UM706xS/UM708xS/UM813xS
Supply Voltage Supervisor w/Watchdog Input and Manual Reset
UM706xS
SOP8
UM708xS
SOP8
UM813xS
SOP8
General Description
The UM706xS/UM708xS/UM813xS series are cost effective system power supply supervisory
circuits designed to monitor the power supplies in digital systems.
The UM706xS provides power-supply monitoring circuitry that generates a reset output during
power-up, power-down, and brownout conditions. The reset output remains operational with V
CC
as low as 1V. Independent watchdog monitoring circuitry is also provided. This is activated if the
watchdog input has not been toggled within 1.6 seconds. In addition, there is a 1.25V threshold
detector for power-fail warning, low battery detection, or to monitor an additional power supply.
An active low debounced manual reset input is also included.
The UM708xS is the same as the UM706xS, except an active-high reset is substituted for the
watchdog timer. The UM813xS is the same as the UM706xS, except RESET is provided instead
_____________
of RESET. All parts are available in a small outline SOP8 package.
Applications
Applications Using DSPs, Microcontrollers
or Microprocessors
Programmable Controls
Computers
Embedded Systems
Industrial Equipments
Intelligent Instruments
Wireless Communications Systems
Features
Wide Operation Voltage Range of 1V to
5.5V
Correct Logic Output Guaranteed to
V
CC
=1.0V
Precision Supply-Voltage Monitor: 2.63V,
2.93V, 3.08V, 4.38V, 4.63V
200ms Reset Pulse Width
Independent
Watchdog
Timer-1.6s
Timeout (UM706xS, UM813xS)
Active-High Reset Output (UM708xS,
UM813xS)
Voltage Monitor for Power-Fail or
Low-Battery Warning
Temperature Range: -40° to +85°
C
C
Supply Current of 80μA (Typ)
Pin Configurations
Top View
8
7
6
5
MR
V
CC
1
2
8 WDO
7
6
5
RESET
WDI
PFO
GND 3
PFI
4
UM706
XS
XX
1
2
3
4
UM706xS
XX: Week Code
UM706xS
SOP8
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UM706xS/UM708xS/UM813xS
Pin Configurations
Top View
8
MR
V
CC
1
2
8 RESET
7
6
5
RESET
NC
PFO
7
6
5
GND 3
PFI
4
UM708
XS
XX
1
2
3
4
UM708xS
XX: Week Code
UM708xS
SOP8
8
7
6
5
MR
V
CC
1
2
8 WDO
7
6
5
RESET
WDI
PFO
GND 3
PFI
4
UM813
XS
XX
1
2
3
4
UM813xS
XX: Week Code
UM813xS
SOP8
Ordering Information
Part Number
UM706LS
UM706MS
UM706TS
UM706SS
UM706RS
UM708LS
UM708MS
UM708TS
UM708SS
UM708RS
UM813LS
UM813MS
UM813TS
UM813SS
UM813RS
Top
Marking
UM706LS
UM706MS
UM706TS
UM706SS
UM706RS
UM708LS
UM708MS
UM708TS
UM708SS
UM708RS
UM813LS
UM813MS
UM813TS
UM813SS
UM813RS
RESET
Threshold (V)
4.63
4.38
3.08
2.93
2.63
4.63
4.38
3.08
2.93
2.63
4.63
4.38
3.08
2.93
2.63
Timeout Period
(ms)
240
240
240
240
240
240
240
240
240
240
240
240
240
240
240
Package Type
SOP8
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UM706xS/UM708xS/UM813xS
Typical Application Circuit
Vcc
μP
Vcc
Vcc
RESET
RESET
I/O
NMI
INT
UM706
PFI
MR
PUSHBUTTON
SWITCH
WDI
WDO
PFO
Figure 1. UM706xS Application Circuit
Vcc
μP
Vcc
Vcc
RESET
RESET
PFI
MR
PUSHBUTTON
SWITCH
RESET
RESET
UM708
PFO
INT
Figure 2. UM708xS Application Circuit
Vcc
μP
Vcc
Vcc
RESET
RESET
I/O
NMI
INT
UM813
PFI
MR
PUSHBUTTON
SWITCH
WDI
WDO
PFO
Figure 3. UM813xS Application Circuit
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UM706xS/UM708xS/UM813xS
Pin Description
Pin
Number
1
Pin Name
_______
Function
Manual-Reset Input triggers a reset pulse when pulled
below 0.8V. This active-low input has an internal 250μA
pull-up current. It can be driven from a TTL or CMOS
logic line as well as shorted to ground with a switch.
Supply Input
Ground Reference for all signals.
Power-Fail Voltage Monitor Input. When PFI is less
_________
than 1.25V, PFO goes low. Connect PFI to GND or
V
CC
when not used.
Power-Fail Output goes low and sinks current when PFI
_________
is less than 1.25V; otherwise PFO stays high.
Watchdog Input. If WDI remains either high or low for
1.6sec, the internal watchdog timer runs out and the
__________
WDO goes low. Floating WDI or connecting WDI to a
high-impedance three-state buffer disables the watchdog
feature. The internal watchdog timer clears whenever
reset is asserted, WDI is three-stated, or WDI sees a
rising or falling edge.
No Connect
Active-Low Reset Output pulses low for 200ms when
trigged, and stays low whenever V
CC
is below the reset
threshold. It remains low for
________
200ms after V
CC
rises
above the reset threshold or M R goes from Low to
High.
____________
MR
2
3
4
V
CC
GND
PFI
_________
5
PFO
6
UM706,
UM813
WDI
UM708
NC
UM706,
UM708
7
UM813
______________
RESET
RESET
Active-High Reset Output is the inverse of RESET .
____________
Whenever RESET is high, RESET is low, and vice
versa.
Watchdog Output pulls low when the internal watchdog
timer finishes its 1.6sec count and does not go high
___________
again until the watchdog is cleared. WDO also goes
low during low-line conditions. Whenever V
CC
is below
___________
the reset
___________
threshold, WDO stays low; however, unlike
______________
RESET , WDO does not have a minimum pulse width.
___________
As soon as V
CC
rises above the reset threshold, WDO
goes high with no delay.
____________
Active-High Reset Output is the inverse of RESET .
____________
Whenever RESET is high, RESET is low, and vice
versa.
UM706,
UM813
8
___________
WDO
UM708
RESET
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UM706xS/UM708xS/UM813xS
Absolute Maximum Ratings (Note 1)
Symbol
V
CC
I
CC
I
O
P
D
T
J
T
STG
Supply Voltage
____________
Parameter
RESET, RESET (Push-Pull)
Input Current, V
CC
____________
Value
-0.3 to +6.0
-0.3 to V
CC
+0.3
20
20
100
471
-40 to +105
-65 to +150
Unit
V
V
mA
mA
V/μs
mW
°
C
°
C
Output Current, RESET, RESET
Rate of Rise, V
CC
Continuous Power Dissipation
Operating Junction Temperature
Storage Temperature Range
Lead Temperature (soldering, 10s)
300
°
C
Note 1: Stresses beyond those listed under “Absolute maximum Ratings” may cause permanent
damage to the device.
Electrical Characteristics
V
CC
=full range, T
A
=-40° to +85° unless otherwise noted. Typical values are at T
A
=+25°
C
C,
C,
V
CC
=5V for L/M versions, V
CC
=3.3V for T/S versions, and V
CC
=3V for R version. (Note 2)
Symbol
V
CC
I
CC
Parameter
V
CC
Range
Supply
Current
Conditions
T
A
=0
°
to +70
°
C
C
T
A
=-40
°
to +85
°
C
C
T
A
=-40
°
to +85
°
C
C
UM706L/
UM708L/UM813L
UM706M/
UM708M/UM813M
T
A
=+25
°
C
T
A
=-40
°
to +85
°
C
C
T
A
=+25
°
C
T
A
=-40
°
to +85
°
C
C
T
A
=+25
°
C
T
A
=-40
°
to +85
°
C
C
T
A
=+25
°
C
T
A
=-40
°
to +85
°
C
C
T
A
=+25
°
C
T
A
=-40
°
to +85
°
C
C
Min
1.0
1.2
Typ
Max
5.5
5.5
Unit
V
μA
80
4.53
4.50
4.29
4.25
3.01
3.00
2.87
2.85
2.57
2.55
40
2.63
2.93
3.08
4.38
4.63
150
4.73
4.75
4.47
4.50
3.15
3.16
2.99
3.00
2.69
2.70
V
TH
Reset
Threshold
UM706T/
UM708T/UM813T
UM706S/
UM708S/UM813S
UM706R/
UM708R/UM813R
V
Reset
Threshold
Hysteresis
t
RS
Reset Pulse
Width
140
mV
200
280
ms
Note 2: Production testing done at T
A
=+25° limits over temperature guaranteed by design only.
C;
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