General Description
The MAX6335/MAX6336/MAX6337 microprocessor (µP)
supervisory circuits monitor the power supplies in 1.8V
to 3.3V µP and digital systems. They increase circuit reli-
ability and reduce cost by eliminating external compo-
nents and adjustments. They also feature a debounced
manual-reset input.
These devices perform a single function: they assert a
reset signal whenever the VCC supply voltage declines
below a preset threshold or whenever manual reset is
asserted. Reset remains asserted for a preset timeout
period after VCC has risen above the reset threshold or
after manual reset is deasserted. The only difference
among the three devices is their output. The MAX6336
(push/pull) and MAX6337 (open-drain) have an active-
low RESET output, while the MAX6335 (push/pull) has
an active-high RESET output. The MAX6335/MAX6336
are guaranteed to be in the correct state for VCC down
to 0.7V. The MAX6337 is guaranteed to be in the cor-
rect state for VCC down to 1.0V.
The reset comparator in these ICs is designed to ignore
fast transients on VCC. Reset thresholds are factory-
trimmable between 1.6V and 2.5V, in approximately
100mV increments. There are 15 standard versions
available (2500 piece minimum-order quantity); contact
the factory for availability of nonstandard versions
(10,000 piece minimum-order quantity). For space-criti-
cal applications, the MAX6335/MAX6336/MAX6337
come packaged in a 4-pin SOT143.
Applications
Pentium II™ Computers
Computers
Controllers
Intelligent Instruments
Critical µP/µC Power Monitoring
Portable/Battery-Powered Equipment
Automotive
Features
♦Ultra-Low 0.7V Operating Supply Voltage
♦Low 3.3µA Supply Current
♦Precision Monitoring of 1.8V and 2.5V Power-
Supply Voltages
♦Reset Thresholds Available from 1.6V to 2.5V,
in Approximately 100mV Increments
♦Debounced Manual Reset
♦Fully Specified over Temperature
♦Three Power-On Reset Pulse Widths Available
(1ms min, 20ms min, 100ms min)
♦Low Cost
♦Three Available Output Structures: Push/Pull
RESET, Push/Pull RESET, Open-Drain RESET
♦Guaranteed RESET/RESET Valid to VCC = 0.7V
(MAX6335/MAX6336)
♦Power-Supply Transient Immunity
♦No External Components
♦4-Pin SOT143 Package
♦Pin Compatible with MAX811/MAX812 and
MAX6314/MAX6315
MAX6335/MAX6336/MAX6337
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
________________________________________________________________ Maxim Integrated Products 1
19-1412; Rev 2; 12/05
PART*
MAX6335US__D_-T
MAX6336US__D_-T
MAX6337US__D_-T -40°C to +125°C
-40°C to +125°C
-40°C to +125°C
TEMP. RANGE PIN-PACKAGE
4 SOT143
4 SOT143
4 SOT143
Ordering Information
* These devices are available in factory-set VCC reset thresh-
olds from 1.6V to 2.5V, in approximately 0.1V increments.
Choose the desired reset threshold suffix from Table 1 and
insert it in the blanks following “US” in the part number.
Factory-programmed reset timeout periods are also available.
Insert the number corresponding to the desired nominal reset
timeout period (1 = 1ms min, 2 = 20ms min, 3 = 100ms min) in
the blank following “D” in the part number. There are 15 stan-
dard versions with a required order increment of 2500 pieces.
Sample stock is generally held on the standard versions only
(see Selector Guide). Contact the factory for availability of non-
standard versions (required order increment is 10,000 pieces).
All devices available in tape-and-reel only.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
Typical Operating Circuit and Pin Configuration appear
at end of data sheet.
Selector Guide appears at end of data sheet.
Pentium II is a trademark of Intel Corp.
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.
MAX6335/MAX6336/MAX6337
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
2_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = full range, MR = VCC or unconnected, TA= -40°C to +125°C, unless otherwise noted. Typical values are at TA= +25°C and
VCC = 3V, reset not asserted.)
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.
Terminal Voltage (with respect to GND)
VCC ......................................................................-0.3V to +6V
Push/Pull RESET or RESET, MR ............-0.3V to (VCC + 0.3V)
Open-Drain RESET ..............................................-0.3V to +6V
Input Current (VCC).............................................................20mA
Output Current (RESET, RESET).........................................20mA
Continuous Power Dissipation (TA= +70°C)
SOT143 (derate 4mW/°C above +70°C) .....................320mW
Operating Temperature Range .........................-40°C to +125°C
Storage Temperature Range .............................-65°C to +160°C
Lead Temperature (soldering, 10s) .................................+300°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage Range VCC
TA = 0°C to +85°C MAX6335/MAX6336 0.7 5.5
V
TA = +25°C VTH - VTH
VTH +
1.8% 1.8%
TA = -40°C to +125°C VTH - VTH
VTH +
3% 3%
Reset Threshold VTH MAX633_US__D_-T,
Table 1 V
VCC Falling Reset Delay VCC falling at 10V/ms 24 µs
MAX633_US__D1-T 1 1.5 2
MAX633_US__D2-T 20 30 40Reset Active Timeout Period tRP
MAX633_US__D3-T 100 150 200
ms
RESET Output Low Voltage
(MAX6336/MAX6337) VOL
ISINK = 50µA, VCC ≥1.0V 0.4
Reset
asserted V
RESET Output High Voltage
(MAX6336) VOH
ISOURCE = 200µA, VCC ≥1.8V 0.8VCC
ISOURCE = 500µA, VCC ≥2.7V 0.8VCC
V
RESET Output Voltage
(MAX6335)
VOH Reset
asserted
ISOURCE = 1µA, VCC ≥1.0V 0.8VCC
ISOURCE = 200µA, VCC ≥1.8V 0.8VCC
V
VOL Reset not
asserted
ISINK = 500µA, VCC ≥1.8V
ISINK = 1.2mA, VCC ≥2.7V
0.3 V
0.3
Reset not
asserted
0.3VCC 0.7VCC
MR Minimum Pulse Width 1
VCC = 2.6V 160
µs
VCC = 2.6V 0.42 µs
V
ns
V MR
MR Threshold
MR Reset Delay
MR Glitch Immunity
12 20 30 kΩ
MR Pull-Up Resistance
ISINK = 500µA, VCC ≥1.8V 0.3
0.5
VCC > VTH, RESET deasserted µA
RESET Output Leakage
Current (MAX6337)
Supply Current ICC No load VCC = 1.8V 3.0 6.0
VCC = 2.5V 3.3 7.0 µA
TA = -40°C to +125°C MAX6335/MAX6336 1.2 5.5
TA = -40°C to +85°C MAX6335/MAX6336 0.78 5.5
MAX6337
MAX6337
MAX6337
1.0 5.5
1.2 5.5
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
_______________________________________________________________________________________ 3
2.0
2.6
2.2
3.0
3.6
3.8
3.4
3.2
4.0
-60
2.4
-40 -20 0
2.8
20 40 60 80 100
SUPPLY CURRENT vs. TEMPERATURE
MAX6335/36/37 toc-1
TEMPERATURE (°C)
ICC (µA)
RESET NOT ASSERTED
VCC = 2.5V
VCC = 1.8V
0.950
0.990
0.970
1.000
1.030
1.040
1.020
1.010
1.050
-60 -40
0.980
-20 0
0.960
20 40 60 80 100
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6335/36/37-2
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
VTH = 2.2V
0
20
10
30
60
70
50
40
80
0.50 1.00 1.50 2.00 2.50 3.00
OUTPUT VOLTAGE LOW
vs. SUPPLY VOLTAGE
MAX6335/36/37 toc-3
VCC (V)
OUTPUT VOLTAGE LOW (mV)
VTH = 2.5V
ISINK = 500µA
RESET ASSERTED
TA = +25°C
TA = +85°C
TA = -40°C
0
40
20
80
60
100
120
140
160
0.5 1.0 1.250.75 1.5 1.75 2.0 2.25 2.5
OUTPUT VOLTAGE HIGH
vs. SUPPLY VOLTAGE
MAX6335/36/37 toc-4
VCC (V)
OUTPUT VOLTAGE HIGH (VCC - VOH) (mV)
VTH = 2.2V
ISOURCE = 100µA
RESET ASSERTED
TA = +25°C
TA = +85°C
TA = -40°C
100 1000
0
100
200
400
300
500
600
0.1 1 10
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
MAX6335/36/37 toc-5
RESET COMPARATOR OVERDRIVE (mV)
MAXIMUM TRANSIENT DURATION (µs)
RESET OCCURS
RESET DOES
NOT OCCUR
10
20
-20
40
30
70
60
50
80
-60 0-40 20 406080100
VCC FALLING PROPAGATION DELAY
vs. TEMPERATURE
MAX6332/33/34 toc-6
TEMPERATURE (°C)
PROPAGATION DELAY (µs)
VCC FALLING AT 10V/ms
VCC FALLING AT 1V/ms
__________________________________________Typical Operating Characteristics
(Reset not asserted, TA= +25°C, unless otherwise noted.)
MAX6335/MAX6336/MAX6337
MAX6335/MAX6336/MAX6337
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
4_______________________________________________________________________________________
Pin Description
GND Ground1
—RESET
Active-Low Reset Output. RESET remains low while VCC is below the reset
threshold, or MR is asserted and for a reset timeout period (tRP) after VCC
rises above the reset threshold, or MR is deasserted. RESET on the
MAX6337 is open-drain.
2RESET
Active-High Reset Output. RESET remains high while VCC is below the
reset threshold, or MR is asserted and for a reset timeout period (tRP) after
VCC rises above the reset threshold, or MR is deasserted. RESET also
asserts when MR is low.
NAME FUNCTION
MAX6335 MAX6336
MAX6337
1
2
—
PIN
Applications Information
Manual-Reset Inputs
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 after MR returns
high. MR has an internal 20kΩpull-up resistor, so it can
be left unconnected if not used. Connect a normally
open momentary switch from MR to GND to create a
manual-reset function; external debounce circuitry is
not required.
Interfacing to µPs with
Bidirectional Reset Pins
Since the RESET output on the MAX6337 is open-drain,
this device interfaces easily with µPs that have bidirec-
tional reset pins, such as the Motorola 68HC11.
Connecting the µP supervisor’s RESET output directly
to the microcontroller’s (µC’s) RESET pin with a single
pull-up resistor allows either device to assert reset
(Figure 1).
Negative-Going VCC Transients
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
VCC transients (glitches). The Typical Operating
Characteristics show the Maximum Transient Duration
vs. Reset Comparator Overdrive graph. The graph
shows the maximum pulse width that a negative-going
VCC transient may typically have without issuing a reset
signal. As the amplitude of the transient increases, the
maximum allowable pulse width decreases.
Ensuring a Valid Reset Output
down to VCC = 0
When VCC falls below 1V and approaches the minimum
operating voltage of 0.7V, push/pull-structured reset
sinking (or sourcing) capabilities decrease drastically.
High-impedance CMOS-logic inputs connected to the
RESET pin can drift to indeterminate voltages. This
does not present a problem in most cases, since most
µPs and circuitry do not operate at VCC below 1V. For
the MAX6336, where RESET must be valid down to 0,
adding a pull-down resistor between RESET and GND
removes stray leakage currents, holding RESET low
VCC
VCC
GND
MAX6337
RESETMR
VCC
GND
RESET
INPUT
MOTOROLA
68HCXX
µP
Figure 1. Interfacing to µPs with Bidirectional Reset Pins
3MR
3
Manual-Reset Input. A logic low on MR asserts reset. Reset remains
asserted as long as MR is low, and for the reset timeout period (tRP) after
MR goes high. Leave unconnected or connect to VCC if not used.
4 VCC
4Supply Voltage (0.7V to 5.5V)
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
_______________________________________________________________________________________ 5
MAX6335/MAX6336/MAX6337
VCC
GND
MAX6336
RESETMR
100k
(a)
VCC
GND
MAX6335
RESET
100k*
(b)
*ASSUMES HIGH-Z RESET INPUT TO THE µP
MR
*Factory-trimmed reset thresholds are available in approximately
100mV increments, with a ±1.8% room-temperature variance.
TA= +25°C TA= -40°C to +125°C
MIN TYP MAX MIN MAX
MAX633_US25D_ 2.46 2.50 2.55 2.43 2.58
MAX633_US24D_ 2.36 2.40 2.44 2.33 2.47
MAX633_US23D_ 2.26 2.30 2.34 2.23 2.37
MAX633_US22D_ 2.16 2.20 2.24 2.13 2.27
MAX633_US21D_ 2.06 2.10 2.14 2.04 2.16
MAX633_US20D_ 1.96 2.00 2.04 1.94 2.06
MAX633_US19D_ 1.87 1.90 1.93 1.84 1.96
MAX633_US18D_ 1.77 1.80 1.83 1.75 1.85
MAX633_US17D_ 1.67 1.70 1.73 1.65 1.75
MAX633_US16D_ 1.57 1.60 1.63 1.55 1.65
RESET
THRESHOLD
SUFFIX
Table 1. Factory-Trimmed Reset
Thresholds*
Figure 2. Ensuring Reset Valid down to VCC = 0
(Figure 2a). The pull-down resistor value is not critical;
100kΩis large enough not to load RESET, and small
enough to pull it low. For the MAX6335, where RESET
must be valid to VCC = 0, a 100kΩpull-up resistor
between RESET and VCC will hold RESET high when
VCC falls below 0.7V (Figure 2b).
Since the MAX6337 has an open-drain, active-low out-
put, it typically uses a pull-up resistor. With this device,
RESET will most likely not maintain an active condition,
but will drift to a non-active level due to the pull-up
resistor and the reduced sinking capability of the open-
drain device. Therefore, this device is not recommend-
ed for applications where the RESET pin is required to
be valid down to VCC = 0.
MAX6335/MAX6336/MAX6337
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
6_______________________________________________________________________________________
PART OUTPUT STAGE NOMINAL VTH (V) MINIMUM RESET
TIMEOUT (ms) SOT TOP MARK
MAX6335US23D3-T Push/Pull RESET 2.30 100 KABQ
MAX6335US22D3-T Push/Pull RESET 2.20 100 KAAR
MAX6335US20D3-T Push/Pull RESET 2.00 100 KABP
MAX6335US18D3-T Push/Pull RESET 1.80 100 KAAQ
MAX6335US16D3-T Push/Pull RESET 1.60 100 KAAP
MAX6336US23D3-T Push/Pull RESET 2.30 100 KAAW
MAX6336US22D3-T Push/Pull RESET 2.20 100 KAAV
MAX6336US20D3-T Push/Pull RESET 2.00 100 KAAU
MAX6336US18D3-T Push/Pull RESET 1.80 100 KAAT
MAX6336US16D3-T Push/Pull RESET 1.60 100 KAAS
MAX6337US23D3-T Open-Drain RESET 2.30 100 KABS
MAX6337US22D3-T Open-Drain RESET 2.20 100 KAAZ
MAX6337US20D3-T Open-Drain RESET 2.00 100 KABR
MAX6337US18D3-T Open-Drain RESET 1.80 100 KAAY
MAX6337US16D3-T Open-Drain RESET 1.60 100 KAAX
Selector Guide (standard versions*)
1
2
4
3
VCC
MR(RESET)
GND
MAX6335
MAX6336
MAX6337
SOT143
TOP VIEW
RESET
( ) ARE FOR MAX6335
MAX6335
MAX6336
VCC
VCC
RESETMR RESET
GND
PUSHBUTTON
SWITCH
VCC
GND
µP
(RESET)
( ) ARE FOR MAX6335
Pin Configuration Typical Operating Circuit
* Sample stock is generally held on all standard versions.
4-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits with Manual Reset
TRANSISTOR COUNT: 505
Chip Information
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.)
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 _____________________ 7
©2005 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products, Inc.
MAX6335/MAX6336/MAX6337
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Maxim Integrated:
MAX6335US16D1+T MAX6335US16D2+T MAX6335US16D3+T MAX6335US17D1+T MAX6335US17D2+T
MAX6335US17D3+T MAX6335US18D1+T MAX6335US18D2+T MAX6335US18D3+T MAX6335US19D1+T
MAX6335US19D2+T MAX6335US19D3+T MAX6335US20D1+T MAX6335US20D2+T MAX6335US20D3+T
MAX6335US21D1+T MAX6335US21D2+T MAX6335US21D3+T MAX6335US22D1+T MAX6335US22D2+T
MAX6335US22D3+T MAX6335US23D1+T MAX6335US23D2+T MAX6335US23D3+T MAX6335US24D1+T
MAX6335US24D2+T MAX6335US24D3+T MAX6335US25D1+T MAX6335US25D2+T MAX6335US25D3+T
MAX6336US16D1+T MAX6336US16D2+T MAX6336US16D3+T MAX6336US17D1+T MAX6336US17D2+T
MAX6336US17D3+T MAX6336US18D1+T MAX6336US18D2+T MAX6336US18D3+T MAX6336US19D1+T
MAX6336US19D2+T MAX6336US19D3+T MAX6336US20D1+T MAX6336US20D2+T MAX6336US20D3+T
MAX6336US21D1+T MAX6336US21D2+T MAX6336US21D3+T MAX6336US22D1+T MAX6336US22D2+T
MAX6336US22D3+T MAX6336US23D1+T MAX6336US23D2+T MAX6336US23D3+T MAX6336US24D1+T
MAX6336US24D2+T MAX6336US24D3+T MAX6336US25D1+T MAX6336US25D2+T MAX6336US25D3+T
MAX6337US16D1+T MAX6337US16D2+T MAX6337US16D3+T MAX6337US17D1+T MAX6337US17D2+T
MAX6337US17D3+T MAX6337US18D1+T MAX6337US18D2+T MAX6337US18D3+T MAX6337US19D1+T
MAX6337US19D2+T MAX6337US19D3+T MAX6337US20D1+T MAX6337US20D2+T MAX6337US20D3+T
MAX6337US21D1+T MAX6337US21D2+T MAX6337US21D3+T MAX6337US22D1+T MAX6337US22D2+T
MAX6337US22D3+T MAX6337US23D1+T MAX6337US23D2+T MAX6337US23D3+T MAX6337US24D1+T
MAX6337US24D2+T MAX6337US24D3+T MAX6337US25D1+T MAX6337US25D2+T MAX6337US25D3+T
