General Description
The MAX6332/MAX6333/MAX6334 microprocessor (µP)
supervisory circuits monitor the power supplies in 1.8V
to 3.3V µP and digital systems. They increase circuit
reliability and reduce cost by eliminating external com-
ponents and adjustments.
These devices perform a single function: they assert a
reset signal whenever the VCC supply voltage declines
below a preset threshold, keeping it asserted for a preset
timeout period after VCC has risen above the reset
threshold. The only difference among the three devices
is their output. The MAX6333 (push/pull) and MAX6334
(open-drain) have an active-low RESET output, while the
MAX6332 (push/pull) has an active-high RESET output.
The MAX6332/MAX6333 are guaranteed to be in the cor-
rect state for VCC down to 0.7V. The MAX6334 is guaran-
teed to be in the correct 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 (2,500 piece minimum-order quantity); con-
tact the factory for availability of nonstandard versions
(10,000 piece minimum-order quantity). For space-criti-
cal applications, the MAX6332/MAX6333/MAX6334
come packaged in a 3-pin SOT23.
Applications
Pentium®II Computers
Computers
Controllers
Intelligent Instruments
Critical µP/µC Power Monitoring
Portable/Battery-Powered Equipment
Automotive
Features
oUltra-Low 0.7V Operating Supply Voltage
oLow 3.3µA Supply Current
oPrecision Monitoring of 1.8V and 2.5V Power-
Supply Voltages
oReset Thresholds Available from 1.6V to 2.5V,
in Approximately 100mV Increments
oFully Specified over Temperature
oThree Power-On Reset Pulse Widths Available
(1ms min, 20ms min, 100ms min)
oLow Cost
oThree Available Output Structures: Push/Pull
RESET, Push/Pull RESET, Open-Drain RESET
oGuaranteed RESET/RESET Valid to VCC = 0.7V
(MAX6332/MAX6333)
oPower-Supply Transient Immunity
oNo External Components
o3-Pin SOT23 Package
oPin Compatible with MAX809/MAX810 and
MAX6326/MAX6327/MAX6328
MAX6332/MAX6333/MAX6334
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
19-1411; Rev 3; 6/12
1
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
Ordering Information
*
These devices are available in factory-set V
CC
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 “UR” 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.
/V denotes an automotive qualified part.
Typical Operating Circuit and Pin Configuration appear
at end of data sheet.
Selector Guide appears at end of data sheet.
Pentium is a registered trademark of Intel Corp.
PART TEMP RANGE PIN-PACKAGE
MAX6332UR__D_-T -40°C to +125°C 3 SOT23
MAX6333UR__D_-T -40°C to +125°C 3 SOT23
MAX6333UR__D_/V-T -40°C to +125°C 3 SOT23
MAX6334UR__D_-T -40°C to +125°C 3 SOT23
MAX6332/MAX6333/MAX6334
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
2
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = full range, 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, RESET .......................-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)
SOT23-3 (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
Soldering Temperature (reflow)
Lead(Pb)-free packages .............................................+260°C
Packages containing lead (Pb)...................................+240°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Supply Voltage Range VCC
TA= 0°C to +85°C MAX6332/MAX6333 0.7 5.5
V
Supply Current ICC No load VCC = 1.8V 3.0 6.0
VCC = 2.5V 3.3 7.0 µA
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_UR__D_-T,
Table 1 V
VCC Falling Reset Delay VCC falling at 10V/ms 24 µs
MAX633_UR__D1-T 1 1.5 2
MAX633_UR__D2-T 20 30 40
Reset Active Timeout Period tRP
MAX633_UR__D3-T 100 150 200
ms
RESET Output Low Voltage
(MAX6333/MAX6334) VOL
0.4
Reset
asserted V
RESET Output High Voltage
(MAX6333) VOH
ISOURCE = 200µA, VCC ≥1.8V 0.8VCC
ISOURCE = 500µA, VCC ≥2.7V 0.8VCC
V
RESET Output Voltage
(MAX6332)
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
ISINK = 50µA, VCC ≥1.0V
ISINK = 500µA, VCC ≥1.8V 0.3
RESET Output Leakage
Current (MAX6334) VCC >V
TH, RESET deasserted 0.5 µA
TA = -40°C to +125°C
TA = -40°C to +85°C
MAX6332/MAX6333
MAX6334
MAX6332/MAX6333
1.2 5.5
0.78 5.5
1.2 5.5
1.0 5.5
MAX6334
MAX6334
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
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
MAX6332/33/34 toc-1
TEMPERATURE (°C)
ICC (µA)
RESET NOT ASSERTED
VCC = 1.8V
VCC = 2.5V
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
MAX6332/33/34-2
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
VTH = 2.2V
0
20
10
30
60
70
50
40
80
0.5 1.00 1.50 2.00 2.50 3.00
OUTPUT VOLTAGE LOW
vs. SUPPLY VOLTAGE
MAX6332/33/34 toc-6
VCC (V)
OUTPUT VOLTAGE LOW (mV)
VTH = 2.5V
ISINK = 500µA
RESET ASSERTED
TA = -40°C
TA = +85°C
TA = +25°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
MAX6332/33/34 toc-5
VCC (V)
OUTPUT VOLTAGE HIGH (VCC - VOH) (mV)
VTH = 2.2V
ISOURCE = 100µA
RESET ASSERTED
TA = -40°C
TA = +85°C
TA = +25°C
100 1000
0
100
200
400
300
500
600
0.1 1 10
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
MAX6332/33/34 toc-4
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 20406080100
VCC FALLING PROPAGATION DELAY
vs. TEMPERATURE
MAX6332/33/34 toc-3
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.)
MAX6332/MAX6333/MAX6334
Pin Description
NAME
GND
MAX6332
Ground1
MAX6333
MAX6334
FUNCTION
1
—RESET
2
Active-Low Reset Output. RESET remains low while VCC is below the reset
threshold and for a reset timeout period (tRP) after VCC rises above the
reset threshold. RESET on the MAX6334 is open-drain.
2RESET—
Active-High Reset Output. RESET remains high while VCC is below the
reset threshold and for a reset timeout period (tRP) after VCC rises above
the reset threshold.
3 VCC
3Supply Voltage (0.7V to 5.5V)
PIN
MAX6332/MAX6333/MAX6334
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
4
______________ Applications Information
Interfacing to µPs with Bidirectional
Reset Pins
Since the RESET output on the MAX6334 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 maxi-
mum pulse width that a negative-going VCC transient may
typically have without issuing a reset signal. As the ampli-
tude of the transient increases, the maximum allowable
pulse width decreases.
Ensuring a Valid Reset Output
Down to V
CC
= 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 MAX6333, where RESET must be valid down to 0,
adding a pull-down resistor between RESET and GND
removes stray leakage currents, holding RESET low
(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 MAX6332, 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 MAX6334 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.
VCC
VCC
GND
MAX6334
RESET
VCC
GND
RESET
INPUT
MOTOROLA
68HCXX
µP
*
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_UR25D_ 2.46 2.50 2.55 2.43 2.58
MAX633_UR24D_ 2.36 2.40 2.44 2.33 2.47
MAX633_UR23D_ 2.26 2.30 2.34 2.23 2.37
MAX633_UR22D_ 2.16 2.20 2.24 2.13 2.27
MAX633_UR21D_ 2.06 2.10 2.14 2.04 2.16
MAX633_UR20D_ 1.96 2.00 2.04 1.94 2.06
MAX633_UR19D_ 1.87 1.90 1.93 1.84 1.96
MAX633_UR18D_ 1.77 1.80 1.83 1.75 1.85
MAX633_UR17D_ 1.67 1.70 1.73 1.65 1.75
MAX633_UR16D_ 1.57 1.60 1.63 1.55 1.65
RESET-
THRESHOLD
SUFFIX
Table 1. Factory-Trimmed Reset
Thresholds*
Figure 1. Interfacing to µPs with Bidirectional Reset Pins
Figure 2. Ensuring Reset Valid Down to VCC = 0
VCC
GND
MAX6333
RESET
100k
(a)
VCC
GND
MAX6332
RESET
100k*
(b)
*ASSUMES HIGH-Z RESET INPUT TO THE µP
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
5
MAX6332/MAX6333/MAX6334
TOP VIEW
1
2
3VCC
RESET (RESET)
MAX6332
MAX6333
MAX6334
SOT23-3
( ) ARE FOR MAX6332
GND
Pin Configuration
Selector Guide (Standard Versions
*
)
PART OUTPUT STAGE NOMINAL VTH (V) MINIMUM RESET
TIMEOUT (ms) SOT TOP MARK
MAX6332UR23D3-T Push/Pull RESET 2.30 100 FZDM
MAX6332UR22D3-T Push/Pull RESET 2.20 100 FZCN
MAX6332UR20D3-T Push/Pull RESET 2.00 100 FZDL
MAX6332UR18D3-T Push/Pull RESET 1.80 100 FZCM
MAX6332UR16D3-T Push/Pull RESET 1.60 100 FZCL
MAX6333UR23D3-T Push/Pull RESET 2.30 100 FZCS
MAX6333UR22D3-T Push/Pull RESET 2.20 100 FZCR
MAX6333UR20D3-T Push/Pull RESET 2.00 100 FZCQ
MAX6333UR18D3-T Push/Pull RESET 1.80 100 FZCP
MAX6333UR16D3-T Push/Pull RESET 1.60 100 FZCO
MAX6334UR23D3-T Open-Drain RESET 2.30 100 FZDO
MAX6334UR22D3-T Open-Drain RESET 2.20 100 FZCV
MAX6334UR20D3-T Open-Drain RESET 2.00 100 FZDN
MAX6334UR18D3-T Open-Drain RESET 1.80 100 FZCU
MAX6334UR16D3-T Open-Drain RESET 1.60 100 FZCT
MAX6332
MAX6333
VCC
VCC
RESET RESET
INPUT
GND
VCC
GND
µP
(RESET)
( ) ARE FOR MAX6332
Typical Operating Circuit
*
Sample stock is generally held on all standard versions.
Package Information
For the latest package outline information and land patterns (footprints), go to www.maxim-ic.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 per-
tains to the package regardless of RoHS status.
PACKAGE TYPE PACKAGE CODE OUTLINE NO. LAND
PATTERN NO.
3 SOT23 U3+1 21-0051 90-0179
MAX6332/MAX6333/MAX6334
3-Pin, Ultra-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. 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.
6
________________Maxim Integrated Products, Inc. 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
© 2012 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 12/98 Initial release —
1 6/00 Revised Ordering Information, Absolute Maximum Ratings, Electrical Characteristics,
and Table 1. 1, 2, 4
2 12/05 Revised Ordering Information to add lead-free information. 1
3 6/12 Update Ordering Information with automotive part. 1
