ADM811-3TART-REEL-7 ,0.3-6V; 200mW; microprocessor supervisory circuit. For microprocessor systems, controllers, intelligent instrumnets, automotive systems, safety systems, portable instrumentsSPECIFICATIONSParameter Min Typ Max Units Test Conditions/CommentsSUPPLYVoltage 1.0 5.5 V T = 0
ADM811-3TART-REEL-7
0.3-6V; 200mW; microprocessor supervisory circuit. For microprocessor systems, controllers, intelligent instrumnets, automotive systems, safety systems, portable instruments
REV.0
Microprocessors
Supervisory Circuit in 4-Lead SOT-143
FUNCTIONAL BLOCK DIAGRAM
FEATURES
Superior Upgrade for MAX811/MAX812
Specified Over Temperature
Low Power Consumption (5 mA Typ)
Precision Voltage Monitor: +3 V, +3.3 V, +5 V Options
Reset Assertion Down to 1 V VCC
140 ms Min Power-On Reset
Logic Low RESET Output (ADM811)
Logic High RESET Output (ADM812)
Built-In Manual Reset
APPLICATIONS
Microprocessor Systems
Controllers
Intelligent Instruments
Automotive Systems
Safety Systems
Portable Instruments
GENERAL DESCRIPTIONThe ADM811/ADM812 are reliable voltage monitoring devices
suitable for use in most voltage monitoring applications.
The ADM811/ADM812 are designed to monitor five different
voltages, each allowing for a 5% or 10% degradation of standard
PSU voltages before a reset occurs. These voltages have been
selected for the effective monitoring of +3 V, +3.3 V and +5 V
supply voltage levels.
Included in this circuit is a debounced Manual Reset input.
Reset can be activated using an electrical switch (or an input
from another digital device) or by a degradation of the supply
voltage. The Manual Reset function is very useful especially if
the circuit in which the ADM811/ADM812 is operating enters
into a state that can only be detected by the user. Allowing the
user to manually reset a system can reduce the damage or dan-
ger that could be otherwise caused by an out-of-control or
locked up system.
Figure 1.Typical Operating Circuit
ADM811/ADM812–SPECIFICATIONS
(VCC = Full Operating Range, TA = TMIN to TMAX, VCC typ = +5 V
for L/M, +3.3 V for T/S, +3 V for R Models unless otherwise noted)RESET VOLTAGE THRESHOLD
MANUAL RESET
RESET Output Voltage
Specifications subject to change without notice.
ABSOLUTE MAXIMUM RATINGS*(Typical values are at TA = +25°C unless otherwise noted)
Terminal Voltage (With Respect to Ground)
VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .–0.3 V to +6 V
All Other Inputs . . . . . . . . . . . . . . . . .–0.3 V to VCC + 0.3 V
Input Current
VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 mA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 mA
Output Current
RESET, RESET . . . . . . . . . . . . . . . . . . . . . . . . . . .20 mA
Operating Temperature Range . . . . . . . . . . .–40°C to +85°C
Storage Temperature Range . . . . . . . . . . . .–65°C to +160°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . .+300°C
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . .+215°C
Infrared (15 secs) . . . . . . . . . . . . . . . . . . . . . . . . . . .+220°C
ESD Rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 kV
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the
device at these or any other conditions above those listed in the operational
sections of this specification is not implied. Exposure to absolute maximum ratings
PIN FUNCTION DESCRIPTIONS
PIN CONFIGURATION
GND
RESET/RESET
VCC
ORDERING GUIDE
ADM811LART-REEL-7
ADM811MART-REEL
ADM811MART-REEL-7
ADM811TART-REEL
ADM811TART-REEL-7
ADM811-3TART-REEL
ADM811-3TART-RL7
ADM811SART-REEL
ADM811SART-REEL-7
ADM811RART-REEL
ADM811RART-REEL-7ADM812LART-REEL
ADM812LART-REEL-7
ADM812MART-REEL
ADM812MART-REEL-7
ADM812TART-REEL
ADM812TART-REEL-7
ADM812SART-REEL
ADM812SART-REEL-7
ADM812RART-REEL
*Only available in reels.
Parts in bold are ex-stock, please contact factory for availability.
ADM811/ADM812
–Typical Performance Characteristics
TEMPERATURE – 8C
IDD
– Figure 2.Supply Current vs. Temperature (ADM81_R/S/T)
TEMPERATURE – 8C
POWER-DOWN RESET DELAY –
100Figure 3.Power-Down RESET Delay vs. Temperature
(ADM81__R/S/T)
TEMPERATURE – 8C
POWER-UP RESET TIMEOUT – ms
244Figure 4.Power-Up Reset Timeout vs. Temperature
TEMPERATURE – 8C
–
100110120125Figure 5.Supply Current vs. Temperature (ADM81_L/M)
TEMPERATURE – 8C
POWER-DOWN RESET DELAY –
100Figure 6.Power-Down RESET Delay vs. Temperature
(ADM81_L/M)
TEMPERATURE – 8C
NORMALIZED RESET THRESHOLD
0.995Figure 7.Reset Threshold Deviation vs. Temperature
CIRCUIT INFORMATION
RESET THRESHOLDSThe reset output provides a RESET (for the ADM811) or a
RESET (for the ADM812) output to the microprocessor when-
ever the VCC input is below the reset threshold. The actual reset
threshold is dependant on whether a L, M, T, S or R suffix is
used. Please refer to Table I.
Table I.Reset Threshold OptionsParts in bold type are ex-stock, please contact factory for availability.
RESET OUTPUTOn power-up and after VCC rises above the reset threshold, an
internal timer holds the reset output active for 240 ms (typical).
This is intended as a power-on reset signal for the processor. It
allows time for both the power supply and the microprocessor
to stabilize after power-up. If a power supply brownout or inter-
ruption occurs, the reset output is similarly activated and re-
mains active for 240 ms (typical) after the supply recovers. This
allows time for the power supply and microprocessor to stabilize.
The ADM811 provides an active low reset output (RESET)
while the ADM812 provides an active high output (RESET).
During power-down of the ADM811, the RESET output re-
mains valid (low) with VCC as low as 1 V. This ensures that the
microprocessor is held in a stable shutdown condition as the
supply falls and also ensures that no spurious activity can occur
via the mP as it powers up.
MANUAL RESETThe ADM811/ADM812 is equipped with a manual reset input.
This input is designed to operate in a noisy environment where
unwanted glitches could be induced. These glitches could be
produced by the bouncing action of a switch contact or where a
Manual Reset switch may be located some distance away from
the circuit (the cabling of which may pickup noise).
The Manual Reset input is guaranteed to ignore logically valid
inputs which are faster than 100 ns and accept inputs longer in
duration than 10 ms.
GLITCH IMMUNITYThe ADM811/ADM812 contain internal filtering circuitry
providing glitch immunity from fast transient glitches on the
power supply line.
Figure 8.Power Fail RESET Timing
INTERFACING TO OTHER DEVICES
OutputThe ADM811/ADM812 series is designed to integrate with
as many devices as possible. One feature of the ADM811/
ADM812 is the reset output, which is directly proportional to
VCC (this is guaranteed only while VCC is greater than 1 V). This
enables the part to be used in both 3 V and 5 V or any nominal
voltage within the minimum and maximum specifications for VCC.
THE BENEFITS OF A VERY ACCURATE RESET
THRESHOLDBecause the ADM811/ADM812 series can operate effectively
even when there are large degradations of the supply voltages,
the possibility of a malfunction during a power failure is greatly
reduced. Another advantage of the ADM811/ADM812 series is
its very accurate internal voltage reference circuit. Combined,
these benefits produce an exceptionally reliable Microprocessor
Supervisory Circuit.
VCCFigure 9.Ensuring a Valid RESET Output Down to
VCC = 0 V
ENSURING A VALID RESET OUTPUT DOWN TO
VCC = 0 VWhen VCC falls below 0.8 V, ADM811s RESET no longer sinks
current. Therefore, a high impedance CMOS logic input con-
nected to RESET may drift to undetermined logic levels. To
eliminate this problem a 100 kW resistor should be connected
from RESET to ground.
ADM811/ADM812
OUTLINE DIMENSIONSDimensions shown in inches and (mm).
C3140–8–3/99
PRINTED IN U.S.A.
4-Lead Plastic Surface Mount Package
(SOT-143)
0.037 (0.94)
0.030 (0.77)SEATING
PLANE
0.021 (0.54)
0.015 (0.38)
0.004 (0.10)
0.001 (0.03)
0.120 (3.05)
0.105 (2.67)
0.040 (1.02)
0.031 (0.79)
PIN 1
0.079 (2.00)
0.055 (1.40)
0.047 (1.20)
0.098 (2.50)
0.083 (2.10)
0.080 (2.03)
0.070 (1.78)
0.010 (0.25)
0.005 (0.13)
0.0059 (0.089)
0.0035 (0.15)
