Datasheet
2.5V to 4.5V, 0.6A 1ch
Synchronous Buck Converter with
Integrated FET
BD9161FVM
General Description
Key Specifications
The BD9161FVM is ROHM’s high efficiency step-down
switching regulator designed to produce a voltage as
low as 1.2V from a supply voltage of 3.3V. It offers high
efficiency by using pulse skip control technology and
synchronous switches and provides fast transient
response to sudden load changes by implementing
current mode control.
Features
Input Voltage Range:
Output Voltage Range:
Output Current:
Switching Frequency:
Pch FET ON-Resistance:
Nch FET ON-Resistance:
Standby Current:
Operating Temperature Range:
Package
Fast Transient Response because of Current Mode
Control System.
High Efficiency for All Load Ranges because of
Synchronous Switches (Nch/Pch FET)
100% Duty Function.
Soft-Start Function.
Thermal Shutdown and ULVO Functions.
Short-Circuit Protection with Time Delay Function.
Shutdown Function.
2.5V to 4.5V
1.0V to 3.3V
0.6A(Max)
1MHz(Typ)
0.35Ω(Typ)
0.37Ω(Typ)
0μA (Typ)
-25°C to +85°C
W(Typ) x D(Typ) x H(Max)
Applications
Power Supply for LSI including HDD, DVD, CPU and
ASIC
MSOP8
2.90 mm x 4.00 mm x 0.90 mm
Typical Application Circuit
VCC
CIN
L
EN
VCC,PVCC
SW
VOUT
ADJ
ITH
R2
CO
GND,PGND
RITH
R1
CITH
Figure 1. Typical Application Circuit
○Product structure：Silicon monolithic integrated circuit
www.rohm.com
© 2012 ROHM Co., Ltd. All rights reserved.
TSZ22111･14･001
○This product has no designed protection against radioactive rays.
1/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Pin Configuration
(TOP VIEW)
VCC
PVCC
Figure 2. Pin Configuration
Pin Description
Pin No.
1
Pin Name
ADJ
2
ITH
GmAmp output pin/connected to phase compensation capacitor
3
EN
Enable pin (active high)
4
GND
5
PGND
6
SW
7
PVCC
8
VCC
Pin Function
Output voltage detection pin
Ground pin
Power switch ground pin
Power switch node
Power switch supply pin
Power supply input pin
Block Diagram
VCC
EN
3
VCC
8
VREF
3.3V
Input
7
PVCC
Current
Comp.
R
Gm Amp
Q
Current
Sense/
Protect
S
SLOPE
VCC
Output
CLK
+
OSC
SW
Driver
Logic
UVLO
Soft
Start
PGND
5
TSD
4
SCP
1
6
GND
2
ADJ
ITH
Figure 3. Block Diagram
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
2/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Absolute Maximum Ratings (Ta=25°C)
Parameter
VCC Voltage
PVCC Voltage
EN Voltage
Symbol
Rating
Unit
(Note 1)
V
PVCC
-0.3 to +7 (Note 1)
V
VCC
-0.3 to +7
VEN
-0.3 to +7
V
VSW,VITH
-0.3 to +7
V
Pd1
0.38(Note 2)
W
Power Dissipation 2
Pd2
0.58(Note 3)
W
Operating Temperature Range
Topr
-25 to +85
°C
Tstg
-55 to +150
°C
Tjmax
+150
°C
SW, ITH Voltage
Power Dissipation 1
Storage Temperature Range
Maximum Junction Temperature
(Note 1) Pd should not be exceeded.
(Note 2) Reduced by 7.2mW/°C for Ta over 25°C
(Note 3) Reduced by 31.2mW/°C for Ta over 25°C. Mounted on 70mm x 70mm x 1.6mm Glass Epoxy PCB.
Caution: 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. 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.
Recommended Operating Conditions (Ta=25°C)
Parameter
Symbol
Min
Limit
Typ
Max
4.5
V
Unit
VCC Voltage
VCC(Note 4)
2.5
3.3
PVCC Voltage
PVCC(Note 4)
2.5
3.3
4.5
V
VEN
0
-
VCC
V
VSW,VITH
1.0
-
3.3
V
-
-
0.6
A
EN Voltage
Output Voltage Setting Range
SW, ITH Average Output Current
ISW
(Note 4)
(Note 4 ) Pd should not be exceeded.
Electrical Characteristics (Ta=25°C,VCC =PVCC =3.3V, VEN=VCC, unless otherwise specified.)
Parameter
Standby Current
Min
Limit
Typ
Max
ISTB
-
0
10
μA
Symbol
Unit
Conditions
EN=GND
ICC
-
200
400
μA
EN Low Voltage
VENL
-
GND
0.8
V
Standby mode
EN High Voltage
VENH
2.0
VCC
-
V
Active mode
EN Input Current
IEN
-
1
10
μA
VEN=3.3V
Oscillation Frequency
fOSC
0.8
1
1.2
MHz
Pch FET ON Resistance
RONP
-
0.35
0.6
Ω
PVCC=3.3V
Nch FET ON Resistance
RONN
-
0.37
0.68
Ω
PVCC=3.3V
Output Voltage
VOUT
0.784
0.8
0.816
V
ITH SInk Current
ITHSI
10
20
-
μA
VOUT =H
ITH Source Current
ITHSO
10
20
-
μA
VOUT =L
UVLO Threshold Voltage
VUVLO1
2.2
2.3
2.4
V
VCC=H to L
UVLO Hysteresis Voltage
VUVLO2
2.22
2.35
2.5
V
VCC=L to H
tSS
0.5
1
2
ms
tLATCH
1
2
3
ms
VSCP
-
0.4
0.56
V
Bias Current
Soft Start Time
Timer Latch Time
Output Short Circuit
Threshold Voltage
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
3/21
SCP/TSD operated
VOUT = H to L
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
[VOUT=2.5V]
Ta=25°C
IO=0A
[VOUT=2.5V]
Output Voltage: VOUT [V]
Output Voltage: VOUT [V]
Typical Performance Curves
VCC=3.3V
Ta=25°C
IO=0A
Input Voltage: VCC [V]
EN Voltage: VEN [V]
Figure 4. Output Voltage vs Input Voltage
Figure 5. Output Voltage vs EN Voltage
[VOUT=2.5V]
Output Voltage: VOUT [V]
Output Voltage : VOUT [V]
[VOUT=2.5V]
VCC=3.3V
IO=0A
VCC=3.3V
Ta=25°C
Output Current: IOUT [A]
Temperature: Ta [°C]
Figure 7. Output Voltage vs Temperature
Figure 6. Output Voltage vs Output Current
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
4/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Typical Performance Curves - continued
[VOUT=2.5V]
Frequency :fOSC[MHz]
Efficiency: η [%]
VCC=3.3V
VCC=3.3V
Ta=25°C
Output Current :IOUT [mA]
Temperature :Ta[°C]
Figure 9. Frequency vs Temperature
Figure 8. Efficiency vs Output Current
EN Voltage :VEN[V]
ON-Resistance :RON[Ω]
VCC=3.3V
VCC=3.3V
Temperature :Ta[°C]
Temperature :Ta[°C]
Figure 11. EN Voltage vs Temperature
Figure 10. ON-Resistance vs Temperature
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
5/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Frequency: fOSC[MHz]
Typical Performance Curves - continued
Input Voltage :VCC [V]
Figure 12. Frequency vs Input Voltage
Typical Waveforms
[SLLMTM control
[VOUT=2.5V]
VCC= PVCC
=EN
VOUT=2.5V]
SW
VOUT
VOUT
VCC=3.3V
Ta=25°C
IO=0A
VCC=3.3V
Ta=25°C
Figure 14. SW Waveform
(IO=10mA)
Figure 13. Soft Start Waveform
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
6/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Typical Waveforms – continued
[PWM control
[100% Duty
VOUT=2.5V]
SW
VOUT=2.5V]
SW
VOUT
VOUT
VCC=2.7V
Ta= 25°C
VCC=3.3V
Ta=25°C
Figure 15. SW Waveform
(IO=500mA)
Figure 16. SW Waveform
(IO =600mA)
[VOUT=2.5V]
VOUT
[VOUT=2.5V]
VOUT
IOUT
IOUT
VCC=3.3V
Ta=25°C
VCC=3.3V
Ta=25°C
Figure 17. Transient Response
(IO=250mA to 500mA, 10μs)
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
Figure 18. Transient Response
(IO=500mA to 250mA, 10μs)
7/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Application Information
1.
Operation
BD9161FVM is a synchronous step-down switching regulator that achieves fast transient response by employing
current mode PWM control system. It utilizes switching operation through PWM (Pulse Width Modulation) mode for
heavier load, and operates on SLLMTM (Simple Light Load Mode) operation for lighter load to improve efficiency.
(1)
Current mode PWM Control
The PWM control signal of this IC depends on two feedback loops, the voltage feedback and the inductor current
feedback.
(a) PWM (Pulse Width Modulation) Control
The clock signal coming from OSC has a frequency of 1Mhz. When OSC sets the RS latch, the P-channel
MOSFET is turned ON and the N-Channel MOSFET is turned OFF. The opposite happens when the current
comparator (Current Comp) resets the RS latch. That is, i.e. the P-Channel MOSFET is turned off and the
N-Channel MOSFET is turned ON. Current Comp’s output is a comparison of two signals, the current
feedback control signal “SENSE”, which is a voltage proportional to the current sense IL, and the voltage
feedback control signal, FB.
(b) SLLMTM (Simple Light Load Mode) Control
When control mode is shifted due to load change, the switching pulse is designed to turn OFF with the device
held in normal PWM control loop. This allows linear operation without voltage drop or deterioration in transient
response during sudden load changes.
Although the PWM control loop continues to operate with a SET signal from OSC and a RESET signal from
Current Comp, it is designed such that the RESET signal is kept constant when shifted to light load mode
where the switching is turned OFF and the switching pulses disappear. Activating the switching occasionally
reduces the switching dissipation and improves efficiency.
(c) 100% Duty Control
During PWM control, when output voltage becomes unstable, oscillation frequency decreases up to a point
where duty cycle is 100%.
SENSE
Current
Comp
VOUT
RESET
Level
Shift
FB
R Q
SET
Gm Amp
RITH
S
IL
Driver
Logic
VOUT
SW
Load
OSC
Figure 19. Diagram of Current Mode PWM Control
PVCC
Current
Comp
SENSE
PVCC
SENSE
Current
Comp
FB
SET
FB
GND
SET
GND
RESET
GND
RESET
GND
SW
GND
SW
IL
GND
IL(AVE)
IL
0A
VOUT
VOUT
VOUT(AVE)
VOUT(AVE)
Not switching
Figure 21. SLLMTM Switching Timing Chart
Figure 20. PWM Switching Timing Chart
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
8/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
2.
Datasheet
Description of Functions
(1)
Soft-Start Function
During start-up, the soft-start circuit gradually establishes the output voltage to limit the input current. This prevents
the overshoot in the output voltage and inrush current.
(2)
Shutdown Function
When the EN terminal is “Low”, the device operates in Standby Mode and all function blocks including reference
voltage circuit, internal oscillator and drivers are turned to OFF. Circuit current during standby is 0μA (Typ).
(3)
UVLO Function
The UVLO circuit detects whether the supplied input voltage is sufficient to obtain the output voltage of this IC.
The UVLO threshold, which has a hysteresis of 50 mV (Typ), prevents output bouncing.
Hysteresis 50mV
VCC
EN
VOUT
tSS
tSS
tSS
Soft start
Standby mode
Operating mode
Standby
mode
Standby
mode
Operating mode
UVLO
UVLO
Operating mode
EN
Standby mode
UVLO
Figure 22. Soft Start, Shutdown, UVLO Timing Chart
(4)
Short-Circuit Protection Circuit with Time Delay Function
To protect the IC from breakdown, the short-circuit protection circuit turns the output OFF when the internal current
limiter is activated continuously for a fixed time (tLATCH) or more. The output that is kept off may be turned ON again
by restarting EN or by re-setting UVLO.
EN
Output OFF
latch
VOUT
Limit
IL
1msec
Standby
mode
Standby
mode
Operating mode
Timer latch
EN
Operating mode
EN
Figure 23. Short-Current Protection Circuit with Time Delay Timing Chart
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
9/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
3.
Datasheet
Information on Advantages
Advantage 1：Offers fast transient response by using current mode control system.
Conventional product (VOUT of which is 2.5V)
BD9161FVM (Load response IO=250mA to 500mA)
VOUT
VOUT
40mV
98mV
IOUT
IOUT
Voltage drop due to sudden change in load was reduced by about 50%.
Figure 24. Comparison of Transient Response
Advantage 2： Offers high efficiency for all load range.
(a) For lighter load:
This IC utilizes the current controlled system called SLLMTM, which reduces various dissipation such as
switching dissipation (PSW), gate charge/discharge dissipation, ESR dissipation of output capacitor (PESR) and
ON-Resistance dissipation (PRON) that may otherwise cause reduction in efficiency.
Achieves efficiency improvement for lighter load.
100
For heavier load:
This IC utilizes the synchronous rectifying mode and uses low
ON-Resistance MOS-FET power transistor.
ON-Resistance of P-Channel MOS FET: 0.35 Ω (Typ)
ON-Resistance of N-Channel MOS FET: 0.37 Ω (Typ)
SLLMTM
Efficiency η [%]
(b)
②
50
①
PWM
①improvement by SLLMTM system
②improvement by synchronous rectifier
0
0.001
0.01
0.1
Output current IOUT[A]
1
Figure 25. Efficiency
Achieves efficiency improvement for heavier load.
Offers high efficiency for all load ranges with the improvements mentioned above.
Advantage 3: ・Supplied in smaller package due to small-sized power MOS-FETs.
・Allows reduction in size of application products
・Output capacitor Co required for current mode control: 10 μF ceramic capacitor
・Inductance L required for the operating frequency of 1 MHz: 4.7 μH inductor
Reduces mounting area required.
VCC
15mm
CIN
CIN
DC/DC
Convertor
Controller
RITH
RITH
L
VOUT
L
10mm
CITH
CO
CO
CITH
Figure 26. Example Application
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
10/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
4.
Datasheet
Switching Regulator Efficiency
Efficiency ŋ may be expressed by the equation shown below:
VOUT IOUT
P
POUT
100 OUT 100
100
VIN I IN
PIN
POUT Pd
[ %]
Efficiency may be improved by reducing the switching regulator power dissipation factors Pdα as follows:
Dissipation factors:
(1) ON-Resistance Dissipation of Inductor and FET：Pd(I2R)
Pd( I 2 R) I OUT 2 ( RCOIL RON )
where:
RCOIL is the DC resistance of inductor.
RON is the ON-Resistance of FET.
IOUT is the Output current.
(2)
Gate Charge/Discharge Dissipation：Pd(Gate)
Pd (Gate) C gs f V
2
where:
Cgs is the Gate capacitance of FET.
f is the Switching frequency.
V is the Gate driving voltage of FET.
(3)
Switching Dissipation：Pd(SW)
Pd ( SW )
V IN 2 C RSS I OUT f
I DRIVE
where:
CRSS is the Reverse transfer capacitance of FET.
IDRIVE is the Peak current of gate.
(4)
ESR Dissipation of Capacitor：Pd(ESR)
Pd( ESR) I RMS 2 ESR
where:
IRMS is the Ripple current of capacitor.
ESR is the Equivalent series resistance.
(5)
Operating Current Dissipation of IC：Pd(IC)
Pd( IC) VIN I CC
where:
ICC is the Circuit current.
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
11/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
5.
Datasheet
Consideration on Permissible Dissipation and Heat Generation
Since this IC functions with high efficiency without significant heat generation in most applications, no special
consideration is needed on permissible dissipation or heat generation. In case of extreme conditions, however, including
lower input voltage, higher output voltage, heavier load, and/or higher temperature, the permissible dissipation and/or
heat generation must be carefully considered.
For dissipation, only conduction losses due to DC resistance of inductor and ON-Resistance of FET are considered.
This is because conduction losses are the most significant among other dissipations mentioned above, such as gate
charge/discharge dissipation and switching dissipation.
Power Dissipation: Pd [mW]]
1000
(1) Using an IC alone
θj-a=322.6°C/W
(2) mounted on glass epoxy PCB
θj-a=212.8°C/W
800
600
400
P I OUT 2 ( RON )
(1) 587.4m
W
RON D RONP (1 D) RONN
(2) 387.5m
where:
D is theON duty (=VOUT/VCC).
RONP is the ON-Resistance of P-Channel MOS FET.
RONN is the ON-Resistance of N-Channel MOS FET.
IOUT is the Output current.
W
200
0
0
25
50
75 85 100
125
150
Ambient Temperature: Ta [°C]
Figure 27. Thermal Derating Curve (MSOP8)
If VCC=3.3V, VOUT=2.5V RONP =0.35Ω, RONN =0.37Ω
IOUT=0.6A, for example,
D VOUT / VCC 2.5 / 3.3 0.758
RON 0.758 0.35 1 0.758 0.758
0.2653 0.08954
0.35484
P 0.6 2 0.35484
127.7 mV
Since RONP is greater than RONN in this IC, the dissipation increases as the ON duty becomes greater. Taking into
consideration the dissipation shown above, thermal design must be carried out with allowable sufficient margin.
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
12/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
6.
Datasheet
Selection of Components Externally Connected
(1)
Selection of Inductor (L)
The inductance significantly depends on output ripple current.
As shown in equation (1), the ripple current decreases as the
inductor and/or switching frequency increases.
IL
ΔIL
I L
VCC
VCC VOUT VOUT
L VCC f
[A] ・・・(1)
Appropriate ripple current at output should be +/-20% to +/-30%
of the maximum output current.
[A] ・・・(2)
I L 0.25 IOUTMax
IL
VOUT
L
CO
L
Figure 28. Output Ripple Current
VCC VOUT VOUT
[H]・・・(3)
I L VCC f
where:
ΔIL is the Output ripple current.
f is the Switching frequency.
Note: Current exceeding the current rating of the inductor results in magnetic saturation of the inductor, which
decreases efficiency. The inductor must be selected allowing sufficient margin with which the peak current may
not exceed its current rating.
If VCC=3.3V, VOUT=2.5V, f=1MHz, ΔIL=0.25x0.6A=0.15A
(3.3 2.5) 2.5
4.04
0.15 3.3 1M
L
Note: Select the inductor of low resistance component (such as DCR and ACR) to minimize dissipation in the
inductor for better efficiency.
(2)
Selection of Output Capacitor (CO)
VCC
Output capacitor should be selected with the consideration of the stability region
and the equivalent series resistance required to minimize ripple voltage.
Output ripple voltage is determined by the equation (4)：
VOUT I L ESR
VOUT
L
where:
ΔIL is the Output ripple current.
ESR is the Equivalent series resistance of output capacitor.
ESR
Co
Figure 29. Output Capacitor
(3)
[V ] ・・・(4)
Note: Rating of the capacitor should be determined allowing sufficient margin
against output voltage. A 10μF to 100μF ceramic capacitor is recommended. Less
ESR allows reduction in output ripple voltage.
Selection of Input Capacitor (CIN)
VCC
Input capacitor selected must be a low ESR capacitor with a capacitance
sufficient to cope with high ripple current to prevent high transient voltage. The
ripple current IRMS is given by the equation (5):
CIN
VOUT
L
Co
I RMS I OUT
VOUT VCC VOUT
A ・・・(5)
VCC
< Worst case > IRMSMax
IOUT
2
If VCC=3.3V, VOUT=2.5V, and IOUTMax=0.6A
When VCC is twice the VOUT, IRMS
Figure 30. Input Capacitor
I RMS 0.6
2.53.3 2.5
0.257
3.3
ARMS
A low ESR 10μF/10V ceramic capacitor is recommended to reduce ESR dissipation of input capacitor for better
efficiency.
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
13/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
(4)
Datasheet
Calculating RITH, CITH for Phase Compensator
As the Current Mode Control is designed to limit the inductor current, a pole (phase lag) appears in the low
frequency area due to a CR filter consisting of an output capacitor and a load resistance, while a zero (phase lead)
appears in the high frequency area due to the output capacitor and its ESR. So, the phases are easily
compensated by adding a zero to the power amplifier output with C and R as described below to cancel a pole
at the power amplifier.
fp
fp(Min)
A
Gain
[dB]
fp(Max)
fzESR
0
fz(ESR)
IOUTMin
Phase
[deg]
1
2 RO C O
IOUTMax
1
2 ESR CO
Pole at power amplifier
0
When the output current decreases, the load resistance
Ro increases and the pole frequency decreases.
-90
fpMin
Figure 31. Open loop gain characteristics
fpMax
A
1
[Hz] ←with lighter load
2 ROMax CO
1
[Hz] ←with heavier load
2 ROMin CO
fz(Amp)
Zero at power amplifier
Gain
[dB]
Increasing capacitance of the output capacitor lowers the
pole frequency while the zero frequency does not change.
(This is because when the capacitance is doubled, the
capacitor ESR reduces to half.)
0
0
Phase
[deg]
-90
f Z Amp
1
2 RITH CITH
Figure 32. Error amp phase compensation characteristics
VCC
CIN
EN
VCC, PVCC
L
SW
ADJ
ITH
VOUT
CO
R2
GND,PGND
RITH
R1
CITH
Figure 33. Typical Application
Stable feedback loop may be achieved by canceling the pole fp (Min) produced by the output capacitor and the
load resistance with CR zero correction by the error amplifier.
fz Amp fp( Min)
1
1
2 RITH CITH
2 ROMax CO
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
14/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
(5)
Datasheet
Setting the Output Voltage
The output voltage VOUT is determined by the equation (6):
VOUT ( R2 / R1 1) V ADJ ・・・(6)
L
6
Output
SW
Where:
VADJ is the Voltage at ADJ terminal (0.8V Typ)
Co
R2
1
ADJ
R1
The required output voltage may be determined by adjusting R1 and R2.
(Adjustable output voltage range：1.0V to 3.3V )
Figure 34. Determination of Output Voltage
Use 1 kΩ to 100 kΩ resistor for R1. If a resistor of the resistance higher than
100 kΩ is used, check the assembled set carefully for ripple voltage etc.
7.
BD9161FVM Cautions on PC Board Layout
VCC
PVCC
Figure 35. Board Layout
① For the sections drawn with heavy line, use thick conductor pattern as short as possible.
② Lay out the input ceramic capacitor CIN closer to the pins PVCC and PGND, and the output capacitor Co
closer to the pin PGND.
③ Lay out CITH and RITH between the pins ITH and GND as neat as possible with least necessary wiring.
8.
Recommended Component Lists On Above Applications
Symbol Part
Value
L
RIN
CIN
CO
Coil
Resistance
Ceramic Capacitor
Ceramic Capacitor
Ceramic Capacitor
CITH
RITH
Resistance
4.7μH
10Ω
10μF
10μF
VOUT=1.0V
VOUT=1.2V
VOUT=1.5V
VOUT=1.8V
VOUT=2.5V
VOUT=1.0V
VOUT=1.2V
VOUT=1.5V
VOUT=1.8V
VOUT=2.5V
820pF
560pF
470pF
470pF
330pF
6.8kΩ
8.2Ω
12kΩ
12kΩ
15kΩ
Manufacturer
TDK
Sumida
Rohm
Kyocera
Kyocera
Murata
Murata
Murata
Murata
Murata
Rohm
Rohm
Rohm
Rohm
Rohm
Series
VLF5014AT-4R7M1R1
CMD6D11B
MCR03 Series
CM316X5R106K10A
CM316X5R106K10A
GRM18 Series
GRM18 Series
GRM18 Series
GRM18 Series
GRM18 Series
MCR03 Series
MCR03 Series
MCR03 Series
MCR03 Series
MCR03 Series
Note: The parts list presented above is an example of recommended parts. Although the parts are standard, actual circuit characteristics should be checked
on your application carefully before use. Be sure to allow sufficient margins to accommodate variations between external devices and this IC when
employing the depicted circuit with other circuit constants modified. Both static and transient characteristics should be considered in establishing these
margins. When switching noise is substantial and may impact the system, a low pass filter should be inserted between the VCC and PVCC pins, and a
schottky barrier diode established between the SW and PGND pins
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
15/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
I/O Equivalent Circuit
PVCC
・SW pin
・EN pin
PVCC
PVCC
10kΩ
EN
SW
・ITH pin
・ADJ pin
VCC
10kΩ
ADJ
ITH
Figure 36. I/O Equivalent Circuit
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
16/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Operational Notes
1.
Reverse Connection of Power Supply
Connecting the power supply in reverse polarity can damage the IC. Take precautions against reverse polarity when
connecting 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. Separate the ground and supply lines of the
digital and analog blocks to prevent noise in the ground and supply lines of the digital block from affecting the analog
block. 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.
Thermal Consideration
Should by any chance the power dissipation rating be exceeded the rise in temperature of the chip may result in
deterioration of the properties of the chip. In case of exceeding this absolute maximum rating, increase the board
size and copper area to prevent exceeding the Pd rating.
6.
Recommended Operating Conditions
These conditions represent a range within which the expected characteristics of the IC can be approximately
obtained. The electrical characteristics are guaranteed under the conditions of each parameter.
7.
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.
8.
Operation Under Strong Electromagnetic Field
Operating the IC in the presence of a strong electromagnetic field may cause the IC to malfunction.
9.
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 during
transport and storage.
10. 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 in
damaging 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.
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
17/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Operational Notes – continued
11. Unused Input Pins
Input pins of an IC are often connected to the gate of a MOS transistor. The gate has extremely high impedance and
extremely 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 and
cause unexpected operation of the IC. So unless otherwise specified, unused input pins should be connected to the
power supply or ground line.
12. Regarding the Input Pin of the IC
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 the P layers with the N layers of other elements, creating a
parasitic diode or transistor. For example (refer to figure below):
When GND > Pin A and GND > Pin B, the P-N junction operates as a parasitic diode.
When GND > Pin B, the P-N junction operates as a parasitic transistor.
Parasitic diodes inevitably occur in the structure of the IC. The operation of parasitic diodes can result in mutual
interference among circuits, operational faults, or physical damage. Therefore, conditions that cause these diodes to
operate, such as applying a voltage lower than the GND voltage to an input pin (and thus to the P substrate) should
be avoided.
Resistor
Transistor (NPN)
Pin A
Pin B
C
E
Pin A
N
P+
P
N
N
P+
N
Pin B
B
Parasitic
Elements
N
P+
N P
N
P+
B
N
C
E
Parasitic
Elements
P Substrate
P Substrate
GND
GND
Parasitic
Elements
GND
Parasitic
Elements
GND
N Region
close-by
Figure 37. Example of monolithic IC structure
13. 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 power dissipation rating. If however the rating is exceeded for a continued period, the junction
temperature (Tj) will rise which will activate the TSD circuit that will turn OFF all 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 no
circumstances, should the TSD circuit be used in a set design or for any purpose other than protecting the IC from
heat damage.
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
18/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Ordering Information
B
D
9
1
6
1
Part Number
F
V
M
Package
FVM: MSOP8
-
TR
Packaging and forming specification
TR: Embossed tape and reel
Marking Diagram
MSOP8 (TOP VIEW)
D
6
9
1
1
Part Number Marking
LOT Number
1PIN MARK
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
19/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Physical Dimension, Tape and Reel information
Package Name
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
MSOP8
20/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
BD9161FVM
Datasheet
Revision History
Date
Revision
02.Mar.2012
06.Oct.2014
001
002
Changes
New Release
Applied the ROHM Standard Style and improved understandability.
www.rohm.com
© 2012, ROHM Co., Ltd. All rights reserved.
TSZ22111･15･001
21/21
TSZ02201-0J3J0AJ00190-1-2
06.Oct.2014 Rev.002
Notice
Precaution on using ROHM Products
1.
Our Products are designed and manufactured for application in ordinary electronic equipments (such as AV equipment,
OA equipment, telecommunication equipment, home electronic appliances, amusement equipment, etc.). If you
(Note 1)
intend to use our Products in devices requiring extremely high reliability (such as medical equipment
, 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, which
a 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 (even if you use no-clean type fluxes, cleaning residue of
flux is recommended); 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 affect
product performance and reliability.
7.
De-rate Power Dissipation (Pd) depending on Ambient temperature (Ta). When used in sealed area, confirm the actual
ambient 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 in
this 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 product
performance 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 – GE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.003
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 the
characteristics 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 be
applied 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 Cl2, 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 is
exceeding 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 of
which storage time is exceeding the recommended storage time period.
Precaution for Product Label
QR code 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 our Products might fall under controlled goods prescribed by the applicable foreign exchange and foreign trade act,
please consult with ROHM representative 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. ROHM shall not be in any way responsible or liable
for infringement of any intellectual property rights or other damages arising from use of such information or data.:
2.
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 information contained in this document.
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 written
consent 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 – GE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.003
Datasheet
General Precaution
1. Before you use our Pro ducts, you are requested to care fully read this document and fully understand its contents.
ROHM shall n ot be in an y way responsible or liabl e for fa ilure, malfunction or acci dent arising from the use of a ny
ROHM’s Products against warning, caution or note contained in this document.
2. All information contained in this docume nt is current as of the issuing date and subj ect to change without any prior
notice. Before purchasing or using ROHM’s Products, please confirm the la test information with a ROHM sale s
representative.
3.
The information contained in this doc ument is provi ded on an “as is” basis and ROHM does not warrant that all
information contained in this document is accurate an d/or error-free. ROHM shall not be in an y way responsible or
liable for an y damages, expenses or losses incurred b y you or third parties resulting from inaccur acy or errors of or
concerning such information.
Notice – WE
© 2014 ROHM Co., Ltd. All rights reserved.
Rev.001
工商网监
湘ICP备2023018690号
