R5108G Series
Watchdog Timer Equipped with SENSE Pin with VD
The R5108G Series are CMOS-based system power ICs with a voltage detector (VD) and watchdog timer (WDT) integrated in a single chip.
R5108G monitors the power system of devices equipped with microprocessors and prevents system runaway with a reset signal when a
malfunction occurs. R5108G is equipped with the function that inhibits clock monitoring of the WDT (INH). Since R5108G has a SENSE pin
for monitoring voltage separately from the power pin, its reset signal does not become unstable under the condition that the power supply
is sufficient to operate the IC, and the "L" can be maintained.
FEATURES
•
Supply Current (I
SS
) ························ Typ. 11μA (V
DD
=-V
DET
+0.5V,
•
Operating Voltage Range (V
DD
) ······ 1.5V to 6.0V
Clock pulse input)
(VD Section)
•
Detector Threshold Range (-V
DET
) ··· 1.5V to 5.5V (internally fixed)
•
Detector Threshold Accuracy ··········
±
1%
•
Temp. coeff. of Detector Threshold ··· Typ.
±
100ppm/°C
•
Output Delay Time (t
PLH
)················· Typ. 370ms (C
D
=0.1μF)
•
Output Delay Time Accuracy ··········
±
16% (-40°C
≤
Topt
≤
105°C)
(WDT Section)
•
Watchdog Timeout Period (t
WD
) ······ Typ. 310ms (C
TW
=0.1μF)
•
Reset Hold Time of WDT (t
WR
) ······· Typ. 34ms (C
TW
=0.1μF)
•
Watchdog Timeout Period Accuracy ····
±
33% (-40°C
≤
Topt
≤
105°C)
•
Package ········································· SSOP-8G
(The above shows specification at Topt=25
°
C. Design assurance value at -40
°
C
≤
Topt
≤
105
°
C is also available. For details, please refer to the datasheet.)
BLOCK DIAGRAMS
R5108Gxx1A
(Nch. open drain output)
SENSE
V
DD
V
DD
TYPICAL APPLICATION
R5108Gxx1C
(CMOS output)
SENSE
Power Supply
R
Microprocessor
V
DD
8
V
DD
C
D
Vref2
Vref1
RESETB
1
RESET
I/O
C
D
Vref2
Vref1
2
SENSE
GND
GND
C
TW
WATCHDOG
TIMER
CLOCK
DETECTOR
C
TW
SCK
WATCHDOG
TIMER
CLOCK
DETECTOR
6
INH
SW
5
R5108Gxx1A
SCK
Series
GND
C
TW
7
SCK
3
C
D
C
D
4
C
TW
RESETB
INH
RESETB
INH
SELECTION GUIDE
Halogen Free
Package
SSOP-8G
Q'ty per Reel
3,000 pcs
Part No.
R5108G
.xx.1.
∗
-TR-FE
TIMING CHART
V
DD
.xx
: Specify the detector threshold within the range of
1.5V (.15.) to 5.5V (.55.) in 0.1V steps.
.∗
: Select the output type from (.A.) Nch. open drain or (.C.) CMOS.
V
INH
PACKAGE (Top View)
V
SENSE
+V
DET
-V
DET
SSOP-8G
8 7 6 5
t
PLH
t
PLH
V
CD
+V
TCD
- V
TCD
t
WD
t
WDI
1
2
3
4
V
ref2H
1
2
3
4
5
6
7
8
RESETB
SENSE
C
D
GND
SCK
INH
C
TW
V
DD
Output pin for Reset "L" signal
Voltage SENSE pin of VD
Ext. Cap. pin for setting output
delay time of VD
Ground pin
Watchdog timer clock input pin
Inhibit pin
Ext. Cap. pin for setting reset and
watchdog timeout period of WDT
Power supply pin
V
CTW
V
ref2L
t
PHL
t
WR
V
SCK
t
PLH
V
RESETB
APPLICATION
•
Monitoring of the power system of devices equipped with microprocessors
No.EK-171-111001
∗V
TCD
∗V
ref2H
∗V
ref2L
∗t
PHL
∗t
WDI
: Threshold voltage of C
D
pin when a power-on reset pulse inverting.
: C
TW
pin voltage at the end of WDT timeout period.
: C
TW
pin voltage at the begin of WDT timeout period.
: Output delay time
: t
WD
/10 (SCK pulses input during this period are ignored.)
CMOS Microprocessor Supervisory
1. The products and the product specifications described in this document are subject to change or
discontinuation of production without notice for reasons such as improvement. Therefore, before
deciding to use the products, please refer to Ricoh sales representatives for the latest
information thereon.
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described herein.
4. The technical information described in this document shows typical characteristics of and
example application circuits for the products. The release of such information is not to be
construed as a warranty of or a grant of license under Ricoh's or any third party's intellectual
property rights or any other rights.
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components in standard applications (office equipment, telecommunication equipment,
measuring instruments, consumer electronic products, amusement equipment etc.). Those
customers intending to use a product in an application requiring extreme quality and reliability,
for example, in a highly specific application where the failure or misoperation of the product
could result in human injury or death (aircraft, spacevehicle, nuclear reactor control system,
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devices, life support system etc.) should first contact us.
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semiconductor products are likely to fail with certain probability. In order to prevent any injury to
persons or damages to property resulting from such failure, customers should be careful enough
to incorporate safety measures in their design, such as redundancy feature, firecontainment
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damage arising from misuse or inappropriate use of the products.
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concerning the products or the technical information.
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