UM807/821/822
μP Reset Circuits with Long Manual Reset Setup Period
UM807/821/822
SOT143
General Description
The UM807/821/822 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 UM807/821/822 also provide a debounced manual reset input with long setup period.
On all devices, the reset output asserts when the V
CC
supply voltage drops below its specified
threshold. The reset output remains asserted for the reset timeout period (240ms typ) after V
CC
rises
above the reset threshold. The reset output is one-shot pulse asserted for the reset timeout period
(140ms min) when manual reset input is held low for a fixed setup timeout period. These devices
ignore manual reset transitions of less than the fixed setup timeout period.
_____________
The UM807 has an active-low RESET with open-drain output, the UM821 has an active-low
_____________
RESET with push-pull output, and the UM822 has an active-high RESET with push-pull output.
These devices, offered in small SOT143 package, are fully guaranteed over the extended
temperature range (-40° to +85°
C
C).
Applications
Set-Top Boxes
Consumer Electronics
DVD Players
Cable/DSL Modems
MP3 Players
Industrial Equipments
Automotive
Medical Devices
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
Available in 3 Manual Reset Setup Periods (t
MR
):
A: 10.08s
B: 6.72s
C: 1.68s
Available in 3 Output Configurations:
__________
Open-Drain Active-Low RESET Output(UM807);
__________
Push-Pull Active-Low RESET Output(UM821)
Push-Pull Active-High RESET Output(UM822)
4-Pin SOT143 Package
Wide Operation Temperature: -40° to +85°
C
C
________________________________________________________________________
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UM807/821/822
Pin Configurations
Top View
GND
1
4
V
CC
4
3
XXX
RESET
2
(RESET)
1
3
MR
M
2
( ) are for UM822
M: Month Code
UM807/821/822
SOT143
Ordering Information
UM8 XX Z T P
XX: Output Type
=07 Open-Drain Active Low
=21 Push-Pull Active Low
=22 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
T: Manual Reset Setup Period (s)
=A 10.08
=B 6.72
=C 1.68
P: Package Type
=E SOT143
________________________________________________________________________
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UM807/821/822
Typical Operating Circuit
+3.3V
V
CC
V
CC
R
pullup
*
UM807
UM821
UM822
RESET
(RESET)
MR
GND
μP
RESET
GND
RESET PULSE WIDTH
240ms
MR SETUP PERIOD
t
MR
t
PW
MR
RESET
RESET
*UM807 ONLY
( ) are for UM822
________________________________________________________________________
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UM807/821/822
Pin Description
Pin
Number
1
Pin Name
GND
Ground
______________
Function
______________
RESET
(UM807/821)
2
Active-Low Push-Pull or Open-Drain Output. RESET changes from
high to low when V
CC
drops below its reset threshold and remains low
for the 240ms reset timeout period after V
CC
exceeds their reset
______________
RESET
(UM822)
threshold. RESET is one-shot pulsed low for the reset timeout period
(140ms min) after the manual reset input is asserted longer than the
specified setup period. For the open-drain output, use a pull-up resistor
to V
CC
.
See Figure 1.
Active-High Push-Pull Output. RESET changes from low to high when
V
CC
drops below its reset threshold and remains high for the 240ms
reset timeout period after V
CC
exceeds their reset threshold. RESET is
one-shot pulsed high for the reset timeout period (140ms min) after the
manual reset input is asserted longer than the specified setup period.
See Figure 1.
Manual Reset Input, Active Low. Internal 22kΩ pull-up to V
CC
. Pull
_______
3
4
_______
MR
V
CC
M R low for the typical input pulse width (t
MR
) to one-shot pulse
_____________
RESET for the reset pulse width (t
PW
).
See Figure 2.
+5V, +3.3V, or +3V Supply Voltage
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
-0.3 to +6.0
20
Unit
RESET, RESET (push-pull)
_____________
V
RESET (open-drain)
_______
MR
I
CC
I
O
P
D
T
A
T
STG
_______
Input Current, V
CC
, M R
_____________
mA
mA
mW
°
C
°
C
°
C
Output Current, RESET, RESET
Continuous Power Dissipation (Derate 4mW/° above
C
70°
C)
Operating Temperature Range
Storage Temperature Range
Lead Temperature (soldering, 10s)
20
320
-40 to +105
-65 to +160
+300
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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UM807/821/822
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
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
A
B
C
6.04
4.03
1.01
140
240
10.08
6.72
1.68
240
100
2.3
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
t
RD
t
RP
Reset Threshold
Tempco
V
CC
to Reset Delay
(Note 3)
Reset Active
Timeout Period
______
ppm/°
C
μs
560
14.11
9.41
2.35
560
ms
s
ms
ns
t
MR
t
PW
MR Minimum
Pulse Width
RESET Pulse
Width
______
MR Glitch
Immunity
(Note 4)
V
IH
V
IL
V
IH
V
IL
______
______
V
CC
> V
TH(MAX)
UM807/821/822L_E/M_E/J_E
MR Input
Threshold
V
CC
> V
TH(MAX)
UM807/821/822T_E/S_E/R_E/Z_E
MR Pull-Up
Resistance
0.7×
CC
V
0.8
V
0.25×
CC
V
10
20
30
kΩ
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