Datasheet
Voltage Detectors
Voltage Detector ICs with Watchdog Timer
BD37Axx Series
General Description
The BD37A19FVM, BD37A41FVM, BD87A28FVM,
BD87A29FVM, BD87A34FVM, BD87A41FVM and
BD99A41F are watchdog timer reset ICs. It delivers a
high precision detection voltage of
±1.5%
and a
super-low current consumption of 5 µA (Typ). It can be
used in a wide range of electronic devices to monitor
power supply voltages and in system operation to
prevent runaway operation.
BD87Axx Series
BD99A41F
Key Specifications
RESET Power Supply Voltage Range: 1.0V to 10V
WDT Power Supply Voltage Range:
2.5V to 10V
High Precision Detection Voltage:
(Ta = 25°C)
±1.5%
(Ta =
−40°C
to 105°C)
±2.5%
Super-Low Current Consumption:
5μA(Typ)
Operating Temperature Range:
-40°C to +105°C
Packages
Features
Built-in Watchdog Timer
Reset delay time can be set with the CT pin's
external capacitance
Watchdog timer monitor time and reset time can be
set with the CTW pin's external capacitance.
Output Circuit Type: N-Channel Open Drain
MSOP8
W (Typ) x D (Typ) x H (Max)
2.90mm x 4.00mm x 0.90mm
Applications
All devices using microcontrollers or DSP, including
vehicle equipment, displays, servers, DVD players,
and telephone systems
SOP8
5.00mm x 6.20mm x 1.71mm
Ordering Information
B
D
3
7
A
1
9
F
V
M
-
TR
Packaging and forming specification
TR: Embossed tape and reel
E2: Embossed tape and reel
Part Number
37A：WDT H Active
87A：WDT L Active
99A：WDT H Active
Detection Voltage
19：1.9V
28：2.8V
29：2.9V
34：3.4V
41：4.1V
Package
FVM : MSOP8
F
: SOP8
Lineup
Detection voltage (Typ)
1.9V
4.1V
2.8V
2.9V
3.4V
4.1V
4.1V
INH logic
H: Active
H: Active
L: Active
L: Active
L: Active
L: Active
H: Active
MSOP8
MSOP8
MSOP8
MSOP8
MSOP8
MSOP8
SOP8
Package
Reel of 3000
Reel of 3000
Reel of 3000
Reel of 3000
Reel of 3000
Reel of 3000
Reel of 2500
Orderable
Part Number
BD37A19FVM-TR
BD37A41FVM-TR
BD87A28FVM-TR
BD87A29FVM-TR
BD87A34FVM-TR
BD87A41FVM-TR
BD99A41F-E2
○Product
structure：Silicon monolithic integrated circuit
.
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© 2013 ROHM Co., Ltd. All rights reserved.
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○This
product has not designed protection against radioactive rays
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TSZ02201-0G1G0AN00130-1-2
05.Sep.2014 Rev.003
BD37Axx Series
Pin Configurations
BD87Axx Series
BD99A41F
Datasheet
MSOP8
(TOP VIEW)
8 7 6 5
SOP8
(TOP VIEW)
8 7 6 5
1 2 3 4
Figure 1. Pin Configurations
1
2
3
4
Pin Descriptions
BD37AxxFVM
No.
1
2
3
4
5
6
7
8
Pin
name
CLK
CT
CTW
VDD
N.C.
GND
INH
Function
Clock input from microcontroller
Reset delay time setting capacitor
connection pin
WDT time setting capacitor connection pin
Power supply pin
NC pin
GND pin
WDT ON/OFF setting pin
INH=H/L:WDT=ON/OFF
No.
1
2
3
4
5
6
7
Pin
name
CTW
CT
CLK
GND
VDD
INH
N.C.
BD87AxxFVM / BD99A41F
Function
WDT time setting capacitor connection pin
Reset delay time setting capacitor
connection pin
Clock input from microcontroller
GND pin
Power supply pin
WDT ON/OFF setting pin
INH=H/L:WDT=OFF/ON(BD87AxxFVM)
INH=H/L:WDT=ON/OFF(BD99A41F)
NC pin
RESET Reset output pin
8 RESET Reset output pin
Block Diagrams
BD37AxxFVM
BD87AxxFVM / BD99A41F
VDD
RESET
CLK
1
R
8
CTW
1
R
Q
Vref
INH
2
VDD
Pulse
Generation
Circuit
3
7
CT
2
VDD
VDD
8
RESET
+
Vref
CT
S
+
S
Q
N.C.
7
+
CTW
R
S
Q
6
GND
CLK
3
Pulse
Generation
Circuit
+
+
VthH
VthL
R
S
Q
INH
6
+
VthH
VthL
VDD
4
5
N.C.
GND
4
5
VDD
CT pin capacitor: 470pF to 3.3µF
CTW pin capacitor: 0.001µF to 10µF
Figure 2.Block Diagrams
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BD37Axx Series
BD87Axx Series
BD99A41F
Datasheet
Absolute Maximum Ratings (Ta=25℃)
Parameter
Power Supply Voltage
*1
CT Pin Voltage
CTW Pin Voltage
RESET Pin Voltage
INH Pin Voltage
CLK Pin Voltage
Power Dissipation
Operating Ambient Temperature
Storage Temperature
Maximum Junction Temperature
Symbol
V
DD
V
CT
V
CTW
V
RESET
V
INH
V
CLK
Pd
Topr
Tstg
Tjmax
Ratings
−0.3
to 10
−0.3
to V
DD
+ 0.3
−0.3
to V
DD
+ 0.3
−0.3
to V
DD
+ 0.3
−0.3
to V
DD
+ 0.3
−0.3
to V
DD
+ 0.3
0.47
*2
0.55
*3
−40
to + 105
−55
to + 125
125
Unit
V
V
V
V
V
V
W
°C
°C
°C
*1 Do not exceed Pd.
*2 MSOP8 : Reduced by 4.70 mW/℃ over 25°C, when mounted on a glass epoxy board (70 mm × 70 mm × 1.6 mm).
*3 SOP8 : Reduced by 5.50 mW/℃ over 25°C, when mounted on a glass epoxy board (70 mm × 70 mm × 1.6 mm).
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.
Recommended Operating Ratings(Ta =
−40°C
to 105°C)
Parameter
RESET Power Supply Voltage
WDT Power Supply Voltage
Symbol
V
DD RESET
V
DD WDT
Min
1.0
2.5
Max
10
10
Unit
V
V
Electrical Characteristics
(Unless otherwise specified, Ta =
−40°C
to 105°C, V
DD
= 5V)
Limits
Parameter
Symbol
Min
Typ
[Overall]
Total Supply Current 1
(during WDT operation)
Total Supply Current 2
(when WDT stopped)
Output Leak Current
Output Current Capacity
[RESET]
1.9V Detect
2.8V Detect
Detection
Voltage 1
2.9V Detect
3.4V Detect
4.1V Detect
1.9V Detect
2.8V Detect
Detection
Voltage 2
2.9V Detect
3.4V Detect
4.1V Detect
1.9V Detect
2.8V Detect
Hysteresis
Width
2.9V Detect
3.4V Detect
4.1V Detect
V
DET1
V
DET1
V
DET1
V
DET1
V
DET1
V
DET2
V
DET2
V
DET2
V
DET2
V
DET2
Vrhys
Vrhys
Vrhys
Vrhys
Vrhys
1.871
2.758
2.886
3.349
4.039
1.852
2.730
2.857
3.315
4.007
V
DET
×0.03
V
DET
×0.018
V
DET
×0.02
V
DET
×0.02
V
DET
×0.018
1.900
2.800
2.930
3.400
4.100
1.900
2.800
2.930
3.400
4.100
V
DET
×0.13
V
DET
×0.045
V
DET
×0.05
V
DET
×0.05
V
DET
×0.035
Max
Unit
Conditions
I
DD1
I
DD2
I
leak
I
OL
—
—
—
0.7
5
5
—
—
14
14
1
—
µA
µA
µA
mA
INH : WDT ON Logic Input
CTW = 0.1µF
INH : WDT OFF Logic Input
V
DD
= V
DS
= 10V
V
DD
= 1.2V, V
DS
= 0.5V
1.929
2.842
2.974
3.451
4.162
1.948
2.870
3.003
3.485
4.202
V
DET
×0.19
V
DET
×0.060
V
DET
×0.06
V
DET
×0.07
V
DET
×0.050
V
V
V
V
V
V
V
V
V
V
V
V
V
V
V
Ta = 25°C
Ta = 25°C
Ta = 25°C
Ta = 25°C
Ta = 25°C
Ta =
−40°C
to 105°C
Ta =
−40°C
to 105°C
Ta =
−40°C
to 105°C
Ta =
−40°C
to 105°C
Ta =
−40°C
to 105°C
Ta=−40°C
to 105°C
Ta=−40°C
to 105°C
Ta=−40°C
to 105°C
Ta=−40°C
to 105°C
Ta=−40°C
to 105°C
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BD37Axx Series
BD87Axx Series
BD99A41F
Datasheet
●Electrical
Characteristics - continued
(Unless otherwise specified, Ta = −40°C
to 105°C, V
DD
= 5V)
Limits
Parameter
Symbol
Min
Typ
RESET Transmission
t
PLH
3.9
6.9
Delay Time: Low
→
High
Delay Circuit Resistance
Delay Pin Threshold
Voltage
Delay Pin Output Current
Min Operating Voltage
[WDT]
WDT Monitor Time
WDT Reset Time
Clock Input Pulse Width
CLK High Threshold
Voltage
CLK Low Threshold Voltage
INH High Threshold Voltage
INH Low Threshold Voltage
CTW Charge Current
CTW Discharge Current
*1
*2
*3
Max
10.1
14.5
V
DD
×0.6
—
—
Unit
ms
MΩ
V
µA
V
Conditions
C
CT
= 0.001µF
*1
When V
DD
= V
DET
±0.5V
V
CT
= GND
R
L
= 470KΩ
V
DD
= 1.50V, V
CT
= 0.5V
V
OL
≤
0.4V, R
L
= 470KΩ
C
CTW
= 0.01µF
*2
C
CTW
= 0.01µF
*3
Rrst
V
CTH
I
CT
V
OPL
5.8
V
DD
×0.3
150
1.0
10.0
V
DD
×0.45
—
—
t
wH
t
wL
t
WCLK
V
CLKH
V
CLKL
V
INHH
V
INHL
I
CTWC
I
CTWO
7.0
2.4
500
V
DD
× 0.8
0
V
DD
× 0.8
0
0.25
0.75
10.0
3.3
—
—
—
—
—
0.50
1.50
20.0
7.0
—
V
DD
V
DD
× 0.3
V
DD
V
DD
× 0.3
0.75
2.00
ms
ms
ns
V
V
V
V
µA
µA
V
CTW
= 0.2V
V
CTW
= 0.8V
t
PLH
can be varied by changing the CT capacitance value.
t
PLH
(s)
≈
0.69 × Rrst (MΩ) ×
C
CT
(µF)
Rrst = 10 MΩ
(Typ)
t
wH
can be varied by changing the CTW capacitance value.
t
wH
(s)
≈
(0.5 × C
CTW
(µF))/I
CTWC
(µA)
I
CTWC
= 0.5 µA(Typ)
t
wL
can be varied by changing the CTW capacitance value.
t
wL
(s)
≈
(0.5 × C
CTW
(µF))/I
CTWO
(µA)
I
CTWO
= 1.5 µA(Typ)
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BD37Axx Series
BD87Axx Series
BD99A41F
Datasheet
Typical Performance Curves
(Unless otherwise specified, Ta = 25°C) : 4.1V Detection
12
RESET VOLTAGE: VRESET [V]
.
10
CIRCUIT CURRENT: IDD [μA]
10
8
6
4
2
0
0
2
4
6
8
10
SUPPLY VOLTAGE: VDD [V]
Figure 3. Detection Voltage
8
Ta=105°C
6
Ta=25°C
4
Ta=-40°C
2
0
0
2
4
6
8
10
SUPPLY VOLTAGE: VDD [V]
Figure 4. Total Supply Current
400
350
2
300
250
200
150
100
50
0
0
1
2
3
4
5
SUPPLY VOLTAGE: VDD [V]
Figure 5. Delay Pin Current vs Power Supply Voltage
CTW PIN CURRENT: ICTW [μA]
1.5
CT PIN CURRENT: ICT [μA]
.
1
0.5
0
-0.5
-1
0
1
2
3
4
CTW PIN VOLTAGE: VCTW [V]
Figure 6. CTW Charge Discharge Current
5
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