General Description
The MAX6381–MAX6390 microprocessor (µP) supervisory
circuits monitor power supply voltages from +1.8V to
+5.0V while consuming only 3µA of supply current at
+1.8V. Whenever VCC falls below the factory-set reset
thresholds, the reset output asserts and remains assert-
ed for a minimum reset timeout period after VCC rises
above the reset threshold. Reset thresholds are available
from +1.58V to +4.63V, in approximately 100mV incre-
ments. Seven minimum reset timeout delays ranging
from 1ms to 1200ms are available.
The MAX6381/MAX6384/MAX6387 have a push-pull
active-low reset output. The MAX6382/MAX6385/
MAX6388 have a push-pull active-high reset output,
and the MAX6383/MAX6386/MAX6389/MAX6390
have an open-drain active-low reset output. The
MAX6384/MAX6385/MAX6386 also feature a
debounced manual reset input (with internal pullup
resistor). The MAX6387/MAX6388/MAX6389 have an
auxiliary input for monitoring a second voltage. The
MAX6390 offers a manual reset input with a longer VCC
reset timeout period (1120ms or 1200ms) and a shorter
manual reset timeout (140ms or 150ms).
The MAX6381/MAX6382/MAX6383 are available in 3-pin
SC70 packages and the MAX6384–MAX6390 are avail-
able in 4-pin SC70 packages.
________________________Applications
Computers
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable/Battery-Powered Equipment
Dual Voltage Systems
Features
♦Factory-Set Reset Threshold Voltages Ranging
from +1.58V to +4.63V in Approximately 100mV
Increments
♦±2.5% Reset Threshold Accuracy Over
Temperature (-40°C to +125°C)
♦Seven Reset Timeout Periods Available: 1ms,
20ms, 140ms, 280ms, 560ms, 1120ms,
1200ms (min)
♦3 Reset Output Options
Active-Low Push-Pull
Active-High Push-Pull
Active-Low Open-Drain
♦Reset Output State Guaranteed Valid
Down to VCC = 1V
♦Manual Reset Input (MAX6384/MAX6385/MAX6386)
♦Auxiliary RESET IN
(MAX6387/MAX6388/MAX6389)
♦VCC Reset Timeout (1120ms or 1200ms)/Manual
Reset Timeout (140ms or 150ms) (MAX6390)
♦Negative-Going VCC Transient Immunity
♦Low Power Consumption of 6µA at +3.6V
and 3µA at +1.8V
♦Pin Compatible with
MAX809/MAX810/MAX803/MAX6326/MAX6327/
MAX6328/MAX6346/MAX6347/MAX6348,
and MAX6711/MAX6712/MAX6713
♦Tiny 3-Pin SC70 and 4-Pin SC70 Packages
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
________________________________________________________________ Maxim Integrated Products 1
RESET
(RESET)
1
3VCC
GND
MAX6381
MAX6382
MAX6383
TOP VIEW
2
SC70
( ) IS FOR MAX6382
PART TEMP RANGE PIN-PACKAGE
MAX6381XR_ _D_-T -40°C to +125°C3 SC70-3
MAX6382XR_ _D_-T -40°C to +125°C3 SC70-3
MAX6383XR_ _D_-T -40°C to +125°C3 SC70-3
Pin Configurations
19-1839; Rev 3; 12/05
Ordering Information
Pin Configurations continued at end of data sheet.
Ordering Information continued at end of data sheet.
Typical Operating Circuit appears at end of data sheet.
Selector Guide appears at end of data sheet.
Note: Insert reset threshold suffix (see Reset Threshold table)
after "XR" or "XS". Insert reset timeout delay (see Reset Timeout
Delay table) after "D" to complete the part number. Sample
stock is generally held on standard versions only (see
Standard Versions table). Standard versions have an order
increment requirement of 2500 pieces. Nonstandard versions
have an order increment requirement of 10,000 pieces.
Contact factory for availability of nonstandard versions.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
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.
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
2_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = full range, TA= -40°C to +125°C, unless otherwise specified. Typical values are at TA= +25°C.) (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.
VCC to GND ..........................................................-0.3V to +6.0V
RESET Open-Drain Output....................................-0.3V to +6.0V
RESET, RESET (push-pull output) ..............-0.3V to (VCC + 0.3V)
MR, RESET IN.............................................-0.3V to (VCC + 0.3V)
Input Current (VCC).............................................................20mA
Output Current (all pins) .....................................................20mA
Continuous Power Dissipation (TA= +70°C)
3-Pin SC70 (derate 2.9mW/°C above +70°C)..............235mW
4-Pin SC70 (derate 3.1mW/°C above +70°C)..............245mW
Operating Temperature Range .........................-40°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Operating Voltage Range VCC 1.0 5.5 V
VCC = 5.5V, no load 7 13
VCC = 3.6V, no load 6 11
VCC = 2.5V, no load 4 7
VCC Supply Current ICC
VCC = 1.8V, no load 3 6
µA
TA = +25°CVTH -
1.5% VTH
VTH +
1.5%
VCC Reset Threshold
(See Reset Thresholds table) VTH
TA = -40°C to +125°CVTH -
2.5% VTH
VTH +
2.5%
V
Reset Threshold Tempco
∆VTH/°C
60
ppm/°C
VCC to Reset Delay VCC falling at 10mV/µs from VTH + 100mV
to VTH - 100mV 35 µs
D1 1 2
D2 20 40
D3
140 280
D5
280 560
D6
560 1120
D4
1120 2240
Reset Timeout Period
MAX6381–MAX6389
(See Reset Timeout table)
tRP
D7
1200 2400
ms
D4
140 280
MR timeout period D7
150 300
D4
1120 2240
Reset Timeout Period
MAX6390 tRP
VCC timeout period D7
1200 2400
ms
VIL 0.3 x
VCC
VIH
VTH < 4V 0.7 x
VCC
VIL 0.8
MR Input Voltage
VIH
VTH > 4V 2.4
V
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC = full range, TA= -40°C to +125°C, unless otherwise specified. Typical values are at TA= +25°C.) (Note 1)
Note 1: Specifications over temperature are guaranteed by design, not production tested.
PARAMETER
SYMBOL
CONDITIONS
MIN TYP MAX
UNITS
MR Minimum Input Pulse Width 1 µs
MR Glitch Rejection
100
ns
MR to Reset Delay
200
ns
MAX6381–MAX6389 32 63
100
kΩ
MR Internal Pullup Resistance MAX6390
500 1560 3000
Ω
TA = +25°C
1.245 1.27 1.295
TA = 0°C to +85°C
1.232 1.308
RESET IN Input Threshold
VTHRST
TA = -40°C to +125°C
1.219 1.321
V
RESET IN to RESET Delay VRESETIN falling at 4mV/µs from
VTHRST + 40mV to VTHRST - 40mV 4.5 µs
RESET IN Input Leakage Current
IRESET IN
-50 ±1
+50
nA
VCC ≥ 4.5V, ISINK = 3.2mA, reset asserted 0.4
VCC ≥ 2.5V, ISINK = 1.2mA, reset asserted 0.3
Open-Drain RESET Output
Voltage VOL
VCC ≥ 1.0V, ISINK = 80µA, reset asserted 0.3
V
Open-Drain RESET Output
Leakage Current ILKG VCC > VTH, RESET not asserted 1.0 µA
VCC ≥ 4.5V, ISINK = 3.2mA, reset asserted 0.4
VCC ≥ 2.5V, ISINK = 1.2mA, reset asserted 0.3
VOL
VCC ≥ 1.0V, ISINK = 80µA, reset asserted 0.3
VCC ≥ 4.5V, ISOURCE = 800µA, reset not
asserted
0.8 x
VCC
Push-Pull RESET Output Voltage
VOH VCC ≥ 2.5V, ISOURCE = 500µA, reset not
asserted
0.8 x
VCC
V
VCC ≥ 4.5V, ISOURCE = 800µA, reset asserted
0.8 x
VCC
VCC ≥ 2.5V, ISOURCE = 500µA, reset asserted
0.8 x
VCC
VCC ≥ 1.8V, ISOURCE = 150µA, reset asserted
0.8 x
VCC
VOH
VCC ≥ 1.0V, ISOURCE = 1µA, reset asserted 0.8 x
VCC
VCC ≥ 4.5V, ISINK = 3.2mA, reset not
asserted 0.4
Push-Pull RESET Output Voltage
VOL VCC ≥ 2.5V, ISINK = 1.2mA, reset not
asserted 0.3
V
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
4______________________________________________________________________________________
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
0
2
1
5
4
3
6
7
8
9
-40 -10 5-25 20 35 50 65 80 95 110 125
SUPPLY CURRENT vs. TEMPERATURE
(NO LOAD)
MAX6381/90 toc01
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
VCC = +1.8V
VCC = +2.5V
VCC = +3.6V
VCC = +5.5V
25
29
27
35
33
31
37
39
41
43
-40 -10 5-25 20 3550658095110 125
POWER-DOWN RESET DELAY
vs. TEMPERATURE
MAX6381/90 toc02
TEMPERATURE (°C)
POWER-DOWN RESET DELAY (µs)
VCC = +1.8V
VCC = +3V
0.94
0.98
0.96
1.02
1.00
1.06
1.04
1.08
-40 -10 5 20-25 35 50658095110125
NORMALIZED POWER-UP RESET TIMEOUT
vs. TEMPERATURE
MAX6381/90 toc03
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
0.990
0.985
1.015
0.995
0.990
1.000
1.005
1.010
1.020
-40 -10 5 20-25 35 50 9580 11065 125
MAX6381/90 toc04
TEMPERATURE (°C)
NORMALIZED RESET THRESHOLD
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
0
0.4
0.2
0.8
0.6
1.0
1.2
063912
OUTPUT-VOLTAGE LOW
vs. SINK CURRENT
MAX6381/90 toc05
ISINK (mA)
VOL (V)
VCC = +3.0V
VCC = +4.5V
0
1.0
0.5
2.0
1.5
2.5
3.0
0500 750250 1000 1250 1500
OUTPUT-VOLTAGE HIGH
vs. SOURCE CURRENT
MAX6381/90 toc06
ISOURCE (µA)
VOH (V)
VCC = +2.5V
VCC = +1.8V
450
0
1100010010
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
150
50
350
250
500
200
100
400
300
MAX6381/90 toc07
RESET COMPARATOR OVERDRIVE, VTH - VCC (mV)
MAXIMUM TRANSIENT DURATION (µs)
RESET ASSERTED
ABOVE THIS LINE
3.5
3.9
3.7
4.5
4.3
4.1
4.7
4.9
5.3
5.1
5.5
-40 -10 5-25 20 3550658095110125
RESET IN TO RESET DELAY
vs. TEMPERATURE
MAX6381/90 toc08
TEMPERATURE (°C)
RESET IN DELAY (µs)
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
_______________________________________________________________________________________ 5
Pin Description
PIN
MAX6381/
MAX6383
MAX6382
MAX6384/
MAX6386/
MAX6390
MAX6385 MAX6387/
MAX689 MAX6388
NAME
FUNCTION
111111GND Ground
—2—2—2
RESET
Active-High Push-Pull Reset Output. RESET
changes from low to high when any
monitored voltage (VCC or VRESETIN) drops
below the reset threshold or MR is pulled low.
RESET remains high for the reset timeout
period after monitored voltages exceed the
reset thresholds or MR is released.
2—2—2—
RESET
Active-Low Open-Drain/Push-Pull Reset
Output. RESET changes from high to low when
any monitored voltage (VCC or VRESETIN)
drops below the reset threshold or MR is
pulled low. RESET remains low for the reset
timeout period after the monitored voltages
exceed the reset thresholds or MR is released.
Open-drain requires an external pullup
resistor.
—— 3 3 ——MR
Active-Low Manual Reset Input. Drive low to
force a reset. Reset remains active as long
as MR is low and for the reset timeout period
after MR is released. Leave unconnected or
connect to VCC if unused. MR has an internal
63kΩ (1.56kΩ for MAX6390) pullup resistor to
VCC.
———— 3 3
RESET
IN
Auxiliary Reset Input. High-impedance input
to the auxiliary reset comparator. Connect
RESET IN to the center point of an external
resistor voltage-divider network to set the
reset threshold voltage. Reset asserts when
either VCC or RESET IN falls below its
threshold voltage.
334444V
CC Supply Voltage for the device and input for
fixed VCC reset threshold monitor.
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
6_______________________________________________________________________________________
Detailed Description
RESET Output
A µP reset input starts the µP in a known state. These
µP supervisory circuits assert reset to prevent code
execution errors during power-up, power-down, or
brownout conditions.
Reset asserts when VCC is below the reset threshold;
once VCC exceeds the reset threshold, an internal timer
keeps the reset output asserted for the reset timeout
period. After this interval, reset output deasserts. Reset
output is guaranteed to be in the correct logic state for
VCC ≥1V.
Manual Reset Input (MAX6384/
MAX6385/MAX6386/MAX6390)
Many µP-based products require manual reset capabil-
ity, 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 (tRP) after MR
returns high. This input has an internal 63kΩpullup
resistor (1.56kΩfor MAX6390), so it can be left uncon-
nected if it is not used. MR can be driven with TTL or
CMOS logic levels, or with open-drain/collector outputs.
Connect a normally open momentary 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 GND
provides additional noise immunity.
RESET IN Comparator
(MAX6387/MAX6388/MAX6389)
RESET IN is compared to an internal +1.27V reference.
If the voltage at RESET IN is less than 1.27V, reset
asserts. Use the RESET IN comparator as a user-
adjustable reset detector or as a secondary power-sup-
ply monitor by implementing a resistor-divider at RESET
IN (shown in Figure 1). Reset asserts when either VCC
or RESET IN falls below its respective threshold volt-
age. Use the following equation to set the threshold:
VINTH = VTHRST (R1/R2 + 1)
where VTHRST = +1.27V. To simplify the resistor selec-
tion, choose a value of R2 and calculate R1:
R1 = R2 [(VINTH/VTHRST) - 1]
Since the input current at RESET IN is 50nA (max),
large values can be used for R2 with no significant loss
in accuracy.
___________Applications Information
Negative-Going VCC Transients
In addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, the
MAX6381–MAX6390 are relatively immune to short dura-
tion negative-going VCC transients (glitches).
The Typical Operating Characteristics section shows the
Maximum Transient Durations vs. Reset Comparator
Overdrive, for which the MAX6381–MAX6390 do not
generate a reset pulse. This graph was generated using
Reset Thresholds (-40°C to +125°C)
SUFFIX VTH (min)
VTH (nom)
VTH (max)
46 4.51 4.63 4.74
45 4.39 4.50 4.61
44 4.27 4.38 4.48
43 4.19 4.30 4.41
42 4.10 4.20 4.31
41 4.00 4.10 4.20
40 3.90 4.00 4.10
39 3.80 3.90 4.00
38 3.71 3.80 3.90
37 3.61 3.70 3.79
36 3.51 3.60 3.69
35 3.41 3.50 3.59
34 3.32 3.40 3.49
33 3.22 3.30 3.38
32 3.12 3.20 3.28
31 3.00 3.08 3.15
30 2.93 3.00 3.08
29 2.85 2.93 3.00
28 2.73 2.80 2.87
27 2.63 2.70 2.77
26 2.56 2.63 2.69
25 2.44 2.50 2.56
24 2.34 2.40 2.46
23 2.26 2.31 2.37
22 2.13 2.19 2.24
21 2.05 2.10 2.15
20 1.95 2.00 2.05
19 1.85 1.90 1.95
18 1.76 1.80 1.85
17 1.62 1.67 1.71
16 1.54 1.58 1.61
a negative-going pulse applied to VCC, starting above
the actual reset threshold and ending below it by the
magnitude indicated (reset comparator overdrive). The
graph indicates the typical maximum pulse width a neg-
ative-going VCC transient may have without causing a
reset pulse to be issued. As the magnitude of the tran-
sient increases (goes farther below the reset threshold),
the maximum allowable pulse width decreases. A 0.1µF
capacitor mounted as close as possible to VCC provides
additional transient immunity.
Ensuring a Valid RESET
Output Down to VCC = 0
The MAX6381–MAX6390 are guaranteed to operate
properly down to VCC = 1V. In applications that require
valid reset levels down to VCC = 0, a pulldown resistor
to active-low outputs (push/pull only, Figure 2) and a
pullup resistor to active-high outputs (push/pull only)
will ensure that the reset line is valid while the reset out-
put can no longer sink or source current. This scheme
does not work with the open-drain outputs of the
MAX6383/MAX6386/MAX6389/MAX6390. The resistor
value used is not critical, but it must be small enough
not to load the reset output when VCC is above the
reset threshold. For most applications, 100kΩis ade-
quate.
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
_______________________________________________________________________________________ 7
MAX6387
MAX6388
MAX6389
RESET IN
( ) IS FOR MAX6388
R1
R2
RESET
(RESET)
GND
VCC
VIN
MAX6381
MAX6384
MAX6387
VCC
R1
100k
RESET
GND
Figure 1. RESET IN Configuration Figure 2. RESET Valid to VCC = Ground Circuit
PART RESET
THRESHOLD
RESET TIMEOUT
46
44
31
29
26
23
22
17
MAX638_
16
D3
46
44
31
29
26
23
22
17
MAX6390
16
D4
Standard Versions
Reset Timeout Delay
SUFFIX MIN
D1 1ms
D2 20ms
D3 140ms
D5 280ms
D6 560ms
D4 1120ms
D7 1200ms
MAX6390XSD4 1120/140ms*
MAX6390XSD7 1200/150ms*
*The MAX6390 has a 1120ms or 1200ms
RESET
timeout and a
140ms or 150ms manual reset timeout.
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
8_______________________________________________________________________________________
Selector Guide
PART NUMBER PUSH-PULL
ACTIVE-LOW
PUSH-PULL
ACTIVE-HIGH
OPEN-DRAIN
ACTIVE-LOW
MANUAL RESET
INPUT MR RESET IN
MAX6381 X
MAX6382 X
MAX6383 X
MAX6384 X X
MAX6385 X X
MAX6386 X X
MAX6390* X X
MAX6387 X X
MAX6388 X X
MAX6389 X X
*The MAX6390 offers a VCC reset timeout of 1120ms or 1200ms (min) and a manual reset timeout of 140ms or 150ms (min).
MAX6381–MAX6390
VCC
µP
MR *
PUSHBUTTON SWITCH
RESET
(RESET)
RESET
INPUT
GND
GND
RESET IN **
VCORE
R1
I/O
VOLTAGE
I/O SUPPLY
CORE
VOLTAGE
R1
Chip Information
TRANSISTOR COUNT: 647
PROCESS: BiCMOS
*
MR
is for MAX6384/MAX6385/MAX6386/MAX6390
**RESET IN is for MAX6387/MAX6388/MAX6389
( ) are for MAX6382/MAX6385/MAX6388
( ) IS FOR MAX6388 SC70
TOP VIEW
1
2
4
3
VCC
RESET
(RESET)
GND
MAX6387
MAX6388
MAX6389
1
2
4
3
VCC
MR
RESET
(RESET)
GND
MAX6384
MAX6385
MAX6386
MAX6390
( ) IS FOR MAX6385 SC70
RESET IN
Pin Configurations (continued)
Typical Operating Circuit
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
_______________________________________________________________________________________ 9
PART TEMP RANGE
PIN-PACKAGE
MAX6384XS_ _D_-T
-40°C to +125°C
4 SC70-4
MAX6385XS_ _D_-T
-40°C to +125°C
4 SC70-4
MAX6386XS_ _D_-T
-40°C to +125°C
4 SC70-4
MAX6387XS_ _D_-T
-40°C to +125°C
4 SC70-4
MAX6388XS_ _D_-T
-40°C to +125°C
4 SC70-4
MAX6389XS_ _D_-T
-40°C to +125°C
4 SC70-4
MAX6390XS_ _D_-T*
-40°C to +125°C
4 SC70-4
Ordering Information
(continued)
Note: Insert reset threshold suffix (see Reset Threshold table)
after "XR" or "XS". Insert reset timeout delay (see Reset Timeout
Delay table) after "D" to complete the part number. Sample
stock is generally held on standard versions only (see
Standard Versions table). Standard versions have an order
increment requirement of 2500 pieces. Nonstandard versions
have an order increment requirement of 10,000 pieces.
Contact factory for availability of nonstandard versions.
*MAX6390 is available with D4 or D7 timing only.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
MAX6381–MAX6390
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
10 ______________________________________________________________________________________
SC70, 4L.EPS
PACKAGE OUTLINE, 4L SC70
21-0098
1
1
C
Package Information
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
SC70, Single/Dual Low-Voltage,
Low-Power µP Reset Circuits
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 11
©2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
SC70, 3L.EPS
PACKAGE OUTLINE, 3L SC70
21-0075
1
1
C
Package Information (continued)
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages.)
