LM809/LM810
3-Pin Microprocessor Reset Circuits
General Description
The LM809/810 microprocessor supervisory circuits can be
used to monitor the power supplies in microprocessor and
digital systems. They provide a reset to the microprocessor
during power-up, power-down and brown-out conditions.
The function of the LM809/810 is to monitor the V
CC
supply
voltage, and assert a reset signal whenever this voltage
declines below the factory-programmed reset threshold. The
reset signal remains asserted for 240ms after V
CC
rises
above the threshold. The LM809 has an active-low RESET
output, while the LM810 has an active-high RESET output.
Seven standard reset voltage options are available, suitable
for monitoring 5V, 3.3V, and 3V supply voltages.
With a low supply current of only 15A, the LM809/810 are
ideal for use in portable equipment. The LM809/LM810 are
available in the 3-pin SOT23 package and in the 6-Lead LLP
package.
Features
n
Precise monitoring of 3V, 3.3V, and 5V supply voltages
n
Superior upgrade to MAX809/810
n
Fully specified over temperature
n
140ms min. Power-On Reset pulse width, 240ms typical
Active-low RESET Output (LM809)
Active-high RESET Output (LM810)
n
Guaranteed RESET Output valid for V
CC
1V
n
Low Supply Current, 15A typ.
n
Power supply transient immunity
Applications
n
Microprocessor Systems
n
Computers
n
Controllers
n
Intelligent Instruments
n
Portable/Battery-Powered Equipment
n
Automotive
Typical Application Circuit
10105701
Connection Diagrams
10105702
( ) are for LM810
10105715
Top View
See NS package Number LDB06A
( ) are for LM810
September 2002
LM809/LM810
3-Pin
Microprocessor
Reset
Circuits
2002 National Semiconductor Corporation
DS101057
www.national.com
Ordering Information
Reset Threshold
(V)
LM809 Supplied as 1000
units, tape & reel
LM809 Supplied as 3000
units, tape & reel
Package
Top Mark
Package
Type
NSC Package
4.63
LM809M3-4.63
LM809M3X-4.63
S8B
SOT23-3
M03B
4.38
LM809M3-4.38
LM809M3X-4.38
S7B
4.00
LM809M3-4.00
LM809M3X-4.00
S6B
3.08
LM809M3-3.08
LM809M3X-3.08
S5B
2.93
LM809M3-2.93
LM809M3X-2.93
S4B
2.63
LM809M3-2.63
LM809M3X-2.63
S3B
2.45
LM809M3-2.45
LM809M3X-2.45
SFB
Reset Threshold
(V)
LM810 Supplied as 1000
units, tape & reel
LM810 Supplied as 3000
units, tape & reel
Package
Top Mark
Package
Type
NSC Package
4.63
LM810M3-4.63
LM810M3X-4.63
SEB
SOT23-3
M03B
4.38
LM810M3-4.38
LM810M3X-4.38
SDB
4.00
LM810M3-4.00
LM810M3X-4.00
SCB
3.08
LM810M3-3.08
LM810M3X-3.08
SBB
2.93
LM810M3-2.93
LM810M3X-2.93
SAB
2.63
LM810M3-2.63
LM810M3X-2.63
S9B
Reset Threshold
(V)
LM809 Supplied as 1000
units, tape & reel
LM809 Supplied as 4500
units, tape & reel
Package
Top Mark
Package
Type
NSC Package
2.63
LM809LD-2.63
LM809LDX-2.63
S13
LLP-6
LDB06A
Custom voltages and improved accuracies are available, subject to minimum orders. Contact your local National Semiconductor Sales Office for information.
Pin Descriptions
PIN
NAME
FUNCTION
(LLP)
SOT-23
1
1
GND
Ground reference
3
2
RESET (LM809)
Active-low output. RESET remains low while V
CC
is below the reset threshold,
and for 240ms after V
CC
rises above the reset threshold.
RESET (LM810)
Active-high output. RESET remains high while V
CC
is below the reset
threshold, and for 240ms after V
CC
rises above the reset threshold.
5
3
V
CC
Supply Voltage (+5V, +3.3V, or +3.0V)
LM809/LM810
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2
Absolute Maximum Ratings
(Note 1)
If Military/Aerospace specified devices are required,
please contact the National Semiconductor Sales Office/
Distributors for availability and specifications.
V
CC
-0.3V to 6.0V
RESET, RESET
-0.3V to (V
CC
+ 0.3V)
Input Current, V
CC
Pin
20mA
Output Current, RESET, RESET
Pin
20mA
Rate of Rise, V
CC
100V/s
ESD Rating (Note 2)
2kV
Continuous Power Dissipation
(Note 4)
320mW
JA
:
LLP-6
152C/W
SOT23-3
326C/W
Ambient Temperature Range
-40C to +105C
Maximum Junction Temperature
125C
Storage Temperature Range
-65C to +160C
Lead Temperature (soldering,
10sec)
+300C
Electrical Characteristics
V
CC
= full range, T
A
= -40C to +105C, unless otherwise noted. Typical values are at T
A
= +25C, V
CC
= 5V for
4.63/4.38/4.00 versions, V
CC
= 3.3V for 3.08/2.93 versions, and V
CC
= 3V for 2.63/2.45 version (Note 3).
Symbol
Parameter
Conditions
Min
Typ
Max
Units
V
CC
Range
T
A
= 0C to +70C
1.0
5.5
V
T
A
= -40C to +105C
1.2
5.5
I
CC
Supply Current
T
A
= -40C to
+85C
V
CC
<
5.5V, LM8_ _
-4.63/4.38/4.00
18
60
A
V
CC
<
3.6V, LM8_ _
-3.08/2.93/2.63/2.45
15
50
T
A
= +85C to
+105C
V
CC
<
5.5V, LM8_ _
-4.63/4.38/4.00
100
V
CC
<
3.6V, LM8_ _
-3.08/2.93/2.63/2.45
100
V
TH
Reset Threshold (Note 5)
LM8_ _ -4.63
T
A
= +25C
4.56
4.63
4.70
V
T
A
= -40C to +85C
4.50
4.75
T
A
= +85C to +105C
4.40
4.86
LM8_ _ -4.38
T
A
= +25C
4.31
4.38
4.45
T
A
= -40C to +85C
4.25
4.50
T
A
= +85C to +105C
4.16
4.56
LM8_ _ -4.00
T
A
= +25C
3.93
4.00
4.06
T
A
= -40C to +85C
3.89
4.10
T
A
= +85C to +105C
3.80
4.20
LM8_ _ -3.08
T
A
= +25C
3.04
3.08
3.11
T
A
= -40C to +85C
3.00
3.15
T
A
= +85C to +105C
2.92
3.23
LM8_ _ -2.93
T
A
= +25C
2.89
2.93
2.96
T
A
= -40C to +85C
2.85
3.00
T
A
= +85C to +105C
2.78
3.08
LM8_ _ -2.63
T
A
= +25C
2.59
2.63
2.66
T
A
= -40C to +85C
2.55
2.70
T
A
= +85C to +105C
2.50
2.76
LM8_ _ -2.45
T
A
= +25C
2.41
2.45
2.49
T
A
= -40C to +85C
2.38
2.52
T
A
= +85C to +105C
2.33
2.57
Reset Threshold
Temperature Coefficient
30
ppm/C
V
CC
to Reset Delay (Note 5)
V
CC
= V
TH
to (V
TH
- 100mV)
20
s
Reset Active Timeout Period
T
A
= -40C to +85C
140
240
560
ms
T
A
= +85C to +105C
100
840
LM809/LM810
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3
Electrical Characteristics
(Continued)
V
CC
= full range, T
A
= -40C to +105C, unless otherwise noted. Typical values are at T
A
= +25C, V
CC
= 5V for
4.63/4.38/4.00 versions, V
CC
= 3.3V for 3.08/2.93 versions, and V
CC
= 3V for 2.63/2.45 version (Note 3).
Symbol
Parameter
Conditions
Min
Typ
Max
Units
V
OL
RESET Output Voltage Low
(LM809)
V
CC
= V
TH
min, I
SINK
= 1.2mA,
LM809-2.45/2.63/2.93/3.08
0.3
V
V
CC
= V
TH
min, I
SINK
= 3.2mA,
LM809-4.63/4.38/4.00
0.4
V
CC
>
1.0V, I
SINK
= 50A
0.3
V
OH
RESET Output Voltage High
(LM809)
V
CC
>
V
TH
max, I
SOURCE
= 500A,
LM809-2.45/2.63/2.93/3.08
0.8V
CC
V
V
CC
>
V
TH
max, I
SOURCE
= 800A,
LM809-4.63/4.38/4.00
V
CC
-1.5
V
OL
RESET Output Voltage Low
(LM810)
V
CC
= V
TH
max, I
SINK
= 1.2mA,
LM810-2.63/2.93/3.08
0.3
V
V
CC
= V
TH
max, I
SINK
= 3.2mA,
LM810-4.63/4.38/4.00
0.4
V
OH
RESET Output Voltage High
(LM810)
1.8V
<
V
CC
<
V
TH
min, I
SOURCE
= 150A
0.8V
CC
V
Note 1: Absolute Maximum Ratings are limits beyond which damage to the device may occur. Operating Ratings are conditions under which the device operates
correctly. Operating ratings do not imply guaranteed performance limits. For guaranteed performance limits and associated test conditions, see the Electrical
Characteristics.
Note 2: The human body model is a 100pF capacitor discharged through a 1.5k
resistor into each pin.
Note 3: Production testing done at T
A
= +25C, over temperature limits guaranteed by design only.
Note 4: At elevated temperatures, devices must be derated based on package thermal resistance. The device in the SOT23-3 package must be derated at 4mW/C
at ambient temperatures above 70C. The device has internal thermal protection.
Note 5: RESET Output for LM809, RESET output for LM810.
LM809/LM810
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4
Typical Performance Characteristics
Supply Current vs Temperature
(No Load, LM8_ _-2.63/2.93/3.08)
10105703
Supply Current vs Temperature
(No Load, LM8_ _-4.63/4.38)
10105704
Power-Down Reset Delay vs Temp
(LM8_ _-2.63/2.93/3.08)
10105705
Power-Down Reset Delay vs Temperature
(LM8_ _-4.63/4.38)
10105706
Power-Up Reset Timeout vs Temperature
10105707
Normalized Reset Threshold vs Temperature
10105708
LM809/LM810
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