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General Description
The MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/
MAX6348 microprocessor (µP) supervisory circuits moni-
tor the power supplies in µP and digital systems. These
devices provide excellent circuit reliability and low cost
by eliminating external components and adjustments
when used with 2.5V, 3V, 3.3V, and 5V powered circuits.
These circuits perform a single function: they assert a
reset signal whenever the V
CC
supply voltage declines
below a preset threshold, keeping it asserted for at least
100ms after V
CC
has risen above the reset threshold.
The only difference between the devices is their output.
The MAX6326/MAX6346 (push-pull) and MAX6328/
MAX6348 (open-drain) have an active-low reset output.
The MAX6327/MAX6347 have an active-high push-pull
reset output. All of these parts are guaranteed to be in
the correct state for V
CC
down to 1V. The reset compara-
tor is designed to ignore fast transients on V
CC
. Reset
thresholds are factory-trimmable between 2.2V and
4.63V, in approximately 100mV increments. Twenty-one
standard versions are available. Contact the factory for
availability of nonstandard versions.
Ultra-low supply currents (1µA max for the MAX6326/
MAX6327/MAX6328) make these parts ideal for use in
portable equipment. All six devices are available in
space-saving SOT23 and SC70 packages.
Applications
Computers
Intelligent Instruments
Controllers
Automotive
Critical µP and µC
Portable/Battery-Powered
Power Monitoring
Equipment
Features
o Ultra-Low 1µA (max) Supply Current
(MAX6326/MAX6327/MAX6328)
o Precision Monitoring of 2.5V, 3V, 3.3V, and 5V
Power-Supply Voltages
o Reset Thresholds Available from 2.2V to 4.63V
o Fully Specified Over Temperature
o 100ms (min) Power-On Reset Pulse Width
o Low Cost
o Available in Three Versions: Push-Pull RESET,
Push-Pull RESET, and Open-Drain RESET
o Power-Supply Transient Immunity
o No External Components
o 3-Pin SC70/SOT23 Packages
o Pin Compatible with MAX803/MAX809/MAX810
MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
µP Reset Circuits
________________________________________________________________ Maxim Integrated Products
1
1
2
3
V
CC
(RESET) RESET
GND
( ) ARE FOR THE MAX6327/MAX6347.
MAX6326
MAX6327
MAX6328
MAX6346
MAX6347
MAX6348
SOT23-3/SC70-3
TOP VIEW
Pin Configuration
19-1294; Rev 3; 1/00
The MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/
MAX6348 are available in factory-set V
CC
reset thresholds from
2.2V to 4.63V, in approximately 0.1V increments. Choose the
desired reset-threshold suffix from Table 1 and insert it in the
blank spaces following "R." There are 21 standard versions with
a required order increment of 2500 pieces. Sample stock is gen-
erally held on the standard versions only (see the Selector
Guide). Required order increment is 10,000 pieces for nonstan-
dard versions (Table 2). Contact factory for availability. All
devices available in tape-and-reel only.
Ordering Information
3 SC70-3
3 SC70-3
3 SC70-3
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
MAX6348XR_ _-T
MAX6347XR_ _-T
MAX6346XR_ _-T
3 SC70-3
3 SC70-3
3 SC70-3
PIN-PACKAGE
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
MAX6328XR_ _-T
MAX6327XR_ _-T
MAX6326XR_ _-T
PART
3 SOT23-3
-40°C to +85°C
MAX6326UR_ _-T
3 SOT23-3
-40°C to +85°C
MAX6327UR_ _-T
3 SOT23-3
-40°C to +85°C
MAX6328UR_ _-T
3 SOT23-3
-40°C to +85°C
MAX6346UR_ _-T
3 SOT23-3
-40°C to +85°C
MAX6347UR_ _-T
3 SOT23-3
-40°C to +85°C
MAX6348UR_ _-T
Selector Guide appears at end of data sheet.
MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
µP Reset Circuits
2
_______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(V
CC
= full range, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C and V
CC
= 3V.) (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.
Terminal Voltage (with respect to GND)
V
CC
...........................................................................-0.3V to +6V
RESET, RESET (push-pull) .........................-0.3V to (V
CC
+ 0.3V)
RESET (open drain)..................................................-0.3V to +6V
Input Current (V
CC
) .............................................................20mA
Output Current (RESET, RESET).........................................20mA
Rate of Rise (V
CC
) ...........................................................100V/µs
Continuous Power Dissipation (T
A
= +70°C)
3-Pin SC70 (derate 2.7mW/°C above +70°C) ...............174mW
3-Pin SOT23 (derate 4mW/°C above +70°C)................320mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Note 1: Overtemperature limits are guaranteed by design and not production tested.
RESET Output Voltage
(MAX6327/MAX6347)
V
OL
0.4
I
SINK
= 3.2mA, V
CC
= V
TH(MAX)
, V
TH
4.5V
0.4
I
SINK
= 3.2mA, V
CC
4.5V, reset not asserted,
V
TH
4.38V
V
V
OH
I
SOURCE
= 50µA, V
CC
1.2V, reset asserted
0.3
I
SINK
= 1.2mA, V
CC
3.2V, reset not asserted,
MAX6327 only
0.8 · V
CC
0.8 · V
CC
I
SOURCE
= 500µA, V
CC
2.1V, reset asserted
1.0
1.75
µA
0.5
1.0
Supply Current
I
CC
V
CC
= 5.5V, no load
Reset Threshold
V
TH
-
V
TH
V
TH
+
1.5%
1.5%
V
V
TH
V
TH
-
V
TH
V
TH
+
2.5%
2.5%
Table 1
T
A
= +25°C
T
A
= -40°C to +85°C
1.2
5.5
1.0
5.5
0.8 · V
CC
0.8 · V
CC
0.8 · V
CC
Open-Drain RESET Output
Leakage Current
µA
0.1
RESET Threshold
Hysteresis
mV
9.5
MAX6346/MAX6347/MAX6348
6.3
MAX6326/MAX6327/MAX6328
V
CC
to Reset Delay
20
µs
V
CC
= V
TH
to (V
TH
- 100mV)
PARAMETER
SYMBOL
MIN
TYP
MAX
UNITS
ms
100
185
280
V
CC
Range
V
Reset Threshold Tempco
V
TH
/°C
40
ppm/°C
CONDITIONS
T
A
= 0°C to +70°C
T
A
= -40°C to +85°C
V
Reset Active Timeout Period
I
SOURCE
= 800µA, V
CC
= V
TH(MAX)
, V
TH
4.5V
RESET Output Voltage
(MAX6326/MAX6346)
I
SOURCE
= 800µA, V
CC
= 4.5V, V
TH
4.38V
V
OH
I
SOURCE
= 500µA, V
CC
= 3.2V, MAX6326 only
MAX632_ only, V
CC
= 3.0V for V
TH
2.93V,
V
CC
= 3.2V for V
TH
> 2.93V, no load
V
0.3
I
SINK
= 1.6mA, V
CC
> 2.1V, reset asserted
RESET Output Voltage
(MAX6326/MAX6328/
MAX6346/MAX6348)
V
OL
0.4
I
SINK
= 100µA, V
CC
1.2V, reset asserted
PIN
MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
µP Reset Circuits
_______________________________________________________________________________________
3
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
0
0.3
0.2
0.1
0.4
0.5
0.6
0.7
0.8
0.9
1.0
-40
0
-20
20
40
60
80
SUPPLY CURRENT vs. TEMPERATURE
MAX6326-01
TEMPERATURE (°C)
SUPPLY CURRENT (
µ
A)
V
CC
= 3.3V
V
CC
= 5V
V
CC
= 1.2V
0
50
100
150
200
-40
0
-20
20
40
60
80
POWER-DOWN RESET DELAY
vs. TEMPERATURE
MAX6326-02
TEMPERATURE (°C)
RESET DELAY (
µ
s)
V
OD
= 200mV
V
OD
= 10mV
V
OD
= 100mV
V
OD
= 20mV
130
150
140
160
170
180
190
200
210
-40
0
-20
20
40
60
80
POWER-UP RESET TIMEOUT
vs. TEMPERATURE
MAX6326-03
TEMPERATURE (°C)
POWER-UP RESET TIMEOUT (ms)
500
0
1
100
1000
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE (SC70)
100
300
400
200
MAX6326-04
RESET THRESHOLD OVERDRIVE,
V
TH
- V
CC
(mV)
MAXIMUM TRANSIENT DURATION (
µ
s)
10
______________________________________________________________Pin Description
FUNCTION
1
1
Ground
2
--
Active-Low Reset Output. RESET remains low while V
CC
is below the reset
threshold and for at least 100ms after V
CC
rises above the reset threshold.
RESET is open-drain on the MAX6328/MAX6348 and push-pull on the
MAX6326/MAX6346.
--
2
Active-High Reset Output. RESET remains high while V
CC
is below the reset
threshold and for at least 100ms after V
CC
rises above the reset threshold.
3
3
Supply Voltage
NAME
GND
RESET
RESET
V
CC
MAX6327
MAX6347
MAX6326/MAX6346
MAX6328/MAX6348
PIN
MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
µP Reset Circuits
4
_______________________________________________________________________________________
____________ Applications Information
Interfacing to µPs with
Bidirectional Reset Pins
Since the RESET output on the MAX6328/MAX6348 is
open drain, these devices interface easily with micro-
processors (µPs) that have bidirectional reset pins,
such as the Motorola 68HC11. Connecting the µP
supervisor's RESET output directly to the microcon-
troller's (µC's) RESET pin with a single pull-up resistor
allows either device to assert reset (Figure 1).
Negative-Going V
CC
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
V
CC
transients (glitches).
The Typical Operating Characteristics show the Maxi-
mum Transient Duration vs. Reset Threshold Overdrive
graph, for which reset pulses are not generated. The
graph shows the maximum pulse width that a negative-
going V
CC
transient may typically have when issuing a
reset signal. As the amplitude of the transient increas-
es, the maximum allowable pulse width decreases.
Figure 1. Interfacing to µPs with Bidirectional Reset Pins
Table 1. Factory-Trimmed Reset Thresholds
Factory-trimmed reset thresholds are available in approximately 100mV increments with a 1.5% room-temperature variance.
RESET
GND
RESET
INPUT
MAX6328
MAX6348
MOTOROLA
68HCXX
µP
GND
V
CC
V
CC
V
CC
3.800
3.895
3.857
3.705
3.700
3.743
38
3.792
3.755
3.607
3.644
37
3.600
3.690
3.654
3.510
3.500
3.546
36
3.587
3.552
3.412
3.447
35
3.400
3.485
3.451
3.315
3.300
3.349
34
3.383
3.350
3.217
3.250
33
3.080
3.150
3.126
3.003
3.000
3.034
31
3.075
3.045
2.925
2.955
30
2.930
3.000
2.974
2.857
2.800
2.886
29
2.870
2.842
2.730
2.758
28
2.700
2.768
2.741
2.633
2.630
2.660
27
2.696
2.669
2.564
2.591
26
2.500
2.562
2.537
2.437
2.400
2.462
25
2.460
2.436
2.340
2.364
24
2.320
2.375
2.355
2.262
2.285
23
MIN
TYP
MAX
MAX
MIN
T
A
= -40°C to +85°C
T
A
= +25°C
2.250
RESET THRESHOLD VOLTAGE, V
TH
(V)
2.145
2.233
2.200
2.167
SUFFIX
MAX634_ _R
MAX634_ _R
MAX634_ _R
MAX634_ _R
MAX634_ _R
MAX634_ _R
MAX632_ _R
MAX632_ _R
MAX632_ _R
MAX632_ _R
MAX632_ _R
MAX632_ _R
MAX632_ _R
MAX632_ _R
MAX632_ _R
PART
22
MAX632_ _R
MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
µP Reset Circuits
_______________________________________________________________________________________
5
Table 1. Factory-Trimmed Reset Thresholds
(continued)
Factory-trimmed reset thresholds are available in approximately 100mV increments with a 1.5% room-temperature variance.
Table 2. Device Marking Codes and Minimum Order Increments
2.5
EHAA
MAX6326_R22-T
10
2.5
EXAA
MAX6326_R24-T
EWAA
MAX6326_R23-T
10
EYAA
MAX6326_R25-T
2.5
10
2.5
FAAA
MAX6326_R27-T
EZAA
MAX6326_R26-T
10
FCAA
MAX6326_R29-T
FBAA
MAX6326_R28-T
10
2.5
10
FDAA
MAX6326_R31-T
FEAA
MAX6326_R30-T
10
10
FZAW
MAX6346_R34-T
FZAV
MAX6346_R33-T
10
10
FZAY
MAX6346_R36-T
FZAX
MAX6346_R35-T
10
FZBA
MAX6346_R38-T
FZAZ
MAX6346_R37-T
10
10
10
FZBC
MAX6346_R40-T
FZBB
MAX6346_R39-T
10
FZBE
MAX6346_R42-T
FZBD
MAX6346_R41-T
2.5
10
FZBG
MAX6346_R44-T
FZBF
MAX6346_R43-T
10
FZBH
MAX6346_R45-T
ORDER
INCREMENT
(k)
PART
2.5
FZBI
MAX6346_R46-T
2.5
2.5
FFAA
MAX6327_R23-T
EIAA
MAX6327_R22-T
10
10
FHAA
MAX6327_R25-T
FGAA
MAX6327_R24-T
2.5
FIAA
MAX6327_R26-T
10
10
10
FKAA
MAX6327_R28-T
FJAA
MAX6327_R27-T
2.5
FNAA
MAX6327_R30-T
FLAA
MAX6327_R29-T
10
10
ORDER
INCREMENT
(k)
2.5
FZBJ
MAX6347_R33-T
PART
FMAA
MAX6327_R31-T
10
10
FZBL
MAX6347_R35-T
FZBK
MAX6347_R34-T
10
10
FZBN
MAX6347_R37-T
FZBM
MAX6347_R36-T
10
FZBP
MAX6347_R39-T
FZBO
MAX6347_R38-T
10
10
10
FZBR
MAX6347_R41-T
FZBQ
MAX6347_R40-T
10
FZBT
MAX6347_R43-T
FZBS
MAX6347_R42-T
10
2.5
FZBV
MAX6347_R45-T
FZBU
MAX6347_R44-T
2.5
FZBW
MAX6347_R46-T
AAH
ACH
ACI
ACP
ACE
ACK
TOP MARK
ACO
SOT23
SC70
ACQ
AAI
ACR
ACS
TOP MARK
ACT
ACL
ACF
SOT23
SC70
SUFFIX
39
3.841
3.802
3.958
RESET THRESHOLD VOLTAGE, V
TH
(V)
3.997
MIN
MAX
MAX
TYP
MIN
40
3.940
3.900
3.900
4.060
4.100
4.000
41
4.038
3.997
4.161
4.202
42
4.137
4.100
4.095
4.263
4.305
4.200
43
4.235
4.192
4.364
4.407
44
4.314
4.300
4.270
4.446
T
A
= +25°C
T
A
= -40°C to +85°C
4.489
4.380
45
4.432
4.387
4.567
4.612
46
4.560
4.500
4.514
4.699
4.746
4.630
PART
MAX634_ _R
MAX634_ _R
MAX634_ _R
MAX634_ _R
MAX634_ _R
MAX634_ _R
MAX634_ _R
MAX634_ _R
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