Datasheet

Synchronous Boost DC/DC Converter(LOAD:500mA@VOUT=3.3V, VIN=1.8V)
BU33UV7NUXGeneral Description

Key Specifications

BU33UV7NUX is a synchronous boost convertor with low■ Input Voltage Range
0.6V to 4.5V
power consumption and provides a power supply for■ Fixed Output Voltage
3.3V
products powered by either two-cell alkaline/NiCd/NiMH■ Efficiency
94%(Max)
or one-cell alkaline/Li-ion or Li-polymer battery.
■ Current Consumption
7μA(MODE=Low)
Output currents can go as high as 500mA(VIN=1.8V).
13μA(MODE=High)BU33UV7NUX has reset circuit. (Detection voltage:1.5V,■ Start-up Voltage
0.9V
Release Voltage:1.9V)
BU33UV7NUX output voltage is fixed 3.3V by internal
resistor divider. VOUT is connected with VIN when VIN Package
W(Typ) x D(Typ) x H(Max)voltage is higher than 3.3V.
VSON010X3020
3.00mm x 2.00mm x 0.60mm

Features
■
■
■
■
■
■
■

Synchronous Boost DC/DC Converter
Iomax 500mA @VOUT=3.3V, VIN =1.8V(Ta=25°C)
Disconnect Function during EN-OFF and UVLO
Auto-PFM/PWM (MODE=H(=VIN)),
Fixed PFM (MODE=L(=0V))
Reset Function (Detect Voltage = 1.5V)
Pass-Through Function (VIN > VOUT)
Thermal Shutdown
10-Pin “VSON010X3020” Package

Typical Application Circuit

Applications
■
■
■
■
■
■
■
■

Single-Cell or Two-Cell Alkaline
NiCd/NiMH or Single-Cell Li Battery-Powered Products
IC Recorders
Wireless Mouse
Portable Audio Players
Cellular Phones
Personal Medical Products
Remote Controllers

Typical Performance Characteristics

Efficiency(VIN=2.4V, VOUT=3.3V)

VIN

100
INTLDO

VIN

AGND

PGND

FB

SW

EN

VOUT

C0:10µF

95

C2:1µF

RSTB

L0:4.7µH

Efficiency [%]

VIN

90

VOUT

C1

85
MODE=L80

MODE=H

75

MODE

70
65
60

MODE=H: Auto-PFM/PWM
MODE=L: Fixed PFM

0.1

Figure 1. Application Circuit〇Product structure : Silicon monolithic integrated circuit
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1

10

100

1000

Output Current:IOUT [mA]

Figure 2. Efficiency〇This product has no designed protection against radioactive rays

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BU33UV7NUXPin Configuration(TOP VIEW)INTLDO 1

10 VINAGND 2

9 PGND

FB 3

8 SW

EN 4

7 VOUTRSTB 5

EXP-PAD

6 MODE

Figure 3. Pin Configuration

Pin Descriptions
Pin No.

Pin Name

Function

1
2
3

INTLDO
AGND
FB

4

EN

5

RSTB

6

MODE

7
8
9
10
-

VOUT
SW
PGND
VIN
EXP-PADInternal power supply
GND
Output feedback
EN= VIN: Power-ON
EN=GND: Power-OFF
Low battery detection
MODE = VIN: Auto-PFM/PWM
MODE =GND: Fixed PFM
Boost voltage output
Inductor connection
Power GND
Power supply
The EXP-PAD is not connected any other pins inside the package.

(Note) Do not use the EN and MODE pin at open.

Block Diagram

Reset circuit
Detect Voltage：1.5V
Release Voltage：1.9V

+
-

VIN

VIN

VIN
LDO

+
-

RSTB

INTLDO
VOUT

OVP

VIN
SWP
CONTROL
LOGIC
VIN

MODE

LEVEL
SHIFT

DRIVER

ENB

SW

SWN

EN
TSD

FB

OSC
ENB

+
-

+
-

AGND
PGND

Figure 4. Circuit Block
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Absolute Maximum Ratings (Ta=25 °C)
Parameter
Maximum Applied Voltage1
Maximum Applied Voltage2 [INTLDO]
Maximum Junction Temperature
Storage Temperature Range

Symbol
Vmax1
Vmax2
Tjmax
Tstg

Ratings
6.5
2.5
125-55 to +125

Unit
V
V
°C
°C

Caution 1: Operating the IC over the absolute maximum ratings may damage the IC. The damage can either be a short circuit between pins or an open circuit
between pins and the internal circuitry. Therefore, it is important to consider circuit protection measures, such as adding a fuse, in case the IC is operated
over the absolute maximum ratings.
Caution 2: Should by any chance the maximum junction temperature rating be exceeded the rise in temperature of the chip may result in deterioration of theproperties of the chip. In case of exceeding this absolute maximum rating, design a PCB with thermal resistance taken into consideration by increasingboard size and copper area so as not to exceed the maximum junction temperature rating.

Thermal Resistance(Note 1)
Parameter

SymbolThermal Resistance (Typ)1s(Note 3)

2s2p(Note 4)

Unit

VSON010X3020
Junction to Ambient

θJA

274.8

39.4

°C/W

Junction to Top Characterization Parameter(Note 2)

ΨJT

31

6

°C/W

(Note 1) Based on JESD51-2A(Still-Air)(Note 2) The thermal characterization parameter to report the difference between junction temperature and the temperature at the top center of the outside surface ofthe component package.
(Note 3) Using a PCB board based on JESD51-3.

Layer Number ofMeasurement Board
SingleMaterial

Board Size

FR-4

114.3mm x 76.2mm x 1.57mmt

Top
Copper Pattern

Thickness

Footprints and Traces

70μm(Note 4) Using a PCB board based on JESD51-5, 7.

Layer Number ofMeasurement Board
4 Layers

Thermal Via(Note 5)

Material

Board Size

FR-4

114.3mm x 76.2mm x 1.6mmt

Top

2 Internal Layers

Pitch
1.20mmDiameterΦ0.30mm
BottomCopper Pattern

Thickness

Copper Pattern

Thickness

Copper Pattern

Thickness

Footprints and Traces

70μm

74.2mm x 74.2mm

35μm

74.2mm x 74.2mm

70μm(Note 5) This thermal via connects with the copper pattern of all layers.

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Recommended Operating Conditions
Parameter
Power Supply Voltage
Operating Temperature

Symbol
VIN
Topr

Min
0.6(Note 1)
-40

Typ
-

Max
4.5
+85

Unit
V
°C

(Note 1) When it is VOUT=3.3V

Electrical Characteristics (Unless otherwise specified VIN=2.4V, L0=4.7µH, C1=22µF×2, Ta=25°C)
Parameter

Symbol

Min

Typ

Max

Unit

Circuit Current1

ICC1

-

2.7

8.0

µA

EN=0V, VIN =1.2V

Circuit Current2

ICC2

-

7

18

μA

Circuit Current3

ICC3

-

13

25

μA

EN=H, MODE=L,
Device not switching
EN=H, MODE=H,
Device not switchingfSW
VOUTMH
VOUTMLIMAX1
IMAX2
VIH_EN
VIL_EN
RSWN
RSWP
VRSTR
VRSTD
VRSTHYS
VOL
VOH
VMIN

720
3.262
3.1
50
500
0.6
1.868
VIN-0.5
0.875

800
3.3
3.3
140
330
1.9
1.5
0.4
0
0.9

880
3.343
3.5
0.2
1.930
0.1
0.925

kHz
V
V
mA
mA
V
V
mΩ
mΩ
V
V
V
V
V
V

VMINAFT

-

0.26

0.6

V

IOCP
VOVPD
RDIS

1.3
5.5
-

1.55
6
90

1.8
6.5
-

A
V
Ω

Switching Frequency
Output Voltage MODE=H
Output Voltage MODE=L
Maximum Output Current1
Maximum Output Current2
EN Input HighEN Input Low
SWN Switch On ResistanceSWP Switch On Resistance
RST Release Threshold
RST Detect Threshold
RST Hysteresis
RSTB Output Low Voltage
RSTB Output High Voltage
Minimum Start-up Voltage
Minimum Input Voltage afterStart-up
Over Current ProtectionOVP Detect Threshold
Discharge ResistanceCondition

IOUT=1mA, MODE=H
IOUT=1mA, MODE=L
MODE=L, VIN =1.8V
MODE=H, VIN =1.8V

Isink=20μA, VIN=0.9V
Isource=1mA(Note 2)VOUT Rising(Note 2) Resistive load = 3.3kΩ, VOUT = 3.3V at 1mA.

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Typical Performance Curves(Unless otherwise indicated, VIN=2.4V,VOUT=3.3V,L0=4.7µH,C1=22μF×2,Ta=25°C)

90

90

80

80

70

70

60

VIN=3.3V

50

VIN=3.0V

40

VIN=2.4V

Efficiency [%]100

Efficiency [%]100

VIN=1.8V

30

VIN=1.5V

20

60

VIN=3.3V

50

VIN=3.0V

40

VIN=2.4V

30

VIN=1.8V
VIN=1.5V

20

VIN=1.2V

VIN=1.2V

10

10
VIN=0.9V
0
0.01

0.1
1
10
Output Current:IOUT [mA]

VIN=0.9V

0
0.01

100

Figure 5. Efficiency vs Output Current(MODE=L: Fixed PFM)

4.3

VIN=0.9V
4.1

VIN=2.4V

3.7

VIN=3.3V

Output Voltage:VOUT [V]Output Voltage:VOUT [V]4.3

VIN=1.8V

3.9

1000

Figure 6. Efficiency vs Output Current(MODE=H: Auto-PFM/PWM)

VIN=0.9V

4.1

0.1
1
10
100
Output Current:IOUT [mA]

3.5
3.3
3.1
2.9

3.9

VIN=2.4V

3.7

VIN=3.3V

3.5
3.3
3.1
2.9

2.7

2.7

2.5

2.5

2.3

VIN=1.8V

2.3
0

50
100
150
Output Current:IOUT [mA]

200

0

Figure 7. Output Voltage vs Output Current(“Load Regulation”, MODE=L: Fixed PFM)

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100
200
300
400
500
Output Current:IOUT [mA]

600

Figure 8. Output Voltage vs Output Current(“Load Regulation”, MODE=H: Auto-PFM/PWM)

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Typical Performance Curves - continued

700

Maximum Output Current:IMAX [mA]6

Output Voltage:VOUT [V]

5
4
3
2

Ta=-50˚C
1

Ta=+25˚C

MODE=H:Auto-PFM/PWM
600

MODE=L:Fixed PFM

500
400
300
200
100

Ta=+105˚C
0

0

0

1
2
3
4
Power Supply Voltage:VIN [V]50.0

Figure 9. Output Voltage vs Power Supply Voltage(“Line Regulation”, MODE=H: Auto-PFM/PWM,
3.3kΩ resistive load)

0.5
1.0
1.5
Power Supply Voltage:VIN [V]2.0

Figure 10. Maximum Output Current vs Power Supply
Voltage

25

2000

20

Circuit Current2:ICC2 [μA]

Circuit Current1:ICC1 [μA]

1800

15

10

5

1600
1400

1200
1000
800
600
400
200

0

0
0

1
2
3
4
Power Supply Voltage:VIN [V]50

Figure 11. Circuit Current1 vs Power Supply Voltage(EN=MODE=L, No load)www.rohm.com© 2016 ROHM Co., Ltd. All rights reserved.
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1
2
3
4
Power Supply Voltage:VIN [V]5

Figure 12. Circuit Current2 vs Power Supply Voltage(MODE=L: Fixed PFM, No load)

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Typical Performance Curves - continued

2000

1000
Ta=-50˚C
Ta=+25˚C
Ta=+105˚C

Switching Frequency:fSW [kHz]Circuit Current3:ICC3 [μA]

1800
1600

1400
1200
1000
800
600
400

900

800

700

200
600

0
0

1
2
3
4
Power Supply Voltage:VIN [V]05

Figure 13. Circuit Current3 vs Power Supply Voltage(MODE=H: Auto-PFM/PWM, No load)

5

Figure 14. Switching Frequency vs Power Supply Voltage(MODE=H: Auto-PFM/PWM)

500

100

MODE=H:Auto-PFM/PWM

90400

MODE=L:Fixed PFM

80
Ripple Voltage [mV]SWP Switch On Resistance:RSW P [mΩ]12
34Power Supply Voltage:V IN [V]

300

200

100

70
60
50

40
30
20

10
0

0
3.0

3.5
4.0
4.5
Power Supply Voltage:VIN [V]

5.0

0.01

1

10

100

1000

Output Current:IOUT [mA]

Figure 15. SWP Switch On Resistance vs Power Supply
Voltage(MODE=H: Auto-PFM/PWM)

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0.1

Figure 16. Ripple Voltage vs Output Current(VIN=2.4V)

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Typical Performance Curves - continued

ch2:VOUT [100mV/div, offset=3.3V]

ch2:VOUT [100mV/div, offset=3.3V]

ch4:IOUT [50mA/div]

ch4:IOUT [50mA/div]
Time[100μs/div]

Time[500μs/div]

Figure 17. Transient Response(VIN=2.4V, MODE=L: Fixed PFM,
Output current 1mA<->100mA)

Figure 18. Transient Response(VIN=2.4V, MODE=L: Fixed PFM,
Output current 1mA<->100mA)

ch2:VOUT [100mV/div, offset=3.3V]
ch2:VOUT [100mV/div, offset=3.3V]

ch4:IOUT [50mA/div]

ch4:IOUT [50mA/div]
Time[100μs/div]

Time[500μs/div]

Figure 19. Transient Response(VIN=2.4V, MODE=H: Auto-PFM/PWM,
Output current 1mA<->100mA)

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Figure 20. Transient Response(VIN=2.4V, MODE=H: Auto-PFM/PWM,
Output current 1mA<->100mA)

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Typical Performance Curves - continued

ch1:EN [1V/div]

ch1:EN [1V/div]

ch2:VOUT [2V/div]

ch2:VOUT [2V/div]

ch3:Icoil [500mA/div]

ch3:Icoil [500mA/div]

Figure 21. Start-up Waveform(VIN=0.9V, 3.3kΩ resistive load, MODE=L: Fixed PFM)

Figure 22. Start-up Waveform(VIN=2.4V, 3.3kΩ resistive load, MODE=L: Fixed PFM)

ch1:EN [1V/div]

ch1:EN [1V/div]

ch2:VOUT [2V/div]

ch2:VOUT [2V/div]

ch3:Icoil [500mA/div]

ch3:Icoil [500mA/div]

Figure 23. Start-up Waveform(VIN=0.9V, 3.3kΩ resistive load, MODE=H: Auto-PFM/PWM)

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Figure 24. Start-up Waveform(VIN=2.4V, 3.3kΩ resistive load, MODE=H: Auto-PFM/PWM)

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Typical Performance Curves - continued

ch1:EN [2V/div]

ch1:EN [2V/div]

ch2:VOUT [2V/div]

ch2:VOUT [2V/div]

ch3:Icoil [500mA/div]

ch3:Icoil [500mA/div]

Figure 25. Shutdown Waveform(VIN=2.4V, Output current=0mA, MODE=L: Fixed PFM)

Figure 26. Shutdown Waveform(VIN=2.4V, Output current=0mA, MODE=H: Auto-PFM/PWM)

100

90

MODE=H:Auto-PFM/PWM
MODE=L:Fixed PFM

Load Resistance [Ω]

80
70
60
50
40
30
20
10
0
0.0

1.0
2.0
3.0
4.0
Power Supply Voltage:VIN [V]5.0

Figure 27. Load Resistance vs Power Supply Voltage(“Minimum Load Resistance”, Start-Up)

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Detailed Description
1.

Start-up (SOFT START)
After being enabled, BU33UV7NUX starts the Soft Start operation. Firstly, high side switch MOSFET is turned on andthe output voltage VOUT is lifted to the input voltage VIN level, applying restriction to current. (Current Restriction
Operation) For this operation, up to around 1mA resistive load is allowed. Then, the device starts switching operation
and VOUT is risen up to setting voltage adjusting the output slew rate by DAC for Soft Start. (Soft Start Operation) This
soft start operation is reset by EN, UVLO, TSD and SCP.
Attention is necessary to change input rush current and start-up time by the output capacitor.

EN

VIN
Soft Start Operation

VOUT“FB” Pin = VOUT
Discharge Tr. is active.

Current restriction control

Figure 28. Start-up (Soft Start) and Shutdown Operation

2.

Discharge for Output Pin
The FB pin is shorted to VOUT; the discharge Tr. in the device is active. The VOUT pin is always discharged when DC/DC
converter is in standby state.

3.

Under Voltage Lock Out (UVLO)
UVLO prevents malfunction of the internal circuit at the time of rising or dropping to a lower value of power supply
voltage. If the VIN voltage becomes lower than 0.26V (Typ), the DC/DC converter is turned off. In order to cancel
UVLO of VIN, it is necessary to set VIN more than 0.9V (Typ).

4.

Over voltage protection (OVP)
BU33UV7NUX turns off the switching operation when the VOUT voltage becomes over OVPD. At that time, the VOUT pin
is not discharge (in the case that the FB pin is shorted to VOUT). If the VOUT voltage becomes less than OVPD, movement
returns it.

5.

Over current protection (OCP)BU33UV7NUX has the function to limit the switching current.
OCP detector is active during low side MOSFET is in ON state.
When the heavy load is connected such that the peak of switching current Ipeak is above OCP threshold, OCP function
becomes active. ON-time of low side MOSFET is limited so that Ipeak does not exceed OCP threshold, and VOUT voltage
decreases.

6.

Short circuit protection (SCP)
BU33UV7NUX has Short Current Protect function.
SCP is detected when the VOUT voltage becomes lower than VIN - 0.750V (Typ). At that moment, the switching operation
is turned off and limited the current.
Then, the device starts the Soft Start operation for reboot without distinction of the value of the load resistance. If the
VOUT pin is shorted to GND or the heavy load exceeding the specification value, the device keeps Current restriction
state.

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Detailed Description - continued
The VOUT pin isshorted to ground.
SCP detect
BU33UV7NUX turns off
switching operation.

VOUT(3.3V)

VOUT (3.3V)
The VOUT pin isreleased to ground.
VIN

VIN - 0.750V

Soft Start Operation

VOUT decrease by OCP.
Current restriction control

It is turned switching off and limited thecurrent.

Figure 29. Output Voltage in SCP Operation

7.

Thermal Shutdown (TSD)
BU33UV7NUX turns off the switching operation when the device temperature exceeds the threshold value for the device
protection. After the device temperature falls below the threshold value, the device starts the Soft Start operation.

8.

Function Select by MODE pin
With the MODE pin, the BU33UV7NUX provides mode selection of PFM control or PFM/PWM automatic switching
control. When load current is large, the product switches automatically to the PWM mode so that high efficiency isachievable over a wide range of load conditions.
BU33UV7NUX operates under forced PWM mode to lower the output ripple when the Input-Output voltage difference issmall at VIN=3.2V to 3.4V.
The operation current increases when running at forced PWM mode.

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Selection of Components Externally Connected
VIN
INTLDO

VIN

AGND

PGND

FB

SW

EN

VOUT

C0:10µF

C2:1µF

RSTB

L0:4.7µH

VIN

VOUT

C1

MODE

Figure 30. Typical Application Circuit (PFM/PWM mode)
Table 1. Components for Application Characteristic Curves
Height
Rated
Value
Area
Parts Number(Max)
Voltage

Name

Type

BU33UV7NUX

Boost
Converter

3.3V

3mm×2mm

0.6mm

7V

BU33UV7NUX-E2

C0Capacitor

10μF

2mm×1.25mm

0.85mm16V

EMK212ABJ106KD-T

Capacitor
Capacitor
Capacitor
Inductor

22μF
22μF×21μF
4.7μH

2mm×1.25mm
2mm×1.25mm
1.6mm×0.8mm
5mm×4mm

1.25mm
1.25mm
0.8mm
1.5mm

25V
25V
16V
-

GRM21BR61E226ME44L
GRM21BR61E226ME44L
C1608X5R1C105K080AA
VLF504015MT-4R7M

C1(Note 1)
C2
L0

Manufacturer
ROHM
TAIYO
YUDEN
muRatamuRataTDK
TDK(Note 1) The effective load capacitance value considering accuracy, temperature characteristic and DC bias characteristic of output capacitors should not be lessthan 22μF. The amount of output capacitance will have a significant effect on the output ripple voltage.

Layout Example
TOP View

Figure 31. Reference Board Layout (TOP Layer)

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Application Information
1.

Inductor Selection
Inductor value of 4.7μH shows good performance over the whole input and output voltage range.
The maximum value of inductor current (Ipeak) can be estimated by using the following Equations.
 Vout   IL 
  
Ipeak Iout  
 Vin     2 (1)

 Vin   Vout  Vin   1 
IL      L   Vout   f (2)

Where:
η is the efficiency.
ΔIL is the ripple Voltage.
f is switching frequency.

Ipeak

ISW

IIN

ΔIL

Figure 32. Switching Current
The inductor should be selected as satisfying above Ipeak value.

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I/O Equivalence Circuits
Pin
Name

Equivalence circuit

Pin
Name

Equivalence circuit

VIN

RDIS

EN
MODE

FB

AGND

AGND

AGND

VIN

AGND

SW

RSTB

VOUT

AGND

AGND

AGND

VOUT

SW

SW

PGND

PGND

VIN

AGND

PGND

VOUT

INTLDO

VIN
AGND

AGND

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Operational Notes
1.

Reverse Connection of Power Supply
Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity whenconnecting the power supply, such as mounting an external diode between the power supply and the IC’s power
supply pins.

2.

Power Supply Lines
Design the PCB layout pattern to provide low impedance supply lines. Furthermore, connect a capacitor to ground at
all power supply pins. Consider the effect of temperature and aging on the capacitance value when using electrolytic
capacitors.

3.

Ground Voltage
Ensure that no pins are at a voltage below that of the ground pin at any time, even during transient condition.

4.

Ground Wiring Pattern
When using both small-signal and large-current ground traces, the two ground traces should be routed separately but
connected to a single ground at the reference point of the application board to avoid fluctuations in the small-signal
ground caused by large currents. Also ensure that the ground traces of external components do not cause variations
on the ground voltage. The ground lines must be as short and thick as possible to reduce line impedance.

5.

Recommended Operating Conditions
The function and operation of the IC are guaranteed within the range specified by the recommended operating
conditions. The characteristic values are guaranteed only under the conditions of each item specified by the electricalcharacteristics.

6.

Inrush Current
When power is first supplied to the IC, it is possible that the internal logic may be unstable and inrush current may
flow instantaneously due to the internal powering sequence and delays, especially if the IC has more than one power
supply. Therefore, give special consideration to power coupling capacitance, power wiring, width of ground wiring,and routing of connections.

7.

Operation Under Strong Electromagnetic Field
Operating the IC in the presence of a strong electromagnetic field may cause the IC to malfunction.

8.

Testing on Application Boards
When testing the IC on an application board, connecting a capacitor directly to a low-impedance output pin may
subject the IC to stress. Always discharge capacitors completely after each process or step. The IC’s power supply
should always be turned off completely before connecting or removing it from the test setup during the inspection
process. To prevent damage from static discharge, ground the IC during assembly and use similar precautions duringtransport and storage.

9.

Inter-pin Short and Mounting Errors
Ensure that the direction and position are correct when mounting the IC on the PCB. Incorrect mounting may result indamaging the IC. Avoid nearby pins being shorted to each other especially to ground, power supply and output pin.
Inter-pin shorts could be due to many reasons such as metal particles, water droplets (in very humid environment)
and unintentional solder bridge deposited in between pins during assembly to name a few.

10. Unused Input Pins
Input pins of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance andextremely low capacitance. If left unconnected, the electric field from the outside can easily charge it. The small
charge acquired in this way is enough to produce a significant effect on the conduction through the transistor andcause unexpected operation of the IC. So unless otherwise specified, unused input pins should be connected to thepower supply or ground line.
11. Regarding the Input Pin of the IC
In the construction of this IC, P-N junctions are inevitably formed creating parasitic diodes or transistors. The
operation of these parasitic elements can result in mutual interference among circuits, operational faults, or physicaldamage. Therefore, conditions which cause these parasitic elements to operate, such as applying a voltage to an
input pin lower than the ground voltage should be avoided. Furthermore, do not apply a voltage to the input pins
when no power supply voltage is applied to the IC. Even if the power supply voltage is applied, make sure that the
input pins have voltages within the values specified in the electrical characteristics of this IC.

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BU33UV7NUX
Operational Notes – continued
12. Ceramic Capacitor
When using a ceramic capacitor, determine a capacitance value considering the change of capacitance withtemperature and the decrease in nominal capacitance due to DC bias and others.
13. Area of Safe Operation (ASO)
Operate the IC such that the output voltage, output current, and the maximum junction temperature rating are allwithin the Area of Safe Operation (ASO).
14. Thermal Shutdown Circuit(TSD)
This IC has a built-in thermal shutdown circuit that prevents heat damage to the IC. Normal operation should always
be within the IC’s maximum junction temperature rating. If however the rating is exceeded for a continued period, thejunction temperature (Tj) will rise which will activate the TSD circuit that will turn OFF power output pins. When the Tj
falls below the TSD threshold, the circuits are automatically restored to normal operation.
Note that the TSD circuit operates in a situation that exceeds the absolute maximum ratings and therefore, under nocircumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC fromheat damage.
15. Over Current Protection Circuit (OCP)
This IC incorporates an integrated overcurrent protection circuit that is activated when the load is shorted. This
protection circuit is effective in preventing damage due to sudden and unexpected incidents. However, the IC should
not be used in applications characterized by continuous operation or transitioning of the protection circuit.

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Ordering Information

B

U

3

3

U

V

7

Part Number

N

U

X

-

Package
NUX: VSON010X3020

E2
Packaging and forming specification
E2: Embossed tape and reel

Marking Diagram
VSON010X3020 (TOP VIEW)
Part Number Marking

BU33

LOT Number

UV7

Pin 1 Mark
MARK

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Physical Dimension and Packing Information

Package Namewww.rohm.com© 2016 ROHM Co., Ltd. All rights reserved.
TSZ22111 • 15 • 001

VSON010X3020

19/20

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21.Feb.2019 Rev.003

BU33UV7NUX
Revision History
Date

Revision

18.Nov.2016

001

21.Aug.2018

002

21.Feb.2019003

Changes
New Release
P.1 Corrected the description “buck-boost->boost”
P.1 Updated Figure 1
P.6 Updated Figure 12
P.7 Updated Figure 13
P.10 Updated Figure 27
P.13 Updated Figure 30
P.4 Added Parameter ”Output Voltage MODE=L”

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Notice
Precaution on using ROHM Products
1.

Our Products are designed and manufactured for application in ordinary electronic equipment (such as AV equipment,
OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you
intend to use our Products in devices requiring extremely high reliability (such as medical equipment (Note 1), transport
equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car
accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or
serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.
Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any
damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific
Applications.
(Note1) Medical Equipment Classification of the Specific Applications
JAPAN
USA
EU
CHINA
CLASSⅢ
CLASSⅡb
CLASSⅢ
CLASSⅢ
CLASSⅣ
CLASSⅢ

2.

ROHM designs and manufactures its Products subject to strict quality control system. However, semiconductor
products can fail or malfunction at a certain rate. Please be sure to implement, at your own responsibilities, adequate
safety measures including but not limited to fail-safe design against the physical injury, damage to any property, whicha failure or malfunction of our Products may cause. The following are examples of safety measures:[a] Installation of protection circuits or other protective devices to improve system safety[b] Installation of redundant circuits to reduce the impact of single or multiple circuit failure

3.

Our Products are designed and manufactured for use under standard conditions and not under any special or
extraordinary environments or conditions, as exemplified below. Accordingly, ROHM shall not be in any way
responsible or liable for any damages, expenses or losses arising from the use of any ROHM’s Products under any
special or extraordinary environments or conditions. If you intend to use our Products under any special or
extraordinary environments or conditions (as exemplified below), your independent verification and confirmation of
product performance, reliability, etc, prior to use, must be necessary:[a] Use of our Products in any types of liquid, including water, oils, chemicals, and organic solvents[b] Use of our Products outdoors or in places where the Products are exposed to direct sunlight or dust[c] Use of our Products in places where the Products are exposed to sea wind or corrosive gases, including Cl2,
H2S, NH3, SO2, and NO2[d] Use of our Products in places where the Products are exposed to static electricity or electromagnetic waves[e] Use of our Products in proximity to heat-producing components, plastic cords, or other flammable items[f] Sealing or coating our Products with resin or other coating materials[g] Use of our Products without cleaning residue of flux (Exclude cases where no-clean type fluxes is used.
However, recommend sufficiently about the residue.) ; or Washing our Products by using water or water-soluble
cleaning agents for cleaning residue after soldering[h] Use of the Products in places subject to dew condensation

4.

The Products are not subject to radiation-proof design.

5.

Please verify and confirm characteristics of the final or mounted products in using the Products.

6.

In particular, if a transient load (a large amount of load applied in a short period of time, such as pulse, is applied,confirmation of performance characteristics after on-board mounting is strongly recommended. Avoid applying power
exceeding normal rated power; exceeding the power rating under steady-state loading condition may negatively affectproduct performance and reliability.

7.

De-rate Power Dissipation depending on ambient temperature. When used in sealed area, confirm that it is the use in
the range that does not exceed the maximum junction temperature.

8.

Confirm that operation temperature is within the specified range described in the product specification.

9.

ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined inthis document.

Precaution for Mounting / Circuit board design
1.

When a highly active halogenous (chlorine, bromine, etc.) flux is used, the residue of flux may negatively affect productperformance and reliability.

2.

In principle, the reflow soldering method must be used on a surface-mount products, the flow soldering method must
be used on a through hole mount products. If the flow soldering method is preferred on a surface-mount products,
please consult with the ROHM representative in advance.

For details, please refer to ROHM Mounting specification

Notice-PGA-E© 2015 ROHM Co., Ltd. All rights reserved.

Rev.004

Precautions Regarding Application Examples and External Circuits
1.

If change is made to the constant of an external circuit, please allow a sufficient margin considering variations of thecharacteristics of the Products and external components, including transient characteristics, as well as static
characteristics.

2.

You agree that application notes, reference designs, and associated data and information contained in this document
are presented only as guidance for Products use. Therefore, in case you use such information, you are solely
responsible for it and you must exercise your own independent verification and judgment in the use of such information
contained in this document. ROHM shall not be in any way responsible or liable for any damages, expenses or losses
incurred by you or third parties arising from the use of such information.

Precaution for Electrostatic
This Product is electrostatic sensitive product, which may be damaged due to electrostatic discharge. Please take proper
caution in your manufacturing process and storage so that voltage exceeding the Products maximum rating will not beapplied to Products. Please take special care under dry condition (e.g. Grounding of human body / equipment / solder iron,
isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).

Precaution for Storage / Transportation
1.

Product performance and soldered connections may deteriorate if the Products are stored in the places where:[a] the Products are exposed to sea winds or corrosive gases, including Cl 2, H2S, NH3, SO2, and NO2[b] the temperature or humidity exceeds those recommended by ROHM
[c] the Products are exposed to direct sunshine or condensation[d] the Products are exposed to high Electrostatic

2.

Even under ROHM recommended storage condition, solderability of products out of recommended storage time period
may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time isexceeding the recommended storage time period.

3.

Store / transport cartons in the correct direction, which is indicated on a carton with a symbol. Otherwise bent leads
may occur due to excessive stress applied when dropping of a carton.

4.

Use Products within the specified time after opening a humidity barrier bag. Baking is required before using Products ofwhich storage time is exceeding the recommended storage time period.

Precaution for Product Label
A two-dimensional barcode printed on ROHM Products label is for ROHM’s internal use only.

Precaution for Disposition
When disposing Products please dispose them properly using an authorized industry waste company.

Precaution for Foreign Exchange and Foreign Trade act
Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign
trade act, please consult with ROHM in case of export.

Precaution Regarding Intellectual Property Rights
1.

All information and data including but not limited to application example contained in this document is for reference
only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any
other rights of any third party regarding such information or data.

2.

ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the
Products with other articles such as components, circuits, systems or external equipment (including software).

3.

No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any
third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM
will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to
manufacture or sell products containing the Products, subject to the terms and conditions herein.

Other Precaution
1.

This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.

2.

The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior writtenconsent of ROHM.

3.

In no event shall you use in any way whatsoever the Products and the related technical information contained in the
Products or this document for any military purposes, including but not limited to, the development of mass-destruction
weapons.

4.

The proper names of companies or products described in this document are trademarks or registered trademarks of
ROHM, its affiliated companies or third parties.

Notice-PGA-E© 2015 ROHM Co., Ltd. All rights reserved.

Rev.004

Datasheet
General Precaution

1. Before you use our Products, you are requested to carefully read this document and fully understand its contents.
ROHM shall not be in any way responsible or liable for failure, malfunction or accident arising from the use of any
ROHM’s Products against warning, caution or note contained in this document.
2. All information contained in this document is current as of the issuing date and subject to change without any priornotice. Before purchasing or using ROHM’s Products, please confirm the latest information with a ROHM sales
representative.

3.

The information contained in this document is provided on an “as is” basis and ROHM does not warrant that all
information contained in this document is accurate and/or error-free. ROHM shall not be in any way responsible or
liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccuracy or errors of orconcerning such information.

Notice – WE

© 2015 ROHM Co., Ltd. All rights reserved.

Rev.001