General Description
The MAX6467/MAX6468 microprocessor (µP) supervi-
sory circuits monitor single power-supply voltages from
+1.8V to +5.0V and assert a reset if the supply voltage
drops below its preset threshold. An edge-triggered,
one-shot manual reset function ensures that the µP
enters the reset mode for a fixed timeout period only,
even in the event of a continuously asserted manual
reset. The MAX6467/MAX6468 significantly improve
system reliability compared to traditional manual reset
supervisory circuits.
A variety of factory-trimmed threshold options accommo-
date different supply voltages and tolerances, eliminating
external components. The factory-set thresholds range
from +1.575V to +4.625V to monitor +5.0V, +3.3V, +3.0V,
+2.5V, and +1.8V supplies with various tolerances. Reset
timeout periods of 150ms (min) and 1200ms (min) are
available to accommodate different µP platforms.
A single, active-low RESET output asserts when VCC
drops below its threshold or if the edge-triggered MR
asserts low. RESET remains low for the reset timeout
period after VCC rises above its threshold and for a fixed,
one-shot timeout period after a manual reset input falling
edge. RESET remains valid as long as VCC remains
above +1V. Open-drain (MAX6467) and push-pull
(MAX6468) output options provide additional flexibility in
the system design.
The MAX6467/MAX6468 are offered in the space-saving
4-pin SOT143 package and the ultra-small 4-pin SC70
package and are specified over the automotive (-40°C to
+125°C) temperature range.
Applications
Cell Phones/PDAs
Embedded Control Systems
Industrial Equipment
Automotive Products
Portable/Battery-Powered Equipment
Medical Devices
DSL Modems
MP3 Players
GPS Systems
Digital Cameras
Features
♦Precision Factory-Set Reset Threshold Voltages
for +5.0V, +3.3V, +3.0V, +2.5V, and +1.8V Supplies
♦Edge-Triggered Manual Reset Input with One-
Shot Pulsed Reset Output
♦Two Reset Timeout Period Options (150ms or
1200ms min)
♦Immune to Short Voltage Transients
♦Low Supply Current (3µA at VCC = +1.8V)
♦RESET Valid to VCC = +1V
♦Active-Low Open-Drain and Push-Pull RESET
Output Options
♦-40°C to +125°C Operating Temperature Range
♦Small 4-Pin SC70 and SOT143 Packages
♦No External Components Required
♦Pin Compatible with MAX811, MAX6315,
MAX6384, and MAX6386
MAX6467/MAX6468
Microprocessor Supervisory Reset Circuits
with Edge-Triggered, One-Shot Manual Reset
________________________________________________________________ Maxim Integrated Products 1
Ordering Information
19-2523; Rev 1; 11/05
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.
Typical Operating Circuit appears at end of data sheet.
PART
TEMP RANGE
PIN-PACKAGE
MAX6467XS_ _D_-T
-40°C to +125°C
4 SC70-4
MAX6467US_ _D_-T
-40°C to +125°C
4 SOT143-4
MAX6468XS_ _D_-T
-40°C to +125°C
4 SC70-4
MAX6468US_ _D_-T
-40°C to +125°C
4 SOT143-4
Note: Insert reset threshold suffix (see Reset Threshold table)
after XS or US. 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.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “T” with “+T” when ordering.
Pin Configurations continued at end of data sheet.
1
2
4
3
VCC
GND
SC70
TOP VIEW
MAX6467XS
MAX6468XS
RESET MR
Pin Configurations
MAX6467/MAX6468
Microprocessor Supervisory Reset Circuits
with Edge-Triggered, One-Shot Manual Reset
2_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = +1.2V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. 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 to GND
Open-Drain........................................................-0.3V to +6.0V
Push-Pull.................................................-0.3V to (VCC + 0.3V)
MR to GND .................................................-0.3V to (VCC + 0.3V)
Input/Output Current (all pins) ............................................20mA
Continuous Power Dissipation (TA= +70°C)
4-Pin SC70 (derate 3.1mW/°C above +70°C)..............245mW
4-Pin SOT143 (derate 4mW/°C above +70°C).............320mW
Operating Temperature Range .........................-40°C to +125°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER
SYM B O L
CONDITIONS
MIN TYP MAX
UNITS
TA = 0°C to +125°C 1.0 5.5
Operating Voltage Range VCC TA = -40°C to 0°C 1.2 5.5 V
VCC = +5.5V, no load 7 13
VCC = +3.6V, no load 6 11
VCC = +2.5V, no load 4 8
Supply Current ICC
VCC = +1.8V, no load 3 7.5
µA
TA = +25°C
-1.5% VTH +1.5%
TA = -40°C to +85°C
-2.5% +2.5%
VCC Reset Threshold
(See the Reset Threshold Table)
VTH
TA = +85°C to +125°C
-3% +3%
V
VCC Reset Delay tRD VCC falling at 10mV/µs from VTH + 100mV
to VTH - 100mV 35 µs
D3 option 150
225
300
VCC Reset Timeout Period tRP D7 option
1200 1800 2400
ms
MR Timeout Period tMRP D3 and D7 options 150
225
300 ms
MR Rising Debounce Period
(Note 2) tDEB D3 and D7 options 150
225
300 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
MR Minimum Input Pulse 1µs
MR Glitch Rejection
100
ns
MR to RESET Delay
200
ns
MR Pullup Resistance MR to VCC 750
1500 2250
Ω
VCC ≥ +2.5V, ISOURCE = 500µA, RESET not
asserted
0.8 x VCC
RESET Output High
(MAX6468 Only) VOH VCC ≥ +4.5V, ISOURCE = 800µA, RESET not
asserted
0.8 x VCC
V
MAX6467/MAX6468
Microprocessor Supervisory Reset Circuits
with Edge-Triggered, One-Shot Manual Reset
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +1.2V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETER
SYM B O L
CONDITIONS
TYP
MAX
UNITS
VCC ≥ +1V, ISINK = 80µA, RESET asserted 0.3
VCC ≥ +2.5V, ISINK = 1.2mA, RESET
asserted 0.3
RESET Output Low VOL
VCC ≥ +4.5V, ISINK = 3.2mA, RESET
asserted 0.3
V
RESET Output Leakage Current
(MAX6467 Only) ILKG RESET not asserted 1 µA
Note 1: Specifications over temperature are guaranteed by design. Production testing at TA= +25°C only.
Note 2: The MR input ignores falling edges that occur within the MR rising debounce period (tDEB) after MR first rises from low to
high (after a valid MR reset assertion). This prevents invalid reset assertion due to switch bounce.
Typical Operating Characteristics
(VCC = +5V, MAX6468US29D3 device, TA= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
MAX6467 toc01
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
1109565 80-10 520 35 50-25
1
2
3
4
5
6
7
8
9
10
0
-40 125
VCC = +5.5V VCC = +3.6V
VCC = +1.8V
VCC = +2.5V
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX6467 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (µA)
5.04.53.5 4.01.0 1.5 2.0 2.5 3.00.5
1
2
3
4
5
6
7
8
9
10
0
0 5.5
VCC TO RESET DELAY
vs. TEMPERATURE
MAX6467 toc03
TEMPERATURE (°C)
VCC TO RESET DELAY (µs)
1109580655035205-10-25
18
20
22
24
26
16
-40 125
VCC = VTH + 100mV TO VTH - 100mV
RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6467 toc04
TEMPERATURE (°C)
RESET TIMEOUT PERIOD (ms)
1109565 80-10 520 35 50-25
201
202
203
204
205
206
207
208
209
210
200
-40 125
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
MAX6467 toc05
TEMPERATURE (°C)
NORMALIZED RESET THRESHOLD (V)
1109580655035205-10-25
0.995
1.000
1.005
1.010
0.990
-40 125
OUTPUT VOLTAGE LOW
vs. SINK CURRENT
MAX6467 toc06
ISINK (mA)
VOL (mV)
986 72 3 4 51
50
100
150
200
250
300
350
400
450
500
550
600
0
010
VCC = 5.0V
MAX6467/MAX6468
Microprocessor Supervisory Reset Circuits
with Edge-Triggered, One-Shot Manual Reset
4_______________________________________________________________________________________
OUTPUT VOLTAGE HIGH
vs. SOURCE CURRENT
MAX6467 toc07
ISOURCE (mA)
VOH (V)
764 52 31
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
0
08
VCC = +5.0V
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX6467 toc08
RESET THRESHOLD OVERDRIVE (mV)
MAXIMUM TRANSIENT DURATION (µs)
5040302010
100
200
300
400
500
600
0
060
RESET ASSERTS
ABOVE THIS LINE
MAX6467 toc09
TEMPERATURE (°C)
110
9565 80-10 520 35 50-25
65
70
75
80
85
90
95
100
105
110
115
120
60
-40 125
MR TO RESET DELAY
vs. TEMPERATURE
MR TO RESET DELAY (ns)
PROPAGATION DELAY
(WITH 100mV OVERDRIVE)
MAX6467 toc10
4µs/div
3.0V
3V
0
2.8V
VCC 100mV/div
AC-COUPLED
RESET 1V/div
RESET PULLUP AND PULLDOWN RESPONSE
MAX6467 toc11
40µs/div
1.675V
1.6V
0
1.475V
VCC 200mV/div
RESET 500mV/div
CRESET = 47pF, RPULLUP = 100kΩ,
VPULLUP = 1.6V
MAX6467_S16D3-T
RESET TIMEOUT PERIOD
MAX6467 toc12
40ms/div
3.3V
3.3V
0
0
VCC 2V/div
RESET 2V/div
Typical Operating Characteristics (continued)
(VCC = +5V, MAX6468US29D3 device, TA= +25°C, unless otherwise noted.)
Detailed Description
Reset Output
The MAX6467 provides an active-low open-drain
RESET output. The MAX6468 provides an active-low
push-pull RESET output. RESET asserts low if VCC
drops below the selected threshold or if a falling edge
occurs on MR. RESET remains low for the VCC reset
timeout period after VCC increases above the threshold
voltage or is one-shot pulsed low for the MR timeout
period after a falling edge on MR.
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 falling edge on MR asserts
RESET low. RESET is one-shot pulsed low for the MR
timeout period after a falling edge on MR. An internal
1.5kΩpullup resistor to VCC allows MR to be left uncon-
nected if not used. MR can be driven with TTL or CMOS-
logic levels, or with open-drain/collector outputs. Connect
a normally open momentary pushbutton switch from MR
to GND to realize a manual reset function. External
debounce circuitry is not required, as the MAX6467/
MAX6468 respond to the first falling edge on MR and
ignore subsequent falling edges within the reset timeout
period and during the MR debounce period (see Figure
1). After MR goes high for 150ms (tDEB), the manual reset
one-shot is ready to trigger a reset on the next MR falling
edge. Connect a 0.1µF capacitor from MR to GND when
using long cables to provide additional noise immunity
(Figure 2).
MAX6467/MAX6468
Microprocessor Supervisory Reset Circuits
with Edge-Triggered, One-Shot Manual Reset
_______________________________________________________________________________________ 5
Pin Description
PIN
NAME
FUNCTION
1GND Ground
2
RESET
Reset Output. RESET is an active-low open-drain (MAX6467) or push-pull (MAX6468) output. RESET asserts
low when VCC drops below the selected threshold and remains low for the VCC reset timeout period after
VCC rises above the threshold. The RESET one-shot asserts low for a fixed MR reset timeout period on the
falling edge of the manual reset input. The open-drain output requires an external pullup resistor.
3MR
Manual Reset Input. Drive MR low to initiate a reset output. MR controls an edge-triggered one-shot that
asserts RESET low for a fixed MR timeout period when MR is driven low. Internal timing circuitry ignores
switch close and open bounce to ensure proper one-shot reset timing.
4V
CC
Power-Supply Input. VCC provides power to the device and is also a monitored voltage. When VCC drops
below the selected threshold, RESET asserts low and remains low for the reset timeout period after VCC rises
above the threshold. For better noise immunity, bypass VCC to GND with a 0.1µF capacitor.
VCC
GND
GND
MR
tRP
GND
RESET
VTH
SWITCH
BOUNCE
SWITCH
BOUNCE
SWITCH
BOUNCE
tMRP tMRP
tDEB
Figure 1. Timing Diagram
MAX6467/MAX6468
Applications Information
Falling VCC Transients
In addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, the MAX6467/
MAX6468 are relatively immune to short-duration falling
VCC transients (glitches). The Typical Operating
Characteristics section shows the Maximum Transient
Duration vs. VCC Overdrive for which the MAX6467/
MAX6468 do not generate a reset pulse. This graph was
generated using a falling pulse applied to VCC starting
above the actual reset threshold and ending below the
threshold by the magnitude indicated (VCC Overdrive).
The graph indicates the typical maximum pulse width a
falling VCC transient can have without initiating a reset
pulse. As the magnitude of the transient increases (goes
farther below the reset threshold), the maximum allowable
pulse width decreases. A 0.1µF bypass capacitor from
VCC to GND provides additional transient immunity.
Ensuring a Valid RESET Output Down
to VCC = 0V
The MAX6467/MAX6468 guarantee proper operation
down to VCC = +1V. In applications that require valid
reset levels down to VCC = 0V, a pulldown resistor to
active-low outputs (MAX6468 only, Figure 3) ensures
that RESET remains valid while the RESET output can
no longer sink current. This scheme does not work with
the open-drain outputs of the MAX6467. Ensure that the
resistor value used does not overload the RESET output
when VCC is above the reset threshold. For most appli-
cations, use 100kΩto 1MΩ.
Microprocessor Supervisory Reset Circuits
with Edge-Triggered, One-Shot Manual Reset
6_______________________________________________________________________________________
RESET TIMEOUT SUFFIX
VCC RESET TIMEOUT PERIOD
(min/max) (ms)
MR TIMEOUT PERIOD
(min/max) (ms)
MR RISING DEBOUNCE PERIOD
(min/max) (ms)
D3 150/300 150/300 150/300
D7 1200/2400 150/300 150/300
Reset Timeout Delay*
*Additional reset timeout options may be available. Contact factory for availability.
MAX6468
VCC
GND
RESET
R1
100kΩ
Figure 3.
RESET
Valid to VCC = 0V
Chip Information
TRANSISTOR COUNT: 748
PROCESS: BiCMOS
1.5kΩ
VCC
MR ONE-SHOT/
DEBOUNCE
RESET
TIMEOUT
PERIOD
RESET
OUTPUT
VCC
1.23V
VCC
MR
RESET
GND
MAX6467
MAX6468
Figure 2. Functional Diagram
MAX6467/MAX6468
Microprocessor Supervisory Reset Circuits
with Edge-Triggered, One-Shot Manual Reset
_______________________________________________________________________________________ 7
PART TOP MARK
MAX6467XS16D3 AGL
MAX6467XS22D3 AGM
MAX6467XS26D3 AGN
MAX6467XS29D3 AGO
MAX6467XS46D3 AGP
MAX6467US16D3 KAFN
MAX6467US22D3 KAFO
MAX6467US26D3 KAFP
MAX6467US29D3 KAFQ
MAX6467US46D3 KAFR
MAX6468XS16D3 AGQ
MAX6468XS22D3 AGR
MAX6468XS26D3 AGS
MAX6468XS29D3 AGC
MAX6468XS46D3 AGB
MAX6468US16D3 KAFS
MAX6468US22D3 KAFT
MAX6468US26D3 KAFU
MAX6468US29D3 KAEW
MAX6468US46D3 KAFV
MAX6467
MAX6468
+1.0V TO +5.5V
VCC
GND
VCC
GND
MR RESET RESET
INPUT
µP
Typical Operating Circuit
SUFFIX VTH (min) VTH (typ) VTH (max)
46 4.509 4.625 4.741
45 4.388 4.500 4.613
44 4.266 4.375 4.484
43 4.193 4.300 4.408
42 4.095 4.200 4.305
41 3.998 4.100 4.203
40 3.900 4.000 4.100
39 3.803 3.900 3.998
38 3.705 3.800 3.895
37 3.608 3.700 3.793
36 3.510 3.600 3.690
35 3.413 3.500 3.588
34 3.315 3.400 3.485
33 3.218 3.300 3.383
32 3.120 3.200 3.280
31 2.998 3.075 3.152
30 2.925 3.000 3.075
29 2.852 2.925 2.998
28 2.730 2.800 2.870
27 2.633 2.700 2.768
26 2.559 2.625 2.691
25 2.438 2.500 2.563
24 2.340 2.400 2.460
23 2.255 2.313 2.370
22 2.133 2.188 2.242
21 2.048 2.100 2.153
20 1.950 2.000 2.050
19 1.853 1.900 1.948
18 1.755 1.800 1.845
17 1.623 1.665 1.707
16 1.536 1.575 1.614
Reset Threshold (-40°C to +85°C)
4
3
1
2
VCC
GND
SOT143
TOP VIEW
MAX6467US
MAX6468US
RESET MR
Pin Configurations (continued)
Standard Versions
MAX6467/MAX6468
Microprocessor Supervisory Reset Circuits
with Edge-Triggered, One-Shot Manual Reset
8_______________________________________________________________________________________
SOT-143 4L.EPS
E
1
1
21-0052
PACKAGE OUTLINE, SOT-143, 4L
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.)
MAX6467/MAX6468
Microprocessor Supervisory Reset Circuits
with Edge-Triggered, One-Shot Manual Reset
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 _____________________ 9
©2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
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.)
SC70, 4L.EPS
PACKAGE OUTLINE, 4L SC70
21-0098
1
1
C