Datasheet
2.7V to 5.5V, 4A 1ch
Synchronous Buck Converter with
Integrated FET
BD9137MUV
General Description
Key Specifications
BD9137MUV is ROHM’s high efficiency step-down
switching regulator designed to produce a voltage as
low as 0.8V from a supply voltage of 5.5V/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.
Input Voltage Range:
Output Voltage Range:
Output Current:
Switching Frequency:
High Side FET ON-Resistance:
Low Side FET ON-Resistance:
Standby Current:
Operating Temperature Range:
2.7V to 5.5V
0.8V to 3.3V
4.0A (Max)
1MHz(Typ)
82mΩ(Typ)
70mΩ(Typ)
0µA (Typ)
-40°C to +105°C
Features
Package
Fast Transient Response because of Current Mode
PWM Control System.
High Efficiency for All Load Ranges because of
Synchronous Switches (Nch/Nch FET) and SLLMTM
(Simple Light Load Mode)
Soft-Start Function
Thermal Shutdown and UVLO Functions
Short-Circuit Protection with Time Delay Function
Shutdown Function
W(Typ) x D(Typ) x H(Max)
Applications
Power Supply for LSI including DSP, Microcomputer
and ASIC
VQFN020V4040
4.00mm x 4.00mm x 1.00mm
Typical Application Circuit
C1
Rf
VCC
CIN
PVCC
EN
VCC
CBST
ADJ
L
ITH
GND, PGND
RITH
VOUT
SW
CO
CITH
R2
R1
Figure 1. Typical Application Circuit
〇Product structure : Silicon monolithic integrated circuit
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〇This product has no designed protection against radioactive rays
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BD9137MUV
(TOP VIEW)
GND
ITH
ADJ
TP.1
PWM
Pin Configuration
15 14 13 12 11
TP.2 16
10 VCC
EN 17
9
18
8
19
7
20
6
PGND
1
2
3
4
BST
PVCC
5
SW
Figure 2. Pin Configuration
Pin Description
Pin
No.
1
2
Pin
Name
SW
SW
Power switch node
Power switch node
Pin
No.
11
12
Pin
Name
GND
ADJ
3
SW
Power switch node
13
ITH
4
SW
Power switch node
14
PWM
5
6
7
8
9
10
SW
PVCC
PVCC
PVCC
BST
VCC
Power switch node
Power switch supply pin
Power switch supply pin
Power switch supply pin
Bootstrapped voltage input pin
Power supply input pin
15
16
17
18
19
20
TP.1
TP.2
EN
PGND
PGND
PGND
Function
Function
Ground pin
Output voltage detection pin
GmAmp output pin/connected to phase
compensation capacitor
Select SLLM / PWM
(H:PWM mode , L:SLLM & PWM mode)
Test pin(connect to GND)
Test pin(connect to GND)
Enable pin(Active high）
Power switch ground pin
Power switch ground pin
Power switch ground pin
Block Diagram
EN
VCC
VREF
BST
Current
Sense/
Protect
Current
Comp
R Q
S
+
Gm Amp
+
3.3V
Input
+
SW
SLOPE
CLK
OSC
VCC
Driver
Logic
Output
PVCC
UVLO
Soft
Start
TSD
SLLM
select
SCP
ADJ
PVCC
ITH
RITH
GND
PWM
CITH
R1 R2
Figure 3. Block Diagram
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BD9137MUV
Absolute Maximum Ratings (Ta=25°C)
Parameter
VCC Voltage
PVCC Voltage
BST Voltage
BST_SW Voltage
EN Voltage
SW,ITH Voltage
Power Dissipation 1
Power Dissipation 2
Power Dissipation 3
Power Dissipation 4
Operating Temperature Range
Storage Temperature Range
Maximum Junction Temperature
Symbol
Limit
Unit
VCC
PVCC
VBST
VBST-SW
VEN
VSW, VITH
Pd1
Pd2
Pd3
Pd4
-0.3 to +7 (Note 1)
-0.3 to +7 (Note 1)
-0.3 to +13
-0.3 to +7
-0.3 to +7
-0.3 to +7
0.34 (Note 2)
0.70 (Note 3)
2.21 (Note 4)
3.56 (Note 5)
V
V
V
V
V
V
W
W
W
W
Topr
-40 to +105
°C
Tstg
-55 to +150
°C
Tjmax
+150
°C
(Note 1)
Pd should not be exceeded.
(Note 2) IC only
(Note 3) Mounted on a 1-layer 74.2mmx74.2mmx1.6mm glass-epoxy board, occupied area by copper foil : 10.29mm2
(Note 4) Mounted on a 4 layer 74.2mmx74.2mmx1.6mm Glass-epoxy PCB (1st ,4th Copper foil area : 10.29mm2 2nd ,3rd Copper foil area : 5505mm2)
(Note 5) Mounted on a 4-layer 74.2mmx74.2mmx1.6mm glass-epoxy board, occupied area by copper foil : 5505mm2, in each layers
Caution: Operating the IC over the absolute maximum ratings may damage the IC. In addition, it is impossible to predict all destructive situations such as
short-circuit modes, open circuit modes, etc. Therefore, it is important to consider circuit protection measures, like adding a fuse, in case the IC is operated in a
special mode exceeding the absolute maximum ratings.
Recommended Operating Conditions (Ta=-40°C to +105°C)
Parameter
Power Supply Voltage
EN Voltage
Output Voltage Setting Range
SW Average Output Current
Symbol
Min
Typ
VCC
PVCC
VEN
VOUT
ISW
2.7
2.7
0
0.8
-
3.3
3.3
-
Max
Unit
5.5
5.5
5.5
3.3(Note 6)
4.0(Note 7)
V
V
V
V
A
(Note 6) In case the output voltage is set to 1.6V or more, VCCMin = VOUT+1.2V.
(Note 7) Pd should not be exceeded.
Electrical Characteristics
(Unless otherwise specified Ta=25°C VCC=PVCC=3.3V, VEN=VCC, R1=10kΩ, R2=5kΩ)
Parameter
Standby Current
Active Current
EN Low Voltage
EN High Voltage
EN Input Current
PWM Low Voltage
PWM High Voltage
PWM Input Current
Oscillation Frequency
High Side FET ON-Resistance
Low Side FET ON-Resistance
ADJ Voltage
ITH SInk Current
ITH Source Current
UVLO Threshold Voltage
UVLO Release Voltage
Soft-Start Time
Hiccup Delay
Cool Down Time
Output Short Circuit
Threshold Voltage
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Symbol
ISTB
ICC
VENL
VENH
IEN
VPWML
VPWMH
IPWM
fOSC
RONH
RONL
VADJ
ITHSI
ITHSO
VUVLO1
VUVLO2
tSS
tHP
tCD
Min
2.0
2.0
0.8
0.788
10
10
2.400
2.425
0.5
0.5
8
Typ
0
250
GND
VCC
2
GND
VCC
2
1
82
70
0.800
18
18
2.500
2.550
1
1
16
Max
10
500
0.8
10
0.8
10
1.2
115
98
0.812
2.600
2.700
2
2
32
Unit
µA
µA
V
V
µA
V
V
µA
MHz
mΩ
mΩ
V
µA
µA
V
V
ms
ms
ms
Conditions
EN=GND
VSCP
-
0.40
0.56
V
VADJ =0.8V to 0V
3/22
Standby mode
Active mode
VEN=3.3V
SLLM & PWM mode
PWM mode
VPWM=3.3V
PVCC=3.3V
PVCC=3.3V
VADJ=1V
VADJ=0.6V
VCC=3.3V to 0V
VCC=0V to 3.3V
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Typical Performance Curves
[VOUT=1.2V]
Ta=25°C
IO=3A
Output Voltage: VOUT[V]
Output Voltage: VOUT[V]
[VOUT=1.2V]
Input Voltage: VCC [V]
VCC=5V
Ta=25°C
IO=0A
EN Voltage: VEN[V]
Figure 4. Output Voltage vs Input Voltage
Figure 5. Output Voltage vs EN Voltage
[VOUT=1.2V]
VVCCCC=5V
Ta=25°C
Output Voltage: VOUT[V]
Output Voltage: VOUT[V]
[VOUT=1.2V]
CC=5V
VVCC
IO=0A
Output Current: IOUT [A]
Temperature: Ta[°C]
Figure 7. Output Voltage vs Temperature
Figure 6. Output Voltage vs Output Current
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Typical Performance Curves – continued
Efficiency: η [%]
Frequency: fOSC [MHz]
[VOUT=1.2V]
VCC=5V
Ta=25°C
VCC=5V
Output Current: IOUT [mA]
Temperature: Ta[°C]
Figure 9. Oscillation Frequency vs
Temperature
EN Voltage: VEN[V]
ON-Resistance: RON [Ω]
Figure 8. Efficiency vs Output Current
VCC=5V
VCC=3.3V
Temperature: Ta[°C]
Temperature: Ta[°C]
Figure 11. EN Voltage vs
Temperature
Figure 10. ON-Resistance vs
Temperature
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Frequency: fOSC [MHz]
Circuit Current: ICC [µA]
Typical Performance Curves – continued
VCC =5V
Ta=25°C
Input Voltage: VCC[V]
Temperature:
Temperature:
Ta[°C]
Figure 12. Circuit Current vs
Temperature
Figure 13. Oscillation Frequency vs
Input Voltage
Typical Waveforms
[VOUT=1.2V]
VOUT=1.2V]
VCC=PVCC
=EN
SW
VOUT
VCC=5V
Ta=25°C
IO=0A
VCC=5V
Ta=25°C
Figure 14. Soft-Start Waveform
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Figure 15. SW Waveform
(IO=10mA)
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Typical Waveforms – continued
[VOUT=1.2V]
VOUT=1.2V]
VOUT
SW
VOUT
IOUT
VCC=5V
Ta=25°C
VCC=5V
Ta=25°C
Figure 17. Transient Response
(IO= 1A to 3A,10μs)
Figure 16. SW Waveform
(IO=10mA)
[VOUT=1.2V]
VOUT
IOUT
VCC=5V
Ta=25°C
Figure 18. Transient Response
(IO=3A to 1A, 10μs)
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BD9137MUV
Application Information
1. Operation
BD9137MUV is a synchronous step-down switching regulator that achieves fast transient response by employing current
mode PWM control system. It utilizes switching operation either in PWM (Pulse Width Modulation) mode for heavier load,
or SLLMTM (Simple Light Load Mode) operation for lighter load to improve efficiency.
(1) Synchronous Rectifier
Integrated synchronous rectification using two MOSFETS reduces power dissipation and increases efficiency when
compared to converters using external diodes. Internal shoot-through current limiting circuit further reduces power
dissipation.
(2) 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 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 IL, and the voltage feedback control signal, FB.
(b) SLLMTM (Simple Light Load Mode) Control
When the control mode is shifted by PWM from heavier load to lighter load or vice versa, the switching pulse is
designed to turn OFF with the device held operating in normal PWM control loop. This allows linear operation
without voltage drop or deterioration in transient response during the 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 so
designed such that the RESET signal is continuously sent even if the load is changed to light mode where the
switching is tuned OFF and the switching pulses disappear. Activating the switching discontinuously reduces the
switching dissipation and improves the efficiency.
SENSE
Current
Comp
RESET
VOUT
Level
Shift
R Q
FB
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
FB
SET
GND
SET
GND
RESET
GND
RESET
GND
SW
GND
SW
IL
IL(AVE)
GND
IL
0A
VOUT
VOUT
VOUT(AVE)
VOUT(AVE)
Not switching
Figure 20. PWM Switching Timing Diagram
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Figure 21. SLLMTM Switching Timing Diagram
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2. Description of Operations
(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
With EN terminal is “Low”, the device operates in Standby Mode, and all the functional blocks including reference
voltage circuit, internal oscillator and drivers are turned to OFF. Circuit current during standby is 0µA (Typ).
(3) UVLO Function
It detects whether the supplied input voltage is sufficient to obtain the output voltage of this IC.
50mV (Typ) is provided to prevent the output from chattering.
A hysteresis width of
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 Diagram
(4)
Switching of SLLM Function to PWM Fixed Function
This IC operates at SLLM control and this control can be cancelled by activating EN terminal. Impressing voltage more
than 2.0V to PWM terminal can activate the EN terminal, at the same time making PWM control to operate during light
load. Constantly operating at fixed frequency can reduce the output ripple voltage.
(5)
Short-circuit Protection 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 resetting UVLO.
Hiccup Delay
1msec
EN
VOUT
Output Current in Non-Control
Cool Down
Time
16msec
1/2VOUT
～
～
Soft start
Soft start
Limit
Output Voltage OFF
～
～
IL
Output Current in control by limit value
(With fall of the output voltage, limit value goes down)
Standby Mode
Operated Mode
EN
～
～
Operated Mode
Cool Down
Output Voltage OFF
Hiccup
Figure 23. Short-Circuit Protection with Time Delay Diagram
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3. Information on Advantages
Advantage 1：Offers fast transient response by using mode control system.
Conventional product (Load response IO=1A to 3A)
VOUT
BD9137MUV (Load response IO=1A to 3A)
VOUT
72mV
145mV
IOUT
IOUT
Voltage drop due to sudden change in load was reduced.
Figure 24. Comparison of Transient Response
Advantage 2： Offers high efficiency for all load ranges.
(a)
For lighter load:
This IC utilizes the current mode control mode called SLLMTM, which reduces various dissipation such as switching
dissipation (PSW), gate charge/discharge dissipation (PGATE), ESR dissipation of output capacitor (PESR) and
ON-Resistance dissipation (PRON) that may otherwise cause reduction in efficiency.
Achieves efficiency improvement for lighter load.
(b)
For heavier load:
This IC utilizes the synchronous rectifying mode and uses low ON-Resistance MOSFETs incorporated as power
transistor.
ON-Resistance of High side MOSFET : 82mΩ(Typ)
ON-Resistance of Low side MOSFET : 70mΩ(Typ)
100
Efficiency η[%]
SLLM
Achieves efficiency improvement for heavier load.
②
50
①
PWM
①improvement by SLLM system
②improvement by synchronous rectifier
0
0.001
Offers high efficiency for all load ranges with the improvements mentioned above.
Advantage 3：・Supplied in smaller package due to small-sized power MOSFET.
0.01
0.1
Output Current IOUT[A]
1
Figure 25. Efficiency
・Output capacitor CO required for current mode control: 22µF ceramic capacitor
・Inductance L required for the operating frequency of 1 MHz: 2.2µH inductor
・Incorporates FET + Boot strap diode
Reduces mounting area requirement.
VCC
EN
VCC
VREF
20mm
BST
Current
Comp
RQ
+
S
Current
Sense/
Protect
PVCC
SLOPE
+
OSC
VCC
Soft
Start
UVLO
SW
Driver
Logic
CBST
Rf
PVCC
15mm
R1
L
CIN
RITH
PGND
TSD
SCP
ADJ
CLK
Cf
R2
Output
+
Gm Amp
3.3V
Input
ITH
SLLM
select
GND
CITH
CO
PWM
RITH CITH
R1 R2
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Figure 26. Example Application
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4. Switching Regulator Efficiency
Efficiency ŋ may be expressed by the equation shown below:
VOUT IOUT
VIN I IN
100
POUT
POUT
100
100
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 of inductor.
RON is the ON-Resistance of FET.
IOUT is the output current.
(2)
Gate Charge/Discharge Dissipation：Pd(Gate)
PdGate 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)
PdESR I RMS 2 ESR
where:
IRMS is the ripple current of capacitor.
ESR is the equivalent series.
(5)
Operating Current Dissipation of IC：Pd(IC)
PdIC VIN I CC
where:
ICC is the circuit current.
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5. 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 dissipation mentioned above such as gate
charge/discharge dissipation and switching dissipation.
4.5
① 4 layers (copper foil area : 5505mm2)
(copper foil in each layers)
θj-a=35.1°C/W
② 4 layers (1st,4thcopper foil area : 10.29mm2)
(2nd ,3rd copper foil area : 5505mm2)
θj-a=56.6°C/W
③ 1 layer (copper foil area :10.29mm2)
θj-a=178.6°C/W
④IC only
θj-a=367.6°C/W
4.0
Power Dissipation: Pd [W]
①3.56W
3.0
②2.21W
2.0
P I OUT 2 RON
RON D RONH 1 D RONL
1.0
③0.70W
④0.34W
0
0
25
50
75
100 105
125
150
where:
D is the ON Duty (=VOUT/VCC).
RONH is the ON Resistance of High side MOSFET.
RONL is the ON Resistance of Low side MOSFET.
IOUT is the Output Current.
Ambient Temperature: Ta [°C]
Figure 27. Thermal Derating Curve
(VQFN020V4040)
If VCC 3.3V, VOUT 1.8V, R ONH 82m , R ONL 70m
IOUT 3A, f or example,
D VOUT/VCC 1.8/3.3 0.545
RON 0.545 0.082 (1 - 0.545) 0.07
0.0447 0.0319
0.0766 []
P 32 0.0766 0.6894 [W]
Since RONH is greater than RONL in this IC, the dissipation increases as the ON duty increases. Taking into consideration the
dissipation shown above, thermal design must be carried out with sufficient margin.
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6. Selection of Components Externally Connected
(1) Selection of Inductor (L)
IL
The inductance significantly depends on the output ripple current.
As seen in equation (1), the ripple current decreases as the
inductor and/or switching frequency increases.
ΔIL
VCC
IL
IL
VCC VOUT VOUT
L VCC f
A
・・・(1)
Appropriate output ripple current should be ±20% of the maximum
output current.
A ・・・(2)
IL 0.2 I OUTMax
VOUT
L
CO
L
Figure 28. Output Ripple Current
VCC VOUT VOUT
IL VCC f
H
・・・(3)
where:
ΔIL is the Output ripple current, and
f is the Switching frequency.
Note: Current exceeding the current rating of an 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=5.0V, VOUT=2.5V, f=1MHz, ΔIL=0.2x3A=0.6A, for example, (BD9137MUV)
L
5 2.5 2.5 2.08 2.2
0.6 5 1M
H
Note: Select an 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 on the stability
region and the equivalent series resistance required to minimize ripple voltage.
VOUT
L
ESR
CO
Figure 29. Output Capacitor
C
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Output ripple voltage is determined by the equation (4) ：
VOUT I L ESR
V ・・・(4)
where:
ΔIL is the Output ripple current.
ESR is the Equivalent series resistance of output capacitor.
Note: Rating of the capacitor should be determined allowing sufficient margin against
output voltage. A 22µF to 100µF ceramic capacitor is recommended.
Less ESR allows reduction in output ripple voltage.
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(3) Selection of Input Capacitor (CIN)
VCC
Input capacitor 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
VCC
A ・・・(5)
< Worst case > IRMSMax
VCC 2 VOUT , IRMS
Figure 30. Input Capacitor
IOUT
2
If VCC=3.3V, VOUT=1.8V, and IOUTMax=3A, (BD9137MUV)
I RMS 3
1.83.3 1.8
1.49
3.3
ARMS
A low ESR 22µF/10V ceramic capacitor is recommended to reduce ESR dissipation of input capacitor for better
efficiency.
(4) Calculating RITH, CITH for Phase Compensation
Since the Current Mode Control is designed to limit an inductor current, a pole (phase lag) appears in the low
frequency area due to a CR filter consisting of a 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. Therefore, 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)
1
2 Ro Co
A
fP(Max)
Gain
[dB]
f Z ESR
0
fZ(ESR)
IOUTMin
Phase
[deg]
IOUTMax
0
1
2 E SR Co
Pole at Power Amplifier
When the output current decreases, the load resistance
RC increases and the pole frequency decreases.
-90
fpMin
1
2 ROMax CO
Hz with lighterload
fpMax
1
2 ROMin CO
Hz with heavier load
Figure 31. Open Loop Gain Characteristics
A
fZ(Amp)
Gain
[dB]
0
0
Phase
[deg]
-90
Zero at Power Amplifier
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 is reduced to half.)
f Z Amp
1
2 RITH CITH
Figure 32. Error Amp Phase Compensation Characteristics
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C1
Rf
VCC
CIN
EN
PVCC
VCC
CBST
ADJ
L
ITH
GND, PGND
VOUT
SW
RITH
CO
CITH
R2
R1
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.
f Z Amp f P Min
1
1
2 R ITH C ITH
2 ROMax CO
(5) Setting the Output Voltage
The output voltage VOUT is determined by the equation (6):
VOUT (R 2/R1 1) VADJ ・・・(6)
L
6
Output
SW
Where:
VADJ is the Voltage at ADJ terminal (0.8V Typ)
The required output voltage may be determined by adjusting R1 and R2.
Co
R2
1
ADJ
R1
Adjustable output voltage range: 0.8V to 3.3V
Figure 34. Setting the Output Voltage
Use 1 kΩ to 100 kΩ resistor for R1. If a resistor with resistance higher than 100 kΩ is used, check the assembled set
carefully for ripple voltage etc.
3.7
The lower limit of input voltage depends on the output voltage.
Basically, it is recommended to use the condition:
VV
1.2V
=V
VOUT
CCMin
CCMin
OUT+1.2V.
Figure 35 shows the necessary output current value at the
lower limit of input voltage. (DCR of inductor: 20mΩ)
This data is the characteristic value, so it’ doesn’t guarantee the
operation range,
Input Voltage : VCC[V]
3.5
VO=2.5V
3.3
VO=2.0V
3.1
VO=1.8V
2.9
2.7
0
1
2
3
Output Current: IOUT[A]
Figure 35. Minimum Input Voltage in Each Output Voltage
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7. Cautions on PC Board Layout
Figure 36. Layout Diagram
(1) Layout the input ceramic capacitor CIN closer to the pins PVCC and PGND, and the output capacitor CO closer to the
pin PGND.
(2) Layout CITH and RITH between the pins ITH and GND as near as possible with least necessary wiring.
Note: VQFN020V4040 (BD9137MUV) has thermal PAD on the reverse of the package.
The package thermal performance may be enhanced by bonding the PAD to GND plane which occupies a large
area of PCB.
8. Recommended Components Lists on Above Application
Symbol
Part
Value
2.0µH
L
Coil
2.2µH
Manufacturer
Sumida
Sumida
Series
CDR6D28MNP-2R0NC
CDR6D26NP-2R2NC
CIN
Ceramic Capacitor
22µF
Murata
GRM32EB11A226KE20
CO
Ceramic Capacitor
22µF
Murata
GRM31CB30J226KE18
Murata
Murata
Murata
Murata
Murata
Murata
Rohm
Rohm
Rohm
Rohm
Rohm
Rohm
GRM18 Series
GRM18 Series
GRM18 Series
GRM18 Series
GRM18 Series
GRM18 Series
MCR03 Series
MCR03 Series
MCR03 Series
MCR03 Series
MCR03 Series
MCR03 Series
1000 pF
Murata
GRM18 Series
10Ω
Rohm
MCR03 Series
0.1 µF
Murata
GRM18 Series
CITH
Ceramic Capacitor
RITH
Resistance
Cf
Ceramic Capacitor
Rf
Resistance
CBST
Ceramic Capacitor
VOUT=1.0V
VOUT=1.2V
VOUT=1.5V
VOUT=1.8V
VOUT=2.5V
VOUT=3.3V
VOUT=1.0V
VOUT=1.2V
VOUT=1.5V
VOUT=1.8V
VOUT=2.5V
VOUT=3.3V
1500pF
1000pF
1000pF
560pF
560pF
330pF
5.6kΩ
6.8kΩ
6.8kΩ
8.2kΩ
12kΩ
15kΩ
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 significant and may affect the system, a low pass filter should be inserted between the VCC and
PVCC pins, and a schottky barrier diode or snubber established between the SW and PGND pins.
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I/O Equivalent Circuit
・EN pin
PVCC
・SW pin
PVCC
PVCC
EN
SW
・ADJ pin
・ITH pin
VCC
ADJ
ITH
・BST pin
PVCC
PVCC
BST
SW
Figure 37. I/O Equivalent Circuits
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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 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.
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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 38. 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. The IC should be
powered down and turned ON again to resume normal operation because the TSD circuit keeps the outputs at the
OFF state even if the TJ falls below the TSD threshold.
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.
14. Selection of Inductor
It is recommended to use an inductor with a series resistance element (DCR) 0.1Ω or less. Especially, note that use
of a high DCR inductor will cause an inductor loss, resulting in decreased output voltage. Should this condition
continue for a specified period (soft start time + timer latch time), output short circuit protection will be activated and
output will be latched OFF. When using an inductor over 0.1Ω, be careful to ensure adequate margins for variation
between external devices and this IC, including transient as well as static characteristics. Furthermore, in any case, it
is recommended to start up the output with EN after supply voltage is within.
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Ordering Information
B
D
9
Part Number
1
3
M
7
U
V
Package
MUV: VQFN020V4040
Type
Adjustable
(0.8V to 3.3V)
E2
Package specification
E2: Embossed taping
Marking Diagram
VQFN020V4040 (TOP VIEW)
Part Number Marking
D 9 1 3 7
LOT Number
1PIN MARK
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Physical Dimension, Tape and Reel Information
Package Name
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Revision History
Date
Revision
02.Mar.2012
31.May.2012
001
002
20.Nov.2014
003
Changes
New Release
page3 Electrical Characteristics
・soft start limit
・Hiccup delay unit
reason for revision: the value and unit corrected
Applied the ROHM Standard Style and improved understandability.
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Datasheet
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)
, transport
intend to use our Products in devices requiring extremely high reliability (such as medical equipment
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-PGA-E
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Datasheet
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 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 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.
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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.
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