19-2242; Rev 1; 1/02
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
General Description
The MAX6832–MAX6840 are microprocessor (µP)
supervisory circuits used to monitor low-voltage power
supplies in µP and digital systems. They provide excel-
lent circuit reliability and low cost by eliminating exter-
nal components and adjustments when used with
+1.2V to +1.8V powered circuits.
These devices assert a reset signal whenever the V
CC
supply voltage declines below a preset threshold or
whenever manual reset (MR) is asserted. Reset remains
asserted for a fixed timeout delay after V
CC
has risen
above the reset threshold or when manual reset is
deasserted. Five different timeout periods are available:
70µs (voltage detector), 1.5ms, 30ms, 210ms, and 1.68s.
Reset thresholds suitable for operation with a variety of
supply voltages are available.
The MAX6832/MAX6835/MAX6838 have a push-pull
active-low reset output (RESET). The MAX6833/
MAX6836/MAX6839 have a push-pull active-high reset
output (RESET) and the MAX6834/MAX6837/MAX6840
have an open-drain active-low reset output (RESET). The
open-drain active-low reset output requires a pullup resis-
tor that can be connected to a voltage higher than V
CC
.
The MAX6835/MAX6836/MAX6837 feature a debounced
manual reset input (MR), while the MAX6838/MAX6839/
MAX6840 provide a RESET-IN input allowing the user to
externally adjust the reset threshold. The reset compara-
tor is designed to ignore fast transients on V
CC
.
Low supply current of 7.5µA makes the MAX6832–
MAX6840 ideal for use in portable equipment. These
devices are available in 3- and 4-pin SC70 packages.
Features
o
Factory-Set Reset Threshold Voltages for
Nominal Supplies from 1.2V to 1.8V
o
Low Power Consumption: 7.5µA (typ)
o
Space-Saving 3- and 4-Pin SC70 Packages
o
±2.5% Reset Threshold Accuracy Over
Temperature
o
Five Different Timeout Periods Available: 70µs
(voltage detector), 1.5ms, 30ms, 210ms, and 1.68s
o
Three Reset Output Configurations
Push-Pull
RESET
Push-Pull RESET
Open-Drain
RESET
o
Guaranteed Reset Valid to V
CC
=
0.55V—Active-Low
0.75V—Active-High
o
Adjustable Threshold Reset-In Option
o
Manual Reset Input Option
o
Immune to Short Negative V
CC
Transients
o
Pin Compatible with MAX803/MAX809/MAX810,
MAX6711/MAX6712/MAX6713, and
MAX6381–MAX6390 Series
MAX6832–MAX6840
Ordering Information
PART
MAX6832_XRD_-T
MAX6833_XRD_-T
MAX6834_XRD_-T
MAX6835_XSD_-T
MAX6836_XSD_-T
MAX6837_XSD_-T
MAX6838XSD_-T
MAX6839XSD_-T
MAX6840XSD_-T
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
3 SC70-3
3 SC70-3
3 SC70-3
4 SC70-4
4 SC70-4
4 SC70-4
4 SC70-4
4 SC70-4
4 SC70-4
Applications
Computers
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable/Battery-Powered Equipment
Pin Configurations appear at end of data sheet.
Typical Operating Circuit apears at end of data sheet.
Selector Guide appears at end of data sheet.
Insert the desired suffix letter from the Threshold Suffix Guide
(MAX6832–MAX6837) and the Active Timeout Period Guide
tables into the blanks to complete the part number. Sample
stock is generally available on standard versions only (see
Standard Versions table). Standard versions require a minimum
order increment of 2.5k units. Nonstandard versions must be
ordered in 10k unit increments. Contact factory for availability.
All parts are offered in tape-and-reel only.
________________________________________________________________
Maxim Integrated Products
1
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.
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
MAX6832–MAX6840
ABSOLUTE MAXIMUM RATINGS
Terminal Voltage (with respect to GND)
V
CC
........................................................................-0.3V to +6.0V
Open-Drain
RESET, MR
.......................................-0.3V to +6.0V
RESET-IN, Push-Pull
RESET
and RESET ..............................................-0.3V to (V
CC
+ 0.3V)
Input/Output Current (all pins) ............................................20mA
Continous Power Dissipation (T
A
= +70°C)
3-Pin SC70 (derate 2.9mW/°C above +70°C) ...............235mW
4-Pin SC70 (derate 3.1mW/°C above +70°C) ...............245mW
Operating Temperature Range ...........................-40°C to +85°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
(V
CC
= +0.55V to +3.6V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
T
A
= -40°C to +85°C
MAX6832/MAX6835/MAX6838
MAX6834/MAX6837/MAX6840
Supply Voltage Range
V
CC
T
A
= -40°C to +85°C
MAX6833/MAX6836/MAX6839
T
A
= 0°C to +85°C
MAX6833/MAX6836/MAX6839
V
CC
= 1.2V, no load, reset not asserted
Supply Current
I
CC
V
CC
= 1.8V, no load, reset not asserted
V
CC
= 3.6V, no load, reset not asserted
W
V
Reset Threshold
V
TH
I
H
G
F (Note 2)
RESET-IN Threshold
RESET-IN Leakage Current
Reset Threshold Hysteresis
V
CC
or RESET-IN to Reset Delay
V
RSTIN
I
RSTIN
V
HYS
V
CC
falling, step signal from
(V
TH
+ 100mV) to (V
TH
- 100mV)
D0
D1
Reset Active Timeout Period
t
RP
D2
D3
D4
1
20
140
1120
1.1V
≤
V
CC
≤
3.3V, 0°C to +85°C
1.1V
≤
V
CC
≤
3.3V, -40°C to +85°C
1.620
1.530
1.350
1.275
1.080
1.020
-2.5%
-3.0%
-25
0.75
60
0.07
1.5
30
210
1680
2
40
280
2240
ms
MIN
0.55
TYP
MAX
3.6
V
UNITS
0.85
0.75
7.5
9
16
1.665
1.575
1.388
1.313
1.110
1.050
444
444
3.6
3.6
13
16
25
1.710
1.620
1.425
1.350
1.140
1.080
+2.5%
+3.0%
+25
µA
V
mV
nA
%V
TH
µs
2
_______________________________________________________________________________________
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +0.55V to +3.6V, T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are at T
A
= +25°C.) (Note 1)
PARAMETER
Propagation Delay (D0 only)
Startup Time (D0 only)
MR
Input Voltage
MR
Minimum Input Pulse Width
MR
Glitch Rejection
MR
to Reset Delay
MR
Pullup Resistance To V
CC
Open-Drain
RESET
Output
Voltage
Open-Drain
RESET
Output
Leakage Current
V
CC
≥
0.55V, I
SINK
=15µA, reset asserted
V
OL
V
CC
≥
1.0V, I
SINK
= 80µA, reset asserted
V
CC
≥
1.5V, I
SINK
= 200µA, reset asserted
I
LKG
V
CC
> V
TH,
reset not asserted
V
CC
≥
0.55V, I
SINK
= 15µA, reset asserted
V
OL
Push-Pull
RESET
Output
Voltage
V
OH
V
CC
≥
1.0V, I
SINK
= 80µA, reset asserted
V
CC
≥
1.5V, I
SINK
= 200µA, reset asserted
V
CC
≥
1.1V, I
SOURCE
= 50µA, reset not
asserted
V
CC
≥
1.5V, I
SOURCE
= 150µA, reset asserted
V
CC
≥
0.75V, I
SOURCE
= 10µA, reset asserted
(Note 2)
Push-Pull RESET Output
Voltage
V
OH
V
CC
≥
0.85V, I
SOURCE
= 10µA, reset asserted
V
CC
≥
1.0V, I
SOURCE
= 50µA, reset asserted
V
CC
≥
1.5V, I
SOURCE
= 150µA, reset asserted
V
OL
V
CC
≥
1.1V, I
SINK
= 80µA, reset not asserted
V
CC
≥
1.5V, I
SINK
= 200µA, reset not asserted
0.8 x V
CC
0.8 x V
CC
0.8 x V
CC
0.8 x V
CC
0.8 x V
CC
0.8 x V
CC
0.2 x V
CC
0.2 x V
CC
V
V
IL
V
IH
MR
driven from V
CC
to 0
MR
driven from V
CC
to 0
MR
driven from V
CC
to 0
14
0.7 x V
CC
2
100
500
20
26
0.15
0.15
0.2
1.0
0.2 x V
CC
0.2 x V
CC
0.2 x V
CC
µA
V
SYMBOL
t
P
CONDITIONS
V
CC
rising, step signal
from (V
TH
- 100mV) to (V
TH
+ 100mV)
V
CC
rising from 0 to 1.1V (t
R
< 1µs)
MIN
TYP
70
150
0.3 x V
CC
MAX
UNITS
µs
µs
V
µs
ns
ns
kΩ
MAX6832–MAX6840
Note 1:
100% production tested at +25°C. Over temperature limits are guaranteed by design.
Note 2:
Temperature range is from 0°C to +85°C.
_______________________________________________________________________________________
3
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
MAX6832–MAX6840
Typical Operating Characteristics
(V
CC
= full range and T
A
= -40°C to +85°C, unless otherwise noted. Typical values are at T
A
= +25°C).
POWER-DOWN RESET DELAY
vs. TEMPERATURE
MAX6832-40 toc01
SUPPLY CURRENT vs. TEMPERATURE
16
V
CC
= 3.6V
14
V
CC
= 3.0V
SUPPLY CURRENT (µA)
12
10
8
6
4
2
0
-40
-20
40
TEMPERATURE (°C)
0
20
60
80
V
CC
= 0.55V
0
-40
V
CC
= 2.5V
V
CC
= 1.8V
V
CC
= 1.5V
300
POWER-DOWN RESET DELAY (µs)
250
200
V
OD
= OVERDRIVE (mV)
V
OD
= 10mV
150
V
OD
= 20mV
100
50
V
OD
= 100mV
V
OD
= 200mV
-20
0
20
40
60
80
TEMPERATURE (°C)
NORMALIZED POWER-UP RESET
TIMEOUT vs. TEMPERATURE
MAX6832-40 toc03
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
V
TH
= 1.665V
1.002
1.001
1.000
0.999
0.998
0.997
0.996
0.995
MAX6832-40 toc04
1.06
NORMALIZED RESET TIMEOUT PERIOD
1.04
1.02
1.00
D2 OPTION
0.98
0.96
0.94
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
D1 OPTION
1.003
NORMALIZED RESET THRESHOLD
0.994
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
4
_______________________________________________________________________________________
MAX6832-40 toc02
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
Pin Description—MAX6832–MAX6837
PIN
MAX6833
SC70-3
1
MAX6832/
MAX6834
SC70-3
1
MAX6836
SC70-4
1
MAX6835/
MAX6837
SC70-4
1
NAME
FUNCTION
MAX6832–MAX6840
GND
Ground
Reset Output, Open-Drain or Push-Pull, Active-Low.
RESET
changes from HIGH to LOW when V
CC
drops below the
selected reset threshold or
MR
is pulled low.
RESET
remains
LOW for the reset timeout period after V
CC
exceeds the device
reset threshold and
MR
is released high.
Reset Output, Push-Pull, Active-High. RESET changes from
LOW to HIGH when the V
CC
input drops below the selected
reset threshold or
MR
is pulled low. RESET remains HIGH for
the reset timeout period after V
CC
exceeds the device reset
threshold and
MR
is released high.
Active-Low Manual Reset Input. Internal 20kΩ pullup to V
CC
.
Pull LOW to force a reset. Reset remains active as long as
MR
is
LOW and for the reset timeout period after
MR
goes HIGH.
Leave unconnected or connect to V
CC
if unused.
Supply Voltage and Monitored Supply
—
2
—
2
RESET
2
—
2
—
RESET
—
—
3
3
MR
3
3
4
4
V
CC
Pin Description—MAX6838/MAX6839/MAX6840
PIN
MAX6839
SC70-4
MAX6838/
MAX6840
SC70-4
NAME
FUNCTION
1
1
RESET-IN
Adjustable Reset Threshold Input. High-impedance input for reset comparator. Connect
this pin to an external resistive-divider network to set the reset threshold voltage; the
typical threshold is 444mV. Reset is asserted when RESET-IN is below the threshold (V
CC
is not monitored).
Supply Voltage (1.1V to 3.3V)
Ground
Reset Output, Push-Pull, Active-High. RESET changes from LOW to HIGH when the
RESET-IN input drops below the typical reset threshold (444mV). RESET remains HIGH for
the reset timeout period after RESET-IN exceeds the reset threshold.
Reset Output, Open-Drain or Push-Pull, Active-Low.
RESET
changes from HIGH to LOW
when RESET-IN drops below the typical reset threshold (444mV).
RESET
remains LOW for
the reset timeout period after RESET-IN exceeds the reset threshold.
2
3
4
2
3
—
V
CC
GND
RESET
—
4
RESET
_______________________________________________________________________________________
5
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