MOTOROLA
Order Number: MAX809/D
Rev. 1, 07/1999
Semiconductor Components
MAX809
MAX810
SOT–23
PLASTIC PACKAGE (TO–236)
CASE 318
3-Pin Microprocessor
Reset Monitors
Features
•
Precision V
CC
Monitor for 3.0V, 3.3V, and 5.0V Supplies
•
140msec Guaranteed Minimum RESET, RESET
Output Duration
•
RESET Output Guaranteed to V
CC
= 1.0V (MAX809)
•
Low 17µA Supply Current
•
V
CC
Transient Immunity
•
Small SOT–23 Package
•
No External Components
•
Wide Operating Temperature: –40°C to 85°C
Typical Applications
•
•
•
•
Computers
Embedded Systems
Battery Powered Equipment
Critical
µP
Power Supply Monitoring
ORDERING INFORMATION
MAX809xTR
MAX810xTR
SOT–23
SOT–23
NOTE: The ”x” denotes a suffix for VCC
threshold – see table below
Suffix
L
M
J*
T
S
R
Reset VCC Threshold (V)
4.63
4.38
4.00
3.08
2.93
2.63
NOTE: *J version is available for MAX809 only
The MAX809 and MAX810 are cost–effective system supervisor circuits designed to monitor V
CC
in digital systems
and provide a reset signal to the host processor when necessary. No external components are required.
The reset output is driven active within 20
µsec
of V
CC
falling through the reset voltage threshold. Reset is main-
tained active for a minimum of 140msec after V
CC
rises above the reset threshold. The MAX810 has an active–high
RESET output while the MAX809 has an active–low RESET output. The output of the MAX809 is guaranteed valid
down to V
CC
= 1V. Both devices are available in a SOT–23 package.
The MAX809/810 are optimized to reject fast transient glitches on the V
CC
line. Low supply current of 17µA (V
CC
=
3.3V) makes these devices suitable for battery powered applications.
©
Motorola, Inc. 1999
1
MAX809 MAX810
TYPICAL OPERATING CIRCUIT
VCC
PIN CONFIGURATION
SOT–23*
VCC
MAX809
RESET
VCC
PROCESSOR
RESET
INPUT
GND
RESET (RESET)**
2
GND 1
TOP VIEW
3
VCC
GND
NOTE: *SOT–23 is equivalent to JEDEC (TO–236)
** RESET is for MAX809
** RESET is for MAX810
ABSOLUTE MAXIMUM RATINGS*
Symbol
Parameter
Supply Voltage (VCC to GND)
RESET, RESET
Input Current, VCC
Output Current, RESET, RESET
dV/dt (VCC)
PD
TA
Tstg
Tsol
Power Dissipation (TA
≤
70°C)
SOT–23 (derate 4mW/°C above +70°C)
Operating Temperature Range
Storage Temperature Range
Lead Temperature (Soldering, 10 Seconds)
Value
6.0
–0.3 to (VCC + 0.3)
20
20
100
230
–40 to +85
–65 to +150
+260
°C
°C
°C
Unit
V
V
mA
mA
V/µsec
mW
* Maximum Ratings are those values beyond which damage to the device may occur.
2
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MAX809 MAX810
ELECTRICAL CHARACTERISTICS
(VCC = Full Range, TA =
–40°C to +85°C unless otherwise noted
. typical values are
at TA = +25C, VCC = 5V for L/M/J, 3.3V for T/S, 3.0V for R)
(Note 1.)
Symbol
VCC Range
TA = 0°C to +70°C
TA = –40°C to +85°C
ICC
Supply Current
MAX8xxL/M/J: VCC < 5.5V
MAX8xxR/S/T: VCC < 3.6V
Reset Threshold (Note NO TAG)
MAX8xxL: TA = 25°C
TA = –40°C to +85°C
MAX8xxM: TA = 25°C
TA = –40°C to +85°C
MAX809J: TA = 25°C
TA = –40°C to +85°C
MAX8xxT: TA = 25°C
TA = –40°C to +85°C
MAX8xxS: TA = 25°C
TA = –40°C to +85°C
MAX8xxR: TA = 25°C
TA = –40°C to +85°C
Reset Threshold Temperature Coefficient
VCC to Reset Delay VCC = VTH to (VTH – 100mV)
Reset Active Timeout Period
VOL
RESET Output Voltage Low (MAX809)
MAX809R/S/T: VCC = VTH min, ISINK = 1.2mA
MAX809L/M/J: VCC = VTH min, ISINK = 3.2mA
VCC > 1.0V, ISINK = 50µA
RESET Output Voltage High (MAX809)
MAX809R/S/T: VCC > VTH max, ISOURCE = 500µA
MAX809L/M/J: VCC > VTH max, ISOURCE = 800µA
RESET Output Voltage Low (MAX810)
MAX810R/S/T: VCC = VTH max, ISINK = 1.2mA
MAX810L/M/J: VCC = VTH max, ISINK = 3.2mA
RESET Output Voltage High (MAX810)
1.8 < VCC < VTH min, ISOURCE = 150µA
Characteristic
Min
1.0
1.2
—
—
4.56
4.50
4.31
4.25
3.93
3.89
3.04
3.00
2.89
2.85
2.59
2.55
—
—
140
—
—
—
0.8 VCC
VCC – 1.5
—
—
0.8 VCC
Typ
—
—
24
17
4.63
—
4.38
—
4.00
—
3.08
—
2.93
—
2.63
—
30
20
240
—
—
—
—
—
—
—
—
Max
5.5
5.5
µA
60
50
V
4.70
4.75
4.45
4.50
4.06
4.10
3.11
3.15
2.96
3.00
2.66
2.70
—
—
560
0.3
0.4
0.3
V
—
—
V
0.3
0.4
V
—
ppm/°C
µsec
msec
V
Unit
V
VTH
VOH
VOL
VOH
1. Production testing done at TA = 25°C, over temperature limits guaranteed by design.
PIN DESCRIPTION
Á
Á
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
Á
Á
Á
Á ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
Á
Á
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
Á
Á
ÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁÁ
ÁÁÁÁÁÁÁÁÁÁ
Á
1
2
2
3
GND
Ground
RESET (MAX809)
RESET output remains low while VCC is below the reset voltage threshold, and for 240msec
(typ.) after VCC rises above reset threshold
RESET output remains high while VCC is below the reset voltage threshold, and for
240msec (typ.) after VCC rises above reset threshold
Supply Voltage (typ.)
RESET (MAX810)
VCC
Pin No.
Symbol
Description
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3
MAX809 MAX810
APPLICATIONS INFORMATION
VCC Transient Rejection
The MAX809/810 provides accurate V
CC
monitoring
and reset timing during power–up, power–down, and
brownout/sag conditions, and rejects negative–going
transients (glitches) on the power supply line. Figure 1
shows the maximum transient duration vs. maximum
negative excursion (overdrive) for glitch rejection. Any
combination of duration and overdrive which lies
under
the curve will
not
generate a reset signal. Combinations
above the curve are detected as a brownout or power–
down. Transient immunity can be improved by adding a
capacitor in close proximity to the V
CC
pin of the
MAX809/810.
VCC
VTH
Overdrive
discharge stray capacitances and hold the output low
(Figure 2). This resistor value, though not critical,
should be chosen such that it does not appreciably load
RESET under normal operation (100k
W
will be suitable
for most applications). Similarly, a pull–up resistor to
V
CC
is required for the MAX810 to ensure a valid high
RESET for V
CC
below 1.0V.
VCC
VCC
MAX809
RESET
R1
100 k
GND
Duration
MAXIMUM TRANSIENT DURATION (
m
sec)
400
TA = +25° C
Figure 2. Ensuring RESET Valid to VCC = 0 V
Processors With Bidirectional I/O Pins
320
240
160
MAX8xxL/M/J
90
0
1
MAX8xxR/S/T
10
100
1000
RESET COMPARATOR OVERDRIVE,
(VTH – VCC (mV)
Some
µP’s
(such as Motorola 68HC11) have bi–
directional reset pins. Depending on the current drive
capability of the processor pin, an indeterminate logic
level may result if there is a logic conflict. This can be
avoided by adding a 4.7k
W
resistor in series with the
output of the MAX809/810 (Figure 3). If there are other
components in the system which require a reset signal,
they should be buffered so as not to load the reset line.
If the other components are required to follow the reset
I/O of the
µP,
the buffer should be connected as shown
with the solid line.
BUFFER
VCC
Figure 1. Maximum Transient Duration vs.
Overdrive for Glitch Rejection at 25° C
RESET Signal Integrity During Power–Down
BUFFERED RESET
TO OTHER SYSTEM
COMPONENTS
VCC
m
P
RESET
GND
VCC
MAX809
47 k
RESET
GND
The MAX809 RESET output is valid to V
CC
= 1.0V.
Below this voltage the output becomes an ”open circuit”
and does not sink current. This means CMOS logic in-
puts to the
µP
will be floating at an undetermined volt-
age. Most digital systems are completely shutdown well
above this voltage. However, in situations where RE-
SET must be maintained valid to V
CC
= 0V, a pull–down
resistor must be connected from RESET to ground to
Figure 3. Interfacing to Bidirectional Reset I/O
4
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MAX809 MAX810
TYPICAL CHARACTERISTICS
35
30
SUPPLY CURRENT (
m
A)
25
20
15
10
5
0
–40
VCC = 1 V
VCC = 3 V
VCC = 5 V
SUPPLY CURRENT (
m
A)
30
VCC = 5 V
25
20
15
10
5
0
–40
VCC = 1 V
VCC = 3 V
–20
0
20
40
TEMPERATURE (C°)
60
85
–20
0
20
40
TEMPERATURE (C°)
60
85
Figure 4. Supply Current vs Temperature
(No Load, MAX8xxR/S/T)
Figure 5. Supply Current vs Temperature
(No Load, MAX8xxL/M/J/)
100
POWER–DOWN RESET DELAY (
m
sec)
80
60
40
20
0
–40
POWER–DOWN RESET DELAY (
m
sec)
VOD = VTH – VCC
VOD = 10 mV
140
VOD = VTH – VCC
120
VOD = 10 mV
100
80
60
40
20
0
–40
VOD = 200 mV
–20
0
20
40
TEMPERATURE (C°)
60
85
VOD = 100 mV
VOD = 20 mV
VOD = 10 mV
VOD = 100 mV
VOD = 200 mV
–20
0
20
40
TEMPERATURE (C°)
60
85
Figure 6. Power–Down Reset Delay vs
Temperature and Overdrive (MAX8xxR/S/T)
Figure 7. Power–Down Reset Delay vs
Temperature and Overdrive (MAX8xxL/M/J)
POWER–UP RESET TIMEOUT (msec)
250
NORMALIZED THRESHOLD
85
245
MAX8xxL/M/J
240
235
230
225
–40
MAX8xxR/S/T
1.003
1.002
1.001
1.000
0.999
0.998
0.997
–20
0
20
40
TEMPERATURE (C°)
60
–40
–20
0
20
40
TEMPERATURE (C°)
60
85
Figure 8. Power–Up Reset Timeout vs
Temperature
Figure 9. Normalized Reset Threshold vs
Temperature
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