MAX6394US___D_/V+T [MAXIM]
High-Accuracy μP Reset Circuit;
| 型号： | MAX6394US___D_/V+T |
| 厂家： | 
MAXIM INTEGRATED PRODUCTS |
| 描述： | High-Accuracy μP Reset Circuit |
| 文件： | 总8页 (文件大小：849K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
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MAX6394
High-Accuracy μP Reset Circuit
General Description
Benefits and Features
● ±0.6% Threshold Accuracy at T = +25°C
The MAX6394 low-power CMOS microprocessor (μP)
supervisory circuit is designed to monitor power supplies in
μP and digital systems. It offers excellent circuit reliability
by providing 1% accurate thresholds over temperature and
by eliminating external components and adjustments. The
MAX6394 also provides a debounced manual reset input.
A
● ±1.0% Threshold Accuracy from -40°C to +125°C
●
Small SOT143 Package
● Open-Drain RESET Output Can Exceed V
CC
● Precision, Factory-Set V
Reset Thresholds:
CC
Nine Options from 2.4V to 4.8V
This device performs a single function: it asserts a reset
signal whenever the V
preset threshold or whenever manual reset is asserted.
RESET remains asserted for an internally programmed
interval (reset timeout period) after V
supply voltage falls below a
CC
● Four Reset Timeout Periods Available:
0.7ms, 14ms, 105ms, and 826ms (minimum)
● Immune to Short V Transients
CC
has risen above
CC
● 5μA Supply Current
the reset threshold or manual reset is deasserted. The
MAX6394’s open-drain RESET output can be pulled up
● AEC-Q100 Qualified, Refer to Ordering Information
to a voltage higher than V
.
CC
for Specific /V Part
The MAX6394 comes with factory-trimmed reset threshold
voltages from 2.4V to 4.8V. Preset timeout periods of
0.7ms, 14ms, 105ms, and 826ms are also available. The
device comes in a SOT143 package.
Ordering Information appears at end of data sheet.
Applications
● Computers
● Controllers
● Intelligent Instruments
● Critical μP and μC Power Monitoring
● Portable/Battery-Powered Equipment
Pin Configuration
Typical Operating Circuit
V
CC
TOP VIEW
+
VCC
MAX6394
LASER-
TRIMMED
1
4
GND
VCC
RESISTORS
MAX6394
P
RESET
RESET
RESET
RESET
2
3
MR
MR
CIRCUITRY
GND
SOT143
19-3202; Rev 5; 12/19
MAX6394
High-Accuracy μP Reset Circuit
Absolute Maximum Ratings
VCC......................................................................-0.3V to +6.0V
Continuous Power Dissipation (T = +70°C)
A
RESET..................................................................-0.3V to +6.0V
SOT143 (derate 3.4mW/°C above +70°C)...............275.9mW
All Other Pins ........................................... -0.3V to (V
+ 0.3V)
Operating Temperature Range......................... -40°C to +125°C
Storage Temperature Range............................ -65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
CC
Input Current (V )............................................................20mA
CC
Output Current (RESET)....................................................20mA
Rate of Rise (V ).........................................................100V/μs
CC
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.
Package Information
4 SOT23
PACKAGE CODE
U4+1/U4+1A
21-0052
90-0183
Outline Number
Land Pattern Number
Thermal Resistance, Single-Layer Board
Junction to Ambient (qJA)
N/A
N/A
Junction to Case (qJC)
Thermal Resistance, Four-Layer Board
Junction to Ambient (qJA)
Junction to Case (qJC)
290
100
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that
a “+”, “#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the
drawing pertains to the package regardless of RoHS status.
Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a four-layer board.
www.maximintegrated.com/thermal-tutorial
For detailed information on package thermal considerations, refer to
.
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MAX6394
High-Accuracy μP Reset Circuit
Electrical Characteristics
(V
= +2.4V to +5.5V, T = -40°C to +125°C, unless otherwise noted. Typical values are at T = +25°C.)
CC
A
A
PARAMETER
Operating Voltage Range
SYMBOL
CONDITIONS
= -40°C to +125°C
A
MIN
TYP
5
MAX
5.5
12
UNITS
V
T
1.0
V
CC
V
V
V
V
= 5.5V, no load (-40°C to +85°C)
= 5.5V, no load (-40°C to +125°C)
= 3.6V, no load (-40°C to +85°C)
= 3.6V, no load (-40°C to +125°C)
CC
CC
CC
CC
15
V
Supply Current
I
µA
CC
CC
4
10
12
V
0.6%
-
V
0.6%
+
TH
TH
T
= +25°C (see Table 1)
V
TH
A
A
Reset Threshold (Note 1)
V
V
TH
V
1.0%
-
V
+
TH
TH
T
= -40°C to +125°C (see Table 2)
1.0%
Reset Threshold Tempco
∆V /°C
60
ppm/°C
TH
V
to Reset Delay
V
= falling at 1mV/µs
35
1.4
µs
CC
CC
MAX6394US_ _ _D1+T
MAX6394US_ _ _D2-T
MAX6394US_ _ _D3-T
MAX6394US_ _ _D4-T
0.7
14
2.0
40
28
Reset Timeout Period
MANUAL RESET INPUT
MR Input Threshold
t
ms
RP
105
826
200
1570
280
2240
V
V
V
> 4.0V
< 4.0V
0.8
IL
TH
TH
V
2.4
IH
V
V
0.3 x V
IL
CC
V
0.7 x V
CC
IH
MR Minimum Input Pulse
MR Glitch Rejection
MR to Reset Delay
1
µs
ns
ns
kΩ
100
500
63
MR Pullup Resistance
32
100
0.4
0.3
0.3
0.3
1
V
V
V
V
V
> 4.25V, I
= 3.2mA
CC
CC
CC
CC
CC
SINK
> 2.5V, I
> 1.2V, I
> 1.0V, I
= 1.2mA
= 0.5mA
= 80µA
SINK
SINK
SINK
RESET Output Voltage
V
V
OL
RESET Output Leakage Current
Note 1: The MAX6394 monitors V
> VTH, RESET deasserted
µA
through an internal factory-trimmed voltage-divider that programs the nominal reset threshold.
CC
Other thresholds may be available. Contact factory for availability.
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MAX6394
High-Accuracy μP Reset Circuit
Typical Operating Characteristics
(T = +25°C, unless otherwise noted.)
A
SUPPLY CURRENT
vs. SUPPLY VOLTAGE
POWER-DOWN RESET DELAY
SUPPLY CURRENT vs. TEMPERATURE
vs. TEMPERATURE
6
6
5
4
3
2
1
0
50
V
CC
FALLING AT 1mV/µs
5
40
30
20
10
0
V
= 5V
CC
4
3
2
1
0
T
A
= +85°C
V
V
= 4.63V
= 3.00V
TH
V
= 3V
CC
TH
T
= +25°C
A
T
= -40°C
4
A
V
CC
= 1V
-50 -30 -10
10
30
50
70
90
0
1
2
3
5
-50 -30 -10
10
30
50
70
90
TEMPERATURE (°C)
SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE (V RISING)
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE (V FALLING)
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
CC
CC
100
80
60
40
20
0
1.04
1.03
1.006
1.004
1.002
1.000
0.998
0.996
0.994
T
= +25°C
A
RESET OCCURS
ABOVE CURVE
1.02
1.01
V
= 4.63V
TH
1.00
0.99
0.98
0.97
V = 3.00V
T
0.96
10
100
1000
-50 -30 -10
10
30
50
70
90
-50 -30 -10
10
30
50
70
90
RESET COMP. OVERDRIVE, V - V (mV)
TEMPERATURE (°C)
TEMPERATURE (°C)
TH
CC
Pin Description
PIN
NAME
FUNCTION
1
GND
Ground
Active-Low Open-Drain Output. Connect to an external pullup resistor. Can be pulled up to a voltage higher
2
RESET
than V , but less than 6V.
CC
Manual Reset Input. A logic-low on MR asserts reset. Reset remains asserted as long as MR is low, and for
3
4
MR
the reset timeout period (t ) after the reset conditions are terminated. Connect to VCC if not used.
RP
VCC
Supply Voltage and Reset Threshold Monitor Input
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MAX6394
High-Accuracy μP Reset Circuit
Detailed Description
+3.3V
VCC
+5.0V
Reset Output
A microprocessor’s (μP’s) reset input starts the μP in
a known state. The MAX6394 asserts a reset signal to
prevent code-execution errors during power-up, power-
down, or brownout conditions. RESET is guaranteed to be
10kΩ
RESET
MR
5V SYSTEM
a logic-low for V
> 1V (see the Electrical Characteristics
CC
table). Once V
exceeds the reset threshold, the internal
CC
timer keeps RESET asserted for the reset timeout period
RP
condition occurs (monitored voltage dips below its pro-
MAX6394
(t ); after this interval RESET goes high. If a brownout
GND
grammed reset threshold), RESET goes low. Any time
V
dips below the reset threshold, the internal timer
CC
Figure 1. MAX6394 Open-Drain RESET Output Allows Use
with Multiple Supplies
resets to zero and RESET goes low. The internal timer
starts when V returns above the reset threshold, and
CC
RESET remains low for the reset timeout period.
switch from MR to GND to create a manual reset function;
external debounce circuitry is not required. If MR is driven
from long cables or if the device is used in a noisy environ-
ment, connecting a 0.1μF capacitor from MR to ground
provides additional noise immunity.
The MAX6394’s RESET output structure is a simple open-
drain n-channel MOSFET switch. Connect a pullup resis-
tor to any supply in the 0 to +6V range. Select a resistor
value large enough to register a logic-low when RESET
is asserted (see the Electrical Characteristics table), and
small enough to register a logic-high while supplying all
input current and leakage paths connected to the RESET
line. A 10kΩ pullup is sufficient in most applications.
Applications Information
Negative-Going V
Transients
CC
In addition to issuing a reset to the μP during power-up,
power-down, and brownout conditions, these devices
are relatively immune to short-duration negative-going
transients (glitches). The Typical Operating Characteristics
show the Maximum Transient Duration vs. Reset Threshold
Overdrive, for which reset pulses are not generated. The
graph was produced using negative-going pulses, starting
at VRST max and ending below the programmed reset
threshold by the magnitude indicated (reset threshold
overdrive). The graph shows the maximum pulse width
Often, the pullup connected to the MAX6394’s RESET
output connects to the supply voltage monitored at the
IC’s VCC pin. However, some systems may use the open-
drain output to level-shift from the monitored supply to
reset circuitry powered by some other supply (Figure 1).
This is one useful feature of an open-drain output. Keep in
mind that as the MAX6394’s V
decreases below 1V, so
CC
does the IC’s ability to sink current at RESET. Finally, with
any pullup, RESET is pulled high as V decays toward
CC
0V. The voltage where this occurs depends on the pullup
resistor value and the voltage to which it connects (see the
Electrical Characteristics table).
that a negative-going V
transient may typically have
CC
without causing a reset pulse to be issued. As the transient
amplitude increases (i.e., goes farther below the reset
threshold), the maximum allowable pulse width decreases.
A 0.1μF bypass capacitor mounted close to VCC provides
additional transient immunity.
Manual-Reset Input
Many μP-based products require manual-reset capability,
allowing the operator, a test technician, or external logic
circuitry to initiate a reset. A logic-low on MR asserts reset.
RESET remains asserted while MR is low, and for the
reset active timeout period after MR returns high.
Chip Information
TRANSISTOR COUNT: 529
MR has an internal 63kΩ pullup resistor, so it can be left
open if not used. Connect a normally open momentary
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MAX6394
High-Accuracy μP Reset Circuit
Table 1. ±0.6% of Thresholds
Table 2. ±1% of Thresholds
±0.6% OF THRESHOLD (V)
±1% OF THRESHOLD (V)
SUFFIX
480
MIN
TYP
MAX
4.829
4.728
4.577
4.477
3.187
3.121
3.021
2.955
2.414
SUFFIX
480
MIN
TYP
MAX
4.848
4.747
4.596
4.495
3.200
3.133
3.033
2.966
2.424
4.771
4.672
4.523
4.423
3.149
3.083
2.985
2.919
2.386
4.800
4.700
4.550
4.450
3.168
3.102
3.003
2.937
2.400
4.752
4.653
4.505
4.406
3.136
3.071
2.973
2.908
2.376
4.800
4.700
4.550
4.450
3.168
3.102
3.003
2.937
2.400
470
470
455
455
445
445
317
317
310
310
300
300
294
294
240
240
Timeout Options
Standard Versions
Selector Guide
SUFFIX
MIN (ms)
TYP (ms)
1.4
MAX (ms)
D1
0.7
14
2
STANDARD VERSIONS
D2
28
40
480
455
310
240
D3
105
826
200
280
2240
D3
D4
1570
Note: Samples are generally available in standard versions.
Contact factory for availability of nonstandard versions.
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MAX6394
High-Accuracy μP Reset Circuit
Ordering Information
TEMPERATURE
RANGE
PIN-
PACKAGE
PART
MAX6394US_ _ _D_+T
MAX6394US_ _ _D_/V+T
MAX6394US317D2/V+T
MAX6394US480D1/V+T
MAX6394US480D3/V+T
-40°C to +125°C 4 SOT143-4
-40°C to +125°C 4 SOT143-4
-40°C to +125°C 4 SOT143-4
-40°C to +125°C 4 SOT143-4
-40°C to +125°C 4 SOT143-4
Note: This device is specified over the -40°C to +125°C operating
temperature range.
+Denotes a lead-free package.
Note: The “_ _ _” is a placeholder for the input voltage thresholds.
Nine threshold options are available. See Tables 1 and 2 for
more information.
Note: The “_” is a placeholder for the timeout option. Four
options are available. See the Timeout Options section for
more information.
Four standard versions are available (see the Standard
Versions Selector Guide section). Samples are generally
available in standard versions. Contact factory for availability of
nonstandard versions.
Note: All devices are available in tape-and-reel only. Tape and
reel is offered in 2.5k increments.
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MAX6394
High-Accuracy μP Reset Circuit
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
DESCRIPTION
0
1/08
Initial release
—
1
12/15
Added lead-free part numbers and added MAX6394US___/V+T
Added Package Information section
1, 2
2
2
3
4
5
3/18
3/18
Updated Ordering Information and Benefits and Features
Updated Package Information section
1, 6
2
8/19
12/19
Updated Chip Information
5
For pricing, delivery, and ordering information, please visit Maxim Integrated’s online storefront at https://www.maximintegrated.com/en/storefront/storefront.html.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
©
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
2019 Maxim Integrated Products, Inc.
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