19-1615; Rev 0; 1/00
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
General Description
The MAX6361/MAX6363/MAX6364 supervisory circuits
reduce the complexity and number of components
required for power-supply monitoring and battery control
functions in microprocessor (µP) systems. The circuits sig-
nificantly improve system reliability and accuracy com-
pared to that obtainable with separate ICs or discrete
components. Their functions include µP reset, backup-
battery switchover, and power failure warning.
The MAX6361/MAX6363/MAX6364 operate from supply
voltages as low as +1.2V. The factory preset reset
threshold voltage ranges from 2.32V to 4.63V (see
Ordering Information).
These devices provide a manual
reset input (MAX6361), battery-on output (MAX6363),
and an auxiliary adjustable reset input (MAX6364). In
addition, each part type is offered in three reset output
versions: an active-low push-pull reset, an active-low
open-drain reset, and an active-high push-pull reset
(see
Selector Guide
at end of data sheet).
Features
o
Low +1.2V Operating Supply Voltage
(V
CC
or V
BATT
)
o
Precision Monitoring of +5.0V, +3.3V, +3.0V, and
+2.5V Power-Supply Voltages
o
Debounced Manual Reset Input (MAX6361)
o
Battery-On Output Indicator (MAX6363)
o
Auxiliary User-Adjustable RESET IN (MAX6364)
o
Three Available Output Structures
Push-Pull
RESET,
Open-Drain
RESET,
Push-Pull RESET
o
RESET/RESET Valid Down to 1.2V Guaranteed
(V
CC
or V
BATT
)
o
Power-Supply Transient Immunity
o
150ms (min) Reset Timeout Period
o
Small 6-Pin SOT23 Package
MAX6361/MAX6363/MAX6364
Applications
Computers
Controllers
Intelligent Instruments
Critical µP/µC
Power Monitoring
Fax Machines
Industrial Control
POS Equipment
Portable/Battery-Powered
Equipment
PART
MAX6361LUT_
_-T
MAX6361PUT_ _-T
MAX6361HUT_ _-T
MAX6363LUT_
_-T
MAX6363PUT_ _-T
MAX6363HUT_ _-T
MAX6364LUT_
_-T
MAX6364PUT_ _-T
MAX6364HUT_ _-T
Ordering Information
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
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
6 SOT23-6
Pin Configurations
TOP VIEW
RESET, RESET
1
6
BATT
GND
2
MAX6361
5
OUT
Note:
These parts offer a choice of reset threshold voltages.
From Table 1, select the suffix corresponding to the desired
threshold voltage and insert it into the part number to complete
it. When ordering from the factory, there is a 2500-piece mini-
mum on the SOT package (tape-and-reel only).
MR
3
4
V
CC
SOT23-6
Pin Configurations continued at end of data sheet.
Selector Guide appears at end of data sheet.
Typical Operating Circuit appears at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
For free samples and the latest literature, visit www.maxim-ic.com or phone 1-800-998-8800.
For small orders, phone 1-800-835-8769.
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
MAX6361/MAX6363/MAX6364
ABSOLUTE MAXIMUM RATINGS
Terminal Voltages (with respect to GND)
V
CC
, BATT, OUT...................................................-0.3V to +6V
RESET
(open drain)..............................................-0.3V to +6V
BATT ON,
MR,
RESET IN .....................-0.3V to (V
OUT
+ 0.3V)
RESET,
RESET......................................-0.3V
to (V
OUT
+ 0.3V)
Input Current
V
CC
Peak ............................................................................1A
V
CC
Continuous ............................................................250mA
BATT Peak ....................................................................250mA
BATT Continuous ............................................................40mA
GND ................................................................................75mA
Output Current
OUT................................Short-Circuit Protection for up to 10s
RESET,
RESET,
BATT ON ..............................................20mA
Continuous Power Dissipation (T
A
= +70°C)
6-Pin SOT23 (derate 8.70mW/°C above +70°C) .........696mW
Operating Temperature Range
MAX636_ .........................................................-40°C to +85°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
= +2.4V to +5.5V, V
BATT
= 3V, T
A
= -40°C to +85°C, reset not asserted, typical values are at T
A
= +25°C, unless otherwise
noted.) (Note 1)
PARAMETER
Operating Voltage Range,
V
CC
or V
BATT
Supply Current
(excluding I
OUT
)
I
SUPPLY
in Battery-Backup
Mode (excluding I
OUT
)
BATT Standby Current
SYMBOL
V
CC
,
V
BATT
I
CC
CONDITIONS
No load (Note 2)
V
CC
= 2.8V
No load, V
CC
> V
TH
V
BATT
= 2.8V,
V
CC
= 0
5.5V > V
CC
>
(V
BATT
+ 0.2V)
V
CC
= 3.6V
V
CC
= 5.5V
I
SUPPLY
I
BATT
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= +25°C
T
A
= -40°C to +85°C
-0.1
-1.0
MIN
0
10
11
15
TYP
MAX
5.5
30
35
50
1
3
0.02
0.02
1.25
2.25
4.6
V
BATT
- 0.2
V
BATT
- 0.15
V
BATT
- 0.15
20
-20
4.50
4.25
3.00
2.85
2.55
2.25
150
4.63
4.38
3.08
2.93
2.63
2.32
35
280
4.75
4.50
3.15
3.00
2.70
2.38
µs
ms
V
mV
V
Ω
µA
µA
µA
UNITS
V
V
CC
= 4.75V, I
OUT
≤
150mA
V
CC
to OUT On-Resistance
R
ON
V
CC
= 3.15V, I
OUT
≤
65mA
V
CC
= 2.38V, I
OUT
≤
25mA
V
BATT
= 4.5V, I
OUT
≤
20mA
V
OUT
in Battery-Backup Mode
Battery-Switchover Threshold
(V
CC
- V
BATT
)
V
BATT
= 3.0V, I
OUT
≤
10mA
V
BATT
= 2.25V, I
OUT
≤
5mA
V
CC
< V
TH
MAX636_UT46
MAX636_UT44
Reset Threshold
V
TH
MAX636_UT31
MAX636_UT29
MAX636_UT26
MAX636_UT23
V
CC
Falling Reset Delay
Reset-Active Timeout Period
t
RP
V
CC
falling at 10V/ms
Power-up
Power-down
2
_______________________________________________________________________________________
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
ELECTRICAL CHARACTERISTICS (continued)
(V
CC
= +2.4V to +5.5V, V
BATT
= 3V, T
A
= -40°C to +85°C, reset not asserted, typical values are at T
A
= +25°C, unless otherwise
noted.) (Note 1)
PARAMETER
SYMBOL
Reset asserted,
V
BATT
= 0
Reset not asserted
(MAX636_L only)
CONDITIONS
I
SINK
= 1.6mA,
V
CC
≥
2.1V
I
SINK
= 100µA,
V
CC
≥
1.2V
I
SOURCE
= 500µA,
V
CC
≥
V
TH(MAX)
I
SOURCE
= 200µA,
V
CC
≥
1.2V
I
SOURCE
= 1mA,
V
CC
≥
1.8V
I
SINK
= 1.6mA,
V
CC
≥
V
TH(MAX)
0.8
·
V
CC
0.7
·
V
CC
0.8
·
V
CC
0.3
1
0.3
·
V
CC
0.7
·
V
CC
20
1
V
CC
= 3.3V
V
CC
= 3.3V
V
OL
I
SINK
= 3.2mA, V
BATT
= 2.1V
Sink current, V
CC
= 5V
Source current, V
BATT
≥
2V
10
1.185
Overdrive voltage = 50mV, RESET IN falling
60
30
1.235
±0.01
1.5
100
1.285
±25
100
120
0.4
µA
V
V
kΩ
µs
ns
ns
V
mA
µA
V
nA
µs
V
MIN
TYP
MAX
0.3
0.4
V
UNITS
MAX6361/MAX6363/MAX6364
V
OL
RESET
Output Voltage
V
OH
V
OH
RESET Output Voltage
V
OL
RESET
Output Leakage Current
MANUAL RESET
(MAX6361 only)
MR
Input Voltage
Pull-Up Resistance
Minimum Pulse Width
Glitch Immunity
MR
to Reset Delay
BATT ON
(MAX6363 only)
Output Voltage
Output Short-Circuit Current
RESET IN
(MAX6364 only)
Input Threshold
RESET IN Leakage Current
RESET IN to Reset Delay
V
IL
V
IH
I
LK
Reset asserted,
V
BATT
= 0
Reset not asserted
MAX636_P only
Note 1:
Overtemperature limits are guaranteed by design and not production tested.
Note 2:
V
BATT
can be 0 anytime or V
CC
can go down to 0 if V
BATT
is active (except at startup).
_______________________________________________________________________________________
3
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
MAX6361/MAX6363/MAX6364
Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
(NO LOAD)
MAX6361 toc01
BATTERY SUPPLY CURRENT
(BACKUP MODE) vs. TEMPERATURE
MAX6361 toc02
BATTERY TO OUT ON-RESISTANCE
vs. TEMPERATURE
MAX6361 toc03
20
1.2
BATTERY SUPPLY CURRENT (µA)
1.0
0.8
0.6
V
BATT
= 2.0V
0.4
0.2
0
V
CC
= 0
V
BATT
= 2.8V
7
BATT TO OUT ON-RESISTANCE (Ω)
6
5
V
BATT
= 2.0V
4
3
2
V
BATT
= 5.0V
1
0
I
OUT
= 25mA
V
CC
= 0
-40
-20
0
20
40
60
80
V
BATT
= 2.8V
SUPPLY CURRENT (µA)
18
16
14
V
BATT
= 0
V
CC
= 5.0V
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
12
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
V
CC
TO OUT ON-RESISTANCE
vs. TEMPERATURE
MAX6361 toc04
RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6361 toc05
V
CC
TO RESET PROPAGATION DELAY
vs. TEMPERATURE
135
120
PROGAGATION DELAY (µs)
105
90
75
60
45
30
15
10V/ms
-40
-20
0
20
40
60
80
1V/ms
V
CC
FALLING
0.25V/ms
MAX6361 toc06
1.2
V
OUT
TO OUT ON-RESISTANCE (Ω)
V
CC
= 2.3V
I
OUT
= 25mA
0.9
210
RESET TIMEOUT PERIOD (ms)
205
0.6
V
CC
= 4.5V
I
OUT
= 150mA
0.3
V
CC
= 3.0V
I
OUT
= 65mA
200
195
0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
190
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
0
TEMPERATURE (°C)
RESET THRESHOLD
vs. TEMPERATURE
MAX6361 toc07
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX6361 toc08
BATTERY SUPPLY CURRENT
vs. SUPPLY VOLTAGE
9
BATTERY SUPPLY CURRENT (µA)
8
7
6
5
4
3
2
1
0
V
BATT
= 2.3V
0
1
2
V
CC
(V)
3
4
V
BATT
= 2.5V
V
BATT
= 2.8V
V
TH
= 2.93V
MAX6361 toc09
5.0
MAX636_46
4.5
THRESHOLD (V)
4.0
3.5
3.0
MAX636_26
2.5
2.0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
400
MAXIMUM TRANSIENT DURATION (µs)
350
300
250
MAX636_46
200
150
100
50
0
1
10
100
1k
MAX636_26
RESET OCCURS
ABOVE CURVE
10
10k
RESET THRESHOLD OVERDRIVE V
TH
- V
CC
(mV)
4
_______________________________________________________________________________________
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
Typical Operating Characteristics (continued)
(T
A
= +25°C, unless otherwise noted.)
MAX6364
RESET IN THRESHOLD
vs. TEMPERATURE
MAX6361 toc10
MAX6361/MAX6363/MAX6364
MAX6364
RESET IN TO RESET PROPAGATION DELAY
vs. TEMPERATURE
2.8
PROPAGATION DELAY (µs)
2.5
2.2
1.9
1.6
1.3
V
OD
= 50mV
MAX6361 toc11
1.236
THRESHOLD (V)
1.235
1.234
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
1.0
-40
-20
0
20
40
60
80
TEMPERATURE (°C)
Pin Description
PIN
NAME
RESET
1
RESET
2
GND
MR
3
BATT ON
RESET IN
4
5
V
CC
OUT
FUNCTION
Active-High Reset Output (for H versions). RESET remains high while V
CC
is below the reset threshold
and for at least 150ms (t
RP
) after V
CC
rises above the reset threshold. RESET also asserts when
MR
or
RESET IN is low.
Active-Low Reset Output (for L and P versions).
RESET
remains low while V
CC
is below the reset thresh-
old and for at least 150ms (t
RP
) after V
CC
rises above the reset threshold.
RESET
also asserts when
MR
or RESET IN is low.
Ground
MAX6361
Manual-Reset Input. Maintaining logic low on
MR
asserts a reset. Reset output remains assert-
ed for at least 150ms (t
RP
) after
MR
transitions from low to high. Leave unconnected or connected to V
CC
if not used.
MAX6363
Battery-On Output. BATT ON goes high in battery backup mode.
MAX6364
Reset Input. When RESET IN falls below 1.235V, reset is asserted. Reset output remains
asserted as long as RESET IN is low and for at least 150ms (t
RP
) after RESET IN goes high.
Supply Voltage. Reset is asserted when V
CC
drops below the reset threshold voltage (V
TH
). Reset
remains asserted until V
CC
rises above V
TH
and for at least 150ms after V
CC
rises above V
TH
.
Output. OUT sources from V
CC
when it is above the reset threshold (V
TH
), and from the greater of V
CC
or
BATT when V
CC
is below V
TH
.
Backup-Battery Input. When V
CC
falls below the reset threshold, BATT switches to OUT if V
BATT
is 20mV
greater than V
CC
. When V
CC
rises 20mV above V
BATT
, V
CC
switches to OUT. The 40mV hysteresis
prevents repeated switching if V
CC
falls slowly.
6
BATT
Detailed Description
The
Typical Operating Circuit
shows a typical connec-
tion for the MAX6361/MAX6363/MAX6364 family. OUT
powers the static random-access memory (SRAM). OUT
is internally connected to V
CC
if V
CC
is greater than the
reset threshold, or to the greater of V
CC
or V
BATT
when
V
CC
is less than the reset threshold. OUT can supply up
to 150mA from V
CC
. When V
CC
is higher than V
BATT
, the
BATT ON (MAX6363) output is low. When V
CC
is lower
than V
BATT
, an internal MOSFET connects the backup
battery to OUT. The on-resistance of the MOSFET is a
function of backup-battery voltage and is shown in the
Battery to Out On-Resistance vs. Temperature graph in
the
Typical Operating Characteristics
section.
5
_______________________________________________________________________________________
