Datashee
t
○Product structure：Silicon monolithic integrated circuit○This product is not designed protection against radioactive rays.
1/23 TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
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TSZ22111・14・001
7.5V to 18V, 6A Integrated MOSFET
1ch Synchronous Buck DC/DC Converter
BD95861MUV
●Description
BD95861MUV is a 1ch synchronous buck converter that
can generate output voltage (0.8V to 5.5V) at the input
voltage range (7.5V to 18V). Space-saving and high
efficient switching regulator can be achieved due to
built-in N-MOSFET power transistors. The IC also
incorporates H3RegTM technology, a Rohm proprietary
constant ON TIME control mode which facilitates
ultra-high transient response against changes in load
without external compensation components. Fixed soft
start function, power good function, and short circuit /
over voltage protection with timer latch functions are
incorporated. The BD95861MUV is designed for power
supplies for Digital AV Equipment.
●Applications
・LCD TVs
・Set Top Boxes (STB)
・DVD/Blu-ray players/recorders
・Broadband Network and Communication Interface
・Amusement, other.
●Typical A pplication
●Features
・Input Voltage Range: 7.5V to 18.0V
・Reference Voltage 0.8V±1.5%
・Output Voltage Range: 0.8V to 5.5V
・Output Current: 6.0A (Max.)
・Switching Frequency: 350kHz to 800kHz
（depend on input-output condition）
・Built-in Power MOS FET
High-side Nch FET ON resistance: 50mΩ(typ.)
Low-side Nch FET ON resistance: 30mΩ(typ.)
・Fast Transient Responses due to H3Reg control
・Over Current Protection (OCP) – Cycle-by-Cycle
・Thermal Shut Down (TSD)
・Under-Voltage Lock-Out (UVLO)
・Short Circuit Protection (SCP)
・Over Voltage Protection (OVP)
・Fixed Soft Start (1msec ; typ)
・Power Good function
●PackageW(Typ.) x D(Typ.) x H(Max.)
・VQFN024V4040 4.0mm x 4.0mm x 1.0mm
●Pin Configuration (TOP VIEW)
Figure.1 Typical Application Circuit Figure.2 Pin Configuration
13
16
14
15
17
18
6
3
5
4
2
1
24 2123 22 20 19
987 1210 11
PGOOD
SW
EN
BOOT
SW
SW
VIN
VIN
VIN
VIN
PGND
PGND
PGND
PGND
PGND
SW
SW
SW
VIN
TEST
VREG
GND
FB
VOUT
Datasheet
Datasheet
2/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
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TSZ22111・15・001
BG
OCP
Thermal
Protection
R
S
Q
TSD
H3RegTM
Controller
Block
VREG
BOOT
SW
Reference
Block UVLO
5V
OVP
Driver
Circuit
5VReg
EN
VREG
EN/UVLO
TSD/SCP
VOUT
VIN
VREG
UVLO
OCP
SCP
TSD
SW
Soft
Start
+
REF
SS
REF
BG
SS
GND
PGND
EN
EN
0.96V
FB
0.56V
FB
+
-
Delay
SCP
OVP
+
-
PGOOD
EN
UVLO
TSD
Power
Good
FB
VIN
BG
SCP
SCP
TEST
+
-
24 22
10
｜
15
19
20
18
17
21 23
16
1
｜
4
5
｜
9
●Block Diagram
●Pin Description
No. Symbol Description
1-4, 24 VIN
Input Voltage Supply pin.
The IC determines the duty cycles internally based on the input voltage. Therefore, variations of VIN pin can
lead to unstable operation. This pin also acts as the input voltage to the internal switching regulator output
block, and is sensitive to the impedance of the power supply.
Connect over 10uF ceramic capacitors for the decoupling capacitors to PGND as near as these pins.
5-9 PGND
Power ground pin connected to the source of the Low side FET.
10-15 SW
Switch node connection between High side FET source and Low side FET drain.
Connect 0.1μF capacitor and 20Ω resistor between BOOT and SW. This pin is also connected
to inductor (L).
16 BOOT
High side FET Gate Driver Power Supply pin.
Connect 0.1μF capacitor and 20Ω resistor between BOOT and SW.
BOOT voltage swings from VREG to (VIN + VREG) during normal switching operation.
17 EN
Enable Input pin.
When the input voltage of the EN pin reaches at least 2.2V, the switching regulator becomes
active. At the voltage less than 0.3 V, the IC becomes standby mode.
18 PGOOD
Open-drain Power Good Output pin.
Due to the open-drain output, a 100k pull-up resistor should be connected between this pin and
VREG or other power supply. In the case of no use, this pin is opened or shortened to ground.
Figure.3 Block Diagram
Datasheet
Datasheet
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BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
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TSZ22111・15・001
●Pin Description (Continued)
No. Symbol Description
19 VOUT
Output Voltage Sense pin.
Connect to output voltage directly. ON TIME is determined by monitoring the output voltage.
20 FB
Output Voltage Feedback pin. FB is compared with REF in the IC. Please set the output voltage
in the feedback resistances of less than total 50k. (Refer to page 15)
21 GND
Sense ground pin for all internal analog and digital power supplies.
22 VREG
Power supply output inside IC. When at least 2.2V is supplied to the EN pin, the VREG is active.
This pin supplies 5.0V at up to 10mA. Insert a 4.7μF capacitor between this pin and ground pin.
23 TEST
TEST Pin. Connect to ground.
Thermal
Pad - Exposed Thermal Pad. Connect to ground.
Datasheet
Datasheet
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BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
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TSZ22111・15・001
●Absolute Maximum Ratings (Ta=25℃)
Parameter Symbol Limit Unit Comment
Input Voltage VIN 20 *1 V
BOOT Voltage BOOT 27 *1 V
BOOT-SW Voltage BOOT-SW 7 *1 V
Output Voltage VOUT 7 *1 V
SW Voltage SW 20*1 V
Output Feedback Voltage FB VREG V
VREG Voltage VREG 7 *1 V
EN Input Voltage EN 20 *1 V
PGOOD Voltage PGOOD 7 *1 V
Power Dissipation 1 Pd1 0.34 W Ta ≧25°C (IC only), power dissipated at
2.72mW / °C.
Power Dissipation 2 Pd2 0.70 W
Ta ≧25°C (70mm×70mm×1.6mm
single-layer board, 6.28mm2 copper heat
dissipation pad), power dissipated at
5.6mW / °C.
Power Dissipation 3 Pd3 2.20 W
Ta≧25°C (70mm×70mm×1.6mm 4-layer
board, 6.28 mm2 copper heat dissipation
pad on top and bottom layer, 5505 mm2
pad on 2nd and 3rd layer), power dissipated
at 17.6mW / °C.
Power Dissipation 4 Pd4 3.55 W
Ta≧25°C (70mm×70mm×1.6mm 4-layer
board, all layers with 5505 mm2 copper
heat dissipation pads), power dissipated at
28.4mW / °C.
Operating Temperature Range Topr -20〜+100 *1 ℃
Storage Temperature Range Tstg -55〜+150 ℃
Junction Temperature Tjmax +150 ℃
*1 Not to exceed Pd.
●Operating Ratings (Ta= -20 to 100℃)
Parameter Symbol Limit Unit
Min Typ Max
Input Voltage VIN 7.5 12 18 V
VREG Voltage VREG 4.5 5.0 5.5 V
BOOT Voltage BOOT 4.5 - 23.5 V
SW Voltage SW -0.7 - 18 V
BOOT-SW Voltage BOOT-SW 4.5 - 5.5 V
EN Input Voltage EN 0 - 18 V
Output Voltage VOUT *2 0.8 - 5.5 V
PGOOD Voltage PGOOD 0 - 5.5 V
Minimum ON Time Tonmin - - 200 nsec
*2 VOUT depends on Input Voltage (VIN) in some cases.
Datasheet
Datasheet
5/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
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TSZ22111・15・001
●Electrical Characteristics
(Unless otherwise noted Ta=25℃, VIN=12V, EN=3V, VOUT=3.3V)
Parameter Symbol Limit Unit Condition
Min Typ Max
VIN Bias Current IIN - 1.2 2.0 mA
VIN Standby Current IIN_STB - 2 15 μA EN=0V
Enable Control
EN Low Voltage ENLOW GND - 0.3 V
EN High Voltage ENHIGH 2.2 - 18 V
EN Bias Current IEN - 3 10 μA EN=3V
VREG Output Voltage
VREG Standby Voltage VREG_STB - - 0.1 V EN=0V
VREG Output Voltage VREG 4.5 5.0 5.5 V IREG=10mA
Maximum Output Current IREG 10 - - mA
Power MOSFET
High side FET ON Resistance R
ONH - 50 100 mΩ
Low side FET ON Resistance R
ONL - 30 60 mΩ
Reference Voltage
FB threshold Voltage VFB 0.788 0.800 0.812 V
FB Input Current IFB -1 - 1 μA
H3Reg Control
ON Time TON - 470 - nsec
Minimum OFF Time TOFFMIN 200 450 - nsec
Soft Start / Output Discharge
Soft Start Time TSOFT - 1.0 - msec
VOUT Discharge Current IVOUT 3 6.6 - mA VOUT=1V, EN=0V, VREG=5V
Datasheet
Datasheet
6/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
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TSZ22111・15・001
●Electrical Characteristics (Co n t inued)
(Unless otherwise noted Ta=25℃, VIN=12V, EN=3V, VOUT=3.3V)
Parameter Symbol Limit Unit Condition
Min Typ Max
Over Current Protection
Over Current Protection
Current Limit IOCP 6.1 10.5 - A *3
SCP
SCP Threshold Voltage VSCP 0.48 0.56 0.64 V VFB=0.8V → 0V
SCP delay time TSCP - 1.0 - msec
OVP
OVP Threshold Voltage VOVP 0.86 0.96 1.06 V VFB=0.8V → 2.0V
OVP delay time TOVP - 1.0 - msec
UVLO
VREG Threshold Voltage VREG_UVLO 3.75 4.20 4.65 V VREG: Sweep up
VREG Hysteresis Voltage dVREG_UVLO 100 160 220 mV VREG: Sweep down
Power Good
VFB Power Good Low Voltage VFB_PL 0.61 0.68 0.75 V VFB=0.8V → 0V
VFB Power Good High Voltage VFB_PH 0.65 0.72 0.79 V VFB=0V → 0.8V
＊3 No tested on outgoing inspection.
Datasheet
Datasheet
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BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
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TSZ22111・15・001
●Typical Performance Curves (Unless otherwise noted Ta=25℃, VIN= 12V)
0
10
20
30
40
50
60
70
80
90
100
0246
Iout [A]
Efficiency [%]
0
20
40
60
80
100
0123456
Iout [A ]
Tc [℃]
Figure.4 Efficiency
(VIN=12V, L=2.2H)
Figure.5 Tc – Iout
(VIN=12V, VOUT=3.3V, L=2.2H)
Figure.6 VOUT Ripple voltage
(VIN=12V, VOUT=3.3V, L=2.2H, COUT=44F, Iout=0A)
Figure.7 VOUT Ripple voltage
(VIN=12V, VOUT=3.3V, L=2.2H, COUT=44F, Iout=6A)
VOUT
(AC)
2
0mV/div
SW
5V/div
VOUT
(AC)
2
0mV/div
SW
5V/div
1sec/div
1sec/div
VOUT = 5.0V
VOUT = 3.3V
VOUT = 1.2V
Datasheet
Datasheet
8/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
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TSZ22111・15・001
●Typical Performance Curves (Unless otherwise noted Ta=25℃, VIN=12V) (Continued)
3.25
3.28
3.30
3.33
3.35
3.38
0123456
Iout [A]
VOUT [V]
500
550
600
650
700
750
8 1012141618
VIN [V]
Frequency [kHz]
3.25
3.28
3.30
3.33
3.35
3.38
-20 0 20 40 60 80 100
Temperature [℃]
VOUT [V]
Figure.8 VOUT Load Regulation
(VIN=12V, VOUT=3.3V, L=2.2H)
Figure.9 VOUT Line Regulation
(VOUT=3.3V, L=2.2H, Iout=0A)
Figure.10 VOUT - Temperature
(VIN=12V, VOUT=3.3V, L=2.2H, Iout=0A)
Figure.11 Frequency - VIN
(VIN=12V, VOUT=3.3V, L=2.2H, Iout=0A)
Iout=0A
Iout=6A
3.25
3.28
3.30
3.33
3.35
3.38
81012141618
VIN[V]
VOUT [V]
Datasheet
Datasheet
9/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
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TSZ22111・15・001
●Typical Performance Curves (Unless otherwise noted Ta=25℃, VIN=12V) (Continued)
Figure.12 Start up with EN
(VIN=12V, VOUT=3.3V, L=2.2H, COUT=44F, Iout=0A)
Figure.13 Power down with EN
(VIN=12V, VOUT=3.3V, L=2.2H, COUT=44F, Iout=0A)
Figure.14 VOUT Transient Response
(VIN=12V, VOUT=3.3V, L=2.2H, COUT=44F)
Iout=0⇔2A (SR=1.0A/usec)
Figure.15 OCP function
(VIN=12V, VOUT=3.3V, L=2.2H, COUT=44F)
(VOUT is shorted to ground)
EN
5V/div
PGOOD
5V/div
SW
10V/div
VOUT
2V/div
200sec/div
EN
5V/div
PGOOD
5V/div
SW
10V/div
VOUT
2V/div
2msec/div
VOUT (AC)
50mV/div
Iout
2A/div
100sec/div
VOUT
2V/div
SW
10V/div
IL
5A/div
200sec/div
Datasheet
Datasheet
10/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
www.rohm.com
TSZ22111・15・001
●Explanation of Operatio n
The BD95861MUV is a 1ch synchronous buck converter incorporating ROHM’s proprietary H3RegTM CONTROLLA system.
When VOUT drops due to a rapid load change, the system quickly restores VOUT by increasing the frequency.
1. H3RegTM System
1-1. Normal Operation
When FB falls below the threshold voltage (REF), a drop is detected, activating the H3RegTM CONTROLLA system.
f
1
V
V
Ton
IN
OUT ×= [sec] (1)
HG (Gate of High side MOSFET) output is determined by the formula (1). LG (Gate of Low side MOSFET) output operates
until FB voltage falls below REF voltage after HG becomes OFF. OFF time is restricted by MIN OFF Time (typ.:450nsec).
Hence, BD95861MUV runs with a constant on time by using the input and output voltage to set the internal on time timer.
1-2. VOUT drops due to a rapid load change
When FB (VOUT) drops due to a rapid load change and the voltage remains below REF, the system quickly restores
VOUT by shortening OFF time of HG (increasing the frequency), improving transient response as shown Fig. 16 (b).
FB
REF
HG
Io
LG
FB
REF
HG
LG
Figure.16 H3REG System
(a) Normal operation (b) Rapid load change
Datasheet
Datasheet
11/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
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TSZ22111・15・001
●Timing Chart
1. Soft Start Function
Soft start is utilized when the EN pin is set high. Current control takes effect at startup, enabling a moderate “ramping start”
on the output voltage. Soft start time is 1.0msec (typ). Rush current is determined via formula (2) below.
1.0msec
VC
IOUTOUT
IN
×
= [A] (2)
COUT: All capacitors connected with VOUT
2. Power Good Function
When FB voltage is more than 0.72V (90%), the integrated open-drain NMOS is set to OFF, and PGOOD outputs High due
to pull-up register. If FB voltage falls below 0.68V (85%), PGOOD becomes Low.
EN
FB
IIN
1.0msec (typ)
VOUT
EN
FB
PGOOD
0.72V
0.68V
Figure.17 Soft Start Timing Chart
Figure.18 Power Good Timing Chart
Datasheet
Datasheet
12/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
www.rohm.com
TSZ22111・15・001
●Protection Operation
1. OCP Operation
Normally, when FB voltage falls below REF voltage, HG becomes high. However, if the current through the inductor (IL)
exceeds OCP current value (IOCP) during LG=ON, HG does not become high and IL is restricted by IOCP. When IL falls down
below IOCP, HG is stricken by the pulse width of Ton decided by formula (1). As the result, the output voltage can decrease
as the frequency and duty are changed.
When OCP is released in the state that the output has decreased by OCP operation, the output voltage might rise up due
to high-speed load response. Also OFF Latch is operated when FB voltage becomes below the SCP setting voltage during
1msec (typ.) (Refer to 2-1).
2. SCP Operation / OVP Operation (OFF Latch)
2-1. SCP Operation
SCP monitors FB voltage. When FB falls below 0.56V, after 1msec (typ.) later, the short circuit protection (SCP) operates,
turning the high side MOSFET and low side MOSFET OFF, and performs OFF latch operation.
2-2. OVP Operation
OVP monitors FB voltage. When FB exceeds 0.96V, after 1msec (typ.) later, the output over voltage protection (OVP)
operates, turning the high side FET OFF and the low side FET ON, and performs OFF latch operation.
2-3. Recovery from OFF Latch mode
Off latch is released by EN=OFF or UVLO operation, and then it returns to standard operation.
Figure.19 OCP Timing Chart
Datasheet
Datasheet
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BD95861MUV
TSZ02201-0F3F0AC00130-1-2
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TSZ22111・15・001
3. TSD Operation (Self Recovery)
TSD is self-activating. If the junction temperature exceeds Tj = 175℃, and HG, LG, PGOOD, and SS become Low.
The IC becomes standby when TSD operating.
When Tj falls below 150℃, it returns to standard operation.
4. UVLO Operation
UVLO operates when VREG voltage falls below 4.05V(VIN=6.05V(typ.)), ad HG, LG, PGOOD and SS become Low.
The IC becomes standby when UVLO operating.
UVLO is released when VREG goes up to 4.2V(VIN=6.1V(typ.)), and starts standard operation
Figure.20 SCP Timing Chart
Figure.21 OVP Timing Chart
HG
LG
FB
0.96V
LG=H
FB > REF, HG=L
SS
Normal Operation
OFF LatchOVPNormal Operation
Stand by
1msec(typ)
VREG
EN Latch Release
by EN or UVLO
Datasheet
Datasheet
14/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
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TSZ22111・15・001
●Selection of Components Externally Connected
1. Output LC Filter Selection (Buck Converter)
1-1. Inductor (L) Selection
The Output LC filter is required to supply constant current to the output load. A larger value inductance at this filter results
in less inductor ripple current (IL) and less output ripple voltage. However, the larger value inductors tend to have less
fast load transient-response, a larger physical size, a lower saturation current and higher series resistance. A smaller
value inductance has almost opposite characteristics above.
The recommended inductor values are shown in Table 1(Refer to page 18).
The value of ΔIL is shown as formula (3).
()
IN
OUTOUTIN
LVfL
VVV
I××
×−
= [A] (3)
For example, with VIN = 12 V, VOUT = 3.3 V, L = 2.2μH and the switching frequency f = 600 kHz, the calculated ripple
current ⊿IL is 1.8A.
Then, the inductor saturation current must be larger than the sum of the maximum output current (IOUTMAX) and 1/2 of
the inductor ripple current (IL / 2). A larger current than the inductor’s saturation current will cause magnetic saturation in
the inductor, and decrease efficiency. When selecting an inductor, be sure to allow enough margins to assure that peak
current does not exceed the inductor’s saturation current value.
※To minimize loss of inductor and improve efficiency, choose a inductor with a low resistance (DCR, ACR).
1-2. Output Capacitor (COUT) Selection
Output Capacitor (COUT) has a considerable influence on output voltage regulation due to a rapid load change and
smoothing output ripple voltage. Determine the capacitor by considering the value of capacity, the equivalent series
resistance, and equivalent series inductance. Also, make sure the capacitor’s voltage rating is high enough for the set
output voltage (including ripple).
Output ripple voltage is determined as in formula (4) below.
ΔVOUT=ΔIL/(8×COUT×f)+ESR×ΔIL +ESL×ΔIL / Ton [V] (4)
(
ΔIL Output ripple current、ESR: Equivalent series resistance、ESL: Equivalent series inductance)
Also, give consideration to the conditions in formula (5) below for output capacitance, bearing in mind that output rise
time must be established within the fixed soft start time. As output capacitance, bypass capacitor will be also connected
to output load side (CEXT, Fig.23). Please set the over current detection value with regards to these capacitance.
()
OUT
OUTOCP
OUT V
II1msec
C−×
≤ [F] (5)
(I
OCP : OCP Current Limit, IOUT : Output Current)
Note: an improper output capacitor may cause startup malfunctions.
VIN
IL
L
COUT
VOUT
HG
SW
LG
Figure.22 Inductor Ripple Current
I
t
Inductor saturation current > IOUTMAX +⊿IL /2
Average inductor current
(Output Current：IOUT)
⊿IL
Datasheet
Datasheet
15/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
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TSZ22111・15・001
2. Input Capacitor (CIN) Selection
3. Output Voltage Setting
The IC controls output voltage as REF≒VFB.
However, the actual output voltage will also reflect the average ripple voltage value.
The output voltage is set with a resistor divider from the output node to the FB pin. The formula for output voltage is given
in (7) below:
Output Voltage =×REF +VOUT [V] (7)
REF = V
FB(TYP 0.8V) + 0.02 – (ON DUTY × 0.05) [V] (8)
ON DUTY = (9)
Please refer to eq. (4) regarding VOUT.
Figure.24 Input Capacitor
In order to prevent transient spikes in voltage, the input capacitor should have a lo
w
enough ESR resistance to fully support a large ripple current. The formula for ripple
current IRMS is given in equation (6) as below.
Where VIN =2×VOUT, IRMS=IOUT
2
VIN
L COUT
VOUT
CIN
HG
SW
LG
A
lo
w
ESR capacitor is recommended to reduce ESR loss and improve efficiency.
R1+R2
R2
H3RegTM
CONTROLLA S
RQ
Driver
Circuit
Output Voltage
VOUT
VFB R1
R2
REF
VIN
6
IN
OUTINOUT
OUTRMS V
)V(VV
II −×
×=
VOUT
VIN
Figure.23 Output Capacitor
[A]
Figure.25 Output Voltage Setting
VIN
L
COUT
VOUT
ESR
ESL
HG
SW
LG Load CEXT
Datasheet
Datasheet
16/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
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TSZ22111・15・001
Set ON DUTY in less than maximum ON DUTY
shown in Fig26.(DCR of inductor : 0.05Ω)
This data is the characteristic value, so it’ doesn’t
guarantee the operation range.
4. Relationship between Output Voltage and ON TIME
BD95861MUV is a synchronous buck converter controlling constant ON TIME. The ON TIME (Ton) depends on the output
voltage settings, as described by the formula (10).
55
V
610
V
V
1770Ton
ININ
OUT +−×= [nsec] (10)
The frequency of the application condition is determined by the formula (13) using the above Ton.
Frequency = [kHz] (11)
However with actual applications, there exists a rising and falling time of the SW due to the gate capacitance of the
integrated MOSFET and the switching speed, which may vary the above parameters. Therefore please also verify those
parameters experimentally.
5. Relationship between Output Current and Frequency
BD95861MUV is a constant on time type of switching regulator. When the output current increases, the switching loss of
the inductor, MOSFET, and output capacitor also increases. Hence the switching frequency speeds up.
The loss of the inductor, MOSFET, and output capacitor is determined as below.
(DCR : Inductor Equivalent series resistance、RONH : On resistance of High-side MOSFET、RONL : On resistance of Low-side MOSFET、
ESR :COUT Equivalent series resistance)
Taking the above losses into the frequency equation, then T (=1/Freq) becomes
[nsec] (12)
However since the parasitic resistance of the PCB layout pattern exists in actual applications and affects the parameter,
please also verify experimentally.
VOUT
VIN ×1
Ton
① Loss of Inductor = IOUT2 × DCR
VIN
VOUT
② Loss of MOSFET (High Side) = IOUT2 × R
ONH ×
VIN
③ Loss of MOSFET (Low Side) = IOUT2 × R
ONL × (1 - VOUT )
④ Loss of Output Capacitor = IOUT2 × ESR
VIN × IOUT × Ton
VOUT × IOUT + ① + ② + ③ + ④
T (=1/Freq) =
Figure.26 Max On Duty in each output current
0.4
0.5
0.6
0.7
0123456
Iout [A]
Max ON Duty : VOUT / VIN
Datasheet
Datasheet
17/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
www.rohm.com
TSZ22111・15・001
●PCB Layout Guide
Two high pulsing current flowing loops exist in the buck regulator system.
The first loop, when FET is ON, starts from the input capacitors, to the VIN terminal, to the SW terminal, to the inductor, to
the output capacitors, and then returns to the input capacitor through GND.
The second loop, when FET is OFF, starts from the low FET, to the inductor, to the output capacitor, and then returns to the
low FET through GND.
To reduce the noise and improve the efficiency, please minimize these two loop area.
Especially input capacitor and output capacitor should be connected to GND (PGND) plain.
PCB Layout may affect the thermal performance, noise and efficiency greatly. So please take extra care when designing
PCB Layout patterns.
・The thermal Pad on the back side of IC has the great thermal conduction to the chip. So using the GND plain as broad and
wide as possible can help thermal dissipation. And a lot of thermal via for helping the spread of heat to the different layer is
also effective.
・The input capacitors should be connected to PGND as close as possible to the VIN terminal.
・The inductor and the output capacitors should be placed close to SW pin as much as possible.
CIN FET COUT
L VOUT
VIN
Figure.27 Current loop Buck regulator system
Datasheet
Datasheet
18/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
www.rohm.com
TSZ22111・15・001
●List of Evaluation Board Circuit
Table 1. Recommended BOM List(VIN=12V)
Symbol Part Value Manufacture Series
C1,2 Capacitor 10F (25V) Murata GRM31CR71E16KA12
C3,4 Capacitor 22F (16V) Murata GRM31CB31C226ME15
C5 Capacitor 0.1F(50V) Murata GRM18 Series
C6 Capacitor 4.7F (16V) Murata GRM31 Series
R1 Resistance 20 ROHM MCR03 Series
R2 Resistance ※ ROHM MCR03 Series
R3 Resistance ※ ROHM MCR03 Series
R4 Resistance ※ ROHM MCR03 Series
R5 Resistance 100k ROHM MCR03 Series
L1 Coil ※ TDK SPM6530 Series
ALPS GLMC Series
SW1 - 2 point switch
※
The above components list is an example. Please check actual circuit characteristics on the application carefully before use.
V
OUT R2 R3 R4 L1
1.0V 130 360 2.2k 1.5H
1.2V 220 2k 4.7k 1.5H
1.8V 110 5.6k 4.7k 2.2H
3.3V 1.5k 13k 4.7k 2.2H
5.0V 680 24k 4.7k 2.2H
Figure.28 Typical Application Circuit
1
2
3
4
5
6
7 8 9 10 11 12
13
14
15
16
17
18
192021222324
VIN
VIN
VIN
VIN
PGND
PGND
PGND
PGND
PGND
SW
SW
SW
PGOOD
EN
BOOT
SW
SW
SW
VIN
TEST
VREG
GND
FB
VOUT
C2C1
VIN
C6
Thermal Pad
VOUT
C4C3
L1
C5
R4 R3
PGOOD
R5 VREG
R1
EN
R2
Datasheet
Datasheet
19/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
www.rohm.com
TSZ22111・15・001
●I/O Equivalence circuit
VIN SW BOOT
EN PGOOD VOUT
FB VREG
BOOT
VREGSW
SW
BOOT
VIN
167k
833k
EN
PGOOD
VOUT
FB
VIN BOOT
VREG
VIN
SW VREG
Datasheet
Datasheet
20/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
www.rohm.com
TSZ22111・15・001
●Operational Notes
(1) Absolute Maximum Ratings
Use of the IC in excess of absolute maximum ratings may result in damage to the IC. Assumptions should not be made
regarding the state of the IC (e.g., short mode or open mode) when such damage is suffered. If operational values are
expected to exceed the maximum ratings for the device, consider adding protective circuitry (such as fuses) to eliminate
the risk of damaging the IC.
(2) GND voltage
The potential of the GND, PGND pin must be the minimum potential in the system in all operating conditions.
(3) Thermal design
Use a thermal design that allows for a sufficient margin for power dissipation (Pd) under actual operating conditions
(4) Inter-pin Shorts and Mounting Errors
Use caution when orienting and positioning the IC for mounting on printed circuit boards. 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
poor soldering or foreign objects may result in damage to the IC.
(5) Operation in Strong Electromagnetic Fields
Using this product in strong electromagnetic fields may cause IC malfunction. Caution should be exercised in
applications where strong electromagnetic fields may be present.
(6) ASO (Area of Safe Operation)
When using the IC, ensure that operating conditions do not exceed absolute maximum ratings or ASO of the output
transistors.
(7) Testing on application boards
When testing the IC on an application board, connecting a capacitor directly to a low-impedance 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 a jig or fixture during the evaluation process. To prevent
damage from static discharge, ground the IC during assembly and use similar precautions during transport and storage.
(8) Electrical Characteristics
The electrical characteristics indicated in this datasheet may change upon the conditions of temperature, supply voltage,
and external components. Please validate/verify your design at the worst case conditions.
(9) Not of a radiation-resistant design.
(10) Back Electromotive Force
If a large inductive load is connected at the output pin that might cause introducing back electromotive force at the start
up and at the output disable, please insert protection diodes.
(11) Regarding input pins of the IC
This monolithic IC contains P+ isolation and P substrate layers between adjacent elements in order to keep them isolated.
PN junctions are formed at the intersection of these P layers with the N layers of other elements, creating parasitic
diodes and/or transistors. For example (refer to the figure below):､
•When GND > Pin A and GND > Pin B, the PN junction operates as a parasitic diode
•When GND > Pin B, the PN junction operates as a parasitic transistor
Parasitic diodes occur inevitably in the structure of the IC, and the operation of these parasitic diodes can result in mutual
interference among circuits, operational faults, or physical damage. Accordingly, 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.
OUTPUT
PIN
Figure.29 Back Electromotive Force
Datasheet
Datasheet
21/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
www.rohm.com
TSZ22111・15・001
(12) Ground Wiring Pattern
When using both small-signal and large-current GND traces, the two ground traces should be routed separately but
connected to a single ground potential within the application in order to avoid variations in the small-signal ground
caused by large currents. Also ensure that the GND traces of external components do not cause variations on GND
voltage.
(13) Operating Condition
The electrical characteristics indicated in this datasheet are not guaranteed for the whole operational and temperature
ranges, however these characteristics do not significantly fluctuate within the operational and temperature ranges.
(14) Thermal shutdown (TSD) circuit
The IC incorporates a built-in thermal shutdown circuit, which is designed to turn the IC off completely in the event of
thermal overload. It is not designed to protect the IC from damage or guarantee its operation. ICs should not be used
after this function has activated, or in applications where the operation of this circuit is assumed. If the thermal
shutdown is activated while the load current exists, the output may possibly be latched off at the release of the thermal
shutdown.
(15) Heat Sink (FIN)
The heat sink (FIN) is connected to the substrate. Please connect it to GND.
TSD ON Temp.[℃] (typ.) Hysteresis Temp[℃] (typ.)
175 25
Figure.30 Example of IC structure
ResistorTransistor (NPN)
N N N P+ P+
P
P substrate
GND
Parasitic element
Pin A
N
N P+ P+
P
P substrate
GND
Parasitic element
Pin B
C B
E
N
GND
Pin A
Parasitic
element
Pin B
Other adjacent
elements
E
B C
GND
Parasitic
element
Datasheet
Datasheet
22/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
www.rohm.com
TSZ22111・15・001
●Thermal Derating Curves
●Ordering Information
B D 9 5 8 6 1 M U V - E 2
Part Numbe
r
Package
MUV: VQFN024V4040
Packaging and forming specification
E2: Embossed tape and reel
●Physical Dimension Tape and Reel Information
●Marking Diagram
Figure.31 Thermal derating curve
(VQFN024V4040)
(1) 4 layer board
(All layers with 5505 mm2 copper heat dissipation pads)
θj-a=35.1℃/W
(2) 4 layer board
(6.28 mm2 copper heat dissipation pad on top and bottom layer,
5505 mm2 pad on 2nd and 3rd layer)
θj-a=56.8℃/W
(3) 1 layer board (6.28 mm2 copper heat dissipation pad)
θj-a=181.2℃/W
VQFN024V4040
(
Unit:mm
)
Ambient temperature[℃]
Power dissipation[W]
050 100 150
0.5
1
1.5
2
2.5
3
4
3.5
(3)0.70W
(2)2.20W
(1)3.55W
VQFN024V4040 (TOP VIEW)
95861
Part Number Marking
LOT Number
1PIN MARK
Datasheet
Datasheet
23/23
BD95861MUV
TSZ02201-0F3F0AC00130-1-2
10.Aug.2017 Rev.005
© 2012 ROHM Co., Ltd. All rights reserved.
www.rohm.com
TSZ22111・15・001
●Revision History
Date Revision Changes
30.Aug.2012 001
New Release
18.Mar.2013 002
Revised the General Description
16.Apr.2014 003
Added the max on-duty graph of output voltage setting
18.Mar.2014 004
Revised the recommended BOM list
10.Aug.2017 005
Revised Tape and Reel Information, and Marking Diagram
Notice-PGA-E Rev.003
© 2015 ROHM Co., Ltd. All rights reserved.
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
intend to use our Products in devices requiring extremely high reliability (such as medical equipment (Note 1), transport
equipment, traffic equipment, aircraft/spacecraft, nuclear power controllers, fuel controllers, car equipment including car
accessories, safety devices, etc.) and whose malfunction or failure may cause loss of human life, bodily injury or
serious damage to property (“Specific Applications”), please consult with the ROHM sales representative in advance.
Unless otherwise agreed in writing by ROHM in advance, ROHM shall not be in any way responsible or liable for any
damages, expenses or losses incurred by you or third parties arising from the use of any ROHM’s Products for Specific
Applications.
(Note1) Medical Equipment Classification of the Specific Applications
JAPAN
USA
EU
CHINA
CLASSⅢ
CLASSⅢ
CLASSⅡb
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 depending on ambient temperature. When used in sealed area, confirm that it is the use in
the range that does not exceed the maximum junction temperature.
8. Confirm that operation temperature is within the specified range described in the product specification.
9. ROHM shall not be in any way responsible or liable for failure induced under deviant condition from what is defined 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 Rev.003
© 2015 ROHM Co., Ltd. All rights reserved.
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
A two-dimensional barcode printed on ROHM Products label is for ROHM’s internal use only.
Precaution for Disposition
When disposing Products please dispose them properly using an authorized industry waste company.
Precaution for Foreign Exchange and Foreign Trade act
Since concerned goods might be fallen under listed items of export control prescribed by Foreign exchange and Foreign
trade act, please consult with ROHM in case of export.
Precaution Regarding Intellectual Property Rights
1. All information and data including but not limited to application example contained in this document is for reference
only. ROHM does not warrant that foregoing information or data will not infringe any intellectual property rights or any
other rights of any third party regarding such information or data.
2. ROHM shall not have any obligations where the claims, actions or demands arising from the combination of the
Products with other articles such as components, circuits, systems or external equipment (including software).
3. No license, expressly or implied, is granted hereby under any intellectual property rights or other rights of ROHM or any
third parties with respect to the Products or the information contained in this document. Provided, however, that ROHM
will not assert its intellectual property rights or other rights against you or your customers to the extent necessary to
manufacture or sell products containing the Products, subject to the terms and conditions herein.
Other Precaution
1. This document may not be reprinted or reproduced, in whole or in part, without prior written consent of ROHM.
2. The Products may not be disassembled, converted, modified, reproduced or otherwise changed without prior 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.
DatasheetDatasheet
Notice – WE Rev.001
© 2015 ROHM Co., Ltd. All rights reserved.
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 any 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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