Datasheet
Voltage Detector IC Series
Counter Timer Built-in
CMOS Voltage Detector IC
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Key Specifications
◼ Detection voltage:
●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)
◼
◼
◼
◼
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
V DD1
V DD1
V DD2
RL
BU45 x x x xx
R ST
Micro
controller
BD46 xx x xx
R ST
CL
CL
(Noise-filtering
Capacitor)
(Noise-filtering
Capacitor)
GND
Micro
controller
GND
(Open Drain Output Type)
BU45xxxxx series
(CMOS Output Type)
BU46xxxxx series
●Connection Diagram
●Pin Descriptions
BU45KxxxG / BU46KxxxG
SSOP3
GND
VDD
GND
Function
3
1
GND
GND
2
1
2
1
2
VOUT
Reset Output
3
VDD
Power Supply Voltage
2
V1
OUT
BU45KxxxG
BU46KxxxG
BU45LxxxG / BU46LxxxG
1
2
PIN No.
Symbol
VOUT
V1
DD
1
VOUT
Reset Output
2
VDD
Power Supply Voltage
3
GND
GND
BU45LxxxG
BU46LxxxG
○Product structure:Silicon monolithic integrated circuit
Function
○This product is not designed for protection against radioactive rays.
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TSZ22111・14・001
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TOP VIEW
1
PIN No.
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TSZ02201-0R7R0G300131-001-1-2
02.Sep.2021 Rev.006
Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●Ordering Information
B
U
Part
Number
x
x
Output Type
45 : Open Drain
46 : CMOS
x
x
Package 1
x
Reset Voltage Value
23 : 2.3V
0.1V step
48 : 4.8V
x
x
-
Counter Timer
Package 2
Delay Time Settings
2 : 200ms
4 : 400ms
T
L
Packaging and
forming specification
TL : Embossed tape
and reel
Package 1 Package 2 Package name
K
G
SSOP3 (1pin GND)
L
G
SSOP3 (3pin GND)
●Lineup
Table 1. Open Drain Output Type
Counter Timer Delay Time Settings
1-Pin GND
200ms
Detection
Part
Marking
Voltage
Number
BU45K482
4.8V
bH
BU45K472
4.7V
bG
BU45K462
4.6V
bF
BU45K452
4.5V
bE
BU45K442
4.4V
bD
BU45K432
4.3V
bC
4.2V
BU45K412
4.1V
bA
BU45K402
4.0V
aY
BU45K392
3.9V
aX
BU45K382
3.8V
aW
BU45K372
3.7V
aT
3.6V
BU45K352
3.5V
aR
BU45K342
3.4V
aP
3.3V
BU45K322
3.2V
aM
BU45K312
3.1V
aK
BU45K302
3.0V
aH
2.9V
BU45K282
2.8V
aF
BU45K272
2.7V
aE
2.6V
BU45K252
2.5V
aC
2.4V
BU45K232
2.3V
aA
3-Pin GND
400ms
Marking
eF
eE
eD
eC
eB
eA
dY
dX
dW
dT
dS
dR
dP
dN
dM
dK
dH
dG
dD
dC
dB
dA
cY
cX
200ms
Part
Number
BU45K484
BU45K474
BU45K464
BU45K454
BU45K444
BU45K434
BU45K424
BU45K414
BU45K404
BU45K394
BU45K384
BU45K374
BU45K364
BU45K354
BU45K344
BU45K334
BU45K324
BU45K314
BU45K284
BU45K274
BU45K264
BU45K254
BU45K244
BU45K234
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TSZ22111・15・001
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Marking
hD
hC
hB
hA
gY
gX
gW
gT
gS
gR
gP
gN
gM
gK
gH
gG
gF
gE
gD
gC
gB
gA
fY
fX
fW
-
400ms
Part
Number
BU45L482
BU45L472
BU45L462
BU45L452
BU45L442
BU45L432
BU45L422
BU45L412
BU45L402
BU45L392
BU45L382
BU45L372
BU45L362
BU45L352
BU45L342
BU45L332
BU45L322
BU45L312
BU45L302
BU45L292
BU45L282
BU45L272
BU45L262
BU45L252
BU45L242
-
Marking
nB
nA
mY
mX
mW
mT
mS
mR
mP
mN
mM
mK
mH
mG
mF
mE
mD
mC
mB
mA
kY
kX
kW
kT
kS
-
Part
Number
BU45L484
BU45L474
BU45L464
BU45L454
BU45L444
BU45L434
BU45L424
BU45L414
BU45L404
BU45L394
BU45L384
BU45L374
BU45L364
BU45L354
BU45L344
BU45L334
BU45L324
BU45L314
BU45L304
BU45L294
BU45L284
BU45L274
BU45L264
BU45L254
BU45L244
-
TSZ02201-0R7R0G300131-001-1-2
02.Sep.2021 Rev.006
Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●Lineup - Continued
Table 2. CMOS Output Type
Counter Timer Delay Time Settings
1-Pin GND
200ms
Detection
Part
Marking
Voltage
Number
BU46K482
4.8V
cW
BU46K472
4.7V
cT
BU46K462
4.6V
cS
BU46K452
4.5V
cR
BU46K442
4.4V
cP
BU46K432
4.3V
cN
BU46K422
4.2V
cM
BU46K412
4.1V
cK
4.0V
BU46K392
3.9V
cG
BU46K382
3.8V
cF
BU46K372
3.7V
cE
BU46K362
3.6V
cD
BU46K352
3.5V
cC
BU46K342
3.4V
cB
BU46K332
3.3V
cA
BU46K322
3.2V
bY
BU46K312
3.1V
bX
BU46K302
3.0V
bW
2.9V
BU46K282
2.8V
bS
BU46K272
2.7V
bR
BU46K262
2.6V
bP
BU46K252
2.5V
bN
BU46K242
2.4V
bM
BU46K232
2.3V
bK
3-Pin GND
400ms
Marking
fS
fR
fP
fN
fM
fK
fH
fG
fF
fE
fD
fC
fB
fA
eY
eX
eW
eT
eS
eR
eP
eN
eM
eK
eH
eG
Part
Number
BU46K484
BU46K474
BU46K464
BU46K454
BU46K444
BU46K434
BU46K424
BU46K414
BU46K404
BU46K394
BU46K384
BU46K374
BU46K364
BU46K354
BU46K344
BU46K334
BU46K324
BU46K314
BU46K304
BU46K294
BU46K284
BU46K274
BU46K264
BU46K254
BU46K244
BU46K234
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TSZ22111・15・001
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200ms
Marking
kP
kN
kM
kK
kH
kG
kF
kE
kD
kC
kB
kA
hY
hX
hW
hT
hS
hR
hP
hN
hM
hK
hH
hG
hF
hE
400ms
Part
Number
BU46L482
BU46L472
BU46L462
BU46L452
BU46L442
BU46L432
BU46L422
BU46L412
BU46L402
BU46L392
BU46L382
BU46L372
BU46L362
BU46L352
BU46L342
BU46L332
BU46L322
BU46L312
BU46L302
BU46L292
BU46L282
BU46L272
BU46L262
BU46L252
BU46L242
BU46L232
Marking
pM
pK
pH
pG
pF
pE
pD
pC
pB
pA
nY
nX
nW
nT
nS
nR
nP
nN
nM
nK
nH
nG
nF
nE
nD
nC
Part
Number
BU46L484
BU46L474
BU46L464
BU46L454
BU46L444
BU46L434
BU46L424
BU46L414
BU46L404
BU46L394
BU46L384
BU46L374
BU46L364
BU45L354
BU46L344
BU46L334
BU46L324
BU46L314
BU46L304
BU46L294
BU46L284
BU46L274
BU46L264
BU46L254
BU46L244
BU46L234
TSZ02201-0R7R0G300131-001-1-2
02.Sep.2021 Rev.006
Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
⚫ Absolute maximum ratings (Ta=25°C)
Parameter
Power Supply Voltage
Nch Open Drain Output
Output Voltage
CMOS Output
Output Current
Power Dissipation (Note1, Note2)
Operating Temperature
Ambient Storage Temperature
Symbol
VDD-GND
VOUT
Io
Pd
Topr
Tstg
Limit
-0.3 to +6.0
GND-0.3 to +6.0
GND-0.3 to VDD+0.3
70
700
-40 to +105
-55 to +125
Unit
V
V
mA
mW
°C
°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
Operating Voltage Range
Symbol
VOPL
Condition
VOL≤0.4V, RL=470kΩ, Ta=25~105°C
VOL≤0.4V, RL=470kΩ, Ta=-40~25°C
VDD=H→L, RL=470kΩ (Note 1)
Ta=25°C
VDET=2.5V
Ta=-40°C to 85°C
Ta=85°C to 105°C
Ta=25°C
VDET=3.0V
Ta=-40°C to 85°C
Ta=85°C to 105°C
Detection Voltage
VDET
Ta=25°C
VDET=3.3V
Ta=-40°C to 85°C
Ta=85°C to 105°C
Ta=25°C
VDET=4.2V
Ta=-40°C to 85°C
Ta=85°C to 105°C
Ta=25°C
VDET=4.8V
Ta=-40°C to 85°C
Ta=85°C to 105°C
Detection Voltage
Temperature coefficient
VDET/∆T -40°C~105°C
Limit
Min.
Typ.
0.6
0.9
VDET(T)
VDET(T)
×0.99
2.475
2.5
2.418
2.404
2.970
3.0
2.901
2.885
3.267
3.3
3.191
3.173
4.158
4.2
4.061
4.039
4.752
4.8
4.641
4.616
-
±50
‘High’ Output
Delay time
tPLH
Circuit Current when ON
Circuit Current when OFF
IDD1
IDD2
VDET(T) VDET(T)
×0.03
×0.05
120
200
Ta=25°C
CL=100pF,
95
BU4XXXX2G Ta=-40°C to 85°C
RL=100kΩ
85
Ta=85°C to 105°C
( Note1,
240
400
Ta=25°C
Note 2,
190
BU4XXXX4G Ta=-40°C to 85°C
Note 3 )
170
Ta=85°C to 105°C
0.60
2.30
VDD=VDET-0.2V, VDET=2.3V~4.8V
1.10
2.80
VDD=VDET+1.0V, VDET=2.3V~4.8V
‘High’ Output Voltage (Pch)
VOH
VDD=5.0V, ISOURCE= 6.8mA, VDET(4.3V to 4.8V)
‘Low’Output Voltage (Nch)
VOL
Leak Current when OFF
Ileak
Hysteresis Voltage
∆VDET
VDD=L→H→L, RL=470kΩ
VDD=1.2V, ISINK = 2.0mA
VDD=2.4V, ISINK = 8.5mA, VDET(2.7V to 4.8V)
VDD=VDS=6.0V (Note 1)
VDD-0.5
-
-
Max.
6.0
6.0
VDET(T)
×1.01
2.525
2.584
2.597
3.030
3.100
3.117
3.333
3.410
3.428
4.242
4.341
4.364
4.848
4.961
4.987
±360
Unit
V
V
ppm/°C
VDET(T)
×0.08
280
460
235
560
920
470
7.00
8.00
ms
-
V
0.3
0.3
1.0
V
V
µA
V
µA
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=VOPL→VDET more than 10µs.
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TSZ02201-0R7R0G300131-001-1-2
02.Sep.2021 Rev.006
Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●Block Diagrams
VDD
Oscillator
VOUT
Circuit Counter
Timer
Vref
GND
Fig.1 BU45xxxxx Series
VDD
Oscillator
Circuit Counter
Timer
Vref
VOUT
GND
Fig.2 BU46xxxxx Series
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TSZ02201-0R7R0G300131-001-1-2
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Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●Typical Performance Curves
16
6
"LOW" OUTPUT CURRENT:IOL[mA]
[BU45K232G]
CIRCUIT CURRENT:IDD[uA]
5
Ta=105°C
4
3
2
Ta=25°C
Ta=-40°C
1
[BU45K232G]
14
12
10
Ta=25°C
8
Ta=105°C
6
4
2
0
0
0
1
2
3
4
5
6
0
7
1
2
3
4
5
6
7
DRAIN-SOURCE VOLTAGE: VDS[V]
Fig.4 “LOW” Output Current
VDD=1.2V
VDD SUPPLY VOLTAGE: VDD[V]
Fig.3 Circuit Current
50
8
[BU46K232G]
Ta=-40°C
40
[BU45K232G]
7
OUTPUT VOLTAGE:VOUT[V]
"HIGH" OUTPUT CURRENT:IOH[mA]
Ta=-40°C
30
Ta=25°C
20
Ta=105°C
10
Ta=25°C
6
Ta=-40°C
5
Ta=105°C
4
3
2
1
0
0
0
1
2
3
4
0
5
2
3
4
5
VDD SUPPLY VOLTAGE: VDD[V]
Fig.5 “HIGH” Output Current
VDD=3.9V
Fig.6 I/O Characteristics
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TSZ22111・15・001
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DRAIN-SOURCE VOLTAGE: VDS[V]
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6
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TSZ02201-0R7R0G300131-001-1-2
02.Sep.2021 Rev.006
Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●Typical Performance Curves - Continued
2.6
3.0
[BU45K232G]
2.8
CIRCUIT CURRENT WHEN ON :IDD1[uA]
DETECTION VOLTAGE:VOUT[V]
[BU45K232G]
2.5
Low to high (V DET + ∆V DET )
2.4
2.3
High to low (V DET )
2.2
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
2.1
-40
-20
0
20
40
60
80
100
-40
3.5
0
20
40
60
80
100
80
100
0.6
[BU45K232G]
3.3
MINIMUM OPERATING VOLTAGE:VOPL [V]
CIRCUIT CURRENT WHEN OFF:IDD2 [uA]
-20
TEMPERATURE: Ta[ C]
Fig.8 Circuit Current when ON
(VDD=VDET-0.2V)
VDD=2.1V
TEMPERATURE:Ta[ C]
Fig.7 Detection Voltage
Release Voltage
3.1
2.9
2.7
2.5
2.3
2.1
1.9
1.7
1.5
[BU45K232G]
0.5
0.4
0.3
0.2
0.1
0.0
-40
-20
0
20
40
60
80
-40
100
TEMPERATURE: Ta[ C]
Fig.9 Circuit Current when OFF
(VDD=VDET+1V)
VDD=3.3 V
0
20
40
60
TEMPERATURE: Ta[ C]
Fig.10 Operating Limit Voltage
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TSZ22111・15・001
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TSZ02201-0R7R0G300131-001-1-2
02.Sep.2021 Rev.006
Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●Typical Performance Curves - Continued
3.0
280
[BU45K232G]
[BU45K232G]
"LOW" DELAY TIME TPHL [µs]
"HIGH" DELAY TIME:TPLH [ms]
300
260
240
220
200
180
160
140
2.0
1.0
120
100
0.0
-40
-20
0
20
40
60
80
-40
100
TEMPERATURE: Ta[ C]
Fig.11 Output Delay Time
“Low” → “High”
0
20
40
60
80
100
TEMPERATURE: Ta[ C]
Fig.11 Output Delay Time
“High” → “Low”
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TSZ02201-0R7R0G300131-001-1-2
02.Sep.2021 Rev.006
Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●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 V DD pins reaches the applicable threshold voltage, the V OUT 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].
VDD
VDD
VDD
R1
R1
Vref
Q2
Vref
Reset
VOUT
Oscillator
Oscillator
Circuit Counter
R2
R2
Timer
Reset
Circuit Counter
Timer
Q1
R3
Q1
R3
GND
VOUT
GND
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
BU45K232G
BU46K232G
tPLH[ms]
208
208
VDD=1.8V→2.8V
tPHL[µs]
1.4
1.4
VDD=2.8V→1.8V
*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
VDD
VDD
VDET+ΔVDET
VDET
0V
⑤
VOPL
VOH
tPLH
tPLH
VOUT
tPHL
VOL
tPHL
①
②
③
Fig.15
④
Timing Waveform
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 V
DD is greater than VOPL but less than the reset release
voltage (VDET + ∆VDET), the output voltages will switch to Low.
3 If V
DD exceeds the reset release voltage (V DET + ∆VDET), the
counter timer start and VOUT switches from L to H.
4 If V
DD 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.
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TSZ22111・15・001
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TSZ02201-0R7R0G300131-001-1-2
02.Sep.2021 Rev.006
Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●Circuit Applications
1. Examples of a common power supply detection reset circuit.
VDD1
Application examples of BU45xxxxx series (Open Drain
output type) and BU46xxxxx series (CMOS output type)
are shown below.
VDD2
RL
BU45xxxxx
RST
Micro
controller
CASE1: Power supply of microcontroller (VDD2) differs
from the power supply of the reset detection (VDD1).
Use an open drain output Type (BU45xxxxx series)
device with a load resistance RL as shown Fig.16.
CL
(Noise-filtering
Capacitor)
GND
Fig.16 Open Drain Output Type
CASE2: Power supply of the microcontroller (VDD1) is
same as the power supply of the reset detection (VDD1).
Use a CMOS output type (BU46xxxxx) device or an open
drain output type (BU45xxxxx) with pull up resistor
between the output and VDD1. (As shown Fig.17)
VDD1
BU46xxxxx
RST
Micro
controller
When a capacitance CL for noise filtering is connected to
the VOUT pin (the reset signal input terminal of the
microcontroller), please take into account the waveform of
the rise and fall of the output voltage (VOUT).
CL
(Noise-filtering
Capacitor)
GND
Fig.17 CMOS Output Type
2. The following is an example of a circuit application in which an OR connection between two types of detection voltage
resets the microcontroller.
VDD1
VDD2
VDD3
RL
BU45xxxxx
BU45xxxxx
RST
Micro
controller
GND
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 (VDD3) as shown in Fig. 18. By pulling-up to VDD3, output “High” voltage of micro-controller power supply is
possible.
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Datasheet
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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.
V1
R2
I1
VDD
BU45xxxxx
BU46xxxxx
R1
CIN
VOUT
CL
GND
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.
IDD
In-rush Current
0
VDD
VDET
Fig. 20 Current Consumption vs. Power Supply Voltage
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Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●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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Datasheet
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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.
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 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 V DD in pull up (VDD)
condition.
19. Power-on Reset Operation
Please note that the power on reset output varies with the V DD 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.
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BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
Datasheet
Physical Dimension, Tape and Reel Information
Package Name
SSOP3
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Datasheet
BU45Kxxxx, BU46Kxxxx, BU45Lxxxx, BU46Lxxxx series
●Revision History
Date
Revision
02.Sep.2021
006
Changes
Divided Not Recommended New Designs product from the datasheet
(TSZ02201-0R7R0G300130-1-2) and new release.
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Notice
Precaution on using ROHM Products
1.
Our Products are designed and manufactured for application in ordinary electronic equipment (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
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 (Exclude cases where no-clean type fluxes is used.
However, recommend sufficiently about the residue.) ; 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
© 2015 ROHM Co., Ltd. All rights reserved.
Rev.004
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 Cl 2, 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
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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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