Packages containing lead (Pb)....................................+240°C
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
PARAMETER
Supply Voltage Range
Supply Current
(V
CC
= 1V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise specified. Typical values are at V
CC
= 5V and T
A
= +25°C.) (Note 1)
SYMBOL
V
CC
V
CC
≤ 5.0V
I
CC
V
CC
≤ 3.3V
V
CC
≤ 2.0V
V
CC
Reset Threshold
Accuracy
Hysteresis
V
CC
to Reset Delay
Reset Timeout Period
V
SRT
Ramp Current
V
SRT
Ramp Threshold
RAMP Threshold Hysteresis
RESET
Output Voltage LOW
V
OL
V
TH
V
HYST
t
RD
t
RP
I
RAMP
V
CC
falling at 1mV/µs
C
SRT
= 1500pF
C
SRT
= 0F
V
SRT
= 0 to 0.65V; V
CC
= 1.6V to 5V
V
RAMP
falling threshold
V
CC
≥ 1.0V, I
SINK
= 50µA
V
CC
≥ 2.7V, I
SINK
= 1.2mA
V
CC
≥ 4.5V, I
SINK
= 3.2mA
RESET
Output Voltage HIGH,
(Push-Pull)
RESET
Output Leakage
Current, (Open-Drain)
V
CC
≥ 1.8V, I
SOURCE
= 200µA
V
OH
V
CC
≥ 2.25V, I
SOURCE
= 500µA
V
CC
≥ 4.5V, I
SOURCE
= 800µA
I
LKG
V
CC
> V
TH
, reset not asserted
V
CC
≥ 1.0V, I
SOURCE
= 1µA
RESET Output Voltage HIGH
V
OH
V
CC
≥ 1.8V, I
SOURCE
= 150µA
V
CC
≥ 2.7V, I
SOURCE
= 500µA
V
CC
≥ 4.5V, I
SOURCE
= 800µA
0.8 x V
CC
0.8 x V
CC
0.8 x V
CC
0.8 x V
CC
V
0.8 x V
CC
0.8 x V
CC
0.8 x V
CC
1.0
µA
V
3.00
T
A
= +25°C
T
A
= -40°C to +125°C
V
TH
-
1.25%
V
TH
-
2.5%
4 x V
TH
100
4.375
0.275
240
0.65
33
0.3
0.3
0.4
V
5.75
CONDITIONS
MIN
1.0
2.6
2
1.7
TYP
MAX
5.5
4.5
3.5
2.5
V
TH
+
1.25%
V
TH
+
2.5%
µA
UNITS
V
V
mV
µs
ms
nA
V
mV
V
TH-RAMP
V
CC
= 1.6V to 5V (V
RAMP
rising)
www.maximintegrated.com
Maxim Integrated
│
2
MAX6412–MAX6420
Low-Power, Single/Dual-Voltage μP Reset Circuits
with Capacitor-Adjustable Reset Timeout Delay
Electrical Characteristics (continued)
(V
CC
= 1V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise specified. Typical values are at V
CC
= 5V and T
A
= +25°C.) (Note 1)
PARAMETER
RESET Output Voltage LOW
RESET IN Leakage Current
RESET IN Threshold
V
RST
V
IH
V
IL
V
IH
MR
Minimum Pulse Width
MR
Glitch Rejection
MR
to RESET Delay
MR
Pullup Resistance
Pull up to V
CC
12
Note 1:
Devices production tested at T
A
= +25°C. Over temperature limits are guaranteed by design.
V
IL
SYMBOL
V
OL
CONDITIONS
V
CC
≥ 1.8V, I
SINK
= 500µA
V
CC
≥ 2.7V, I
SINK
= 1.2mA
V
CC
≥ 4.5V, I
SINK
= 3.2mA
V
RST
falling, V
CC
= 1.6V to 5.0V
V
CC
> 4.0V
V
CC
< 4.0V
1.205
2.4
0.3 x V
CC
0.7 x V
CC
1
75
20
20
28
µs
ns
ns
kΩ
1.255
0.8
V
MIN
TYP
MAX
0.3
0.3
0.4
10
nA
V
V
UNITS
MR
Input
Typical Operating Characteristics
(V
CC
= 5V, C
SRT
= 1500pF, T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs.
SUPPLY VOLTAGE
MAX6412-20 toc01
SUPPLY CURRENT vs.
TEMPERATURE
3.0
SUPPLY CURRENT (µA)
2.5
2.0
1.5
1.0
0.5
MAX6412-20 toc02
SUPPLY CURRENT (µA)
3
T
A
= +125°C
T
A
= +25°C
V
CC
= 5V
V
CC
= 3.3V
V
CC
= 1.8V
RESET TIMEOUT PERIOD (ms)
1000
100
10
1
0.1
0.001
2
T
A
= -40°C
1
V
CC
= 1V
0
0
1
2
3
4
5
6
0
-50
-25
0
25
50
75
100
125
0.01
0.1
1
C
SRT
(nF)
10
100
1000
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
www.maximintegrated.com
Maxim Integrated
│
3
MAX6412-20 toc03
4
3.5
10,000
RESET TIMEOUT PERIOD vs. C
SRT
MAX6412–MAX6420
Low-Power, Single/Dual-Voltage μP Reset Circuits
with Capacitor-Adjustable Reset Timeout Delay
Typical Operating Characteristics (continued)
(V
CC
= 5V, C
SRT
= 1500pF, T
A
= +25°C, unless otherwise noted.)
C
SRT
= 1500pF
MAX6412-20 toc04
RESET TIMEOUT PERIOD (ms)
RESET TIMEOUT PERIOD (µs)
4.25
4.20
4.15
4.10
4.05
550
500
450
400
350
300
250
C
SRT
= 0
-50
-25
0
25
50
75
100
125
200
-50
-25
0
TEMPERATURE (C)
25
75
50
TEMPERATURE (°C)
100
125
RESET IN THRESHOLD VOLTAGE
vs. TEMPERATURE
MAX6412-20 toc06
RESET IN THRESHOLD VOLTAGE (V)
TRANSIENT DURATION (µs)
1.275
1.270
1.265
1.260
1.255
1.250
150
125
100
75
50
25
RESET OCCURS
ABOVE THE CURVE
-50
-25
0
25
50
75
100
125
0
V
TH
= 3.0V
0
200
400
600
800
1000
RESET THRESHOLD OVERDRIVE (mV)
TEMPERATURE (°C)
www.maximintegrated.com
Maxim Integrated
│
4
MAX6412-20 toc07
1.280
175
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX6412-20 toc05
4.30
RESET TIMEOUT PERIOD
vs. TEMPERATURE
600
RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6412–MAX6420
Low-Power, Single/Dual-Voltage μP Reset Circuits
with Capacitor-Adjustable Reset Timeout Delay
Pin Description
PIN
MAX6412/
MAX6413/
MAX6414
MAX6415/
MAX6416/
MAX6417
MAX6418/
MAX6419/
MAX6420
NAME
FUNCTION
RESET
1
1
1
RESET
2
—
3
4
5
2
3
—
4
5
2
3
—
4
5
GND
RESET
IN
MR
SRT
V
CC
RESET
changes from high to low whenever V
CC
or RESET IN drops below the
selected reset threshold voltage (V
TH
or V
RESET IN
, respectively) or manual
reset is pulled low.
RESET
remains low for the reset timeout period after all
reset conditions are deasserted and then goes high.
RESET changes from low to high whenever the V
CC
or RESET IN drops below
the selected reset threshold voltage (V
TH
or V
RESET IN
) or manual reset is
pulled low. RESET remains high for the reset timeout period after all reset
conditions are deasserted and then goes low.
Ground
Reset Input. High-impedance input to the adjustable reset comparator. Connect
RESET IN to the center point of an external resistor-divider network to set the
threshold of the externally monitored voltage. See
Reset Threshold
section.
Manual Reset Input. Pull this pin low to manually reset the device. Reset
remains asserted for the reset timeout period after
MR
is released.
Set Reset Timeout Input. Connect a capacitor between SRT and ground to
set the timeout period. Determine the period as follows:
t
RP
= (2.71 x 10
6
) x C
SRT
+ 275µs with t
RP
in seconds and C
SRT
in Farads.
Supply Voltage and Input for Fixed-Threshold V
CC
Monitor
Detailed Description
The MAX6412–MAX6420 low-power microprocessor (μP)
supervisory circuits provide maximum adjustability for
supply-voltage monitoring and reset functionality. In addi-
tion, the MAX6412–MAX6420 reset timeout period is
adjustable using an external capacitor.
The MAX6412/MAX6413/MAX6414 have factory-trimmed
reset threshold voltages in approximately 100mV incre-
ments from 1.575V to 5.0V with a manual reset input. The
MAX6415/MAX6416/MAX6417 contain a reset threshold
that can be adjusted to any voltage above 1.26V using
external resistors. The MAX6418/MAX6419/MAX6420
offer both a factory-trimmed reset threshold and an adjust-
able reset threshold input for dual-voltage monitoring.
A reset signal is asserted when V
CC
and/or RESET IN
falls below the preset values or when
MR
is asserted.
The reset remains asserted for an externally programmed
interval after V
CC
and/or RESET IN has risen above the
reset threshold or
MR
is deasserted.
known state. The MAX6412–MAX6420 μP supervisory
circuits provide the reset logic to prevent code-execution
errors during power-up, power-down, and brownout con-
ditions (see
Typical Operating Circuit).
For the MAX6413, MAX6416, and MAX6419, RESET
changes from low to high whenever V
CC
or RESET IN
drops below the reset threshold voltages. Once RESET
IN and V
CC
exceed their respective reset threshold
voltage(s), RESET remains high for the reset timeout
period, then goes low.
On power-up, once V
CC
reaches 1V, RESET is guaran-
teed to be a logic high. For applications requiring valid
reset logic when V
CC
is less than 1V, see the section
Ensuring a Valid RESET/RESET Output Down to V
CC
= 0V.
The active-low
RESET
output of the remaining super-
visors is the inverse of the MAX6413, MAX6416, and
MAX6419 active-high RESET output and is guaranteed
valid for V
CC
≥ 1V.
Reset Output
Reset Threshold
The reset output is typically connected to the reset input
of a μP. A μP’s reset input starts or restarts the μP in a
The MAX6415–MAX6420 monitor the voltage on RESET
IN with an external resistor voltage-divider (Figure 1).
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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