Maxim MAX6332UR 3-pin, ultra-low-voltage, low-power up reset circuit Datasheet

19-1411; Rev 2; 12/05
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
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 components 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 correct state for VCC down to 0.7V. The MAX6334 is
guaranteed 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 factorytrimmable between 1.6V and 2.5V, in approximately
100mV increments. There are 15 standard versions
available (2,500 piece minimum-order quantity); contact the factory for availability of nonstandard versions
(10,000 piece minimum-order quantity). For space-critical applications, the MAX6332/MAX6333/MAX6334
come packaged in a 3-pin SOT23.
Features
♦ Ultra-Low 0.7V Operating Supply Voltage
♦ Low 3.3µA Supply Current
♦ Precision Monitoring of 1.8V and 2.5V PowerSupply Voltages
♦ Reset Thresholds Available from 1.6V to 2.5V,
in Approximately 100mV Increments
♦ 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
(MAX6332/MAX6333)
♦ Power-Supply Transient Immunity
♦ No External Components
♦ 3-Pin SOT23 Package
♦ Pin Compatible with MAX809/MAX810 and
MAX6326/MAX6327/MAX6328
Ordering Information
Applications
Pentium II™ Computers
Computers
Controllers
TEMP. RANGE
PIN-PACKAGE
MAX6332UR__D_-T
-40°C to +125°C
3 SOT23-3
MAX6333UR__D_-T
-40°C to +125°C
-40°C to +125°C
3 SOT23-3
3 SOT23-3
PART*
MAX6334UR__D_-T
Intelligent Instruments
Critical µP/µC Power Monitoring
Portable/Battery-Powered Equipment
Automotive
Typical Operating Circuit and Pin Configuration appear
at end of data sheet.
Selector Guide appears at end of data sheet.
* These devices are available in factory-set VCC reset thresholds 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 standard 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 nonstandard 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.
Pentium II is a trademark of Intel Corp.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX6332/MAX6333/MAX6334
General Description
MAX6332/MAX6333/MAX6334
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
ABSOLUTE MAXIMUM RATINGS
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
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.
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 assertPARAMETER
Supply Voltage Range
SYMBOL
VCC
CONDITIONS
MAX6332/MAX6333
TA = 0°C to +85°C
MAX6334
MIN
0.7
1.0
5.5
MAX6332/MAX6333
0.78
5.5
MAX6334
1.2
5.5
MAX6332/MAX6333
MAX6334
1.2
5.5
TA = -40°C to +85°C
TA = -40°C to +125°C
Supply Current
Reset Threshold
No load
VTH
MAX633_UR__D_-T,
Table 1
VCC Falling Reset Delay
3.0
3.3
TA = +25°C
VTH 1.8%
VTH
TA = -40°C to +125°C
VTH 3%
VTH
VCC falling at 10V/ms
MAX633_UR__D1-T
MAX633_UR__D2-T
MAX633_UR__D3-T
1
20
100
24
1.5
30
150
MAX
5.5
6.0
7.0
VTH +
1.8%
VTH +
3%
tRP
RESET Output Low Voltage
(MAX6333/MAX6334)
VOL
Reset
asserted
ISINK = 50µA, VCC ≥ 1.0V
0.4
ISINK = 500µA, VCC ≥ 1.8V
0.3
RESET Output High Voltage
(MAX6333)
VOH
Reset not
asserted
ISOURCE = 200µA, VCC ≥ 1.8V
0.8VCC
ISOURCE = 500µA, VCC ≥ 2.7V
0.8VCC
VOH
Reset
asserted
ISOURCE = 1µA, VCC ≥ 1.0V
0.8VCC
ISOURCE = 200µA, VCC ≥ 1.8V
0.8VCC
VOL
Reset not
asserted
ISINK = 500µA, VCC ≥ 1.8V
0.3
ISINK = 1.2mA, VCC ≥ 2.7V
0.3
RESET Output Leakage
Current (MAX6334)
VCC > VTH, RESET deasserted
_______________________________________________________________________________________
UNITS
V
µA
V
µs
2
40
200
Reset Active Timeout Period
RESET Output Voltage
(MAX6332)
2
VCC = 1.8V
VCC = 2.5V
ICC
TYP
ms
V
V
V
0.5
V
µA
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
VCC = 2.5V
3.0
VCC = 1.8V
2.8
2.6
2.4
2.2
1.010
1.000
0.990
0.980
-20
0
20
40
60
80
100
40
MAX6332/33/34 toc-6
TA = +25°C
TA = +85°C
30
20
TA = -40°C
0
-40
-20
0
20
40
60
80
0.5
100
1.00
1.50
2.00
2.50
3.00
TEMPERATURE (°C)
TEMPERATURE (°C)
VCC (V)
OUTPUT VOLTAGE HIGH
vs. SUPPLY VOLTAGE
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
VCC FALLING PROPAGATION DELAY
vs. TEMPERATURE
140
120
600
100
80
60
TA = +25°C
40
TA = -40°C
500
400
RESET OCCURS
300
200
RESET DOES
NOT OCCUR
100
80
70
PROPAGATION DELAY (µs)
VTH = 2.2V
ISOURCE = 100µA
RESET ASSERTED
MAXIMUM TRANSIENT DURATION (µs)
160
20
50
10
-60
MAX6332/33/34 toc-5
-40
60
0.970
0.950
-60
VTH = 2.5V
ISINK = 500µA
RESET ASSERTED
70
0.960
RESET NOT ASSERTED
2.0
OUTPUT VOLTAGE HIGH (VCC - VOH) (mV)
1.020
80
MAX6332/33/34 toc-3
3.2
1.030
MAX6332/33/34 toc-4
ICC (µA)
3.4
VTH = 2.2V
1.040
OUTPUT VOLTAGE LOW (mV)
3.6
1.050
MAX6332/33/34-2
3.8
NORMALIZED RESET TIMEOUT PERIOD
MAX6332/33/34 toc-1
4.0
OUTPUT VOLTAGE LOW
vs. SUPPLY VOLTAGE
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
SUPPLY CURRENT vs. TEMPERATURE
60
VCC FALLING AT 1V/ms
50
40
30
VCC FALLING AT 10V/ms
20
TA = +85°C
10
0
0
0.1
0.5 0.75 1.0 1.25 1.5 1.75 2.0 2.25 2.5
VCC (V)
1
10
100
1000
RESET COMPARATOR OVERDRIVE (mV)
-60
-40
-20
0
20
40
60
80
100
TEMPERATURE (°C)
Pin Description
PIN
NAME
FUNCTION
1
MAX6333
MAX6334
1
—
2
RESET
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.
2
—
RESET
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
3
VCC
MAX6332
GND
Ground
Supply Voltage (0.7V to 5.5V)
_______________________________________________________________________________________
3
MAX6332/MAX6333/MAX6334
Typical Operating Characteristics
(Reset not asserted, TA = +25°C, unless otherwise noted.)
MAX6332/MAX6333/MAX6334
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
______________Applications Information
VCC
Interfacing to µPs with Bidirectional
Reset Pins
VCC
Since the RESET output on the MAX6334 is open-drain,
this device interfaces easily with µPs that have bidirectional 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 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;
100kΩ is 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 100kΩ pull-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 output, 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 opendrain device. Therefore, this device is not recommended for applications where the RESET pin is required to
be valid down to VCC = 0.
VCC
µP
MOTOROLA
68HCXX
RESET
INPUT
MAX6334
RESET
GND
GND
Figure 1. Interfacing to µPs with Bidirectional Reset Pins
VCC
VCC
100k*
MAX6333
MAX6332
RESET
RESET
100k
GND
(a)
GND
(b)
*ASSUMES HIGH-Z RESET INPUT TO THE µP
Figure 2. Ensuring Reset Valid Down to VCC = 0
Table 1. Factory-Trimmed Reset
Thresholds*
RESETTHRESHOLD
SUFFIX
MAX633_UR25D_
MIN TYP MAX
MIN
MAX
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
TA = +25°C
TA = -40°C to +125°C
* Factory-trimmed reset thresholds are available in approximately
100mV increments, with a ±1.8% room-temperature variance.
4
_______________________________________________________________________________________
3-Pin, Ultra-Low-Voltage, Low-Power
µP Reset Circuits
Typical Operating Circuit
TOP VIEW
VCC
GND 1
VCC
VCC
µP
MAX6332
MAX6333
MAX6332
MAX6333
MAX6334
3 VCC
RESET
(RESET)
RESET
INPUT
GND
GND
RESET (RESET) 2
SOT23-3
( ) ARE FOR MAX6332
( ) ARE FOR MAX6332
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
* Sample stock is generally held on all standard versions.
_______________________________________________________________________________________
5
MAX6332/MAX6333/MAX6334
Pin Configuration
Chip Information
TRANSISTOR COUNT: 505
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.)
SOTPO3L.EPS
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.
6 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2005 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products, Inc.
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