19-1615; Rev 0; 1/00
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
Features
♦ Low +1.2V Operating Supply Voltage
(VCC or VBATT)
♦ Precision Monitoring of +5.0V, +3.3V, +3.0V, and
+2.5V Power-Supply Voltages
♦ Debounced Manual Reset Input (MAX6361)
♦ Battery-On Output Indicator (MAX6363)
♦ Auxiliary User-Adjustable RESET IN (MAX6364)
♦ Three Available Output Structures
Push-Pull RESET, Open-Drain RESET,
Push-Pull RESET
♦ RESET/RESET Valid Down to 1.2V Guaranteed
(VCC or VBATT)
♦ Power-Supply Transient Immunity
♦ 150ms (min) Reset Timeout Period
♦ Small 6-Pin SOT23 Package
Ordering Information
Applications
Computers
Fax Machines
PART
TEMP. RANGE
PIN-PACKAGE
-40°C to +85°C
6 SOT23-6
Controllers
Industrial Control
MAX6361LUT_ _-T
Intelligent Instruments
POS Equipment
MAX6361PUT_ _-T
-40°C to +85°C
6 SOT23-6
Critical µP/µC
Power Monitoring
Portable/Battery-Powered
Equipment
MAX6361HUT_ _-T
-40°C to +85°C
6 SOT23-6
MAX6363LUT_ _-T
-40°C to +85°C
6 SOT23-6
MAX6363PUT_ _-T
-40°C to +85°C
6 SOT23-6
MAX6363HUT_ _-T
-40°C to +85°C
6 SOT23-6
MAX6364LUT_ _-T
-40°C to +85°C
6 SOT23-6
MAX6364PUT_ _-T
-40°C to +85°C
6 SOT23-6
MAX6364HUT_ _-T
-40°C to +85°C
6 SOT23-6
Pin Configurations
TOP VIEW
RESET, RESET 1
GND 2
MAX6361
MR 3
6
BATT
5
OUT
4
VCC
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 minimum on the SOT package (tape-and-reel only).
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.
MAX6361/MAX6363/MAX6364
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 significantly improve system reliability and accuracy compared to that obtainable with separate ICs or discrete
components. Their functions include µP reset, backupbattery 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).
MAX6361/MAX6363/MAX6364
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
ABSOLUTE MAXIMUM RATINGS
Terminal Voltages (with respect to GND)
VCC, BATT, OUT...................................................-0.3V to +6V
RESET (open drain)..............................................-0.3V to +6V
BATT ON, MR, RESET IN .....................-0.3V to (VOUT + 0.3V)
RESET, RESET......................................-0.3V to (VOUT + 0.3V)
Input Current
VCC Peak ............................................................................1A
VCC 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 (TA = +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
(VCC = +2.4V to +5.5V, VBATT = 3V, TA = -40°C to +85°C, reset not asserted, typical values are at TA = +25°C, unless otherwise
noted.) (Note 1)
PARAMETER
Operating Voltage Range,
VCC or VBATT
Supply Current
(excluding IOUT)
SYMBOL
VCC,
VBATT
ICC
CONDITIONS
TYP
0
No load (Note 2)
No load, VCC > VTH
MIN
MAX
UNITS
5.5
V
VCC = 2.8V
10
30
VCC = 3.6V
11
35
VCC = 5.5V
15
50
1
TA = -40°C to +85°C
3
ISUPPLY
VBATT = 2.8V,
VCC = 0
TA = +25°C
BATT Standby Current
IBATT
5.5V > VCC >
(VBATT + 0.2V)
TA = +25°C
-0.1
0.02
TA = -40°C to +85°C
-1.0
0.02
VCC = 4.75V, IOUT ≤ 150mA
1.25
VCC to OUT On-Resistance
RON
VCC = 3.15V, IOUT ≤ 65mA
2.25
ISUPPLY in Battery-Backup
Mode (excluding IOUT)
VCC = 2.38V, IOUT ≤ 25mA
VOUT in Battery-Backup Mode
Battery-Switchover Threshold
(VCC - VBATT)
Reset Threshold
VTH
VCC Falling Reset Delay
Reset-Active Timeout Period
2
VBATT - 0.2
VBATT = 3.0V, IOUT ≤ 10mA
VBATT - 0.15
VBATT = 2.25V, IOUT ≤ 5mA
VBATT - 0.15
µA
Ω
V
20
Power-up
Power-down
mV
-20
MAX636_UT46
4.50
4.63
4.75
MAX636_UT44
4.25
4.38
4.50
MAX636_UT31
3.00
3.08
3.15
MAX636_UT29
2.85
2.93
3.00
MAX636_UT26
2.55
2.63
2.70
MAX636_UT23
2.25
2.32
2.38
35
VCC falling at 10V/ms
tRP
µA
4.6
VBATT = 4.5V, IOUT ≤ 20mA
VCC < VTH
µA
150
_______________________________________________________________________________________
V
µs
280
ms
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
(VCC = +2.4V to +5.5V, VBATT = 3V, TA = -40°C to +85°C, reset not asserted, typical values are at TA = +25°C, unless otherwise
noted.) (Note 1)
PARAMETER
SYMBOL
VOL
RESET Output Voltage
Reset asserted,
VBATT = 0
VOH
Reset not asserted
(MAX636_L only)
VOH
Reset asserted,
VBATT = 0
RESET Output Voltage
RESET Output Leakage Current
CONDITIONS
VOL
Reset not asserted
ILK
MAX636_P only
MIN
TYP
MAX
ISINK = 1.6mA,
VCC ≥ 2.1V
0.3
ISINK = 100µA,
VCC ≥ 1.2V
0.4
ISOURCE = 500µA,
VCC ≥ VTH(MAX)
0.8 · VCC
ISOURCE = 200µA,
VCC ≥ 1.2V
0.7 · VCC
ISOURCE = 1mA,
VCC ≥ 1.8V
0.8 · VCC
UNITS
V
V
ISINK = 1.6mA,
VCC ≥ VTH(MAX)
0.3
1
µA
MANUAL RESET (MAX6361 only)
0.3 · VCC
VIL
MR Input Voltage
0.7 · VCC
VIH
20
Pull-Up Resistance
kΩ
1
Minimum Pulse Width
V
V
µs
Glitch Immunity
VCC = 3.3V
100
ns
MR to Reset Delay
VCC = 3.3V
120
ns
BATT ON (MAX6363 only)
Output Voltage
VOL
Output Short-Circuit Current
0.4
ISINK = 3.2mA, VBATT = 2.1V
60
Sink current, VCC = 5V
Source current, VBATT ≥ 2V
10
V
mA
30
100
1.235
1.285
V
±0.01
±25
nA
µA
RESET IN (MAX6364 only)
1.185
Input Threshold
RESET IN Leakage Current
RESET IN to Reset Delay
Overdrive voltage = 50mV, RESET IN falling
1.5
µs
Note 1: Overtemperature limits are guaranteed by design and not production tested.
Note 2: VBATT can be 0 anytime or VCC can go down to 0 if VBATT is active (except at startup).
_______________________________________________________________________________________
3
MAX6361/MAX6363/MAX6364
ELECTRICAL CHARACTERISTICS (continued)
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
SUPPLY CURRENT vs. TEMPERATURE
(NO LOAD)
14
VBATT = 0
VCC = 5.0V
-20
VBATT = 2.0V
0.4
0.2
20
40
60
80
MAX6361 toc03
MAX6361 toc02
0.6
0
0
6
5
VBATT = 2.0V
4
VBATT = 2.8V
3
2
VBATT = 5.0V
1
IOUT = 25mA
VCC = 0
0
-40
-20
0
20
40
60
80
-40
-20
60
80
RESET TIMEOUT PERIOD
vs. TEMPERATURE
VCC TO RESET PROPAGATION DELAY
vs. TEMPERATURE
MAX6361 toc04
VCC = 3.0V
IOUT = 65mA
0.6
VCC = 4.5V
IOUT = 150mA
0.3
210
135
205
200
195
VCC FALLING
120
0.25V/ms
105
90
75
60
45
1V/ms
30
10V/ms
15
190
0
20
40
60
80
0
-40
-20
0
TEMPERATURE (°C)
RESET THRESHOLD
vs. TEMPERATURE
4.5
4.0
3.5
3.0
MAX636_26
2.5
2.0
40
60
80
-40
0
20
40
TEMPERATURE (°C)
60
80
350
300
250
MAX636_46
200
RESET OCCURS
ABOVE CURVE
150
100
40
60
VTH = 2.93V
9
8
VBATT = 2.8V
7
6
5
VBATT = 2.5V
4
3
2
VBATT = 2.3V
0
10
100
1k
10k
RESET THRESHOLD OVERDRIVE VTH - VCC (mV)
80
10
1
MAX636_26
1
20
BATTERY SUPPLY CURRENT
vs. SUPPLY VOLTAGE
0
-20
0
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
400
50
-20
TEMPERATURE (°C)
MAX6361 toc08
MAX636_46
MAXIMUM TRANSIENT DURATION (µs)
MAX6361 toc07
5.0
20
TEMPERATURE (°C)
BATTERY SUPPLY CURRENT (µA)
-20
MAX6361 toc06
VCC TO OUT ON-RESISTANCE
vs. TEMPERATURE
0
4
40
TEMPERATURE (°C)
0.9
-40
20
TEMPERATURE (°C)
VCC = 2.3V
IOUT = 25mA
-40
0
TEMPERATURE (°C)
1.2
VOUT TO OUT ON-RESISTANCE (Ω)
0.8
PROGAGATION DELAY (µs)
-40
VBATT = 2.8V
MAX6361 toc05
12
1.0
7
MAX6361 toc09
16
VCC = 0
BATTERY TO OUT ON-RESISTANCE
vs. TEMPERATURE
BATT TO OUT ON-RESISTANCE (Ω)
18
1.2
BATTERY SUPPLY CURRENT (µA)
MAX6361 toc01
BATTERY SUPPLY CURRENT
(BACKUP MODE) vs. TEMPERATURE
RESET TIMEOUT PERIOD (ms)
SUPPLY CURRENT (µA)
20
THRESHOLD (V)
MAX6361/MAX6363/MAX6364
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
0
1
2
VCC (V)
_______________________________________________________________________________________
3
4
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
MAX6361 toc10
1.235
2.8
PROPAGATION DELAY (µs)
THRESHOLD (V)
1.236
MAX6361 toc11
MAX6364
RESET IN TO RESET PROPAGATION DELAY
vs. TEMPERATURE
MAX6364
RESET IN THRESHOLD
vs. TEMPERATURE
VOD = 50mV
2.5
2.2
1.9
1.6
1.3
1.0
1.234
-40
-20
0
20
40
60
-40
80
-20
0
20
40
60
80
TEMPERATURE (°C)
TEMPERATURE (°C)
Pin Description
PIN
NAME
FUNCTION
RESET
Active-High Reset Output (for H versions). RESET remains high while VCC is below the reset threshold
and for at least 150ms (tRP) after VCC rises above the reset threshold. RESET also asserts when MR or
RESET IN is low.
RESET
Active-Low Reset Output (for L and P versions). RESET remains low while VCC is below the reset threshold and for at least 150ms (tRP) after VCC rises above the reset threshold. RESET also asserts when MR
or RESET IN is low.
1
2
GND
Ground
MAX6361 Manual-Reset Input. Maintaining logic low on MR asserts a reset. Reset output remains asserted for at least 150ms (tRP) after MR transitions from low to high. Leave unconnected or connected to VCC
if not used.
MR
3
BATT ON
MAX6363 Battery-On Output. BATT ON goes high in battery backup mode.
RESET IN
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 (tRP) after RESET IN goes high.
4
VCC
Supply Voltage. Reset is asserted when VCC drops below the reset threshold voltage (VTH). Reset
remains asserted until VCC rises above VTH and for at least 150ms after VCC rises above VTH.
5
OUT
Output. OUT sources from VCC when it is above the reset threshold (VTH), and from the greater of VCC or
BATT when VCC is below VTH.
6
BATT
Backup-Battery Input. When VCC falls below the reset threshold, BATT switches to OUT if VBATT is 20mV
greater than VCC. When VCC rises 20mV above VBATT, VCC switches to OUT. The 40mV hysteresis
prevents repeated switching if VCC falls slowly.
Detailed Description
The Typical Operating Circuit shows a typical connection for the MAX6361/MAX6363/MAX6364 family. OUT
powers the static random-access memory (SRAM). OUT
is internally connected to VCC if VCC is greater than the
reset threshold, or to the greater of VCC or VBATT when
VCC is less than the reset threshold. OUT can supply up
to 150mA from VCC. When VCC is higher than VBATT, the
BATT ON (MAX6363) output is low. When VCC is lower
than VBATT, 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
MAX6361/MAX6363/MAX6364
Typical Operating Characteristics (continued)
(TA = +25°C, unless otherwise noted.)
MAX6361/MAX6363/MAX6364
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
Backup-Battery Switchover
In a brownout or power failure, it may be necessary to
preserve the contents of the RAM. With a backup battery installed at BATT, the MAX6361/MAX6363/
MAX6364 automatically switch the RAM to backup
power when VCC falls. The MAX6363 has a BATT ON
output that goes high when in battery-backup mode.
These devices require two conditions before switching
to battery-backup mode:
1) VCC must be below the reset threshold.
2) VCC must be below VBATT. Table 2 lists the status
of the inputs and outputs in battery-backup mode.
The device will not power up if the only voltage
source is on BATT. OUT will only power up from
VCC at startup.
Manual Reset Input (MAX6361 only)
Many µP-based products require manual reset capability, allowing the operator, a test technician, or external
logic circuitry to initiate a reset. For the MAX6361, a logic
low on MR asserts reset. Reset remains asserted while
MR is low, and for a minimum of 150ms (tRP) after it
returns high. MR has an internal 20kΩ pull-up resistor.
This input can be driven with TTL/CMOS logic levels or
with open-drain/collector outputs. Connect a normally
open momentary switch from MR to GND to create a
manual reset function; external debounce circuitry is not
required. If MR is driven from long cables or the device
is used in a noisy environment, connect a 0.1µF capacitor from MR to GND to provide additional noise immunity.
Reset In (MAX6364 only)
RESET IN is compared to an internal 1.235V reference.
If the voltage at RESET IN is less than 1.235V, reset is
asserted. The RESET IN comparator may be used as
an undervoltage detector to signal a failing power supply. It can also be used as a secondary power-supply
reset monitor.
Applications Information
Operation Without a Backup
Power Source
The MAX6361/MAX6363/MAX6364 were designed for
battery-backed applications. If a backup battery is not
used, connect VCC to OUT and connect BATT to GND.
Replacing the Backup Battery
If BATT is decoupled with a 0.1µF capacitor to ground,
the backup power source can be removed while VCC
remains valid without danger of triggering a reset pulse.
The device does not enter battery-backup mode when
VCC stays above the reset threshold voltage.
Negative-Going VCC Transients
These supervisors are relatively immune to short-duration, negative-going VCC transients. Resetting the µP
when VCC experiences only small glitches is usually not
desirable.
The Typical Operating Characteristics section shows a
graph of Maximum Transient Duration vs. Reset
Threshold Overdrive for which reset is not asserted.
The graph was produced using negative-going VCC
pulses, starting at V CC and ending below the reset
threshold by the magnitude indicated (reset threshold
overdrive). The graph shows the maximum pulse width
Table 1. Reset Threshold Ranges
SUFFIX
RESET THRESHOLD RANGES (V)
MIN
TYP
MAX
46
4.50
4.63
4.75
44
4.25
4.38
4.50
31
3.00
3.08
3.15
29
2.85
2.93
3.00
26
2.55
2.63
2.70
23
2.25
2.32
2.38
Reset Output
A µP’s reset input starts the µP in a known state. The
MAX6361/MAX6363/MAX6364 µP supervisory circuits
assert a reset to prevent code-execution errors during
power-up, power-down, and brownout conditions.
RESET is guaranteed to be a logic low or high depending on the device chosen (see Ordering Information).
RESET or RESET asserts when VCC is below the reset
threshold and for at least 150ms (tRP) after VCC rises
above the reset threshold. RESET or RESET also
asserts when MR is low (MAX6361) and when RESET
IN is less than 1.235V (MAX6364).
Table 2. Input and Output Status in
Battery-Backup Mode
PIN
Disconnected from OUT
OUT
Connected to BATT
BATT
Connected to OUT. Current drawn from
the battery is less than 1µA (at VBATT =
2.8V, excluding IOUT) when VCC = 0.
RESET/RESET
Asserted
BATT ON
High state
MR, RESET IN
6
STATUS
VCC
Inputs ignored
_______________________________________________________________________________________
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
PART
MANUAL RESET INPUT,
MR
MAX6361LUT_ _
✓
MAX6361PUT_ _
✓
MAX6361HUT_ _
✓
BATT
ON
RESET
IN
RESET
PUSH-PULL
RESET
OPEN-DRAIN
RESET
PUSH-PULL
✓
✓
✓
MAX6363LUT_ _
✓
MAX6363PUT_ _
✓
MAX6363HUT_ _
✓
✓
✓
✓
MAX6364LUT_ _
✓
MAX6364PUT_ _
✓
MAX6364HUT_ _
✓
✓
✓
✓
Device Marking Codes
PART
TOP MARK
PART
TOP MARK
PART
TOP MARK
MAX6361LUT23
AAEI
MAX6361LUT26
AAEH
MAX6363LUT23
AAFS
MAX6364LUT23
AAGK
MAX6363LUT26
AAFR
MAX6364LUT26
MAX6361LUT29*
AAGJ
AAEG
MAX6363LUT29*
AAFQ
MAX6364LUT29*
MAX6361LUT31
AAGI
AAEF
MAX6363LUT31
AAFP
MAX6364LUT31
AAGH
AAGG
MAX6361LUT44
AAEE
MAX6363LUT44
AAFO
MAX6364LUT44
MAX6361LUT46*
AAED
MAX6363LUT46*
AAFN
MAX6364LUT46*
AAGF
MAX6361PUT23
AAEO
MAX6363PUT23
AAFY
MAX6364PUT23
AAGQ
MAX6361PUT26
AAEN
MAX6363PUT26
AAFX
MAX6364PUT26
AAGP
MAX6361PUT29*
AAEM
MAX6363PUT29*
AAFW
MAX6364PUT29*
AAGO
MAX6361PUT31
AAEL
MAX6363PUT31
AAFV
MAX6364PUT31
AAGN
MAX6361PUT44
AAEK
MAX6363PUT44
AAFU
MAX6364PUT44
AAGM
MAX6361PUT46*
AAEJ
MAX6363PUT46*
AAFT
MAX6364PUT46*
AAGL
MAX6361HUT23
AAEU
MAX6363HUT23
AAGE
MAX6364HUT23
AAGW
MAX6361HUT26
AAET
MAX6363HUT26
AAGD
MAX6364HUT26
AAGV
MAX6361HUT29
AAES
MAX6363HUT29
AAGC
MAX6364HUT29
AAGU
MAX6361HUT31
AAER
MAX6363HUT31
AAGB
MAX6364HUT31
AAGT
MAX6361HUT44
AAEQ
MAX6363HUT44
AAGA
MAX6364HUT44
AAGS
MAX6361HUT46*
AAEP
MAX6363HUT46*
AAFZ
MAX6364HUT46*
AAGR
*Sample stock generally held on standard versions only. Contact factory for availability of nonstandard versions.
that a negative-going VCC transient can typically have
without triggering a reset pulse. As the amplitude of the
transient increases (i.e., goes further below the reset
threshold), the maximum allowable pulse width
decreases. Typically, a VCC transient that goes 100mV
below the reset threshold and lasts for 30µs will not
trigger a reset pulse.
A 0.1µF bypass capacitor mounted close to the VCC
pin provides additional transient immunity.
_______________________________________________________________________________________
7
MAX6361/MAX6363/MAX6364
Selector Guide
Pin Configurations (continued)
TOP VIEW
Typical Operating Circuit
UNREGULATED
DC VOLTAGE
RESET, RESET 1
6
BATT
VCC
R1
GND 2
MAX6363
BATT ON 3
2.4V TO 5.5V
5
OUT
4
VCC
0.1µF
VCC
RESET
RESET µP
RESET IN
GND
R2
MAX6364
BUS
MAX6361/MAX6363/MAX6364
SOT23, Low-Power µP Supervisory Circuits
with Battery Backup
OUT
SOT23-6
RESET, RESET 1
GND 2
MAX6364
RESET IN 3
3.6V Li+
BATTERY
6
BATT
5
OUT
4
VCC
BATT
VCC
GND
0.1µF
SRAM
GND
Chip Information
TRANSISTOR COUNT: 720
SOT23-6
Package Information
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.
8 _____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600
© 2000 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
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