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LXDC55FAAA-203
Micro DC-DC converter
1. Features
 Wide Input voltage range : 4.0V to 14.0V
 User Adjustable Output voltage : 0.8 to 5.3V
 Small footprint Buck converter for up to 1.5A output current application
 Low EMI noise by using an inductor-embedded ferrite substrate
 High efficiency using synchronous rectifier technology at 2MHz operation
 Superior transient response using quasi-fixed-frequency COT technology
 Seamless Power-Save Mode Transition
 Power-Good function ,Over current protection, Over temperature protection
 Quiescent Current of 150 μA (typ.)
2. Description
The LXDC55F series is an easy-to-use synchronous step-down DC-DC converter optimized for applications with
high power density. The device utilizes an inductor-embedded ferrite substrate, and the substrate eliminates
radiated EMI noise and conduction noise efficiently.
With its wide operating input voltage range of 4 V to 14 V, the devices are ideally suited for systems powered from
either a Li-Ion or other batteries, as well as from 12-V intermediate power rails. It supports up to 1.5 A of
continuous output current at output voltages between 0.8 V and 5.3 V
The LXDC55F series utilizes a constant on time feedback technology and has superior load transient response. It
has a unique circuit that roughly keeps the switching frequency constant, which makes it easy to filter the
switching noise.
The output voltage of LXDC55F series can be adjusted from 0.8 V to 5.3 V by using a resistor (RFB) between FB
pin and GND pin. In terms of resistor value is calculated by RFB = 7.28/(Vout-0.8V) – 1.6 [kohm]
The LXDC55F series has Power Good Output function. It’s to indicate whether the output voltage has reached its
appropriate level or not.
The device has an internal soft-start function to control the output voltage slope during start-up.
In power-save mode, the devices show quiescent current of about 150 μA from VIN. Power-save mod e, it enters
automatically and seamlessly if load is small, maintains high efficiency over the entire load range.
3. Typical Application Circuit
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Micro DC-DC converter
4. Mechanical details
4-1 Outline
Top View
Side View
Bottom View
Unit:(mm)
Mark
Dimension
Mark
Dimension
L
5.0 +/- 0.2
e
1.1
W
5.7 +/- 0.2
f
0.6
T
2.1 MAX
g
0.35
a
0.25
h
0.6
b
0.7
i
0.35
c
0.4
j
1.0
d
0.8
4-2. Pin Function
Pin No.
1
Symbol
EN
I/O
Input
Description
This is the ON/OFF control pin of the device. The device is in
shutdown when the voltage to this pin is below 0.3V. Pulling this pin
above 0.9V enables the device with soft start. This pin should not be
left floating.
EN=H: Device ON,
EN=L: Device OFF
2
NC
-
No connection
3,4,5
Vin
Input
Vin pin supplies current to the LXDC55F internal regulator.
6,12,13,14
GND
-
Ground pin
7,8,9
Vout
Output
10
PG
Output
11
FB
Input
Regulated voltage output pin.
Apply output load between this pin and GND.
Power good voltage output pin (Open drain). This is to indicate
whether the output voltage has reached its appropriate level or not.
External resistor connection pin for output voltage setting
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4-3. Functional Block Diagram
5. Ordering Information
Part number
Device Specific Feature
MOQ
LXDC55FAAA-203
Standard Type
T/R, 1,000pcs/R
LXDC55FAAAA203
Standard Type
T/R, 300pcs/R
6. Electrical Specification
6-1
Absolute maximum ratings
Parameter
symbol
rating
Unit
Input voltage
Vin
16
V
Enable voltage
EN
Vin
V
FB pin voltage
FB
6
V
PG pin voltage
PG
6
Operating Ambient temperature
Operating IC temperature
Storage temperature
V
-40 to +85
o
TIC
-40 to +125
o
TSTO
-40 to +85
o
Ta
C
C
C
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6-2 Electrical characteristics (Ta=25℃)
Parameter
Symbol
Condition
Min.
Typ.
Max.
Unit
Input voltage
Vin
4
14
V
Output voltage range
Vout
0.8
5.3
V
2.8
V
UVLO
UVLO
Standby current
IinOFF
Vin Falling
2.6
Hysteresis
2.7
200
Vin=12V,,EN=0.3V
Quiescent current
Iin0
Vin=12V, RFB=1312Ω
(Vout=3.3V) Iout=0A
Output voltage
accuracy
Vacc
PWM mode
Load current range
Iout
Over current protection
OCP
Auto-recovery
mV
3
7
uA
150
200
uA
-3.0
+3.0
%
0
1500
mA
1500
3500
mA
Vin=12.0V, RFB=1.31kohm,
Ripple voltage
Vrpl
(Vout=3.3V)
20
mV
87
%
Iout=1A, BW=100MHz
Vin=12.0V, RFB=1.31kohm,
Efficiency
EFF
(Vout=3.3V)
Iout=1000mA
EN control voltage
Switching frequency
Power good threshold
VENH
ON ; Enable
VENL
OFF ; Disable
0.9
Vin
V
0
0.3
V
Vin=12V, RFB=1312Ω
(Vout=3.3V) Iout=1000mA
2
MHz
PGTHH
Output voltage rising
95
%
PGTHL
Output voltage falling
90
%
Vin=12V, Iout=0A
0,8
msec
fosc
Rise time
TSU
Power good
sink current
IPG
2
mA
(*1) External capacitors (Cout:22uF) shall be placed near the module in order to proper operation.
(*2) The above characteristics are tested using the application circuit on section 8.
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Micro DC-DC converter
6-3
Thermal and Current De-rating Information
The following figure shows the power dissipation and temperature rise characteristics example. These data are
measured on Murata’s evaluation board of this device at no air-flow condition.
Io-Loss characteristics (Vin=12V, Vout=3.3V)
Power Dissipation(mW)
Io-Loss characteristics (Vin=12V, Vout=3.3V)
The output current of the device may need to be de-rated if it is operated in a high ambient temperature or in a
continuous power delivering application. The amount of current de-rating is highly dependent on the
environmental thermal conditions, i.e. PCB design, nearby components or effective air flows. Care should
o
especially be taken in applications where the device temperature exceeds 85 C.
o
The IC temperature of the device must be kept lower than the maximum rating of 125 C. It is generally
recommended to take an appropriate de-rating to IC temperature for a reliable operation. A general de-rating for
the temperature of semiconductor is 80%.
MLCC capacitor’s reliability and lifetime are also depending on temperature and applied voltage stress. Higher
temperature and/or higher voltage cause shorter lifetime of MLCC, and the degradation can be described by the
Arrhenius model. The most critical parameter of the degradation is IR (Insulation Resistance). The below figure
shows MLCC’s B1 life based on a failure rate reaching 1%. It should be noted that wear-out mechanisms in
MLCC capacitor is not reversible but cumulative over time.
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Micro DC-DC converter
Capacitor B1 Life vs Capacitor Case Temperature
100000000
Vin=12V
Capacitor B1 Life (Thousand Hours)
10000000
Vin=10V
1000000
Vin=8V
Vin=5V
100000
10000
1000
100
10
1
20
40
60
80
100
o
Capacitor Case Temperature ( C )
120
The following steps should be taken before the design fix of user’s set for a reliable operation.
o
1. The ambient temperature of the device should be kept below 85 C
2. The IC temperature should be measured on the worst condition of each application. The temperature must be
o
kept below 125 C. An appropriate de-rating of temperature and/or output current should be taken.
3. The MLCC temperature should be measured on the worst condition of each application. Considering the
above figure, it should be checked if the expected B1 life of MLCC is acceptable or not.
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Micro DC-DC converter
7. Detailed Description
Adjustable output voltage
The output voltage of LXDC55F series can be adjusted from 0.8 V to 5.3 V by using a resistor (RFB) between FB
pin and GND pin. In terms of resistor value is calculated by RFB = 7.28/(Vout-0.8V) – 1.6 [kohm].
Pulse-Width Modulation (PWM) Operation
The LXDC55F series operates with pulse-width modulation in continuous-conduction mode (CCM). The device
operates in PWM mode as long the output current is higher than half the inductor ripple current. To maintain high
efficiency at light loads, the device enters power-save mode at the boundary to discontinuous conduction mode
(DCM). This happens if the output current becomes smaller than half the inductor ripple current.
Power-Save Mode Operation
The LXDC55F series enters its built-in power-save mode seamlessly if the load current decreases. This secures a
high efficiency in light-load operation. The device remains in power-save mode as long as the inductor current is
discontinuous. In power-save mode, the switching frequency decreases linearly with the load current, maintaining
high efficiency. The transition into and out of power-save mode happens within the entire regulation scheme and
is seamless in both directions.
UVLO (Under Voltage Lock Out)
The input voltage (Vin) must reach or exceed the UVLO voltage (2.7Vtyp) before the device begins the start up
sequence even when the EN pin is kept high. The UVLO function protects against unstable operation at low Vin
levels
Enable
The device starts operation when EN is set high and starts up with soft start. For proper operation, the EN pin
must be terminated to logic high and must not left floating. Pulling the EN pin to logic low forces the device
shutdown.
Power Good (PG)
The LXDC55F series has a built-in power-good (PG) function to indicate whether the output voltage has reached
its appropriate level or not. It can sink 2mA current and maintain its specified logic-low level.
100% Duty Cycle Operation
The duty cycle of the buck converter is given by D = Vout/Vin and increases as the input voltage comes close to
the output voltage. In this case, the device starts 100% duty-cycle operation, turning on the high-side switch 100%
of the time. The high-side switch stays turned on as long as the output voltage is below the internal set point. This
allows the conversion of small input-to-output voltage differences, e.g., for longest operation time of
battery-powered applications. In 100% duty-cycle mode, the low-side FET is switched off.
Over Current Protection
The device integrates a current limit function to protect internal components against heavy load or short circuits.If
the OCP event is removed, the output voltage recovers to the nominal value automatically.
Thermal Shutdown
As soon as the internal IC’s junction temperature exceeds 160℃ (typ), the device goes into thermal shutdown.
The device continues its operation when the Internal IC’s junction temperature again falls below 140℃ (typ).
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Micro DC-DC converter
8. Test Circuit
COUT: GRM21BB30J226 (22uF/6.3V MLCC)
9.Output Voltage adjustment
Output voltage can be adjusted by using a resistor (RFB) between FB pin and GND pin.
RFB = 7.28/(Vout-0.8V) – 1.6 [kohm]
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10. Measurement Data
Micro DC-DC Converter evaluation board
(P2LX1568F)
Measurement setup
Power good
Vout_S
Load
A
GND_S
Output voltage
adjustment resistor
Vout
GND
Vin
V
V
GND
EN
ON
GND_S
EN
OFF
Vin_S
A
V
Enable SW
* Evaluation board initial output Voltage setting : 3.3V ( resistor : 1.3kΩ + 12Ω )
The enable switch has three positions.
1. When it is toggled to “ON” side, the device starts operation.
2. When it is toggled to “OFF” side, the device stop operation and keep shut down status.
3. When it is set to middle of “ON” and “OFF”, the EN pin becomes floated and can be applied an external
voltage through the EN terminal pin on the EVB. If you don’t apply external voltage to EN pin, the enable
switch should not to be set to the middle position.
※The 47uF capacitor is for the evaluation kit only, and has been added to compensate for the long test cables.
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Micro DC-DC converter
Typical Measurement Data (reference purpose only)
(Ta=25℃)
Efficency
Vin=12.0V,
Output Ripple-Noise
Vin=12.0V,
BW : 100MHz
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Micro DC-DC converter
Load Regulation
Vin=12.0V, Vout=0.8V
Vin=12.0V, Vout=1.8V
Vin=12.0V, Vout=3.3V
Vin=12.0V, Vout=5.0V
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Micro DC-DC converter
Load Transient Response
・Vin=12V, Vout=5V
・Vin=12V, Vout=3.3V
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Micro DC-DC converter
Start Up Waveform
・Vin=12V, Vout=5V
・Vin=12V, Vout=3.3V
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Micro DC-DC converter
11.Reliability Tests
No.
1
2
3
Items
Vibration
Resistance
Result
(NG)
18
G
(0)
Frequency : 10~2000 Hz
2
Acceleration : 196 m/s
Direction : X,Y,Z 3 axis
Period
: 2 h on each direction
Total 6 h.
Solder specimens on the testing jig
(glass epoxy boards) shown in
appended Fig.2 by a Pb free solder.
The soldering shall be done either by
iron or reflow and be conducted with
care so that the soldering is uniform
and free of defect such as by heat
shock.
Deflection : 1.6mm
Solder specimens onto test jig shown
below. Apply pushing force at 0.5mm/s
until electrode pads are peeled off or
ceramics are broken. Pushing force is
applied to longitudinal direction.
18
G
(0)
Pushing Direction
18
G
(0)
18
G
(0)
18
G
(0)
Test Methods
Appearance :
No severe damages
Solder specimens on the testing jig
(glass fluorine boards) shown in
appended Fig.1 by a Pb free solder.
The soldering shall be done either by
iron or reflow and be conducted with
care so that the soldering is uniform
and free of defect such as by heat
shock.
Deflection
Soldering strength
(Push Strength)
QTY
Specifications
9.8 N Minimum
Specimen
4
5
Solderability of
Termination
Resistance to
Soldering Heat
(Reflow)
75%
of
the
terminations is to be
soldered evenly and
continuously.
Appearance
No severe damages
Electrical
specifications
Satisfy
specifications listed
in paragraph 6-2.
Jig
Immerse specimens first an ethanol
solution of rosin, then in a Pb free
solder solution for 3±0.5 sec. at
245±5 °C.
Preheat
: 150 °C, 60 sec.
Solder Paste : Sn-3.0Ag-0.5Cu
Flux : Solution of ethanol and rosin
(25 % rosin in weight proportion)
Preheat Temperature : 150-180 °C
Preheat Period
: 90+/-30 sec.
High Temperature
: 220 °C
High Temp. Period
: 20sec.
Peak Temperature
: 260+5/-0 °C
Specimens are soldered twice with
the above condition, and then kept in
room condition for 24 h before
measurements.
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Micro DC-DC converter
No.
6
7
8
9
Items
Specifications
Test Methods
High Temp.
Exposure
Temperature:85±2 ℃
Period:1000+48/-0 h
Room Condition:2~24h
Temperature
Cycle
Condition:100 cycles in the following
table
Humidity
(Steady State)
Appearance
No severe damages
Electrical
specifications
Satisfy
specifications listed
in paragraph 6-2.
Low Temp.
Exposure
Step
Temp(°C)
Time(min)
1
Min.
Operating
Temp.+0/-3
30±3
2
Max.
Operating
Temp.+3/-0
30±3
Temperature:85±2 ℃
Humidity:80~90%RH
Period:1000+48/-0 h
Room Condition:2~24h
Temperature:-40±2 ℃
Period:1000+48/-0 h
Room Condition:2~24h
QTY
Result
(NG)
18
G
(0)
18
G
(0)
18
G
(0)
18
G
(0)
10
ESD(Machine
Model)
C:200pF、R:0Ω
TEST Voltage :+/-100V
Number of electric discharges:1
5
G
(0)
ESD(Human
Body Model)
C:100pF、R:1500Ω
TEST Voltage :+/-1000V
Number of electric discharges:1
5
G
(0)
11
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LXDC55FAAA-203
Micro DC-DC converter
Fig.1
Land Pattern
e
f
e
f
e
(5)
(4)
(3)
(6)
(14)
(13)
(7)
(8)
(9)
(2)
(1)
(12)
(10) (11)
b cb cd c b cb
unit (mm)
Mark
Dimension
b
0.7
c
0.4
d
0.8
e
1.1
f
0.6
・Reference purpose only.
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Micro DC-DC converter
Fig.2
Testing board
Unit:mm
100
■: Land pattern is same as figure1
Glass-fluorine board t=1.6mm
Copper thickness over 35 mm
40
Mounted situation
Unit:mm
チップ
Device
45
45
Test method
Unit:mm
20
50
R230
たわみ量
deflection
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LXDC55FAAA-203
Micro DC-DC converter
13. Tape and Reel Packing
1)Dimensions of Tape (Plastic tape)
(Unit : mm)
Feeding direction
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LXDC55FAAA-203
Micro DC-DC converter
2) Dimensions of Reel
2-1.
(Unit : mm)
LXDC55FAAA-203 : 1,000pcs/reel
2±0.5
Φ100
φ13±0.2
Φ330
(13.5)
17.5±1.0
2-2.
LXDC55FAAAA203 : 300pcs/reel
Unit: mm
2±0.5
Φ60
φ13±0.2
Φ180
(13.0)
15.4±1.0
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Micro DC-DC converter
3) PACKAGE Diagrams (Humidity proof Packing)
Tape and reel must be sealed with the anti-humidity plastic bag. The bag contains the desiccant and the humidity
indicator.
Label
表示ラべル
Desiccant
乾燥剤
Humidity
湿度
インジケ-タ
Indicator
表示ラベル
Label
Anti-humidity
防湿梱包袋
Aluminum foil pack
4) Taping Diagrams(LXDC55F)
[1] Feeding Hole
: As specified in (1)
[2] Hole for chip
: As specified in (1)
[3] Cover tape : 50um in thickness
[4] Base tape : As specified in (1)
[3]
[1]
[2]
[3]
[4]
1pin Mark
Feeding hole
Feedeng Direction
Chip
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Micro DC-DC converter
5) Leader and Tail tape
Tail tape
(No components) Components
No components
Leader tape
(Cover tape alone)
Over100mm
Over160m
Over400mm
Feeding direction
6) The tape for chips are wound clockwise, the feeding holes to the right side as the tape is pulled
toward the user.
7)Material : Base tape
...... Plastic
Reel and Cover tape
......Plastic
Base tape, Reel and Cover tape have an anti-ESD function.
8) Peeling of force : 0.1~1.3 N in the direction of peeling as shown below.
0.7N
max
0.1~1.3N
165 ~ 180 °
Cover tape
Base tape
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Micro DC-DC converter
NOTICE
1. Storage Conditions:
・The product shall be stored without opening the packing under the ambient temperature from 5 to 35 deg.C
and humidity from 20 to 70%RH.
(Packing materials, in particular, may be deformed at the temperature over 40 deg.C.)
・The product left more than 6 months after reception, it needs to be confirmed the solderbility before used.
- The product shall be stored in non corrosive gas (Cl2, NH3, SO2, Nox, etc.).
- Any excess mechanical shock including, but not limited to, sticking the packing materials by sharp object
and dropping the product, shall not be applied in order not to damage the packing materials.
・After the packing opened, the product shall be stored at < 30 deg.C / < 60 %RH and the product shall be
used within 168 hours.
When the color of the indicator in the packing changed, the product shall be baked before
soldering.
This product is applicable to MSL3 (Based on IPC/JEDEC J-STD-020)
2. Handling Conditions:
Be careful in handling or transporting the product. Excessive stress or mechanical shock may damage the
product because of the nature of ceramics structure.
Do not touch the product, especially the terminals, with bare ear hands. Doing so that may result in poor
solderability.
3. Standard PCB Design (Land Pattern and Dimensions):
All the ground terminals should be connected to the ground patterns. Furthermore, the ground pattern
should be provided between IN and OUT terminals. Please refer to the specifications for the standard
land dimensions.
The recommended land pattern and dimensions are shown for a reference puerpose only.
Electrical, mechanical and thermal characteristics of the product shall depend on the pattern design and
material / thickness of the PCB. Therefore, be sure to check the product performance in the actual set.
When using underfill materials, be sure to check the mechanical characteristics in the actual set.
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Micro DC-DC converter
4. Soldering Conditions:
Soldering is allowed up through 2 times.
Carefully perform preheating :△T less than 130 °C.
When products are immersed in solvent after mounting, pay special attention to maintain the temperature
difference within 100 °C. Soldering must be carried out by the above mentioned conditions to prevent
products from damage. Contact Murata before use if concerning other soldering conditions.
Reflow soldering standard conditions (example)
Use rosin type flux or weakly active flux with a chlorine content of 0.2 wt % or less.
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Micro DC-DC converter
5. Cleaning Conditions:
The product is not designed to be cleaned after soldering.
6. Operational Environment Conditions:
Products are designed to work for electronic products under normal environmental conditions (ambient
temperature, humidity and pressure). Therefore, products have no problems to be used under the similar
conditions to the above-mentioned. However, if products are used under the following circumstances, it
may damage products and leakage of electricity and abnormal temperature may occur.
- In an atmosphere containing corrosive gas ( Cl2, NH3, SOx, NOx etc.).
- In an atmosphere containing combustible and volatile gases.
- In a dusty environment.
- Direct sunlight
- Water splashing place.
- Humid place where water condenses.
- In a freezing environment.
If there are possibilities for products to be used under the preceding clause, consult with Murata before
actual use.
If static electricity is added to this product, degradation and destruction may be produced.
Please use it after consideration enough so that neither static electricity nor excess voltage is added at the
time of an assembly and measurement.
If product malfunctions may result in serious damage, including that to human life, sufficient fail-safe
measures must be taken, including the following:
(1) Installation of protection circuits or other protective device to improve system safety
(2) Installation of redundant circuits in the case of single-circuit failure
7. Input Power Capacity:
Products shall be used in the input power capacity as specified in this specifications.
Inform Murata beforehand, in case that the components are used beyond such input power capacity range.
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Micro DC-DC converter
8. Limitation of Applications:
The products are designed and produced for application in ordinary electronic equipment
(AV equipment, OA equipment, telecommunication, etc). If the products are to be used in devices requiring
extremely high reliability following the application listed below, you should consult with the Murata staff in
advance.
- Aircraft equipment.
- Aerospace equipment
- Undersea equipment.
- Power plant control equipment.
- Medical equipment.
- Transportation equipment (vehicles, trains, ships, etc.).
- Automobile equipment which includes the genuine brand of car manufacture, car factory-installed option
and dealer-installed option.
- Traffic signal equipment.
- Disaster prevention / crime prevention equipment.
- Data-procession equipment.
- Application which malfunction or operational error may endanger human life and property of assets.
- Application which related to occurrence the serious damage
- Application of similar complexity and/ or reliability requirements to the applications listed in the above.
! Note:
Please make sure that your product has been evaluated and confirmed against your specifications when
our product is mounted to your product.
Product specifications are subject to change or our products in it may be discontinued without advance
notice.
This catalog is for reference only and not an official product specification document, therefore, please
review and approve our official product specification before ordering this product.
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February 2016
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