MAXIM MAX6328

19-1933 Rev 1; 2/01
3-Pin, Low-Power
µP Reset Circuits
Applications
Features
♦ Ultra-Low 0.7V Operating Supply Voltage
♦ Low 4.0µA Supply Current
♦ Precision Monitoring of 2.85V to 5.0V PowerSupply Voltages
♦ Reset Thresholds Available from 2.63V to 4.80V,
in Approximately 100mV Increments
♦ Fully Specified over Temperature
♦ Three Power-On Reset Timeout Periods 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
(MAX6800/MAX6801)
♦ Power-Supply Transient Immunity
♦ No External Components Required
♦ 3-Pin SOT23 Package
♦ Pin Compatible with MAX809/MAX810,
MAX6326/MAX6327/MAX6328, and
MAX6346/MAX6347/MAX6348
Computers
Controllers
Ordering Information
Intelligent Instruments
Critical µP/µC Power Monitoring
Portable/Battery-Powered Equipment
Automotive
TEMP. RANGE
PIN-PACKAGE
MAX6800UR_ _D_-T
-40°C to +125°C
3 SOT23-3
MAX6801UR_ _D_-T
-40°C to +125°C
-40°C to +125°C
3 SOT23-3
3 SOT23-3
PART*
MAX6802UR_ _D_-T
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 2.63V to 4.80V, 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.
________________________________________________________________ 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
MAX6800/MAX6801/MAX6802
General Description
The MAX6800/MAX6801/MAX6802 microprocessor (µP)
supervisory circuits monitor the power supplies in 2.85V
to 5.0V 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 V CC has risen above the reset
threshold. The only difference among the three devices
is their output. The MAX6801 (push/pull) and MAX6802
(open-drain) have an active-low RESET output, while the
MAX6800 (push/pull) has an active-high RESET output.
The MAX6800/MAX6801 are guaranteed to be in the correct state for VCC down to 0.7V. The MAX6802 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 2.63V and 4.80V, in approximately
100mV increments. These devices are available with a
1ms (min), 20ms (min), or 100ms (min) reset pulse
width. Ideal for space-critical applications, the
MAX6800/MAX6801/MAX6802 come packaged in a 3pin SOT23. For a lower threshold voltage version, see
the MAX6332/MAX6333/MAX6334.
MAX6800/MAX6801/MAX6802
3-Pin, 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)
3-Pin SOT23 (derate 4mW/°C above +70°C) ..............320mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range .............................-65°C to +150°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 VCC = +5.0V and TA = +25°C, reset not
asserted.) (Note 1)
PARAMETER
Supply Voltage Range
(Note 2)
SYMBOL
CONDITIONS
TA = 0°C to +125°C
VCC
TA = -40°C to +125°C
Supply Current
Reset Threshold
ICC
No load
VTH
MAX680_UR_ _D_-T,
Table 1
MAX6802
1.0
5.5
MAX6800/MAX6801
0.78
5.5
MAX6802
1.2
4
10
VCC = +5.0V
5
12
VTH
- 1.8%
VTH
VTH
+ 1.8%
VTH
- 3%
VTH
VTH
+ 3%
1
1.5
TA = +25°C
RESET Output Low Voltage
(MAX6801/MAX6802)
RESET Output High Voltage
(MAX6801)
RESET Output Voltage
(MAX6800)
VOL
RESET Output Leakage Current
(MAX6802)
µs
20
30
40
150
200
VOH
Reset
asserted
Reset not
asserted
µA
2
100
Reset not
asserted
VOL
30
MAX680_UR_ _D3-T
VOH
V
V
MAX680_UR_ _D2-T
Reset
asserted
UNITS
5.5
VCC = +3.0V
VCC falling at 10V/ms
tRP
MAX
5.5
MAX680_UR_ _D1-T
Reset Active Timeout Period
TYP
0.7
TA = -40°C to +125°C
VCC Falling Reset Delay
MIN
MAX6800/MAX6801
ISINK = 50µA, VCC ≥ 1.0V
0.4
ISINK = 1.2mA, VCC ≥ 2.5V
0.3
ISINK = 1.2mA, VCC ≥ 4.25V
0.4
ISOURCE = 500µA, VCC ≥ 3.0V
0.8 x VCC
ISOURCE = 800µA, VCC ≥ 5.0V
0.8 x VCC
ISOURCE = 1µA, VCC ≥ 1.0V
0.8 x VCC
ISOURCE = 200µA, VCC ≥ 1.8V
0.8 x VCC
ISOURCE = 800µA, VCC ≥ 4.25V
0.8 x VCC
V
V
V
ISINK = 1.2mA, VCC ≥ 3.0V
0.3
ISINK = 3.2mA, VCC ≥ 5.0V
0.4
VCC > VTH, RESET not asserted
ms
0.5
µA
Note 1: All parts are production tested at TA = +25°C. Overtemperature limits are guaranteed by design and not production tested.
Note 2: ISOURCE for the MAX6800 is I00nA. ISINK for the MAX6801 is 100nA. ISINK for the MAX6802 is 50µA.
2
_______________________________________________________________________________________
3-Pin, Low-Power
µP Reset Circuits
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
5.0
4.5
VCC = +3.3V
4.0
3.5
1.020
1.010
1.000
0.990
0.980
0.970
80
VTH = 2.93V
ISINK = 500µA
RESET ASSERTED
MAX6801/MAX6802
+125°C
60
+85°C
40
+25°C
-40°C
20
0.960
3.0
0.950
-25
0
25
50
75
100
125
0
-50
-25
0
25
50
75
100
125
1.5
2.0
2.5
3.0
TEMPERATURE (°C)
VCC (V)
RESET (VOH)
vs. SUPPLY VOLTAGE
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
VCC FALLING PROPAGATION DELAY
vs. TEMPERATURE
+125°C
50
+85°C
+25°C
25
500
400
RESET OCCURS
300
200
RESET DOES
NOT OCCUR
100
2.0
2.5
VCC (V)
70
VCC = FALLING AT 1V/ms
60
50
40
30
VCC = FALLING AT 10V/ms
0
0.1
3.0
80
10
0
1.5
90
20
-40°C
0
100
MAX6800/01/02 toc06
75
600
PROPAGATION DELAY (µs)
VTH = 2.93V
ISOURCE = 100µA
RESET ASSERTED
(MAX6800)
MAXIMUM TRANSIENT DURATION (µs)
100
1.0
1.0
TEMPERATURE (°C)
MAX6800/01/02 toc04
-50
OUTPUT VOLTAGE HIGH (VCC - VOH) (mV)
1.030
MAX6800/01/02 toc05
ICC (µA)
VCC = +5.0V
1.040
MAX6800/01/02 toc03
5.5
MAX6800/01/02 toc02
6.0
1.050
NORMALIZED RESET TIMEOUT PERIOD
MAX6800/01/02 toc01
6.5
RESET (VOL)
vs. SUPPLY VOLTAGE
OUTPUT VOLTAGE LOW (mV)
SUPPLY CURRENT vs. TEMPERATURE
1
10
100
1000
RESET COMPARATOR OVERDRIVE (mV)
-50
-25
0
25
50
75
100
125
TEMPERATURE (°C)
Pin Description
PIN
MAX6800
1
MAX6801/
MAX6802
1
NAME
GND
FUNCTION
Ground
—
2
RESET
Active-Low Reset Output. RESET is asserted while VCC is below the reset
threshold and remains asserted for a reset timeout period (tRP) after VCC
rises above the reset threshold. RESET on the MAX6801 is push/pull.
RESET on the MAX6802 is open-drain.
2
—
RESET
Active-High Reset Output. RESET is asserted while VCC is below the reset
threshold and remains asserted for a reset timeout period (tRP) after VCC
rises above the reset threshold. RESET on the MAX6800 is push/pull.
3
3
VCC
Supply Voltage Input
_______________________________________________________________________________________
3
MAX6800/MAX6801/MAX6802
Typical Operating Characteristics
(Reset not asserted, TA = +25°C, unless otherwise noted.)
MAX6800/MAX6801/MAX6802
3-Pin, Low-Power
µP Reset Circuits
Applications Information
Interfacing to µPs with Bidirectional
Reset Pins
Since the RESET output on the MAX6802 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
pullup 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.
VCC
VCC
VCC
VCC
VCC
100kΩ
MAX6802
RESET
100kΩ*
µP
MOTOROLA
68HCXX
RESET
GND
MAX6801
MAX6800
RESET
RESET
100kΩ
GND
GND
(a)
GND
(b)
*ASSUMES HIGH-Z RESET INPUT TO THE µP
Figure 1. Interfacing to µPs with Bidirectional Reset Pins
Figure 2. Ensuring Reset Valid Down to VCC = 0
Pin Configuration
Typical Operating Circuit
TOP VIEW
VCC
GND 1
MAX6800
MAX6801
MAX6802
3 VCC
VCC
VCC
MAX6801
µP
RESET
RESET
GND
RESET (RESET) 2
SOT23-3
( ) ARE FOR MAX6800
4
_______________________________________________________________________________________
GND
3-Pin, Low-Power
µP Reset Circuits
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 when V CC drops
below 1V. For the MAX6801 application, where RESET
must be valid down to 0, adding a pulldown resistor
between RESET and GND removes stray leakage currents, holding RESET low (Figure 2a). The pulldown
resistor value is not critical; 100kΩ is large enough not
to load RESET and small enough to pull it low. For the
MAX6800 application, where RESET must be valid to
VCC = 0, a 100kΩ pullup resistor between RESET and
VCC will hold RESET high when VCC falls below 0.7V
(Figure 2b).
Since the MAX6802 has an open-drain, active-low output, it typically uses a pullup resistor. With this device,
RESET will most likely not maintain an active condition,
but will drift to a non-active level due to the pullup
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.
Table 1. Factory-Trimmed Reset Thresholds
RESET
THRESHOLD
SUFFIX
MIN
TYP (VTH)
MAX
MIN
MAX
48
4.714
4.80
4.886
4.656
4.944
47
4.615
4.70
4.785
4.559
4.841
46
4.547
4.63
4.713
4.491
4.769
45
4.419
4.50
4.581
4.365
4.635
44
4.301
4.38
4.459
4.249
4.511
43
4.223
4.30
4.377
4.171
4.429
42
4.124
4.20
4.276
4.074
4.326
41
4.026
4.10
4.174
3.977
4.223
40
3.928
4.00
4.072
3.880
4.120
39
4.830
3.90
3.970
3.783
4.017
38
3.732
3.80
3.868
3.686
3.914
37
3.633
3.70
3.767
3.589
3.811
36
3.535
3.60
3.665
3.492
3.708
35
3.437
3.50
3.563
3.395
3.605
34
3.339
3.40
3.461
3.298
3.502
33
3.241
3.30
3.359
3.201
3.399
32
3.142
3.20
3.258
3.104
3.296
31
3.025
3.08
3.135
2.988
3.172
30
2.946
3.00
3.054
2.910
3.090
29
2.877
2.93
2.983
2.842
3.018
28
2.750
2.80
2.850
2.716
2.884
27
2.651
2.70
2.749
2.619
2.781
26
2.583
2.63
2.677
2.551
2.709
TA = +25°C
TA = -40°C to +125°C
_______________________________________________________________________________________
5
MAX6800/MAX6801/MAX6802
Ensuring a Valid Reset Output
Down to VCC = 0
MAX6800/MAX6801/MAX6802
3-Pin, Low-Power
µP Reset Circuits
Selector Guide (Standard Versions*)
PART
OUTPUT STAGE
NOMINAL VTH (V)
MIN RESET
TIMEOUT (ms)
SOT
TOP MARK
MAX6800UR26D3-T
Push/Pull RESET
2.63
100
FZIE
MAX6800UR29D3-T
Push/Pull RESET
2.93
100
FZIF
MAX6800UR31D3-T
Push/Pull RESET
3.08
100
FZIG
MAX6800UR44D3-T
Push/Pull RESET
4.38
100
FZIH
MAX6800UR46D3-T
Push/Pull RESET
4.63
100
FZII
MAX6801UR26D3-T
Push/Pull RESET
2.63
100
FZIK
MAX6801UR29D3-T
Push/Pull RESET
2.93
100
FZIM
MAX6801UR31D3-T
Push/Pull RESET
3.08
100
FZIN
MAX6801UR44D3-T
Push/Pull RESET
4.38
100
FZIO
MAX6801UR46D3-T
Push/Pull RESET
4.63
100
FZIP
MAX6802UR26D3-T
Open-Drain RESET
2.63
100
FZIQ
MAX6802UR29D3-T
Open-Drain RESET
2.93
100
FZIR
MAX6802UR31D3-T
Open-Drain RESET
3.08
100
FZIS
MAX6802UR44D3-T
Open-Drain RESET
4.38
100
FZIT
MAX6802UR46D3-T
Open-Drain RESET
4.63
100
FZIU
*Sample stock is generally held on all standard versions.
Chip Information
TRANSISTOR COUNT: 505
PROCESS: BiCMOS
6
_______________________________________________________________________________________
3-Pin, Low-Power
µP Reset Circuits
SOTPO3L.EPS
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.
7 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2001 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX6800/MAX6801/MAX6802
Package Information