURES
MAX38640AELT+*
MAX38641AELT+*
MAX38642AELT+*
MAX38643AELT+*
MAX38640BELT+*
MAX38641BELT+*
MAX38642BELT+*
MAX38643BELT+*
0.25
0.50
0.50
1.00
0.25
0.50
0.50
1.00
Yes
Yes
—
6-pin 2mm x 2mm
μDFN
0.7V to 3.3V Resistor-Selectable Output Voltage
Using RSEL (Resistor Select) Pin
Yes
Yes
Yes
—
0.5V to 5V Preprogrammed Output Voltage
Yes
MAX38640AENT+
MAX38641AENT+*
MAX38642AENT+*
MAX38643AENT+*
MAX38640BENT+*
MAX38641BENT+*
MAX38642BENT+*
MAX38643BENT+*
0.25
0.50
0.50
1.00
0.25
0.50
0.50
1.00
Yes
Yes
—
0.7V to 3.3V Resistor-Selectable Output Voltage
Using RSEL (Resistor Select) Pin
Yes
Yes
Yes
—
6-pin 2mm x 3
0.4mm Pitch WLP
0.5V to 5V Preprogrammed Output Voltage
Yes
*Future product—contact factory for availability.
+Denotes a lead(Pb)-free/RoHS-compliant package.
T Denotes tape-and-reel.
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Maxim Integrated | 14
MAX38640/1/2/3/A/B
Tiny 1.8V - 5.5V Input, 330nA I , 700mA
Q
nanoPower Buck Converter
Revision History
REVISION REVISION
PAGES
CHANGED
DESCRIPTION
NUMBER
DATE
0
10/18
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.
© 2018 Maxim Integrated Products, Inc.
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