Bellnix BUD Series User manual

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
1
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
BUD series is a non-isolated DC/DC converter that features wide input / output,
buck-boost, ±output, small size (10×11×6mm). It is ideal for supplying power to analog
circuits from unstable bus voltages for batteries, unstable power supplies and so on.
■Features
･Wide input / output
･Buck-boost type
･± Output
･Ultra small size: SMD package
･High efficiency
･Max 1.8Woutput
(Input / output voltage derating required）
･Over-power protection
･UVLO function
･Remote ON/OFFcontrol
･Equipped with skip mode at light load
･Non-isolated type
･Operating temp. Ta = -40°C to +85°C
･RoHS compliance
･Output voltage setting is determined by the
single resistor
■Model & rating
Models
BUD Series
Input V
Vdc
Output V
Vdc
Output P
W
Line Reg.
% (max.)
Load Reg.
% (max.)
Ripple noise
mVpp (typ.)
Efficiency
% (typ.)
BUD12-12W042
12
(3 to 18)
±12
(±3 to 18)
1
(±0.5W each)
1.0
1.0
10
87.5
(Po=0.8W×2)
Note 1: In the measurement circuit in section 4-3.
Note 2: Unless otherwise specified the product is measured at input voltage 12V, output voltage ±12V, output power 0.5W×2, and
ambient temperature 25°C±5°C.
Note 3: Ripple noise is measured at BW=20MHz.
Note 4: The usable input / output voltage range is within the range shown in Fig. 1.
Note 5: The output voltage settings for positive and negative outputs are equal (Voutp = | Voutn |).
Note 6: Maximum output power of 1.8W (±0.9W each) can be output depending on input/ output conditions. For details, refer to section
4-4.
■Specificatiom
Input/ output voltage range
Refer to Figure 1.
Rated input voltage
12V
Rated output voltage
±12V
Rated output power
0.5W ×2
Output voltage accuracy
±5% max.
Line regulation
Refer to Table 1 (To the regulation of the input voltage range in Table 1)
Load regulation
Refer to Table 1 (To the regulation of Poutp,n = 0.05 to 0.5W)
Mutual regulation
100mV typ, 200mV max (10% ≤ Poutp,n ≤ 100%)
Ripple noise
Refer to Table 1 (Measurement frequency bandwidth 20MHz)
Efficiency
Refer to Table 1
Standby current
0.1uA typ., 1.1uA max. (Input voltage 4.2V)
Over-current protection
Operates at 105% or more of the rated output power, automatic restoration.
UVLO
Available
Remote On/ Off
Available
Operating temperature range
-40°C to +85°C
Storage temperature range
-40°C to +85°C
Operating humidity
20 to 95%R.H. (Max. wet bulb temperature 69℃with non-condensing)
Storage condition
Until being mounted, keep below 30°C/60% R.H.
Cooling condition
Natural air cooling
Mass
0.7g
Outer dimension
W=10 L=11 H=6 (mm) (For details refer to section 6-1)
＊The above specifications are provided with rated value, unless otherwise specified.
＊The contents provided in this data sheet may be changed at any time without prior notice.
Figure 1 Input/ output voltage range
Table 2
Table 1

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
2
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
1. Scope
These specifications shall apply to the non-isolated DC/DC converter BUD12-12W042 series.
2. Model/ Rating
Model name
Rated input voltage
Rated output
Shape
Remarks
BUD12-12W042
DC 12V
DC ±12V, 0.5W×2
SMD
3. Environmental conditions
3-1. Temperature range
In operation -40°C to +85°C (Refer to section 5 for details)
In storage -40°C to +85°C
3-2. Humidity range
In operation 20 to 95%RH (However, max. wet bulb temperature 69°C, no condensation)
In storage Same as above
Note) Refer to section 10-2 for details of storage before mounting.
4. Specifications & standards
This product is RoHS compliance.
4-1. Recommended operating conditions
Item
Mark
min.
max.
Unit
Conditions
Input (VIN pin) voltage
Vin
3
18
V
Output (+VOUT, -VOUT pin)
voltage*1
Voutp,n
3
18 or
30 - Vin
V
The smaller one as
the max value.
Output power*2,*3
Poutp,n
0
0.5
W
*1 The absolute values of the output voltage settings for positive and negative outputs are equal
(Voutp = | Voutn |).
*2 The power described is for one side. Depending on the input /output voltage, it can output ±0.9W each,
up to 1.8W in total. For details refer to section 4-4.
*3 Poutp= Voutp × Ioutp, Poutn= Voutn × Ioutn

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
3
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
4-2．Electrical characteristics Electrical characteristics*1, *2
Item
Mark
min.
typ.
max.
Unit
Conditions
Input characteristics
UVLO operation voltage
Vuv
2.2
2.5
V
When Vin drops
Standby current*4,*6
Ioff
0.1
1.1
uA
Vin = 4.2V, Von/off = 0V
13.5
uA
Vin = 18V, Von/off = 0V
Output characteristics
Output voltage accuracy
*7
-5
+5
%Vout
3V ≤ |Voutp,n| ≤ 18V
Poutp= Poutn= 0.5W
Static line regulation
0.5
1.0
%Vout
Vin = 3V to 18V
3V ≤ |Voutp,n| ≤ 18V(fixed
value)
Poutp,n =100% (fixed value)
Static load regulation*3 *8
0.5
1.0
%Vout
3V ≤ Vin ≤ 18V(fixed value)
3V ≤ |Voutp,n| ≤ 18V(fixed
value)
Poutp,n = 0.05W to 100%
Static mutual load
regulation*3
100
200
mV
3V ≤ Vin ≤ 18V(fixed value)
3V ≤ |Voutp,n| ≤ 18V(fixed
value)
10% ≤ Poutp,n ≤ 100%
300
500
mV
3V ≤ Vin ≤ 18V(fixed value)
3V ≤ |Voutp,n| ≤ 18V(fixed
value)
0% ≤ Poutp,n ≤ 100%
Output ripple noise
ΔVpp
10
20
mVpp
Vin = 12V
Vout = ±12V
Poutp= Poutn= 0.5W
Over-power protection*3
Pop
105
%
ON/OFF control
ON/OFF pin ON voltage
VH
1.2
V
ON/OFF pin OFF voltage
VL
0.4
V
Shutdown time
Toff
2.5
ms
Von/off = Low(OFF) to
High(ON) interval must be
Toff or more.
ON/OFF pin
input impedance
Rin
400
800
1600
kΩ

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
4
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
Item
Mark
min.
typ.
max.
Unit
Conditions
Other functions, characteristics
Efficiency*3
η
87.5
%
Poutp,n = 100%
Switching frequency
fsw
1.0
1.2
1.5
MHz
Fixed switching frequency
3V ≤ Vin ≤ 18V
3V ≤ |Voutp,n| ≤ 18V
Turn-on delay*6 *9
td
7
ms
3V ≤ Vin ≤ 18V
3V ≤ |Voutp,n| ≤ 18V
Temperature drift
0.008
%Vout
/°C
Output load capacity
Coutp,
Coutn
3000
uF
Skip mode operating
range *5, *6
Pskipp,
Pskipn
75
mW
Vin = 18V
Voutp,n = ±12V
4.6×Vin - 8
mW
3V ≤ Vin ≤ 18V
3V ≤ |Voutp,n| ≤ 18V
Mass
m
0.7
g
*1 With measurement circuit of 4-3.
*2 Unless otherwise specified, the following measurement conditions will apply. Rated input, rated output,
balance load (Ioutp= |Ioutn|), Vin + |Voutp,n| ≤ 30V, ambient temperature 25°C±5°C.
*3 Maximum output power Poutp,n(max) shown in section 4-4 is 100%.
*4 Only the sink current of the VIN pin is measured.
*5 Fixed switching frequency for Poutp ≥ Pskippand Poutn ≥ Pskipn.
*6 This is a design value and not all inspected.
*7 When the output voltage setting resistance accuracy is ±1% with respect to the Radj calculated value
(Section 7-2-Formula (1)).
*8 If the load is less than 0.05W each, the regulation rate may increase depending on the conditions.
*9 Turn-on time varies depending on load characteristics and additional capacity.
4-3. Measurement circuit
Measurement circuit

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
5
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
4-4. Maximum output power
The input and output voltage conditions allow the maximum output power Poutp(max) and Poutn(max) to be
output up to 0.9W each, for a total of 1.8W.
The maximum output power Poutp,n(max) due to the input and output voltage is specified by the figure
below, and the main maximum output power and current values are shown in the table below.
Maximum output power, output current
Vin
[V]
Voutp,n
[V]
Poutp,n(max)
[W]
Pout(total)
[W]
Ioutp,n(max)
[A]
Vin
[V]
Voutp,n
[V]
Poutp,n(max)
[W]
Pout(total)
[W]
Ioutp,n(max)
[A]
3
±3
0.50
1.00
±0.167
3
±12
0.60
1.20
±0.050
5
±3
0.53
1.07
±0.178
5
±12
0.68
1.37
±0.057
12
±3
0.65
1.30
±0.217
12
±12
0.80
1.60
±0.067
15
±3
0.70
1.40
±0.233
15
±12
0.85
1.70
±0.071
18
±3
0.75
1.50
±0.250
18
±12
0.90
1.80
±0.075
3
±5
0.53
1.07
±0.107
3
±15
0.60
1.20
±0.040
5
±5
0.57
1.13
±0.113
5
±15
0.73
1.47
±0.049
12
±5
0.68
1.37
±0.137
12
±15
0.85
1.70
±0.057
15
±5
0.73
1.47
±0.147
15
±15
0.90
1.80
±0.060
18
±5
0.78
1.56
±0.156
3
±18
0.60
1.20
±0.033
-
-
-
-
-
5
±18
0.78
1.56
±0.043
-
-
-
-
-
12
±18
0.90
1.80
±0.050
(b) Poutp,n(max) - Vin
(c) Poutp,n(max) - Vout
(a) Poutp,n(max) - Vout, Vin
Maximum output power

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
6
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
5. Temperature derating
Install this product in a good place for convection. Also, be sure to mount it on the board before use.
This product is designed to radiate heat using the mounted board. Make the line connecting to the
converter wide. Especially, the heat radiation from the GND terminal is large, so make the GND line
wide.
The derating curve below is the data when mounted on a double-sided board with a copper foil
thickness of 35μm, a copper foil area of 60 x 60 mm (both sides), and a board thickness of 1.6 mm.
Please use it for reference as the heat radiation characteristics will change depending on the wiring.
The temperature characteristics of this converter are greatly affected by the mounted board and
ambient conditions. Therefore, eventually be sure to mount the converter in the device that will be
actually installed in and when operating at the maximum ambient temperature of the equipment to be
used, make sure that the surface temperature of the temperature measurement parts shown below
does not exceed 112.5°C.
Temperature derating curve
Note 1: 3V ≤ Vin ≤ 18V,3V ≤ |Voutp,n|≤ 18V
Note 2: 60mm×60mm, copper foil thickness of 35μm, two-layer (double-sided) board
Note 3: Maximum output power Poutp,n(max) shown in section 4-4 is 100%.
Temperature measuring parts
Temperature
measuring
parts

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
7
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
Note 1: When mounting with an
automatic machine, please pick
up at point A.
Unit: mm
Dimensional tolerance: ±0.2mm
Pin flatness: 0.127mm
6. Dimensions and pin description
6-1. Shape and dimensions (SMD type)
Model name
1 pin
11.0±0.3
Company name
10.0±0.5
Lot.No.
Top View
Side View
6.00 max.
Bottom View
1
34
7
7-Φ1.0±0.1
5.08
7.45
1.05
8.9
2-3.45
6.9
3-2.3
1.55
A
(1.3)
Shape, dimensions (SMD type)
6-2. Recommended footprint
Top View
3
1
7
4
1.6
1.6
1.05
8.9
1.55
2-3.45
8.45
6.15
3-2.3
Recommended footprint
A
Note 1: Dimensions are recommended
values. Please consider the
design criterion of the customer
when designing.
Unit: mm

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
8
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
6-3. Pin description
Pin
Name
Function
1
VIN
Power input pin. Connect to a power supply voltage of +3 to 18V.
2, 6
GND
Ground pin
3
ON/OFF
Remote ON/OFF signal input pin. High voltage input turns the output
on, and low voltage input turns the output off. Please refer to section
7-3 for the control method.
4
ADJ
Output voltage setting pin. Connect an output voltage setting resistor
between the ADJ pin and -VOUT pin. Refer to section 7-2 for the
selection method of the output voltage setting resistor.
5
-VOUT
(-) Output pin
7
+VOUT
(+) Output pin
6-4. Lot. No.
9 1 (Manufactured in January, 2019)
9D2 (Manufactured in December, 2019)
Production code for manufacture control (may not be indicated)
Manufacturing month (Jan to Sep=1 to 9, Oct=O, Nov=N, Dec=D)
Manufacturing year (the last digit ofA.D.)

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
9
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
7. How to use
7-1. Standard connection diagram and recommended layout
Standard connection diagram
Recommended layout
Note 1: Radj is the output voltage setting resistor. Be sure to connect a resistor with a value according to
the output voltage setting (Section 7-2), and do not leave it OPEN.
Note 2: Connect the input and output capacitors Cin, Coutp, Coutnas close as possible to the converter pin.
Note 3: The recommended layout diagram shows only the mounting surface. Design the pattern in
consideration of the input and output conditions and the ambient temperature to be used.
Note 4: If the output load is less than 0.05W on one side, the regulation rate may increase depending on the
conditions.

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
10
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
(1)
7-2. Output voltage adjustment method
The output voltage can be adjusted by connecting a resistor between the ADJ pin and the -VOUT pin.
Connect a resistor Radj of the value according to the following equation.
Radj = 1.039 - 1.217 × |Voutp,n|
2.589 × |Voutp,n| - 60.17 × 106 - 33000 [Ω]
However, 3V ≤ |Voutp,n| ≤ 18V and Vin + |Voutp,n| ≤ 30V.Refer to the table below for main setting
examples.
Note 1: Be sure not to leave Radj OPEN. Overvoltage (±23.3V typ. at OPEN) may be output, which
may lead to damage the converter.
Typical example
|Voutp,n| Settings
[V]
Radj
[kΩ]
3.3
24.7(≈22 + 2.7)
5
73.8(≈27 + 47)
12
433(≈330 + 47 + 56)
15
774(≈680 + 47 + 47)
7-3. ON/ OFF control
By setting the voltage between the ON/OFF pins Von/off to High or Low, the output settings can be
controlled without switching the input on or off physically. For ON/OFF pin threshold voltage VH, VL and
input resistor, refer to section 4-2.
ON/OFF control can be performed with the circuit shown below.
Note 1 Be careful not to cause chattering between the ON/OFF and GND pins, and make sure that there
is an interval of Toff (section 4-2) or more from OFF to ON.
ON/OFF control
ON/OFF pin voltage
Von/off [V]
Output
setting
High (Von/off > VH)
ON
Low (Von/off < VL)
OFF
ON/OFF control circuit example
(pull-down configuration)
ON/OFF control circuit example
(push-pull configuration)

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
11
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
7-4. Skip mode
In the range where the output current is small, the mode is skip mode (intermittent switching
operation, shown below), and the loss at light load is suppressed.
Output ripple increases in the skip mode.
7-5. Thermal shutdown
When the detected temperature of this product is 160°C typ. or more, the thermal shutdown operates and
the switching operation stops.
7-6. Over-power protection
It limits the output power when the converter is overpowered (Section 4-2 –Pop) and automatically
recovers when the overpowered state is removed. Avoid maintaining overpowered conditions for extended
periods of time.
(b) Vin = 12V, Voutp,n = ±12V, Poutp,n = 0.5W
At fixed switching frequency
(a) Vin = 18V, Voutp,n = ±12V, Poutp,n = 0W
At skip mode
X:500μs/div
X:1μs/div
CH1: Voutp (5mV/div), CH2: Voutn (5mV/div)
Output ripple noise waveform

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
12
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
8. Reverse polarity protection at the input (Example)
Inadvertently, reversing the polarity of the input connected to the product can lead to product damage.
If there is a possibility that the polarity reversal may occur, add a protection circuit to the product. The
figure below is an example of a protection circuit using a fuse and diode
Reverse polarity protection circuit
9. Over-voltage protection (Example)
This product does not have a built-in over-voltage protection function. If the output voltage setting
resistor Radj becomes OPEN, please add the input blocking circuit as shown in the figure below in
case the internal element of the product is damaged in short mode.
Over-voltage protection circuit (Example)
Note1: If the converter is damaged in over-voltage mode, ON/OFF control will not operate.
Note2: If the power source of the converter has an ON/OFF function, over-current protection
function, etc., t this can be used.
Note3: Allow enough capacity in the DC power supply for the fuse to blow.

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
13
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
10. Mounting requirements
The following conditions will apply to soldering temperature, time and storage before mounting.
This converter cannot be implemented in a flow.
10-1. Reflow method
Pre-heat temperature: 150 to 180°C, 120sec max. (See the figure below)
Peak temperature: 250°C max.
220°C or more 60sec max.
The number or times of reflow: Once
Note1: Refrain from giving vibrations during reflow, for it may cause converter components to move.
Note2: After mounting the converter onto the board, reflow cannot be made again by turning over
the mounted boards.
10-2. Storage before mounting
Humidity control level for this product is MSL2. For storage before mounting, please keep it at
30°C/60% R.H. or less.
After mounting, it depends on the storage conditions.
180°C
150°C
60 to 120s 60s max.
220°C
Peak 250°C max.
Time
Temperature
Mounting conditions
11. Vibration and shock testing
Vibration:
5 to 10Hz, total amplitude 10mm, 10 to 55Hz acceleration 2G (1 hour each in 3
directions)
Shock:
Acceleration
20G (3 times each in three directions)
Shock time
11±5ms

Wide input / output, Buck-boost, ±Output DC/DC Converter
1 Watt BUD Series
14
Bellnix DC-DC Converter BDD20200930_Z02(BDD20190924_Z02)
12. Cleaning
This product is not for immersible cleaning. No-clean flux is recommended for this product.
13. Precautions for use
To ensure user’s safety, check specifications before using the product and always observe the following
precautions for use.
- The product is intended for use in general electronics equipment (office equipment, communication
equipment, measurement equipment). Do not use the product for medical equipment, nuclear
equipment, trains, etc., whereby human life or property may be directly affected by a damaged
product. Consult with us for any use other than for such general electronics equipment.
- The product is not suitable for series operation.
- Do not use connectors and sockets for mounting the product. Contact resistance may have an adverse
effect on the performance. Use soldering method for mounting on a printed circuit board.
- The product has a built-in overcurrent protection circuit but avoid a prolonged short circuit state
which may lead to failure.
- The product may be damaged if used under nonstandard electrical conditions or nonstandard
environmental conditions including temperature. Ensure use within the standards.
- Avoid storing or using the product in a place that generates corrosive gas or dust.
- The product may be damaged by static electricity. Make sure that the workplace is guarded against
static buildup and static electricity on operators by use of proper grounding.
- A fuse mechanism is not built in the product. Connect a fuse to the + input line to guard against
excessive input current under abnormal circumstances. Allow enough capacity in the power supply
for a fuse to blow.
- This product does not have built-in overvoltage protection. If the converter is damaged for any
reason, there is a mode in which the input voltage appears directly at the output, causing smoke and
ignition. In order to prevent these, add an overvoltage protection circuit.
- The product does not come with a test report.
- Specifications may be changed without prior notice for product improvement.
14. Warranty
The warranty term of the product is one year after shipment. Should the product become defective
within the warranty period due to our design or workmanship, the product will be repaired free of charge
or replaced.
However, this warranty does not cover products which have been subjected to unauthorized inner
modifications, etc.
The scope of our warranty is limited to that of the product concerned.
15. Other matters
If any doubt arises regarding this specification, it will be decided after consultation between the two
parties.