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.
Electrical Characteristics
(V
CC
= 1.0V to 5.5V, T
A
= -40°C to +85°C, unless otherwise specified. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
V
CC
Supply Current
SYMBOL
V
CC
I
CC
V
CC
= 5.5V, no load
V
CC
= 3.6V, no load
46
44
31
29
V
CC
Reset Threshold
V
TH
26
23
22
17
16
Reset Threshold Tempco
Reset Threshold Hysteresis
RSTIN Threshold
RSTIN Threshold Hysteresis
RSTIN Input Current
RSTIN to Reset Output Delay
Reset Timeout Period
V
CC
to
RESET
Output Delay
Manual Reset Minimum Setup
Period Pulse Width
t
RP
t
RD
V
CC
falling at 1mV/µs
K
t
MR
L
S
T
6.72
4.48
2.24
1.12
V
TH-RSTIN
MAX6449–MAX6452
V
HYST
I
RSTIN
MAX6449–MAX6452
MAX6449–MAX6452
MAX6449–MAX6452, V
RSTIN
falling at
1mV/µs
140
-25
15
210
20
10.08
6.72
3.36
1.68
13.44
8.96
4.48
2.24
s
280
T
A
= 0°C to +85°C
T
A
= -40°C to +85°C
0.615
0.610
2.5
+25
4.50
4.25
3.00
2.85
2.55
2.25
2.12
1.62
1.52
CONDITIONS
MIN
1.0
7
6
4.63
4.38
3.08
2.93
2.63
2.32
2.19
1.67
1.58
60
2 × V
TH
0.630
0.645
0.650
TYP
MAX
5.5
20
16
4.75
4.50
3.15
3.00
2.70
2.38
2.25
1.71
1.62
ppm/°C
mV
V
mV
nA
µs
ms
µs
V
UNITS
V
µA
www.maximintegrated.com
Maxim Integrated
│
2
MAX6443–MAX6452
Electrical Characteristics (continued)
µP Reset Circuits with Long Manual Reset
Setup Period
(V
CC
= 1.0V to 5.5V, T
A
= -40°C to +85°C, unless otherwise specified. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
MR2 Minimum Setup Period
Pulse Width
MR2 Glitch Rejection
MR2 to
RESET
Delay
Manual Reset Timeout Period
MR1
to V
CC
Pullup Impedance
MR2
to V
CC
Pullup Impedance
MAX6445/MAX6446/MAX6449/MAX6450
V
CC
≥ 1.00V, I
SINK
= 50µA,
RESET
asserted
RESET
Output Low
(Open Drain or Push-Pull)
V
CC
≥ 1.20V, I
SINK
= 100µA,
RESET
asserted
V
CC
≥ 2.55V, I
SINK
= 1.2mA,
RESET
asserted
V
CC
≥ 4.25V, I
SINK
= 3.2mA,
RESET
asserted
V
CC
≥ 1.80V, I
SOURCE
= 200µA,
RESET
deasserted
RESET
Output High
(Push-Pull)
V
OH
V
CC
≥ 3.15V, I
SOURCE
= 500µA,
RESET
deasserted
V
CC
≥ 4.75V, I
SOURCE
= 800µA,
RESET
deasserted
RESET
Open-Drain Leakage
Current
MR1, MR2,
MR2
Input Low Voltage
MR1, MR2,
MR2
Input High Voltage
I
LKG
V
IL
V
IH
0.7 × V
CC
RESET
deasserted
0.8 × V
CC
0.8 × V
CC
0.8 × V
CC
1
0.3 × V
CC
µA
V
V
V
t
MRP
SYMBOL
CONDITIONS
MAX6447/MAX6448/MAX6451/MAX6452
MAX6447/MAX6448/MAX6451/MAX6452
MAX6447/MAX6448/MAX6451/MAX6452
140
25
25
MIN
1
100
200
210
50
50
280
75
75
0.3
0.3
V
0.3
0.4
TYP
MAX
UNITS
µs
ns
ns
ms
kW
kW
V
OL
Note 1:
Devices production tested at T
A
= +25°C. Overtemperature limits are guaranteed by design.
www.maximintegrated.com
Maxim Integrated
│
3
MAX6443–MAX6452
µP Reset Circuits with Long Manual Reset
Setup Period
Typical Operating Characteristics
(V
CC
= 3.3V, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
8
SUPPLY CURRENT (µA)
7
6
5
4
3
2
1
0
1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5
SUPPLY VOLTAGE (V)
T
A
= -40°C
T
A
= +25°C
T
A
= +85°C
MAX6443/52 toc01
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6443/52 toc02
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX6443/52 toc03
9
1.05
NORMALIZED TIMEOUT PERIOD
1.04
1.03
1.02
1.01
1.00
0.99
0.98
0.97
0.96
0.95
-40
-15
10
35
60
250
200
150
100
50
0
TRANSIENT DURATION (µs)
RESET OCCURS
ABOVE THE CURVE
V
TH
= 4.4V
0
200
400
600
800
1000
85
TEMPERATURE (°C)
RESET THRESHOLD OVERDRIVE (mV)
NORMALIZED V
CC
RESET THRESHOLD
vs. TEMPERATURE
MAX6443/52 toc04
V
CC
TO RESET DELAY
vs. TEMPERATURE
23.6
V
CC
TO RESET DELAY (µs)
23.2
22.8
22.4
22.0
21.6
21.2
20.8
20.4
20.0
V
CC
= FALLING AT 1mV/µs
MAX6443/52 toc05
RSTIN TO RESET DELAY
vs. TEMPERATURE (RSTIN FALLING)
23.6
RSTIN TO RESET DELAY (µs)
23.2
22.8
22.4
22.0
21.6
21.2
20.8
20.4
20.0
RSTIN FALLING AT 1mV/µs
MAX6443/52 toc06
1.03
NORMALIZED V
CC
RESET THRESHOLD
1.02
1.01
1.00
0.99
0.98
0.97
24.0
24.0
-40
-15
10
35
60
85
-40
-15
10
35
60
85
-40
-15
10
35
60
85
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
MANUAL RESET TO RESET DELAY
(MAX6445L/MAX6446L/MAX6449L/MAX6450L)
MAX6443/52 toc07
V
CC
TO
RESET
DELAY
V
CC
= 4.5V
MAX6443/52 toc08
V
CC
= 5V
MR1
(5V/div)
V
TH
= 4.392V
V
CC
= 4.3V
V
CC
(100mV/div)
MR2
(5V/div)
RESET
(5V/div)
TIME (1s/div)
TIME (100µs/div)
RESET
(2V/div)
www.maximintegrated.com
Maxim Integrated
│
4
MAX6443–MAX6452
µP Reset Circuits with Long Manual Reset
Setup Period
Pin Description
PIN
MAX6443
MAX6444
1
MAX6445
MAX6446
2
MAX6447
MAX6448
2
MAX6449
MAX6450
2
MAX6451
MAX6452
2
NAME
GND
Ground
Active-Low Push-Pull or Open-Drain Output.
RESET
changes from high to low when V
CC
or RSTIN drops below
its selected reset threshold and remains low for the 210ms
reset timeout period after all monitored power-supply inputs
exceed their selected reset thresholds.
RESET
is one-shot
pulsed low for the reset timeout period (140ms min) after
selected manual reset inputs are asserted longer than the
specified setup period. For the open-drain output, use a
minimum 20kW pullup resistor to V
CC
.
Manual Reset Input, Active Low. Internal 50kW pullup to
V
CC
. Pull
MR1
low for the typical input pulse width (t
MR
)
to one-shot pulse
RESET
for the reset timeout period.
Manual Reset Input, Active Low. Pull both
MR1
and
MR2
low for the typical input pulse width (t
MR
) to one-
shot pulse
RESET
for the reset timeout period.
V
CC
Voltage Input. Power supply and input for the
primary microprocessor voltage reset monitor.
Manual Reset Input, Active Low. Internal 50kW pullup to
V
CC
. Pull both
MR1
and
MR2
low for the typical input
pulse width (tMR) to one-shot pulse
RESET
for the reset
timeout period.
Manual Reset Input. Pull the MR2 high to immediately
one-shot pulse
RESET
for the reset timeout period.
Reset Input. High-impedance input to the adjustable
reset comparator. Connect RSTIN to the center point
of an external resistor-divider to set the threshold of the
externally monitored voltage.
FUNCTION
2
1
1
1
1
RESET
3
—
3
—
3
MR1
—
4
3
4
—
4
3
4
—
4
V
CC
—
5
—
6
—
MR2
—
—
5
—
6
MR2
—
—
—
5
5
RSTIN
Detailed Description
Reset Output
The reset output is typically connected to the reset
input of a microprocessor (µP). A µP’s reset input starts
or restarts the µP in a known state. The MAX6443–
MAX6452 µP supervisory circuits provide the reset
logic to prevent code-execution errors during power-
1. Introduction
Electronic scales are gradually replacing traditional measuring tools like springs and balances in everyday life, such as electronic price computing scales and electronic weigh...[详细]
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