Datasheet
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TSZ22111･14･001 1/15 03.July.2014 Rev.005
Voltage Detector IC Series
Counter Timer Built-in
CMOS Voltage Detector IC
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●General Description
ROHM’s BU45xxxxx and BU46xxxxx series are highly
accurate, low current consumption voltage detector IC
series. Because the counter timer delay circuit is built-in,
an external capacitor for the delay time setting is
unnecessary. Two output types are available (Nch open
drain and CMOS output) and detection voltages range
from 2.3V to 4.8V in increments of 0.1V with fixed delay
time of 200ms and 400ms, that may be selected
according to application.
●Features
Counter Timer Built-in
No delay time setting capacitor required
Low current consumption
Two output types (Nch open drain and CMOS output)
Package SSOP3 is similar to SOT-23-3 (JEDEC)
Key Specifications
Detection voltage: 2.3V to 4.8V (Typ.)
0.1V steps
High accuracy detection voltage: ±1.0%
Low current consumption: 2.3µA (Typ.)
Operating temperature range: -40°C to +105°C
Two internal, fixed delay time: 200ms
400ms
●Package
SSOP3 2.92mm x 2.80mm x 1.25mm
●Applications
Circuits using microcontrollers or logic circuits that require
a reset
●Typical Application Circuit
●Connection Diagram
●Pin Descriptions
BU45KxxxG / BU46KxxxG
BU45LxxxG / BU46LxxxG
PIN No. Symbol Function
1 GND GND
2 VOUT Reset Output
3 VDD Power Supply Voltage
PIN No. Symbol Function
1 VOUT Reset Output
2 VDD Power Supply Voltage
3 GND GND
（Open Drain Output Type）
BU45xxxxx series （CMOS Output Type）
BU46xxxxx series
○Product structure：Silicon monolithic integrated circuit ○This product is not designed for protection against radioactive rays.
V
DD1
V
DD2
GND
BU45x
x
x
xx
C
L
（
Noise-filtering
Capacitor
）
RL
R
ST Micro
controller
TOP VI
EW
SSOP3
BU45Kxxx
xxxxxx
xxxG
BU46Kxxx
xxxxxx
xxxG
1
2
3
VOUT
VDD
GND
C
L
（Noise-filtering
Capacitor
）
V
DD1
GND
BD46xx
x
xx
R
ST
Micro
controller
BU45Lxxx
xxxxxx
xxxG
BU46Lxxx
xxxxxx
xxxG
1
2
3
GND VOUT
VDD
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TSZ22111･15･001 2/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
B
BB
B U
UU
U x
xx
x x
xx
x x
xx
x x
xx
x x
xx
x x
xx
x x
xx
x -
--
- T
TT
T L
LL
L
Part Output Type Package 1 Reset Voltage Value Counter Timer Package 2 Packaging and
Number 45 : Open Drain 23 : 2.3V Delay Time Settings forming specification
46 : CMOS 0.1V step 2 : 200ms TL : Embossed tape
48 : 4.8V 4 : 400ms and reel
Package 1
Package 2 Package name
K G SSOP3 (1pin GND)
L G SSOP3 (3pin GND)
●Ordering Information
●Lineup
Table 1. Open Drain Output Type
Counter Timer Delay Time Settings
1-Pin GND 3-Pin GND
200ms 400ms 200ms 400ms
Detection
Voltage Marking
Part
Number Marking Part
Number Marking Part
Number Marking Part
Number
4.8V
bH
BU45K482
eF
BU45K484
hD
BU45L482
nB
BU45L484
4.7V
bG
BU45K472
eE
BU45K474
hC
BU45L472
nA
BU45L474
4.6V
bF
BU45K462
eD
BU45K464
hB
BU45L462
mY
BU45L464
4.5V
bE
BU45K452
eC
BU45K454
hA
BU45L452
mX
BU45L454
4.4V
bD
BU45K442
eB
BU45K444
gY
BU45L442
mW
BU45L444
4.3V
bC
BU45K432
eA
BU45K434
gX
BU45L432
mT
BU45L434
4.2V
bB
BU45K422
dY
BU45K424
gW
BU45L422
mS
BU45L424
4.1V
bA
BU45K412
dX
BU45K414
gT
BU45L412
mR
BU45L414
4.0V
aY
BU45K402
dW
BU45K404
gS
BU45L402
mP
BU45L404
3.9V
aX
BU45K392
dT
BU45K394
gR
BU45L392
mN
BU45L394
3.8V
aW
BU45K382
dS
BU45K384
gP
BU45L382
mM
BU45L384
3.7V
aT
BU45K372
dR
BU45K374
gN
BU45L372
mK
BU45L374
3.6V
aS
BU45K362
dP
BU45K364
gM
BU45L362
mH
BU45L364
3.5V
aR
BU45K352
dN
BU45K354
gK
BU45L352
mG
BU45L354
3.4V
aP
BU45K342
dM
BU45K344
gH
BU45L342
mF
BU45L344
3.3V
aN
BU45K332
dK
BU45K334
gG
BU45L332
mE
BU45L334
3.2
V
aM
BU45K322
dH
BU45K324
gF
BU45L322
mD
BU45L324
3.1V
aK
BU45K312
dG
BU45K314
gE
BU45L312
mC
BU45L314
3.0V
aH
BU45K302
dF
BU45K304
gD
BU45L302
mB
BU45L304
2.9V
aG
BU45K292
dE
BU45K294
gC
BU45L292
mA
BU45L294
2.8V
aF
BU45K282
dD
BU45K284
gB
BU45L282
kY
BU45L284
2.7V
aE
BU45K272
dC
BU45K274
gA
BU45L272
kX
BU45L274
2.6V
aD
BU45K262
dB
BU45K264
fY
BU45L262
kW
BU45L264
2.5V
aC
BU45K252
dA
BU45K254
fX
BU45L252
kT
BU45L254
2.4V
aB
BU45K242
cY
BU45K244
fW
BU45L242
kS
BU45L244
2.3V
aA
BU45K232
cX
BU45K234
fT
BU45L232
kR
BU45L234
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TSZ22111･15･001 3/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
●Lineup - Continued
Table 2. CMOS Output Type
Counter Timer Delay Time Settings
1-Pin GND 3-Pin GND
200ms 400ms 200ms 400ms
Detection
Voltage Marking
Part
Number Marking Part
Number Marking Part
Number Marking Part
Number
4.8V
cW
BU46K482
fS
BU46K484
kP
BU46L482
p
M
BU46L484
4.7V
cT
BU46K472
fR
BU46K474
kN
BU46L472
p
K
BU46L474
4.6V
cS
BU46K462
fP
BU46K464
kM
BU46L462
p
H
BU46L464
4.5V
cR
BU46K452
fN
BU46K454
kK
BU46L452
p
G
BU46L454
4.4V
cP
BU46K442
fM
BU46K444
kH
BU46L442
p
F
BU46L444
4.3V
cN
BU46K432
fK
BU46K434
kG
BU46L432
p
E
BU46L434
4.2V
cM
BU46K422
fH
BU46K424
kF
BU46L422
p
D
BU46L424
4.1V
cK
BU46K412
fG
BU46K414
kE
BU46L412
p
C
BU46L414
4.0V
cH
BU46K402
fF
BU46K404
kD
BU46L402
p
B
BU46L404
3.9V
cG
BU46K392
fE
BU46K394
kC
BU46L392
p
A
BU46L394
3.8V
cF
BU46K382
fD
BU46K384
kB
BU46L382
nY
BU46L384
3.7V
cE
BU46K372
fC
BU46K374
kA
BU46L372
nX
BU46L374
3.6V
cD
BU46K362
fB
BU46K364
hY
BU46L362
nW
BU46L364
3.5V
cC
BU46K352
fA
BU46K354
hX
BU46L352
nT
BU45L354
3.4V
cB
BU46K342
eY
BU46K344
hW
BU46L342
nS
BU46L344
3.3V
cA
BU46K332
eX
BU46K334
hT
BU46L332
nR
BU46L334
3.
2
V
bY
BU46K322
eW
BU46K324
hS
BU46L322
nP
BU46L324
3.1V
bX
BU46K312
eT
BU46K314
hR
BU46L312
nN
BU46L314
3.0V
bW
BU46K302
eS
BU46K304
hP
BU46L302
nM
BU46L304
2.9V
bT
BU46K292
eR
BU46K294
hN
BU46L292
nK
BU46L294
2.8V
bS
BU46K282
eP
BU46K284
hM
BU46L282
nH
BU46L284
2.7V
bR
BU46K272
eN
BU46K274
hK
BU46L272
nG
BU46L274
2.6V
bP
BU46K262
eM
BU46K264
hH
BU46L262
nF
BU46L264
2.5V
bN
BU46K252
eK
BU46K254
hG
BU46L252
nE
BU46L254
2.4V
bM
BU46K242
eH
BU46K244
hF
BU46L242
nD
BU46L244
2.3V
bK
BU46K232
eG
BU46K234
hE
BU46L232
nC
BU46L234
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TSZ22111･15･001 4/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
Absolute maximum ratings (Ta=25°C)
Parameter Symbol Limit Unit
Power Supply Voltage VDD-GND -0.3 to +6.0 V
Output Voltage Nch Open Drain Output VOUT GND-0.3 to +6.0 V
CMOS Output GND-0.3 to VDD+0.3
Output Current Io 70 mA
Power Dissipation (Note1, Note2) Pd 700 mW
Operating Temperature Topr -40 to +105 °C
Ambient Storage Temperature Tstg -55 to +125 °C
(Note 1) Use above Ta=25°C results in a 7.0mW loss per degree.
(Note 2) When mounted on ROHM standard circuit board (70mmx70mmx1.6mm, glass epoxy board).
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 and the internal circuitry. 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.
●Electrical characteristics (Unless Otherwise Specified Ta=-40 to 105°C)
Parameter Symbol Condition Limit Unit
Min. Typ. Max.
Operating Voltage Range VOPL VOL≤0.4V, RL=470kΩ, Ta=25~105°C 0.6 - 6.0 V
VOL≤0.4V, RL=470kΩ, Ta=-40~25°C 0.9 - 6.0
Detection Voltage VDET
VDD=HL, RL=470kΩ (Note 1)
VDET(T)
×0.99 VDET(T)
VDET(T)
×1.01
V
VDET=2.5V Ta=25°C 2.475 2.5 2.525
Ta=-40°C to 85°C 2.418 - 2.584
Ta=85°C to 105°C 2.404 - 2.597
VDET=3.0V Ta=25°C 2.970 3.0 3.030
Ta=-40°C to 85°C 2.901 - 3.100
Ta=85°C to 105°C 2.885 - 3.117
VDET=3.3V Ta=25°C 3.267 3.3 3.333
Ta=-40°C to 85°C 3.191 - 3.410
Ta=85°C to 105°C 3.173 - 3.428
VDET=4.2V Ta=25°C 4.158 4.2 4.242
Ta=-40°C to 85°C 4.061 - 4.341
Ta=85°C to 105°C 4.039 - 4.364
VDET=4.8V Ta=25°C 4.752 4.8 4.848
Ta=-40°C to 85°C 4.641 - 4.961
Ta=85°C to 105°C 4.616 - 4.987
Detection Voltage
Temperature coefficient VDET/∆T -40°C~105°C - ±50 ±360 ppm/°C
Hysteresis Voltage ∆VDET VDD＝LHL, RL=470kΩ VDET(T)
×0.03 VDET(T)
×0.05 VDET(T)
×0.08 V
‘High’ Output
Delay time tPLH
CL=100pF,
RL=100kΩ
( Note1,
Note 2,
Note 3 )
BU4XXXX2G Ta=25°C 120 200 280
ms
Ta=-40°C to 85°C 95 - 460
Ta=85°C to 105°C
85 - 235
BU4XXXX4G Ta=25°C 240 400 560
Ta=-40°C to 85°C 190 - 920
Ta=85°C to 105°C
170 - 470
Circuit Current when ON IDD1 VDD=VDET-0.2V, VDET=2.3V~4.8V 0.60 2.30 7.00 µA
Circuit Current when OFF IDD2 VDD=VDET+1.0V, VDET=2.3V~4.8V 1.10 2.80 8.00 µA
‘High’ Output Voltage (Pch) VOH VDD=5.0V, ISOURCE= 6.8mA, VDET(4.3V to 4.8V) VDD-0.5
- V
‘Low’Output Voltage (Nch) VOL VDD=1.2V, ISINK = 2.0mA - - 0.3 V
VDD=2.4V, ISINK = 8.5mA, VDET(2.7V to 4.8V) - - 0.3 V
Leak Current when OFF Ileak VDD=VDS=6.0V (Note 1) - - 1.0 µA
VDET(T):Standard Detection Voltage (2.3V to 4.8V, 0.1V step)
RL :Pull-up resistor to be connected between VOUT and power supply.
CL :Capacitor to be connected between VOUT and GND.
(Note 1) Guarantee is Ta=25°C.
(Note 2) tPLH:VDD=(VDET(T)-0.5V)(VDET(T)+0.5V)
(Note 3) tPLH:VDD=Please set up the rise up time between VDD=VOPLVDET more than 10µs.
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TSZ22111･15･001 5/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
●Block Diagrams
Fig.1 BU45xxxxx Series
Fig.2 BU46xxxxx Series
Vref
VOUT
V
DD
GND
Oscillator
Circuit Counter
Timer
VOUT
Vref
V
DD
GND
Oscillator
Circuit Counter
Timer
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TSZ22111･15･001 6/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
●Typical Performance Curves
0
1
2
3
4
5
6
01234567
CIRCUIT CURRENT:I
DD
[uA]
VDD SUPPLY VOLTAGE: V
DD
[V]
Ta=105°C
Ta=-40°C
Ta=25°C
[BU45K232G]
Fig.3 Circuit Current
0
2
4
6
8
10
12
14
16
0 1 2 3 4 5 6 7
"LOW" OUTPUT CURRENT:IOL[mA]
DRAIN-SOURCE VOLTAGE: VDS[V]
Ta=-40°C
Ta=105°C
Ta=25°C
[BU45K232G]
Fig.4 “LOW” Output Current
VDD=1.2V
0
10
20
30
40
50
012345
"HIGH" OUTPUT CURRENT:IOH[mA]
DRAIN-SOURCE VOLTAGE: VDS[V]
Ta=-40°C
Ta=105°C
Ta=25°C
[BU46K232G]
Fig.5 “HIGH” Output Current
VDD=3.9V
0
1
2
3
4
5
6
7
8
0 1 2 3 4 5 6 7
OUTPUT VOLTAGE:VOUT[V]
VDD SUPPLY VOLTAGE: VDD[V]
Ta=-40°C
Ta=105°C
Ta=25°C
[BU45K232G]
Fig.6 I/O Characteristics
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TSZ22111･15･001 7/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
2.1
2.2
2.3
2.4
2.5
2.6
-40 -20 0 20 40 60 80 100
DETECTION VOLTAGE:VOUT[V]
TEMPERATURE:Ta[°C]
[BU45K232G]
Low to high (V
DET
+ ∆V
DET
)
High to low (V
DET
)
1.0
1.2
1.4
1.6
1.8
2.0
2.2
2.4
2.6
2.8
3.0
-40 -20 0 20 40 60 80 100
CIRCUIT CURRENT WHEN ON :IDD1[uA]
TEMPERATURE: Ta[°C]
[BU45K232G]
●Typical Performance Curves - Continued
Fig.7 Detection Voltage
Release Voltage
Fig.8 Circuit Current when ON
(VDD=VDET-0.2V)
VDD=2.1V
1.5
1.7
1.9
2.1
2.3
2.5
2.7
2.9
3.1
3.3
3.5
-40 -20 0 20 40 60 80 100
CIRCUIT CURRENT WHEN OFF:IDD2 [uA]
TEMPERATURE: Ta[
°
C]
[BU45K232G]
Fig.9 Circuit Current when OFF
(VDD=VDET+1V)
VDD=3.3 V
0.0
0.1
0.2
0.3
0.4
0.5
0.6
-40 -20 0 20 40 60 80 100
MINIMUM OPERATING VOLTAGE:VOPL[V]
TEMPERATURE: Ta[°C]
[BU45K232G]
Fig.10 Operating Limit Voltage
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TSZ22111･15･001 8/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
●Typical Performance Curves - Continued
100
120
140
160
180
200
220
240
260
280
300
-40 -20 0 20 40 60 80 100
"HIGH" DELAY TIME:TPLH [ms]
TEMPERATURE: Ta[
°
C]
[BU45K232G]
Fig.11 Output Delay Time
“Low” → “High”
0.0
1.0
2.0
3.0
-40 -20 0 20 40 60 80 100
"LOW" DELAY TIME TPHL [µs]
TEMPERATURE: Ta[
°
C]
[BU45K232G]
Fig.11 Output Delay Time
“High” → “Low”
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TSZ22111･15･001 9/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
●Application Information
Explanation of Operation
For both the open drain type (Fig.13) and the CMOS output type (Fig.14), the detection and release voltages are used as
threshold voltages. When the voltage applied to the VDD pins reaches the applicable threshold voltage, the VOUT terminal
voltage switches from either “High” to “Low” or from “Low” to “High”. Because the BU45xxxxx series uses an open drain
output type, it is necessary to connect a pull-up resistor to VDD or another power supply if needed [The output “High” voltage
(VOUT) in this case becomes VDD or the voltage of the other power supply].
Fig.13 (BU45xxxxx Type Internal Block Diagram) Fig.14 (BU46xxxxx Type Internal Block Diagram)
Reference Data
Examples of Leading (tPLH) and Falling (tPHL) Output
Part Number tPLH[ms] tPHL[µs]
BU45K232G 208 1.4
BU46K232G 208 1.4
VDD=1.8V2.8V VDD=2.8V1.8V
*This data is for reference only.
The figures will vary with the application, so please confirm actual operating conditions before use.
Timing Waveform
Example: The following shows the relationship between the input voltages VDD and the output voltage VOUT when the input
power supply voltage VDD is made to sweep up and sweep down (the circuits are those in Fig. 13 and 14).
1
When the power supply is turned on, the output is unstable from
after over the operating limit voltage (VOPL) until tPHL. Therefore it is
possible that the reset signal is not outputted when the rise time of
VDD is faster than tPHL.
2
When VDD is greater than VOPL but less than the reset release
voltage (VDET + ∆VDET), the output voltages will switch to Low.
3
If VDD exceeds the reset release voltage (VDET + ∆VDET), the
counter timer start and VOUT switches from L to H.
4
If VDD drops below the detection voltage (VDET) when the power
supply is powered down or when there is a power supply fluctuation,
VOUT switches to L (with a delay of tPHL).
5
The potential difference between the detection voltage and the
release voltage is known as the hysteresis width (∆VDET). The
system is designed such that the output does not toggle with power
supply fluctuations within this hysteresis width, thus, preventing
malfunctions due to noise.
Timing may change depending on application and use. Please verify and confirm using practical applications.
Fig.15 Timing Waveform
V
DD
VDET+ΔVDET
VDET
V
OPL
0V
tPHL
①
②
V
OUT tPLH
tPHL
tPLH
③
V
OL
V
OH
V
DD
④
⑤
Vref
R1
R2
R3
V
DD
GND
Oscillator
Circuit Counter
Timer Q1
V
OUT
V
DD
Reset
GND
Reset
Q2
Q1
Vref
R1
R2
R3
VDD
Oscillator
Circuit Counter
Timer
VOUT
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TSZ22111･15･001 10/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
●Circuit Applications
1. Examples of a common power supply detection reset circuit.
Application examples of BU45xxxxx series (Open Drain
output type) and BU46xxxxx series (CMOS output type)
are shown below.
CASE1: Power supply of microcontroller (V
DD
2) differs
from the power supply of the reset detection (V
DD
1).
Use an open drain output Type (BU45xxxxx series)
device with a load resistance R
L
as shown Fig.16.
CASE2: Power supply of the microcontroller (V
DD1
) is
same as the power supply of the reset detection (V
DD1
).
Use a CMOS output type (BU46xxxxx) device or an open
drain output type (BU45xxxxx) with pull up resistor
between the output and V
DD1
. (As shown Fig.17)
When a capacitance C
L
for noise filtering is connected to
the V
OUT
pin (the reset signal input terminal of the
microcontroller), please take into account the waveform of
the rise and fall of the output voltage (V
OUT
).
2. The following is an example of a circuit application in which an OR connection between two types of detection voltage
resets the microcontroller.
Fig. 18
To reset the microcontroller when many independent power supplies are used in the system, OR connect an open drain
output type (BU45xxxxx series) to the microcontroller’s input with pull-up resistor to the supply voltage of the
microcontroller (V
DD3
) as shown in Fig. 18. By pulling-up to V
DD3
, output “High” voltage of micro-controller power supply is
possible.
Fig.16 Open Drain Output Type
Fig.17 CMOS Output Type
V
DD1
V
DD2
GND
BU45xxxxx
C
L
（Noise-filtering
Capacitor）
R
L
R
ST
Micro
controller
C
L
（Noise-filtering
Capacitor）
V
DD1
GND
BU46xxxxx
R
ST
Micro
controller
V
DD2
V
DD1
V
DD3
GND
R
ST
Micro
controller
R
L
BU45xxxxx BU45xxxxx
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TSZ22111･15･001 11/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
Examples of the power supply with resistor dividers.
In applications wherein the power supply voltage of an IC comes from a resistor divider circuit, an in-rush current will flow
into the circuit when the output level switches from “High” to “Low” or vice versa. In-rush current is a sudden surge of
current that flows from the power supply (VDD) to ground (GND) as the output logic changes its state. This current flow
may cause malfunction in the systems operation such as output oscillations, etc.
Fig. 19
When an in-rush current (I1) flows into the circuit (Refer to Fig. 19) at the time when output switches from “Low” to “High”,
a voltage drop of I1×R2 (input resistor) will occur in the circuit causing the VDD supply voltage to decrease. When the VDD
voltage drops below the detection voltage, the output will switch from “High” to “Low”. While the output voltage is at “Low”
condition, in-rush current will stop flowing and the voltage drop will be reduced. As a result, the output voltage will switches
again from “Low” to “High” which causes an in-rush current and a voltage drop. This operation repeats and will result to
oscillation.
VOUT
R2
VDD
BU45xxxxx
BU46xxxxx
GND
R1
I1
V1
CIN
CL
IDD
VDD
VDET
0
In-rush Current
Fig. 20 Current Consumption vs. Power Supply Voltage
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TSZ22111･15･001 12/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
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
terminals.
2. Power Supply Lines
Design the PCB layout pattern to provide low impedance ground and 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 GND 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 GND traces of external components do not cause variations on
the GND voltage. The power supply and 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. The absolute maximum rating of the Pd stated in this specification is when
the IC is mounted on a 70mm x 70mm x 1.6mm glass epoxy board. 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. Rush 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 GND 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. 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.
11. Unused Input Terminals
Input terminals 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 terminals should be connected to
the power supply or ground line.
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TSZ22111･15･001 13/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
12. 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. 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.
Figure 21. Example of monolithic IC structure
13. Ceramic Capacitor
When using a ceramic capacitor, determine the dielectric constant considering the change of capacitance with
temperature and the decrease in nominal capacitance due to DC bias and others.
14. Bypass Capacitor for Noise Rejection
To help reject noise, put a 1µF capacitor between VDD pin and GND and 1000pF capacitor between VOUT pin and
GND. Be careful when using extremely big capacitor as transient response will be affected.
15. The VDD line impedance might cause oscillation because of the detection current.
16. A VDD to GND capacitor (as close connection as possible) should be used in high VDD line impedance condition.
17. External Parameters
The recommended parameter range for RL is 50kΩ to 470kΩ. There are many factors (board layout, etc) that can
affect characteristics. Please verify and confirm using practical applications.
18. Lower than the mininum input voltage puts the VOUT in high impedance state, and it must be VDD in pull up (VDD)
condition.
19. Power-on Reset Operation
Please note that the power on reset output varies with the VDD rise time. Please verify the behavior in the actual
operation.
20. This IC has extremely high impedance terminals. Small leak current due to the uncleanness of PCB surface might
cause unexpected operations. Application values in these conditions should be selected carefully.
www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ02201-0R7R0G300130-1-2
TSZ22111･15･001 14/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
Physical Dimension, Tape and Reel Information
Package Name SSOP3
www.rohm.com © 2014 ROHM Co., Ltd. All rights reserved. TSZ02201-0R7R0G300130-1-2
TSZ22111･15･001 15/15 03.July.2014 Rev.005
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
●
●●
●Revision History
Date Revision Changes
03.Feb.2014 004 New Release
03.July.2014 005 Updated Fig.5 VDD condition
Updated Operational Notes and Notice
Datasheet
Datasheet
Notice – GE Rev.002
© 2013 ROHM Co., Ltd. All rights reserved.
Notice
Precaution on using ROHM Products
1. Our Products are designed and manufactured for application in ordinar y elec tronic eq uipm ents (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, RO HM shall not be in any way responsible or liable for any
damages, expenses or losses incurred b y you or third parti es arising from the use of an y ROHM’s Prod ucts 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 d esign against the physical injur y, damage to any property, which
a failure or malfunction of our Products may cause. T he following are examples of safet y 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-produci ng comp onents, 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 flu x (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 nor mal rated power; exceeding the power rating under steady-state loading condition may negatively affect
product performance and reliability.
7. De-rate Power Dissipation (Pd) depe nding on Ambient temper ature (Ta). When us ed 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 an y way responsible or liable for failure induced un der deviant condition from what is defined in
this document.
Precaution for Mounting / Circuit board design
1. When a highly active halogenous (chlor ine, bromine, etc.) flux is used, the residue of flux ma y negatively affect product
performance and reliability.
2. In principle, the reflow soldering method must be used; if flow soldering method is preferred, please consult with the
ROHM representative in advance.
For details, please refer to ROHM Mounting specificati on
Datasheet
Datasheet
Notice – GE Rev.002
© 2013 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 indepe ndent verificati on and judgme nt in the use of such information
contained in this document. ROHM shall no t be in any way responsible or lia ble 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 t ake special care under dry con dition (e.g. Grounding of human body / equipment / sol der iron,
isolation from charged objects, setting of Ionizer, friction prevention and temperature / humidity control).
Precaution for Storage / Transportati on
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, i nclud ing 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 condensatio n
[d] the Products are exposed to high Electrostatic
2. Even under ROHM recommended storage condition, sold erability of products out of recommende d storage time period
may be degraded. It is strongly recommended to confirm solderability before using Products of which storage time is
exceeding the recommen de d 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 openin g 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 pl ease dispose them properly using an authorized in dustry 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 foregoi ng information or data will not infringe any int ellectual 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 an y 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 b ut not limited to, the developm ent 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
© 2014 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 an y damages, expenses or losses incurred by you or third parties resulting from inaccur acy or errors of or
concerning such information.
