General Description
The MAX803/MAX809/MAX810 are microprocessor (P)
supervisory circuits used to monitor the power supplies
in P and digital systems. They provide excellent circuit
reliability and low cost by eliminating external compo-
nents and adjustments when used with +5V, +3.3V,
+3.0V, or +2.5V powered circuits.
These circuits perform a single function: they assert a
reset signal whenever the V
CC
supply voltage declines
below a preset threshold, keeping it asserted for at
least 140ms after V
CC
has risen above the reset thresh-
old. Reset thresholds suitable for operation with a vari-
ety of supply voltages are available.
The MAX803 has an open-drain output stage, while the
MAX809/MAX810 have push-pull outputs. The
MAX803's open-drain RESET output requires a pull-up
resistor that can be connected to a voltage higher than
V
CC
. The MAX803/MAX809 have an active-low RESET
output, while the MAX810 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 MAX803/MAX809/
MAX810 ideal for use in portable equipment. The
MAX803 is available in a 3-pin SC70 package, and the
MAX809/MAX810 are available in 3-pin SC70 or SOT23
packages.
Applications
Computers
Controllers
Intelligent Instruments
Critical P and C Power Monitoring
Portable/Battery-Powered Equipment
Automotive
____________________________Features
o Precision Monitoring of +2.5V, +3V, +3.3V, and
+5V Power-Supply Voltages
o Fully Specified Over Temperature
o Available in Three Output Configurations
Open-Drain RESET Output (MAX803)
Push-Pull RESET Output (MAX809)
Push-Pull RESET Output (MAX810)
o 140ms min Power-On Reset Pulse Width
o 12A Supply Current
o Guaranteed Reset Valid to V
CC
= +1V
o Power Supply Transient Immunity
o No External Components
o 3-Pin SC70 and SOT23 Packages
MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
3-Pin Microprocessor Reset Circuits
________________________________________________________________ Maxim Integrated Products
1
TOP VIEW
RESET (RESET)
1
GND
V
CC
MAX803
MAX809
MAX810
SC70-3/SOT23-3
2
3
( ) ARE FOR MAX810.
MAX803 AVAILABLE IN SC70-3 ONLY.
MAX803
MAX809
V
CC
V
CC
R
PULL-UP
*
RESET
RESET
INPUT
GND
V
CC
GND
*MAX803 ONLY
P
Pin Configuration
Typical Operating Circuit
19-0344; Rev 5; 1/01
Note: These parts are offered in 2.5k or 10k reels, and must be
ordered in 2.5k or 10k increments. Order MAX803_EXR-T for
2.5k reels and MAX803_EXR-T10 for 10k reels. Insert the
desired suffix letter from the Selector Guide into the blank to
complete the part number. All versions of these products may
not be available at the time of announcement. Contact factory for
availability.
3 SC70-3
-40C to +125C
MAX803_EXR-T10
3 SC70-3
PIN-PACKAGE
TEMP. RANGE
-40C to +125C
MAX803_EXR-T
PART
3 SC70-3
-40C to +125C
MAX809_EXR-T10
3 SC70-3
-40C to +125C
MAX809_EXR-T
3 SOT23-3
-40C to +105C
MAX809_EUR-T10
3 SOT23-3
-40C to +105C
MAX809_EUR-T
3 SC70-3
-40C to +125C
MAX810_EXR-T10
3 SC70-3
-40C to +125C
MAX810_EXR-T
3 SOT23-3
-40C to +105C
MAX810_EUR-T10
3 SOT23-3
-40C to +105C
MAX810_EUR-T
Ordering Information
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim's website at www.maxim-ic.com.
MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
3-Pin Microprocessor Reset Circuits
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC
= full range, T
A
= -40C to +105C (SOT23) or T
A
= -40C to +125C (SC70), unless otherwise noted. Typical values are at T
A
=
+25C, 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.) (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 is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.
Terminal Voltage (with respect to GND)
V
CC
....................................................................-0.3V to +6.0V
RESET, RESET (push-pull) .....................-0.3V to (V
CC
+ 0.3V)
RESET (open drain)...........................................-0.3V to +6.0V
Input Current, V
CC
..............................................................20mA
Output Current, RESET, RESET ..........................................20mA
Rate of Rise, V
CC
............................................................100V/s
Continuous Power Dissipation (T
A
= +70C)
3-Pin SC70 (derate 2.17mW/C above +70C) ............174mW
3-Pin SOT23 (derate 4mW/C above +70C)...............320mW
Operating Temperature Range
3-Pin SC70 .....................................................-40C to +125C
3-Pin SOT23...................................................-40C to +105C
Storage Temperature Range .............................-65C to +150C
Lead Temperature (soldering, 10s) .................................+300C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
T
A
= 0C to +70C
1.0
5.5
T
A
= -40C to +105C (MAX8_ _ _EUR)
1.2
5.5
V
CC
Range
T
A
= -40C to +125C (MAX8_ _ _EXR)
1.2
5.5
V
V
CC
< 5.5V, MAX8_ _L/M
24
60
T
A
= -40C
to +85C
V
CC
< 3.6V, MAX8_ _R/S/T/Z
17
50
V
CC
< 5.5V, MAX8_ _L/M
100
Supply Current (SOT23)
I
CC
T
A
= +85C
to +105C
V
CC
< 3.6V, MAX8_ _R/S/T/Z
100
V
CC
< 5.5V, MAX8_ _L/M
24
35
T
A
= -40C
to +85
C
V
CC
< 3.6V, MAX8_ _R/S/T/Z
17
30
V
CC
< 5.5V, MAX8_ _L/M
60
Supply Current (SC70)
I
CC
T
A
= +85C
to +125C
V
CC
< 3.6V, MAX8_ _R/S/T/Z
60
A
T
A
= +25C
4.56
4.63
4.70
T
A
= -40C to +85C
4.50
4.75
MAX8_ _L
T
A
= -40C to +125C
4.40
4.86
T
A
= +25C
4.31
4.38
4.45
T
A
= -40C to +85C
4.25
4.50
MAX8_ _M
T
A
= -40C to +125C
4.16
4.56
T
A
= +25C
3.93
4.00
4.06
T
A
= -40C to +85C
3.89
4.10
MAX809J
(SOT only)
T
A
= -40C to +125C
3.80
4.20
T
A
= +25C
3.04
3.08
3.11
T
A
= -40C to +85C
3.00
3.15
MAX8_ _T
T
A
= -40C to +125C
2.92
3.23
T
A
= +25C
2.89
2.93
2.96
T
A
= -40C to +85C
2.85
3.00
MAX8_ _S
T
A
= -40C to +125C
2.78
3.08
T
A
= +25C
2.59
2.63
2.66
T
A
= -40C to +85C
2.55
2.70
Reset Threshold
(SOT only)
V
TH
MAX8_ _R
T
A
= -40C to +125C
2.50
2.76
V
MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
3-Pin Microprocessor Reset Circuits
_______________________________________________________________________________________
3
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= full range, T
A
= -40C to +105C (SOT23) or T
A
= -40C to +125C (SC70), unless otherwise noted. Typical values are at T
A
=
+25C, 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.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
T
A
= +25C
4.56
4.63
4.70
T
A
= -40C to +85C
4.50
4.75
MAX8_ _L
T
A
= -40C to +125C
4.44
4.82
T
A
= +25C
4.31
4.38
4.45
T
A
= -40C to +85C
4.25
4.50
MAX8_ _M
T
A
= -40C to +125C
4.20
4.56
T
A
= +25C
3.04
3.08
3.11
T
A
= -40C to +85C
3.00
3.15
MAX8_ _T
T
A
= -40C to +125C
2.95
3.21
T
A
= +25C
2.89
2.93
2.96
T
A
= -40C to +85C
2.85
3.00
MAX8_ _S
T
A
= -40C to +125C
2.81
3.05
T
A
= +25C
2.59
2.63
2.66
T
A
= -40C to +85C
2.55
2.70
MAX8_ _R
T
A
= -40C to +125C
2.52
2.74
T
A
= +25C
2.28
2.32
2.35
T
A
= -40C to +85C
2.25
2.38
Reset Threshold
(SC70 only)
V
TH
MAX8_ _Z
(SC70 only)
T
A
= -40C to +125C
2.22
2.42
V
Reset Threshold Tempco
30
ppm/C
V
CC
to Reset Delay (Note 2)
V
CC
= V
TH
to (V
TH
- 100 mV)
20
s
T
A
= -40C to +85C
140
240
560
Reset Active Timeout Period
(SOT23)
T
A
= +85C to +105C
100
840
ms
T
A
= -40C to +85C
140
240
460
Reset Active Timeout Period
(SC70)
T
A
= +85C to +125C
100
840
ms
V
CC
= V
TH
min, I
SINK
= 1.2mA,
MAX803R/S/T/Z, MAX809R/S/T/Z
0.3
V
CC
= V
TH
min, I
SINK
= 3.2mA,
MAX803L/M, MAX809J/L/M
0.4
RESET Output Voltage Low (push-
pull active low and open-drain
active low, MAX803 and MAX809)
V
OL
V
CC
> 1.0V, I
SINK
= 50A
0.3
V
V
CC
> V
TH
max, I
SOURCE
= 500A,
MAX803R/S/T/Z, MAX809R/S/T/Z
0.8V
CC
RESET Output Voltage High
(push-pull active low MAX809)
V
OH
V
CC
> V
TH
max, I
SOURCE
= 800A,
MAX803L/M, MAX809J/L/M
V
CC
- 1.5
V
V
CC
= V
TH
max, I
SINK
= 1.2mA,
MAX810R/S/T/Z
0.3
RESET Output Voltage Low (push-
pull active high, MAX810)
V
OL
V
CC
= V
TH
max, I
SINK
= 3.2mA,
MAX810L/M
0.4
V
MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
3-Pin Microprocessor Reset Circuits
4
_______________________________________________________________________________________
225
POWER-UP RESET TIMEOUT
vs. TEMPERATURE
245
250
MAX803-TOC5
TEMPERATURE (C)
POWER-UP RESET TIMEOUT (ms)
235
230
240
-40
85
20
-20
0
60
40
MAX8_ _R/S/T/Z
MAX8_ _J/L/M
0.997
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
1.001
1.002
1.003
MAX803-TOC6
TEMPERATURE (C)
NORMALIZED THRESHOLD
0.999
0.998
1.000
-40
85
20
-20
0
60
40
0
POWER-DOWN RESET DELAY vs.
TEMPERATURE (MAX8_ _J/L/M)
80
100
120
140
MAX803-TOC4
TEMPERATURE (C)
POWER-DOWN RESET DELAY (
s)
40
20
60
-40
85
20
-20
0
60
40
V
OD
= V
TH
- V
CC
V
OD
= 10mV
V
OD
= 100mV
V
OD
= 200mV
V
OD
= 20mV
0
POWER-DOWN RESET DELAY vs.
TEMPERATURE (MAX8_ _R/S/T/Z)
80
100
MAX803-TOC3
TEMPERATURE (C)
POWER-DOWN RESET DELAY (
s)
40
20
60
-40
85
20
-20
0
60
40
V
OD
= V
TH
- V
CC
V
OD
= 20mV
V
OD
= 10mV
V
OD
= 200mV
V
OD
= 100mV
Typical Operating Characteristics
(V
CC
= full range, T
A
= -40C to +105C, unless otherwise noted. Typical values are at T
A
= +25C, 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.)
-40
20
40
40
-20
0
60
85
SUPPLY CURRENT vs. TEMPERATURE
(SC70 PACKAGE, NO LOAD)
MAX803 toc01
TEMPERATURE (C)
SUPPLY CURRENT (
A)
0
5
10
15
MAX8_ _R/S/T, V
CC
= 3.3V
MAX8_ _L/M/R/S/T/Z, V
CC
= 1V
MAX8_ _Z, V
CC
= 2.5V
MAX8_ _L/M, V
CC
= 5V
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= full range, T
A
= -40C to +105C (SOT23) or T
A
= -40C to +125C (SC70), unless otherwise noted. Typical values are at T
A
=
+25C, 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.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
RESET Output Voltage High
(push-pull active high, MAX810)
V
OH
1.8V < V
CC
< V
TH
min, I
SOURCE
= 150A
0.8V
CC
V
RESET Open-Drain Output
Leakage Current (MAX803)
(Note 3)
V
CC
> V
TH
, RESET deasserted
1
A
Note 1: Production testing done at T
A
= +25C; limits over temperature guaranteed by design only.
Note 2: RESET output for MAX803/MAX809; RESET output for MAX810.
Note 3: Guaranteed by design, not production tested.
MAX803L/M/R/S/T/Z, MAX809J/L/M/R/S/T/Z, MAX810L/M/R/S/T/Z
_______________________________________________________________________________________
5
Detailed Description
A microprocessor's (P's) reset input starts the P in a
known state. The MAX803/MAX809/MAX810 assert
reset to prevent code-execution errors during power-
up, power-down, or brownout conditions. They assert a
reset signal whenever the V
CC
supply voltage declines
below a preset threshold, keeping it asserted for at
least 140ms after V
CC
has risen above the reset thresh-
old. The MAX803 uses an open-drain output, and the
MAX809/MAX810 have a push-pull output stage.
Connect a pull-up resistor on the MAX803's RESET out-
put to any supply between 0 and 6V.
Applications Information
Negative-Going V
CC
Transients
In addition to issuing a reset to the P during power-up,
power-down, and brownout conditions, the MAX803/
MAX809/MAX810 are relatively immune to short-duration
negative-going V
CC
transients (glitches).
Figure 1 shows typical transient duration vs. reset com-
parator overdrive, for which the MAX803/MAX809/
MAX810 do not generate a reset pulse. The graph was
generated using a negative-going pulse applied to V
CC
,
starting 0.5V above the actual reset threshold and end-
ing below it by the magnitude indicated (reset compara-
tor overdrive). The graph indicates the maximum pulse
width a negative-going V
CC
transient can have without
causing a reset pulse. As the magnitude of the transient
increases (goes farther below the reset threshold), the
maximum allowable pulse width decreases. Typically, for
the MAX8__L and MAX8__M, a V
CC
transient that goes
100mV below the reset threshold and lasts 20s or less
will not cause a reset pulse. A 0.1F bypass capacitor
mounted as close as possible to the V
CC
pin provides
additional transient immunity.
Ensuring a Valid Reset Output
Down to V
CC
= 0
When V
CC
falls below 1V, the MAX809 RESET output
no longer sinks current--it becomes an open circuit.
3-Pin Microprocessor Reset Circuits
2
RESET
(MAX803/
MAX809)
RESET Output remains low while V
CC
is below the reset threshold, and for at
least 140ms after V
CC
rises above the
reset threshold.
1
GND
Ground
PIN
NAME
FUNCTION
RESET
(MAX810)
RESET Output remains high while V
CC
is below the reset threshold, and for at
least 140ms after V
CC
rises above the
reset threshold.
3
V
CC
Supply Voltage (+5V, +3.3V, +3.0V, or
+2.5V)
Selector Guide
TOP MARK
PART/SUFFIX
RESET THRESHOLD (V)
OUTPUT TYPE
SOT
SC70
MAX803L
4.63
OPEN-DRAIN RESET
AAZ
MAX803M
4.38
OPEN-DRAIN RESET
ABA
MAX803T
3.08
OPEN-DRAIN RESET
ABB
MAX803S
2.93
OPEN-DRAIN RESET
ABC
MAX803R
2.63
OPEN-DRAIN RESET
ABD
MAX803Z
2.32
OPEN-DRAIN RESET
ABE
MAX809L
4.63
PUSH-PULL RESET
AAAA
AAN
MAX809M
4.38
PUSH-PULL RESET
ABAA
AAO
MAX809J
4.00
PUSH-PULL RESET
CWAA
MAX809T
3.08
PUSH-PULL RESET
ACAA
AAP
MAX809S
2.93
PUSH-PULL RESET
ADAA
AAQ
MAX809R
2.63
PUSH-PULL RESET
AFAA
AAR
MAX809Z
2.32
PUSH-PULL RESET
AAS
MAX810L
4.63
PUSH-PULL RESET
AGAA
AAT
MAX810M
4.38
PUSH-PULL RESET
AHAA
AAU
MAX810T
3.08
PUSH-PULL RESET
AJAA
AAV
MAX810S
2.93
PUSH-PULL RESET
AKAA
AAX
MAX810R
2.63
PUSH-PULL RESET
ALAA
AAW
MAX810Z
2.32
PUSH-PULL RESET
AAY
Pin Description
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