BD8152FVM
Single-chip Type with Built-in FET Switching Regulators
High-efficiency
Step-up Switching Regulators
with Built-in Power MOSFET
BD8152FVM,BD8158FVM
No.11027ECT20
٨Description
BD8152FVM,BD8158FVM are the 1-channel step-up switching regulator which builds in the low voltage FET. Input voltage is
2.5 V to 5.5 V (BD8152FVM), 2.1V to 5.5V(BD8158FVM) realizing the low consumption power. High accuracy feedback
voltage r1% is established and the brightness dispersion of TFT-LCD panel is suppressed.
٨Features
1) Current mode PWM system
2) Input voltage is 2.5 V to 5.5 V (BD8152FVM), 2.1 V to 5.5 V (BD8158FVM, providing the low power input)
3) Switching frequency is variable as 600 kHz/1,200 kHz.
4) Built-in 0.25 ǡ power switch
5) Feedback voltage 1.245 r 1%
6) Built-in under-voltage lockout protection circuit
7) Built-in overcurrent protection circuit
8) Built-in thermal shutdown circuit
٨Applications
7 to 17 inches panels for the satellite navigation system, laptop PC
TFT-LCD panels
٨Absolute maximum ratings (Ta = 25͠)
Parameter
Symbol
Limit
Unit
Vcc
7
V
588*
mW
Power supply voltage
Power dissipation
Operating
temperature range
Pd
BD8152FVM
í40 to +85
Topr
BD8158FVM
͠
í40 to +125
Storage temperature range
Tstg
í55 to +150
͠
Switch pin current
Isw
1.5**
A
Switch pin voltage
Maximum junction temperature
Vsw
15
V
Tjmax
150
͠
* Reduced by 4.7 mW/͠ over 25͠, when mounted on a glass epoxy board (70 mm u 70 mm u 1.6 mm).
** Must not exceed Pd.
٨Recommended Operating Ranges (Ta = 25͠)
Parameter
Symbol
Limit
Unit
Min.
Typ.
Max.
Vcc
2.5
3.3
5.5
V
Power supply voltage (BD8158FVM)
Vcc
2.1
2.5
4.0(5.5)*
V
Switch current
ISW
-
-
1.4
A
Switch pin voltage
VSW
-
-
14
V
Power supply voltage (BD8152FVM)
*Specified at 600kHz switching operating.
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1/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
٨Electrical Characteristics BD8152FVM (Unless otherwise specified, Ta = 25͠; Vcc = 3.3 V; ENB = 3.3 V)
Limit
Parameter
Symbol
Unit
Conditions
Min.
Typ.
Max.
[triangular waveform oscillator]
Oscillating frequency 1
FOSC1
540
600
660
kHz
FCLK = 0 V
Oscillating frequency 2
FOSC2
1.08
1.20
1.32
MHz FCLK = Vcc
[Overcurrent protection circuit]
Overcurrent limit
ISW
2
A
[Soft start circuit]
SS source current
ISO
6
10
14
µA
Vss = 0.5 V
[Under-voltage lockout protection circuit]
Off threshold voltage
VUTOFF
2.1
2.2
2.3
V
On threshold voltage
VUTON
2.0
2.1
2.2
V
[Error amp]
Input bias current
IB
0.1
0.5
µA
Feedback voltage
VFB
1.232
1.245
1.258
V
Buffer
[Output]
ON resistance
RON
250
380
mȍ
*Isw = 1 A
Max. duty ratio
DMAX
72
80
88
%
RL = 100 ǡ
[ENB]
ENB on voltage
VON
Vccu0.7
Vcc
V
ENB off voltage
VOFF
0
Vccu0.3
V
[Overall]
Standby current
ISTB
0
10
µA
VENB = 0 V
Average consumption current
ICC
1.2
2.4
mA
no switching
{
*
This product is not designed for protection against radio active rays.
Design guarantee (No total shipment inspection is made.)
٨Electrical Characteristics BD8158FVM (Unless otherwise specified, Ta = 25͠; Vcc = 2.5 V; ENB = 2.5 V)
Limit
Parameter
Symbol
Unit
Conditions
Min.
Typ.
Max.
[triangular waveform oscillator]
Oscillating frequency 1
FOSC1
480
600
720
kHz
FCLK = 0 V
Oscillating frequency 2
FOSC2
0.96
1.20
1.44
MHz FCLK = Vcc
[Overcurrent protection circuit]
Overcurrent limit
ISW
2
A
[Soft start circuit]
SS source current
ISO
6
10
14
µA
Vss = 0.5 V
[Under-voltage lockout protection circuit]
Off threshold voltage
VUTOFF
1.7
1.8
1.9
V
On threshold voltage
VUTON
1.6
1.7
1.8
V
[Error amp]
Input bias current
IB
0.1
0.5
µA
Feedback voltage
VFB
1.232
1.245
1.258
V
Buffer
[Output]
ON resistance
RON
250
mȍ
*Isw = 1 A
Max. duty ratio
DMAX
85
%
RL = 100 ǡ
[ENB]
ENB on voltage
VON
Vccu0.7
Vcc
V
ENB off voltage
VOFF
0
Vccu0.3
V
[Overall]
Standby current
ISTB
0
10
µA
VENB = 0 V
Average consumption current
ICC
1.2
2.4
mA
no switching
{
*
This product is not designed for protection against radio active rays.
Design guarantee (No total shipment inspection is made.)
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2/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
2.000
1.75
1.500
1.50
1.25
-40°C
1.00
25°C
0.75
0.50
125°C
1.260
1.000
125°C
0.500
0.000
-0.500
25°C
-2.000
0.00
0
1
2
3
1.255
1.250
1.245
1.240
1.235
1.230
0
4
1
SUPPLY VOLTAGE:Vcc [V]
2
3
4
-40
SUPPLY VOLTAGE:Vcc [V]
-8
-12
-16
0
0.5
1
1.5
VFCLK=VCC
1.4
1.2
1.0
0.8
0.2
0
2
4
-40
Fig. 5 Reference Voltage vs
Power Supply Voltage
-40°C
1.0
1.5
2.0
2.5
3.0
FCLK VOLTAGE:VFCLK[V]
Fig. 7 FCLK Pin Current
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35
60
85
110
Fig. 6 Switching Frequency
Temperature
100
15
50
125°C
10
ICOMP[uA]
ENB CURRENT:IENB[uA]
25°C
10
㪭㪚㪦㪤㪧㪲㪭㪴
20
0.5
-15
SUPPLY VOLTAGE:VCC[V]
10
0
0.0
VFCLK=GND
500
0.4
Fig. 4 SS Source Current
5
1000
0.6
0
125°C
110
1500
SS VOLTAGE:VSS[V]
15
85
1.6
2
20
60
2000
0.0
-20
35
BD8158FVM
1.8
ICOMP[uA]
REFERENCE VOLTAGE:VREF[V
-4
10
Fig. 3 Reference Voltage vs
Temperature
2.0
0
-15
AMBIENT TEMPERATURE:Ta [㷄]
Fig. 2 Standby Current
Fig. 1 Total Supply Current
SS CURRENT:ISS[uA]
-40°C
-1.000
-1.500
0.25
FCLK CURRENT:IFCLK[uA]
REFERENCE VOLTAGE:VREF[V]
2.00
STANDBY CURRENT:Icc [uA]
SUPPLY CURRENT:Icc [mA]
٨Reference Data (Unless otherwise specified, Ta = 25͠)
25°C
5
0
-50
-40°C
0
0.0
-100
0.5
1.0
1.5
2.0
2.5
ENB VOLTAGE:VENB[V]
Fig. 8 ENB Pin Current
3/17
3.0
1.0
1.1
1.2
1.3
1.4
1.5
㪭㪚㪦㪤㪧㪲㪭㪴
Fig. 9 COMP Sinking vs Source
Current
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
٨Reference Data (Unless otherwise specified, Ta = 25͠)
100
90
90
90
85
EFFICIENCY [%]
EFFICIENCY [%]
Max Duty [%]
95
80
VCC = 2.5 V f = 1200 kHz
70
VCC = 2.5 V f = 600 kHz
80
70
60
60
BD8152FVM
BD8158FVM
80
-40
-15
10
35
60
85
50
0.05
110
0.2
0.25
50
0.05
0.3
0.15
0.25
0.35
0.45
OUTPUT CURRENT:Io[A]
Fig. 11 Vcc = 2.5V Power Efficiency
Fig. 10 Max. Duty Ratio Temperature
Fig. 12 Vcc = 5V Power Efficiency
0.8
MAXIMUM CURRENT:IOMAX[A]
100
90
80
70
60
BD8158FVM
50
2.0
2.5
3.0
3.5
BD8158FVM
0.4
Vo
F = 600 kHz
20 us
0.2
2.4
2.8
3.2
3.6
4.0
SUPPLY VOLTAGE:Vcc[V]
SUPPLY VOLTAGE:Vcc[V]
Fig. 13 Power Efficiency vs
Power Supply Voltage
Fig. 14 Max. Load Current vs
Power Supply Voltage
9
100 mV
F = 1200 kHz
0
2.0
4.0
Io = 100 mA
Io = 0 mA
0.6
Fig. 15 Load Response
Waveform
9
9
OUTPUT VOLTAGE:Vo[V]
Vcc = 2.5 V
8.8
8.6
8.4
8.2
OUTPUT VOLTAGE:Vo[V]
EFFICIENCY [%]
0.15
OUTPUT CURRENT:Io[A]
AMBIENT TEMPERATURE:Ta [㷄]
OUTPUT VOLTAGE:Vo[V]
0.1
8.8
8.6
8.4
8.2
8.8
Vcc=5V
8.6
8.4
8.2
BD8152FVM
BD8158FVM
8
2.0
2.5
3.0
3.5
4.0
SUPPLY VOLTAGE:Vcc[V]
Fig. 16 Output Voltage
Line Regulation
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8
0.0
0.1
LOAD CURRENT:Io[A]
Fig. 17 Output Voltage
Load Regulation 1
4/17
1.0
8
0.0
0.1
1.0
LOAD CURRENT:Io[A]
Fig. 18 Output Voltage
Load Regulation 2
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
٨Block Diagram
SS
FCLK
VCC
SW
8
7
6
5
CURRENT
SENSE
OSC
+
Set
SW
FCLK
SOFT
START
LOGIC
Reset
DRV
SDWN
PWM
+ -
Vcc
SS
SLOPE
OCP
UVLO/TSD
ERR
- +
GND
ENB
FB
COMP
VREF
1.245V
TOP VIEW
1
2
COMP
FB
3
4
ENB
GND
Fig. 19 Pin Arrangement Diagram and Block Diagram
٨Pin Assignment Diagram and Function
Pin No.
Pin name
2
FB
3
ENB
Control input pin
4
GND
Ground pin
Function
Error amp inversion input pin
5
SW
N-channel power FET drain output
6
Vcc
Power supply input pin
7
FCLK
8
SS
Frequency switching pin
Soft start current output pin
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5/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
٨Description of Operation of Each Block
D1
RB161M-20
10uH
L1
VOUT
9V
VCC
C1
10uF
C0
10uF
8
6
7
SS
5
VCC
FCLK
SW
CURRENT
SENSE
C2
0.01uF
SLOPE
OSC
+
Set
SOFT
START
Reset
LOGIC DRV
SDWN
PWM
+ OCP
UVLO/TSD
ERR
- +
VREF
1.245V
COMP
FB
ENB
2
1
3
GND
4
C4 㧖
100pF
R3
5.1kǡ
C3
3300pF
R1
110kǡ
R2
18kǡ
Fig. 20 Application Circuit Diagram Example
x Error amp (ERR)
This is the circuit to compare the reference voltage 1.245 V (Typ.) and the feedback voltage of output voltage. Switching
duty is decided by the COMP pin voltage which is the comparison result. At the time of start, since the soft start is operated
by the SS pin voltage, the COMP pin voltage is limited to the SS pin voltage.
x Oscillator (OSC)
This block generates the oscillating frequency. It is possible to select 600 kHz/1.2 MHz (Typ.) by the FCLK pin.
x SLOPE
This block generates the triangular waveform from the clock generated by OSC. Generated triangular waveform is sent to
the PWM comparator.
x PWM
Output COMP voltage of the error amp and the triangular waveform of the SLOPE block are compared to decide the
switching duty. Since the switching duty is limited by the maximum duty ratio which is decided internally, it does not
become 100%.
x Reference voltage (VREF)
This block generates the internal reference voltage of 1.245 V (Typ.).
x Protection circuit (UVLO/TSD)
UVLO (under-voltage lockout protection circuit) shuts down the circuits when the voltage is 2.2 V (TYP.BD8152FVM),1.8 V
(TYP.BD8158FVM) or lower. Thermal shutdown circuit shuts down IC at 175͠ (Typ.) and recovers at 160͠ (Typ.).
x Overcurrent protection circuit (OCP)
Current flowing to the power FET is detected by voltage at the CURRENT SENSE and the overcurrent protection operates
at 3 A (Typ.). When the overcurrent protection operates, switching is turned off and the SS pin capacity is discharged.
x Soft start circuit
Since the output voltage rises gradually while restricting the current at the time of startup, it is possible to prevent the
output voltage overshoot or the inrush current.
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2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
٨Timing Chart
Startup sequence
VCC
ENB
SS
SW
VO
Fig. 21 Startup Sequence Waveform
Overcurrent protection operating
2.5V
VCC,ENB
SS
SW
VO
IO
Fig. 22 Overcurrent Protection Operating Waveform
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7/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
٨Selecting Application Components
(1) Setting the output L constant
The coil L to use for output is decided by the rating current ILR and input current maximum value IINMAX of the coil.
IINMAX + 'IL should not
IL
VCC
reach the rating value level
L
IL
ILR
Vo
IINMAX average
current
Co
t
Fig. 24 Output Application Circuit Diagram
Fig. 23 Coil current waveform
Adjust so that IINMAX + ¨IL does not reach the rating current value ILR. At this time, ¨IL can be obtained by the following
equation.
1
Vo - Vcc
1
[A]
Where, f is the switching frequency.
Vcc u
u
¨IL=
L
Vo
f
Set with sufficient margin because the coil L value may have the dispersion of approx. r30%. If the coil current exceeds
the rating current ILR of the coil, it may damage the IC internal element.
BD8152FVM,BD8158FVM use the current mode DC/DC converter control and has the optimized design at the coil value.
The following coil values are recommended from the aspects of power efficiency, response and safety. When the coil out
of this range is selected, the stable continual operation is not guaranteed such as the switching waveform becomes
irregular. Please pay attention to it.
Switching frequency: L = 10 uH to 22 uH at 600 kHz
Switching frequency: L = 4.7 uH to 15 uH at 1,200 kHz
(2) Setting the output capacitor
For the capacitor C to use for the output, select the capacitor which has the larger value in the ripple voltage VPP
allowance value and the drop voltage allowance value at the time of sudden load change. Output ripple voltage is decided
by the following equation.
¨VPP
=
ILMAX u RESR +
1
fCo
u
Vcc
Vo
u
(ILMAX -
¨IL
2
)
[V]
Where, f is the switching frequency.
Perform setting so that the voltage is within the allowable ripple voltage range.
For the drop voltage during sudden load change; VDR, please perform the rough calculation by the following equation.
VDR =
¨I
Co
u 10u sec
[V]
However, 10 Ps is the rough calculation value of the DC/DC response speed. Please set the capacitance considering the
sufficient margin so that these two values are within the standard value range.
(3) Selecting the input capacitor
Since the peak current flows between the input and output at the DC/DC converter, a capacitor is required to install at the
input side. For this reason, the low ESR capacitor is recommended as an input capacitor which has the value more than
10ȝF and less than 100 mǡ. If a capacitor out of this range is selected, the excessive ripple voltage is superposed on the
input voltage, accordingly it may cause the malfunction of IC.
However these conditions may vary according to the load current, input voltage, output voltage, inductance and switching
frequency. Be sure to perform the margin check using the actual product.
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8/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
(4) Selecting the output rectification diode
Schottky barrier diode is recommended as the rectification diode to use at the DC/DC converter output stage. Select the
diode paying attention to the max. inductor current and max. output voltage.
<
Rating current of diode
Max. Inductor current
IINMAX + ¨IL
<
Rating voltage of diode
Max. output voltage VOMAX
Since each parameter has 30% to 40% of dispersion, be sure to design providing sufficient margins.
(5) Design of the feedback resistor constant
Refer to the following equation to set the feedback resistor. As the setting range, 10 kǡ to 330 kǡ is recommended. If
the resistor is set to 10 kǡ or lower, it causes the reduction of power efficiency. If it is set to 330 kǡ or larger, the offset
voltage becomes larger by the input bias current 0.4 µA (Typ.) in the internal error amp.
Step-up
Vo =
R8 + R9
u 1.245
[V]
Reference voltage 1.245 V
Vo
R8
R9
㧗
ERR
2
㧙㩷
FB
R9
Fig. 25 Feedback Resistor Setting
As the capacitance, 0.001 µF to 0.1 µF is recommended. If the capacitance is
set to 0.001 µF or lower, the overshooting may occur on the output voltage. If
the capacitance is set to 0.1 µF or larger, the excessive back current flow may
occur in the internal parasitic elements when the power is turned off and it
may damage IC. When the capacitor to 0.1 µF or larger is used, be sure to
insert a diode to VCC in series, or a bypass diode between the SS pin and
VCC.
10
DELAY TIME[ms]
(6) Setting the soft start time
Soft start is required to prevent the coil current at the time of startup from
increasing and the overshoot of the output voltage at the starting time. Fig.26
shows the relation between the capacitance and soft start time. Please refer
to it to set the capacitance.
1
0.1
0.01
0.001
0.01
0.1
SS CAPACITANCE[uF]
Bypass diode
Fig. 26 SS Pin Capacitance vs
Delay Time
Back current prevention diode
VCC
Output pin
Fig. 27 Bypass Diode Example
When there is the startup relation (sequences) with other power supplies, be sure to use the high accuracy product (such as X5R).
Soft start time may vary according to the input voltage, output voltage, loads, coils and output capacity. Be sure to verify
the operation using the actual product.
(7) Setting the ENB pin
When the ENB pin is set to Hi, the internal circuit becomes active and the DC/DC converter starts operating. When it is set
to Low, the shut down is activated and all circuits will be turned off.
(8) Setting the frequency by FCLK
It is possible to change the switching frequency by setting the FCLK pin to Hi or Low. When it is set to Low, the product
operates at 600 kHz (Typ.). When it is set to Hi, the product operates at 1,200 kHz (Typ.).
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9/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
(9)Setting RC, CC of the phase compensation circuit
In the current mode control, since the coil current is controlled, a pole (phase lag) made by the CR filter composed of the
output capacitor and load resistor will be created in the low frequency range, and a zero (phase lead) by the output
capacitor and ESR of capacitor will be created in the high frequency range. In this case, to cancel the pole of the power
amplifier, it is easy to compensate by adding the zero point with CC and RC to the output from the error amp as shown in
the illustration.
Open loop gain
fp =
fp(Min)
A
fp(Max)
[Hz]
1
0
Gain
1
2S u R O u CO
fz (ESR) =
ޣdBޤ
[Hz]
2S u E SR u CO
lOUT Min
fz(ESR)
lOUT Max
Pole at the power amplification stage
When the output current reduces, the load resistance
Ro increases and the pole frequency lowers.
0
Phase
ޣdegޤ
-90
fp (Min) =
fz (Max) =
A
ޣdBޤ
0
0
ޣdegޤ-90
fp (Amp.) =
Fig. 28 Gain vs Phase
[Hz] m At heavy-load
Vcc,PVcc
Cin
[Hz]
Ro
ESR
SW
COMP
1
2S u R c u Cc
Vo
L
Rc
2S u ROMin u CO
[Hz] m At light-load
Zero at the power amplification stage
When the output capacitor is set larger, the pole
frequency lowers but the zero frequency will not
change. (This is because the capacitor ESR
becomes 1/2 when the capacitor becomes 2 times.)
Gain
VCC
2S u ROMax u C O
1
Error amp phase compensation
Phase
1
Co
GND,PGND
Cc
Fig. 29 Application Circuit Diagram
It is possible to realize the stable feedback loop by canceling the pole fp (Min.), which is created by the output capacitor
and load resistor, with CR zero compensation of the error amp as shown below.
fz (Amp.) = fp (Min.)
1
2S u Rc u Cc
1
=
[Hz]
2S u Romax u Co
As the setting range for the resistor, 1 kǡ to 10 kǡ is recommended. When the resistor is set to 1 kǡ or lower, the effect
by phase compensation becomes low and it may cause the oscillation of output voltage. When it is set to 10 kǡ or larger,
the COMP pin becomes Hi-Z and the switching noise becomes easy to superpose. Therefore the stable switching pulse
cannot be generated and the irregular ripple voltage may be generated on the output voltage.
As the setting range for the capacitance, 3,300 pF to 10,000 pF is recommended. When the capacitance is set to 3,300 pF
or lower, the irregular ripple voltage may be generated on the output voltage due to the effect of switching noise. When it is
set to 10,000 pF or larger, the response becomes worse and the output voltage fluctuation becomes large. Accordingly it
may require the output capacitor which is larger than the necessary value.
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10/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
٨Application Examples
Although ROHM is sure that the application examples are recommendable ones, further check the characteristics of
components that require high precision before using them.
When a circuit is used modifying the externally connected circuit constant, be sure to decide allowing sufficient margins
considering the dispersion of values by external parts as well as our IC including not only the static but also the transient
characteristic.For the patent, we have not acquired the sufficient confirmation. Please acknowledge the status.
(1) When the charge pump is removed from the DC/DC converter to make it 3-channel output mode:
It is possible to create the charge pump by using the switching operation of DC/DC converter. When the application
shown in the following diagram is used, 1-channel DC/DC converter output, 1-channel positive side charge pump and
1-channel negative side charge pump can be output as a total of 3-channels.
0.1µF
0.1µF
D1
RB161M-20
L1 10µH
V CC
Vo
9V
DAN217U
C0
10µF
1µF
C1
10µF
8
6
7
SS
FCLK
SLOPE
1kȍ
2SD2657k
0.1µF
SW
VGH
UDZ
Series
CU R REN T
SENSE
C2
0.01µF
1µF
5
VCC
DAN217U
OSC
1µF
100kȍ
+
Set
SOFT
START
Reset
LOGIC DRV
SDWN
1µF 1kȍ
2SB1695k
VGL
PWM
+ -
UDZ
Series
OCP
FB
ENB
2
1
R3
5.1kȍ
C3
3300pF
1µF
VREF
1.245V
COMP
100kȍ
UVLO/TSD
ERR
- +
3
GND
4
R1
110kȍ
R2
18kȍ
Fig. 30 3ch Application Circuit Diagram Example
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11/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
(2) When the output voltage is set to 0 V:
Since the switch does not exist between the input and output in the application using the step-up type DC/DC converter,
the output voltage is generated even if the IC is turned off. When it is intended to keep the output voltage 0 V until IC
operates, insert the switch as shown in the following circuit diagram.
D1
RB161M-20
1kǡ
10uH
L1
Vo
VCC
C1
10uF
10uF
8
6
7
SS
5
VCC
FCLK
Switches of PNP or
PFET
SW
CURRENT
SENSE
C2
0.01uF
SLOPE
OSC
+
Set
SOFT
START
LOGIC DRV
SDWN
Reset
PWM
+ -
OCP
UVLO/TSD
ERR
- +
VREF
1.245V
COMP
FB
GND
ENB
2
1
3
4
R1
R3
5.1kǡ
C3
3300pF
110kǡ
R2
18kǡ
Fig. 31 Switch Application Circuit Diagram Example
٨Application Examples
(3) When the circuit is intended to operate at the lower voltage than the IC operating range:
Although the recommended operating range of IC starts from 2.5 V / 2.1 V (BD8152FVM,BD8158FVM), it is possible to
continue operating by composing the self-energizing type step-up DC/DC converter application even if the input voltage
lowered than 2.1 V. This example is recommended for the application with battery input.
D1
RB161M-20
10uH
L1
VCC
2.0V
C1
10uF
Vo
3.3V
10uF
8
6
7
SS
5
VCC
FCLK
SW
CURRENT
SENSE
C2
0.01uF
SLOPE
OSC
+
Set
SOFT
START
Reset
LOGIC DRV
SDWN
PWM
+ OCP
UVLO/TSD
ERR
- +
VREF
1.245V
COMP
FB
R3
5.1kǡ
C3
3300pF
GND
ENB
2
1
3
4
R1
110kǡ
R2
18kǡ
Fig. 32 Self-Energizing Application Circuit Diagram Example
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12/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
(4) SEPIC type application
When it is intended to compose the step-up type DC/DC converter, the SEPIC type application is recommended. Since the
switching voltage is generated by the value of input voltage + output voltage, pay utmost attention to the withstand voltage
of SW pin.
D1
4.7uF
10uH
L1
RB161M-20
Vo
VCC
10uF
10uH
C1
10uF
8
6
7
SS
5
VCC
FCLK
SW
CURRENT
SENSE
C2
0.01uF
SLOPE
OSC
+
Set
SOFT
START
LOGIC DRV
SDWN
Reset
PWM
+ -
OCP
UVLO/TSD
ERR
- +
VREF
1.245V
COMP
FB
ENB
2
1
GND
3
4
R1
R3
5.1kǡ
C3
3300pF
110kǡ
R2
18kǡ
Fig. 33 SEPIC Application Circuit Diagram Example
(5) When the Supply Voltage is over 4.0 V (BD8158FVM only)
The Capacitor C4 is inserted to COMP pin, and it operates when the Supply Voltage is over 4.0 V.
In this case, Switching Frequency is limited to 600kHz.
D1
RB161M-20
10uH
L1
Vo
10uF
C1
10uF
8
6
7
SS
5
VCC
FCLK
SW
CURRENT
SENSE
C2
0.01uF
SLOPE
OSC
+
Set
SOFT
START
Reset
LOGIC DRV
SDWN
PWM
+ OCP
UVLO/TSD
ERR
- +
VREF
1.245V
COMP
FB
C4
100pF
R3
5.1kǡ
C3
3300pF
GND
ENB
2
1
3
4
R1
110kǡ
R2
18kǡ
Fig.34 Circuit Diagram Example(Supply Voltage over 4.0 V )
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© 2011 ROHM Co., Ltd. All rights reserved.
13/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
٨I/O Equivalent Circuit Diagrams
1.COMP
5.SW
Vcc
2.FB
8.SS
Vcc
Vcc
Vcc
3.ENB 7.FCLK
Vcc
130kǡ
Fig. 34 I/O Equivalent Circuit Diagram
٨Notes of Use
1) Absolute maximum ratings
Use of the IC in excess of absolute maximum ratings such as the applied voltage or operating temperature range may
result in IC damage. Assumptions should not be made regarding the state of the IC (short mode or open mode) when such
damage is suffered. A physical safety measure such as a fuse should be implemented when use of the IC in a special
mode where the absolute maximum ratings may be exceeded is anticipated.
2) GND potential
Ensure a minimum GND pin potential in all operating conditions.
3) Setting of heat
Use a thermal design that allows for a sufficient margin in light of the power dissipation (Pd) in actual operating conditions.
4) Pin short and mistake fitting
Use caution when orienting and positioning the IC for mounting on an application board. Improper mounting may result in
damage to the IC. Shorts between output pins or between output pins and the power supply and GND pins caused by the
presence of a foreign object may result in damage to the IC.
5) Action in strong magnetic field
Use caution when using the IC in the presence of a strong magnetic field as doing so may cause the IC to malfunction.
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14/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
6) Testing on application boards
When testing the IC on an application board, connecting a capacitor to a pin with low impedance subjects the IC to stress.
Always discharge capacitors after each process or step. Ground the IC during assembly steps as an antistatic measure,
and use similar caution when transporting or storing the IC. Always turn the IC's power supply off before connecting it to or
removing it from a jig or fixture during the inspection process.
7) Ground wiring patterns
When using both small signal and large current GND patterns, it is recommended to isolate the two ground patterns,
placing a single ground point at the application's reference point so that the pattern wiring resistance and voltage
variations caused by large currents do not cause variations in the small signal ground voltage. Be careful not to change the
GND wiring patterns of any external components.
8) This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated.
P/N junctions are formed at the intersection of these P layers with the N layers of other elements to create a variety of
parasitic elements.
For example, when the resistors and transistors are connected to the pins as shown in Fig. 35, a parasitic diode or a
transistor operates by inversing the pin voltage and GND voltage.
The formation of parasitic elements as a result of the relationships of the potentials of different pins is an inevitable result
of the IC's architecture. The operation of parasitic elements can cause interference with circuit operation as well as IC
malfunction and damage. For these reasons, it is necessary to use caution so that the IC is not used in a way that will
trigger the operation of parasitic elements, such as the application of voltages lower than the GND (P substrate) voltage to
input and output pins.
Resistor
Transistor (NPN)
(Pin B)
C
B
E
C
㨪
㨪
㨪
㨪
(Pin B)
㨪
㨪
B
(Pin A)
E
GND
P㧗
N
N
N
Parasitic elements
P㧗
N
N
(Pin A)
P substrate
Parasitic element
GND
P
㨪
㨪
P㧗
N
P
GND
N
P
P㧗
Parasitic elements
Parasitic
element
GND
GND
Fig.35 Example of a Simple Monolithic IC
9) Overcurrent protection circuits
An overcurrent protection circuit designed according to the output current is incorporated for the prevention of IC
destruction that may result in the event of load shortning. This protection circuit is effective in preventing damage due to
sudden and unexpected accidents. However, the IC should not be used in applications characterized by the continuous
operation or transitioning of the protection circuits. At the time of thermal designing, keep in mind that the current capability
has negative characteristics to temperatures.
10) Thermal shutdown circuit (TSD)
This IC incorporates a built-in TSD circuit for the protection from thermal destruction. The IC should be used within the
specified power dissipation range. However, in the event that the IC continues to be operated in excess of its power
dissipation limits, the attendant rise in the chip's temperature Tj will trigger the temperature protection circuit to turn off all
output power elements. The circuit automatically resets once the chip's temperature Tj drops. Operation of the TSD circuit
presumes that the IC's absolute maximum ratings have been exceeded. Application designs should never make use of the
TSD circuit.
11) Testing on application boards
At the time of inspection of the installation boards, when the capacitor is connected to the pin with low impedance, be sure
to discharge electricity per process because it may load stresses to the IC. Always turn the IC's power supply off before
connecting it to or removing it from a jig or fixture during the inspection process. Ground the IC during assembly steps as
an antistatic measure, and use similar caution when transporting or storing the IC.
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15/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
POWER DISSIPATION:Pd[mW]
٨Power Dissipation Reduction
800
On 70701.6mm Board
588
600
400
200
BD8152FVM
0
25
50
75
85
BD8158FVM
100
125
150
AMBIENT TEMPERATURE[͠]
Fig. 36 Power Dissipation Reduction
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16/17
2011.08 - Rev.C
Technical Note
BD8152FVM, BD8158FVM
٨Ordering part number
B
D
8
1
5
2
Part No.
8152
8158
Part No.
F
V
M
-
Package
FVM:MSOP8
E
2
Packaging and forming specification
TR: Embossed tape and reel
(MSOP8)
MSOP8
<Tape and Reel information>
2.8±0.1
4.0±0.2
8 7 6 5
0.6±0.2
+6°
4° −4°
0.29±0.15
2.9±0.1
(MAX 3.25 include BURR)
Tape
Embossed carrier tape
Quantity
3000pcs
Direction
of feed
TR
The direction is the 1pin of product is at the upper right when you hold
( reel on the left hand and you pull out the tape on the right hand
)
1 2 3 4
1PIN MARK
1pin
+0.05
0.145 –0.03
0.475
0.08±0.05
0.75±0.05
0.9MAX
S
+0.05
0.22 –0.04
0.08 S
Direction of feed
0.65
Reel
(Unit : mm)
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17/17
∗ Order quantity needs to be multiple of the minimum quantity.
2011.08 - Rev.C
Notice
Notes
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consent of ROHM Co.,Ltd.
The content specified herein is subject to change for improvement without notice.
The content specified herein is for the purpose of introducing ROHM's products (hereinafter
"Products"). If you wish to use any such Product, please be sure to refer to the specifications,
which can be obtained from ROHM upon request.
Examples of application circuits, circuit constants and any other information contained herein
illustrate the standard usage and operations of the Products. The peripheral conditions must
be taken into account when designing circuits for mass production.
Great care was taken in ensuring the accuracy of the information specified in this document.
However, should you incur any damage arising from any inaccuracy or misprint of such
information, ROHM shall bear no responsibility for such damage.
The technical information specified herein is intended only to show the typical functions of and
examples of application circuits for the Products. ROHM does not grant you, explicitly or
implicitly, any license to use or exercise intellectual property or other rights held by ROHM and
other parties. ROHM shall bear no responsibility whatsoever for any dispute arising from the
use of such technical information.
The Products specified in this document are intended to be used with general-use electronic
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While ROHM always makes efforts to enhance the quality and reliability of its Products, a
Product may fail or malfunction for a variety of reasons.
Please be sure to implement in your equipment using the Products safety measures to guard
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