UM805/811/812
4-Pin μP Voltage Monitors with Manual Reset Input
UM805/811/812
SOT143
General Description
The UM805/811/812 are low-power microprocessor (μP) supervisory circuits used to monitor power
supplies in μP and digital systems. They provide excellent circuit reliability and low cost by
eliminating external components and adjustments when used with 5V-powered or 3V-powered
circuits. The UM805/811/812 also provide a debounced manual reset input.
These devices perform a single function: They assert a reset signal whenever the V
CC
supply voltage
falls below a preset threshold, keeping it asserted for at least 140ms after V
CC
has risen above the
reset threshold. Reset thresholds are available for operation with a variety of supply voltages.
The UM805 has an open-drain output stage, while the UM811/812 have push-pull outputs. The
UM805’s open-drain RESET output requires a pull-up resistor that can be connected to a voltage
_____________
_____________
higher than V
CC
. The UM805/811 have an active-low RESET output, while the UM812 has an
active-high RESET output. The reset comparator is designed to ignore fast transients on V
CC
, and
the outputs are guaranteed to be in the correct logic state for V
CC
down to 1V.
Low supply current makes the UM805/811/812 ideal for use in portable equipments. The devices
come in a 4-pin SOT143 package.
Applications
Computers
Controllers
Portable/Battery-Powered Equipments
Intelligent Instruments
Critical μP and μC Power Monitoring
Features
No External Components
V
CC
Transient Immunity
Correct Logic Output Guaranteed to V
CC
=1.0V
Precision V
CC
Monitoring of 3.0V, 3.3V and 5.0V
Supplies
2μA Supply Current
140ms Minimum Power-On Reset Pulse Width
Guaranteed Over Temperature
Available in 3 Output Configurations:
__________
Open-Drain Active-Low RESET Output(UM805)
__________
Push-Pull Active-Low RESET Output(UM811)
Push-Pull Active-High RESET Output(UM812)
4-Pin SOT143 Package
Wide Operation Temperature: -40° to +85°
C
C
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UM805/811/812
Pin Configurations
Top View
GND
1
4
V
CC
4
3
XXX
RESET
2
(RESET)
1
3
MR
M
2
( ) are for UM812
M: Month Code
UM805/811/812
SOT143
Ordering Information
UM8 XX Z P
XX: Output Type
=05 Open-Drain Active Low
=11 Push-Pull Active Low
=12 Push-Pull Active High
Z: Reset Threshold (V)
=L 4.63
=M 4.38
=J 4.00
=T 3.08
=S
2.93
=R 2.63
=Z 2.32
P: Package Type
=E SOT143
Typical Operating Circuit
V
CC
V
CC
V
CC
R
pullup
*
UM805
UM811
UM812
RESET
(RESET)
MR
GND
μP
RESET
INPUT
GND
PUSHBUTTON
SWITCH
*UM805 ONLY
( ) are for UM812
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UM805/811/812
Pin Description
Pin
Number
1
Pin Name
GND
Ground
_____________
Function
Active-Low Reset Output. RESET remains low while V
CC
is below
_______
______________
RESET
(UM805/811)
2
the reset threshold or while M R is held low. It remains low for the
Reset Active Timeout Period (t
RP
) after the reset conditions are
terminated.
See Figure 1.
UM811:
CMOS push-pull output (sources and sinks current)
UM805:
Open-drain, active low, NMOS output (sinks current only). Connect a
______________
pull-up resistor from RESET to any supply voltage up to 6V.
Active-High Reset Output. RESET remains high while V
CC
is below
RESET
(UM812)
_______
the reset threshold or while MR is held low. RESET remains high for
Reset Active Timeout Period (t
RP
) after the reset conditions are
terminated.
_______
Manual Reset Input. A logic low on M R asserts reset. Reset remains
_______
_______
3
_______
MR
asserted as long as M R is low and for 240ms after M R returns high.
This active-low input has an internal 20kΩ pull-up resistor. It can be
driven from a TTL or CMOS-logic line, or shorted to ground with a
switch. Leave open if unused.
See Figure 2.
+5V, +3.3V, or +3V Supply Voltage
4
V
CC
Absolute Maximum Ratings (Note 1)
Symbol
V
CC
Supply Voltage
_____________
Parameter
Value
-0.3 to +6.0
-0.3 to (V
CC
+0.3)
-0.3 to +6.0
20
Unit
V
mA
mA
mW
°
C
°
C
RESET, RESET (push-pull)
_____________
RESET (open-drain)
I
CC
I
O
P
D
T
A
T
STG
_______
Input Current, V
CC
, M R
_____________
Output Current, RESET, RESET
Continuous Power Dissipation (Derate 4mW/° above
C
70°
C)
Operating Temperature Range
Storage Temperature Range
20
320
-40 to +105
-65 to +160
Lead Temperature (soldering, 10s)
+300
°
C
Note 1: Stresses beyond those listed under “Absolute maximum Ratings” may cause permanent
damage to the device. These are stress ratings only and functional operation of the device at these or
any other conditions beyond those indicated in the operational sections of the specifications are not
implied. Exposure to absolute maximum rating conditions for extended periods may affect device
reliability.
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UM805/811/812
Electrical Characteristics
(V
CC
= 5V for L/M/J versions, V
CC
= 3.3V for T/S versions, V
CC
= 3V for R version, and V
CC
=
2.5V for Z version, T
A
= -40° to +85° unless otherwise noted. Typical values are at T
A
= +25°
C
C,
C.)
(Note 2)
Symbol
V
CC
I
CC
Parameter
Supply Voltage
Range
Supply Current
L version
M version
J version
Conditions
T
A
=0° to +70°
C
C
Min
1.0
Typ
Max
5.5
Unit
V
μA
2.0
T
A
=+25℃
T
A
=-40℃ to + 85℃
T
A
=+25℃
T
A
=-40℃ to + 85℃
T
A
=+25℃
T
A
=-40℃ to + 85℃
T
A
=+25℃
T
A
=-40℃ to + 85℃
T
A
=+25℃
T
A
=-40℃ to + 85℃
T
A
=+25℃
T
A
=-40℃ to + 85℃
T
A
=+25℃
T
A
=-40℃ to + 85℃
4.56
4.50
4.31
4.25
3.93
3.89
3.04
3.00
2.89
2.85
2.59
2.55
2.28
2.25
4.63
4.38
4.00
3.08
2.93
2.63
2.32
150
10
140
10
100
0.5
2.3
240
5.0
4.70
4.75
4.45
4.50
4.06
4.10
3.11
3.15
2.96
3.00
2.66
2.70
2.35
2.38
V
TH+
Reset Threshold
T version
S version
R version
Z version
V
Reset Threshold
Tempco
V
CC
to Reset Delay
(Note 3)
t
RP
t
MR
Reset Active
Timeout Period
______
ppm/°
C
μs
560
ms
μs
ns
μs
MR Minimum
Pulse Width
______
MR Glitch
Immunity
(Note 4)
______
t
MD
V
IH
V
IL
V
IH
V
IL
MR to Reset
Propagation Delay
V
CC
> V
TH(MAX)
UM805/811/812LE/ME/JE
______
0.8
V
0.7×
CC
V
0.25×
CC
V
10
20
30
kΩ
MR Input
Threshold
V
CC
> V
TH(MAX)
UM805/811/812TE/SE/RE/ZE
______
MR Pull-Up
Resistance
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UM805/811/812
Electrical Characteristics (Continued)
(V
CC
= 5V for L/M/J versions, V
CC
= 3.3V for T/S versions, V
CC
= 3V for R version, and V
CC
=
2.5V for Z version, T
A
= -40° to +85° unless otherwise noted. Typical values are at T
A
= +25°
C
C,
C.)
(Note 2)
Symbol
V
OH
RESET Output
Voltage
V
OL
Parameter
Conditions
I
SOURCE
=150μA, 1.8V<V
CC
<V
TH(MIN)
UM812LE/ME/JE/TE/SE/RE/ZE
I
SINK
=1.2mA
UM812TE/SE/RE/ZE
I
SINK
=3.2mA
UM812LE/ME/JE
I
SOURCE
=500μA, V
CC
>V
TH(MAX)
UM811TE/SE/RE/ZE
I
SOURCE
=800μA, V
CC
>V
TH(MAX)
UM811LE/ME/JE
I
SINK
=1.2mA, V
CC
=V
TH(MIN)
UM805/811TE/SE/RE/ZE
I
SINK
=3.2mA, V
CC
=V
TH(MIN)
UM805/811LE/ME/JE
I
SINK
=50μA, V
CC
>1.0V
Min
0.8×
CC
V
Typ
Max
Unit
0.3
0.4
0.8×
CC
V
V
CC
-1.5
0.3
0.4
0.3
V
V
OH
____________
RESET Output
Voltage
V
OL
V
Note 2:
Production testing done at T
A
= +25° limits over temperature guaranteed by design only.
_____________
C;
Note 3:
RESET output for UM805/811; RESET output for UM812.
Note 4:
“Glitches” of 100ns or less typically will not generate a reset pulse.
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