!
Precision Voltage Monitor for 3V, 3.3V or 5V Power Supplies
!
6mA Supply Current
!
140ms Minimum Reset Pulse Width
!
RESET Remains Valid with V
CC
as Low as 1.4V
!
Active Low Manual Reset Input
!
No External Components
!
4-Pin SOT-143 Package
!
Critical Microprocessor Power Monitoring
!
Portable Equipment
!
Intelligent Instruments
!
Computers & Printers
!
Controllers
ILC811
V
CC
Top View
RESET
MR
GND
2
1
4
3
ILC812
V
CC
RESET
MR
GND
2
1
4
3
ILC811
ILC812
P
V
CC
V
CC
V
CC
RESET
RESET
INPUT
MR
(RESET)
( ) = ILC812
The ILC811/ILC812 is a low cost microprocessor superviso-
ry circuit that asserts a reset if the power supply drops below
a designated threshold or the manual reset pin is forced low.
Several different reset thresholds are available to accom-
modate systems operating at 3V, 3.3V or 5V.
The ILC811 has an active low RESET output, while the
ILC812 offers an active high RESET output. The reset output
is guaranteed to remain asserted for a minimum of 140ms
after V
CC
has risen above the designated reset threshold.
The ILC811/ILC812 is available in a 4-pin SOT-143
ILC811/812
Microprocessor Reset Circuits
Impala Linear Corporation
Impala Linear Corporation
1
(408) 574-3939
www.impalalinear.com
Sept 1999
ILC811/812 1.3
Preliminary
Part
Package
Temp. Range
ILC811_U
4-Lead SOT-143
-40C to +85C
ILC812_U
4-Lead SOT-143
-40C to +85C
Place the device suffix of desired reset threshold voltage from the
table [below] in the blank to complete the part number.
Reset Threshold Voltage (V)
Device Suffix
4.63
L
4.38
M
4.00
J
3.08
T
2.93
S
2.63
R
Typical Circuit
Pin Package Configuration
General Description
Features
Applications
Ordering Information
Microprocessor Reset Circuits
Impala Linear Corporation
2
(408) 574-3939
www.impalalinear.com
Sept 1999
ILC811/812 1.3
Preliminary
Parameter
Symbol
Ratings
Units
Terminal Voltage
V
CC
-0.3 to 6.0
V
MR
-0.3 to (V
CC
+ 0.3)
V
Input Current
V
CC
, MR
20
mA
Output Current
RESET, RESET
20
mA
Rate of Rise
V
CC
100
V/
s
Operating Temperature Range
T
A
-40 to +85
C
Storage Temperature Range
-65 to +150
C
Lead Temperature (Soldering - 10 sec.)
300
C
Power Dissipation (T
A
= +70C)
320
mW
Stresses above those listed under ABSOLUTE MAXIMUM RATINGS may cause permanent device failure. Functionality at
or above these limits is not implied. Exposure to absolute maximum ratings for extended periods may affect device reliabil-
ity. Operating ranges define those limits between which the functionality of the device is guaranteed.
V
CC
= 5V for ILC81_L/M/J, V
CC
= 3.3V for ILC81_S/T, V
CC
= 3V for ILC81_R, T
A
=
Operating Temperature Range, unless
otherwise noted.
Parameter
Conditions
Min
Typ
Max
Units
Operating Voltage Range, V
CC
T
A
= 0C to 70C
T
A
= -40C to 85C
1.4
1.6
5.5
5.5
V
Supply Current, I
CC
ILC811L/M/J, ILC812L/M/J
V
CC
< 3.6V, ILC811R/S/T, ILC812R/S/T
9
6
15
10
A
Reset Voltage Threshold, V
TH
ILC811L, ILC812L
ILC811M, ILC812M
ILC811J, ILC812J
ILC811T, ILC812T
ILC811S, ILC812S
ILC811R, ILC812R
4.50
4.25
3.89
3.00
2.85
2.55
4.63
4.38
4.00
3.08
2.93
2.63
4.75
4.50
4.10
3.15
3.00
2.70
V
Reset Timeout Period, t
R
140
240
560
ms
RESET Output Voltage, V
OH
I
SOURCE
= 800
A, ILC811L/M/J
I
SOURCE
= 500
A, ILC811R/S/T
V
CC
1.5
0.8 x V
CC
V
RESET Output Voltage, V
OL
V
CC
= V
TH
Min., I
SINK
= 3.2mA, ILC811L/M/J
V
CC
= V
TH
Min., I
SINK
= 1.2mA, ILC811R/S/T
V
CC
> 1.4V, I
SINK
= 50
A, T
A
= 0C to 70C
V
CC
> 1.6V, I
SINK
= 50
A, T
A
= -40C to 85C
0.4
0.3
0.3
0.3
V
RESET Output Voltage, V
OH
1.8V < V
CC
< V
TH
Min., I
SOURCE
= 150
A
0.8 x V
CC
V
RESET Output Voltage, V
OL
I
SINK
= 3.2mA, ILC812L/M/J
I
SINK
= 1.2mA, ILC812R/S/T
0.4
0.3
V
MR Minimum Pulse Width
10
s
MR to Reset Delay
0.5
s
MR Input Threshold, V
IH
V
CC
> V
TH
Max., ILC81_L/M/J
ILC81_R/S/T
2.3
0.7 x V
CC
V
MR Input Threshold, V
IL
V
CC
> V
TH
Max., ILC81_L/M/J
ILC81_R/S/T
0.8
0.25 x
V
CC
V
MR Pull-Up Resistance
10
20
30
k
MR Glitch Immunity
100
ns
Absolute Maximum Ratings
Electrical Characteristics
Microprocessor Reset Circuits
Impala Linear Corporation
3
(408) 574-3939
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Sept 1999
ILC811/812 1.3
Preliminary
4
3
Reset
Generator
2
1
-
+
Reset
Threshold (V)
V
CC
MR
RESET (ILC811)
RESET (ILC812)
GND
Pin Number
Pin Name ILC811
ILC812 Description
GND
1
1
Ground Pin.
RESET
2
N/A
RESET goes low if V
CC
falls below the reset threshold and
remains asserted for one reset timeout period (140ms min.)
after V
CC
exceeds the reset threshold.
RESET
N/A
2
RESET goes high if V
CC
falls below the reset threshold and
remains asserted for one reset timeout period (140ms min.)
after V
CC
exceeds the reset threshold.
MR
3
3
Manual reset input. A logic low on MR forces a reset. The
reset will remain asserted as long as MR is held low and for
one reset timeout period (140ms min.) after MR goes high.
This input can be shorted to ground via a switch or driven
from CMOS or TTL logic. Float if unused.
V
CC
4
4
Power supply input, 3V, 3.3V or 5V.
Microprocessor Reset
The RESET pin is asserted whenever V
CC
falls below the
reset threshold voltage or if MR (manual reset) is forced
low. The reset pin remains asserted for a period of 240ms
after V
CC
has risen above the reset threshold voltage or MR
has returned high. The reset function ensures the micro-
processor is properly reset and powers up into a known
condition after a power failure. RESET will remain valid with
V
CC
as low as 1.4V.
VCC Transients
The ILC811/ILC812 are relatively immune to negative-going
V
CC
glitches below the reset threshold. Typically, a nega-
tive-going transient 125
V below the reset threshold with a
duration of 50ms (25
s for ILC81_R/S/T) or less will not
cause an unwanted reset.
Interfacing to Bidirectional Reset Pins
The ILC811/ILC812 can interface with
Ps with bidirection-
al reset pins by connecting a 4.7k
resistor in series with
the ILC811/ILC812 output and the
P reset pin.
RESET Valid to 0V
A resistor can be added from the RESET pin to ground to
ensure the RESET output remains low with VCC down to
0V. A 100kW resistor connected from RESET to ground is
recommended. The size of the resistor should be large
enough to not load the RESET output and small enough to
pull-down any stray leakage currents.
ILC811
P
100
K
V
CC
V
CC
V
CC
RESET
RESET
Reset Valid to V
CC
=0V
V
TH
V
CC
t
R
MR
RESET
t
R
Pin Functions
Circuit Description
Microprocessor Reset Circuits
Impala Linear Corporation
4
(408) 574-3939
www.impalalinear.com
Sept 1999
ILC811/812 1.3
Preliminary
Industry P/N
ILC Direct
Replacement
MAX811JEUS-T
ILC811JU
MAX811LEUS-T
ILC811LU
MAX811MEUS-T
ILC811MU
MAX811REUS-T
ILC811RU
MAX811SEUS-T
ILC811SU
MAX811TEUS-T
ILC811TU
MAX812JEUS-T
ILC812JU
MAX812LEUS-T
ILC812LU
MAX812MEUS-T
ILC812MU
MAX812REUS-T
ILC812RU
MAX812SEUS-T
ILC812SU
MAX812TEUS-T
ILC812TU
SOT-143
ILC811J KJYY
ILC811L KLYY
ILC811M KMYY
ILC811R KRYY
ILC811S KSYY
ILC811T KTYY
ILC812J LJYY
ILC812L LLYY
ILC812M LMYY
ILC812R LRYY
ILC812S LSYY
ILC812T LTYY
YY = Lot Code
Alternate Source Cross Reference Guide
Device Marking Information
Microprocessor Reset Circuits
Impala Linear Corporation
5
(408) 574-3939
www.impalalinear.com
Sept 1999
ILC811/812 1.3
Preliminary
0.120
0.105
0.004
0.001
0.040
0.031
0.079
0.071
0.055
0.047
0.098
0.083
0.010
0.005
0.0059
0.0035
0-8
0.037
0.030
0.021
0.015
0.080
0.070
Dimensions are in inches
O1.5 0.1
3.5 0.05
8.0 0.3
1.75 0.1
4.0 0.1
2.0 0.05
4.0 0.1
O1.1 0.1
3.1 0.1
1.2 0.1
2.7 0.1
Dimensions are in millimeters
Devices sold by Impala Linear Corporation are covered by the warranty and patent indemnification provisions appearing
in its Terms of Sale only. Impala Linear Corporation makes no warranty, express, statutory, implied, or by description
regarding the information set forth herein or regarding the freedom of the described devices from patent infringement.
Impala Linear Corporation makes no warranty of merchantability or fitness for any purpose. Impala Linear Corporation
reserves the right to discontinue production and change specifications and prices at any time and without notice.
This product is intended for use in normal commercial applications. Applications requiring an extended temperature
range, unusual environmental requirements, or high reliability applications, such as military and aerospace, are specif-
ically not recommended without additional processing by Impala Linear Corporation.
Impala Linear Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in an
Impala Linear Corporation product. No other circuits, patents, licenses are implied.
Life Support Policy
Impala Linear Corporation's products are not authorized for use as critical components in life support devices or systems.
1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or
(b) support or sustain life, and whose failure to perform, when properly used in accordance with instructions for use pro-
vided in the labeling, can be reasonably expected to result in a significant injury to the user.
2. A critical component is any component of a life support device or system whose failure to perform can be reason-
ably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness.
Packaging Information
Tape and Reel Information
4-Pin SOT-143
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