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19-1615; Rev 0; 1/00
SOT23, Low-Power P 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 (P) systems. The circuits significantly improve system reliability and accuracy compared to that obtainable with separate ICs or discrete components. Their functions include P 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).
Features
o Low +1.2V Operating Supply Voltage (VCC or VBATT) 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 (VCC or VBATT) 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 P/C 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 -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C -40C to +85C 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 minimum on the SOT package (tape-and-reel only).
MR 3
4
VCC
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
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SOT23, Low-Power P Supervisory Circuits with Battery Backup MAX6361/MAX6363/MAX6364
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 = +70C) 6-Pin SOT23 (derate 8.70mW/C above +70C) .........696mW Operating Temperature Range MAX636_ .........................................................-40C to +85C Storage Temperature Range .............................-65C to +150C Lead Temperature (soldering, 10s) .................................+300C
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 = -40C to +85C, reset not asserted, typical values are at TA = +25C, unless otherwise noted.) (Note 1) PARAMETER Operating Voltage Range, VCC or VBATT Supply Current (excluding IOUT) ISUPPLY in Battery-Backup Mode (excluding IOUT) BATT Standby Current SYMBOL VCC, VBATT ICC CONDITIONS No load (Note 2) VCC = 2.8V No load, VCC > VTH VBATT = 2.8V, VCC = 0 5.5V > VCC > (VBATT + 0.2V) VCC = 3.6V VCC = 5.5V ISUPPLY IBATT TA = +25C TA = -40C to +85C TA = +25C TA = -40C to +85C -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 VBATT - 0.2 VBATT - 0.15 VBATT - 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 s ms V mV V A A A UNITS V
VCC = 4.75V, IOUT 150mA VCC to OUT On-Resistance RON VCC = 3.15V, IOUT 65mA VCC = 2.38V, IOUT 25mA VBATT = 4.5V, IOUT 20mA VOUT in Battery-Backup Mode Battery-Switchover Threshold (VCC - VBATT) VBATT = 3.0V, IOUT 10mA VBATT = 2.25V, IOUT 5mA VCC < VTH MAX636_UT46 MAX636_UT44 Reset Threshold VTH MAX636_UT31 MAX636_UT29 MAX636_UT26 MAX636_UT23 VCC Falling Reset Delay Reset-Active Timeout Period tRP VCC falling at 10V/ms Power-up Power-down
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SOT23, Low-Power P Supervisory Circuits with Battery Backup
ELECTRICAL CHARACTERISTICS (continued)
(VCC = +2.4V to +5.5V, VBATT = 3V, TA = -40C to +85C, reset not asserted, typical values are at TA = +25C, unless otherwise noted.) (Note 1) PARAMETER SYMBOL Reset asserted, VBATT = 0 Reset not asserted (MAX636_L only) CONDITIONS ISINK = 1.6mA, VCC 2.1V ISINK = 100A, VCC 1.2V ISOURCE = 500A, VCC VTH(MAX) ISOURCE = 200A, VCC 1.2V ISOURCE = 1mA, VCC 1.8V ISINK = 1.6mA, VCC VTH(MAX) 0.8 * VCC 0.7 * VCC 0.8 * VCC 0.3 1 0.3 * VCC 0.7 * VCC 20 1 VCC = 3.3V VCC = 3.3V VOL ISINK = 3.2mA, VBATT = 2.1V Sink current, VCC = 5V Source current, VBATT 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 A V V k s ns ns V mA A V nA s V MIN TYP MAX 0.3 0.4 V UNITS
MAX6361/MAX6363/MAX6364
VOL RESET Output Voltage VOH
VOH RESET Output Voltage VOL 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 VIL VIH ILK
Reset asserted, VBATT = 0
Reset not asserted MAX636_P only
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).
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SOT23, Low-Power P Supervisory Circuits with Battery Backup MAX6361/MAX6363/MAX6364
Typical Operating Characteristics
(TA = +25C, 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 (A) 1.0 0.8 0.6 VBATT = 2.0V 0.4 0.2 0
VCC = 0 VBATT = 2.8V
7 BATT TO OUT ON-RESISTANCE () 6 5 VBATT = 2.0V 4 3 2 VBATT = 5.0V 1 0 IOUT = 25mA VCC = 0 -40 -20 0 20 40 60 80 VBATT = 2.8V
SUPPLY CURRENT (A)
18
16
14 VBATT = 0 VCC = 5.0V -40 -20 0 20 40 60 80 TEMPERATURE (C)
12
-40
-20
0
20
40
60
80
TEMPERATURE (C)
TEMPERATURE (C)
VCC TO OUT ON-RESISTANCE vs. TEMPERATURE
MAX6361 toc04
RESET TIMEOUT PERIOD vs. TEMPERATURE
MAX6361 toc05
VCC TO RESET PROPAGATION DELAY vs. TEMPERATURE
135 120 PROGAGATION DELAY (s) 105 90 75 60 45 30 15 10V/ms -40 -20 0 20 40 60 80 1V/ms VCC FALLING 0.25V/ms
MAX6361 toc06
1.2 VOUT TO OUT ON-RESISTANCE () VCC = 2.3V IOUT = 25mA 0.9
210
RESET TIMEOUT PERIOD (ms)
205
0.6 VCC = 4.5V IOUT = 150mA 0.3
VCC = 3.0V IOUT = 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 (A) 8 7 6 5 4 3 2 1 0 VBATT = 2.3V 0 1 2 VCC (V) 3 4 VBATT = 2.5V VBATT = 2.8V VTH = 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 (s) 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 VTH - VCC (mV)
4
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SOT23, Low-Power P Supervisory Circuits with Battery Backup
Typical Operating Characteristics (continued)
(TA = +25C, 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 (s) 2.5 2.2 1.9 1.6 1.3 VOD = 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 VCC OUT FUNCTION 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. 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. 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. 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 (tRP) after RESET IN goes high. 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. 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. 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.
6
BATT
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.
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SOT23, Low-Power P Supervisory Circuits with Battery Backup MAX6361/MAX6363/MAX6364
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.
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 0.1F 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.
Manual Reset Input (MAX6361 only)
Many P-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 20k 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 0.1F capacitor from MR to GND to provide additional noise immunity.
Negative-Going VCC Transients These supervisors are relatively immune to short-duration, negative-going VCC transients. Resetting the P 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 46 44 31 29 26 23 RESET THRESHOLD RANGES (V) MIN 4.50 4.25 3.00 2.85 2.55 2.25 TYP 4.63 4.38 3.08 2.93 2.63 2.32 MAX 4.75 4.50 3.15 3.00 2.70 2.38
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.
Reset Output
A P's reset input starts the P in a known state. The MAX6361/MAX6363/MAX6364 P 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 VCC OUT BATT RESET/RESET BATT ON MR, RESET IN STATUS Disconnected from OUT Connected to BATT Connected to OUT. Current drawn from the battery is less than 1A (at VBATT = 2.8V, excluding IOUT) when VCC = 0. Asserted High state Inputs ignored
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SOT23, Low-Power P Supervisory Circuits with Battery Backup
Selector Guide
PART MAX6361LUT_ _ MAX6361PUT_ _ MAX6361HUT_ _ MAX6363LUT_ _ MAX6363PUT_ _ MAX6363HUT_ _ MAX6364LUT_ _ MAX6364PUT_ _ MAX6364HUT_ _ MANUAL RESET INPUT, MR BATT ON RESET IN RESET PUSH-PULL RESET OPEN-DRAIN RESET PUSH-PULL
MAX6361/MAX6363/MAX6364
Device Marking Codes
PART MAX6361LUT23 MAX6361LUT26 MAX6361LUT29* MAX6361LUT31 MAX6361LUT44 MAX6361LUT46* MAX6361PUT23 MAX6361PUT26 MAX6361PUT29* MAX6361PUT31 MAX6361PUT44 MAX6361PUT46* MAX6361HUT23 MAX6361HUT26 MAX6361HUT29 MAX6361HUT31 MAX6361HUT44 MAX6361HUT46* TOP MARK AAEI AAEH AAEG AAEF AAEE AAED AAEO AAEN AAEM AAEL AAEK AAEJ AAEU AAET AAES AAER AAEQ AAEP PART MAX6363LUT23 MAX6363LUT26 MAX6363LUT29* MAX6363LUT31 MAX6363LUT44 MAX6363LUT46* MAX6363PUT23 MAX6363PUT26 MAX6363PUT29* MAX6363PUT31 MAX6363PUT44 MAX6363PUT46* MAX6363HUT23 MAX6363HUT26 MAX6363HUT29 MAX6363HUT31 MAX6363HUT44 MAX6363HUT46* TOP MARK AAFS AAFR AAFQ AAFP AAFO AAFN AAFY AAFX AAFW AAFV AAFU AAFT AAGE AAGD AAGC AAGB AAGA AAFZ PART MAX6364LUT23 MAX6364LUT26 MAX6364LUT29* MAX6364LUT31 MAX6364LUT44 MAX6364LUT46* MAX6364PUT23 MAX6364PUT26 MAX6364PUT29* MAX6364PUT31 MAX6364PUT44 MAX6364PUT46* MAX6364HUT23 MAX6364HUT26 MAX6364HUT29 MAX6364HUT31 MAX6364HUT44 MAX6364HUT46* TOP MARK AAGK AAGJ AAGI AAGH AAGG AAGF AAGQ AAGP AAGO AAGN AAGM AAGL AAGW AAGV AAGU AAGT AAGS 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 30s will not trigger a reset pulse.
A 0.1F bypass capacitor mounted close to the VCC pin provides additional transient immunity.
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SOT23, Low-Power P Supervisory Circuits with Battery Backup MAX6361/MAX6363/MAX6364
Pin Configurations (continued)
TOP VIEW
RESET, RESET 1 6 BATT R1 GND 2 0.1F VCC RESET RESET IN R2 GND RESET P UNREGULATED DC VOLTAGE
Typical Operating Circuit
2.4V TO 5.5V VCC
MAX6363
5
OUT
BATT ON 3 SOT23-6
4
VCC
MAX6364
BUS OUT 3.6V Li+ BATTERY BATT GND 0.1F VCC SRAM GND
RESET, RESET 1
6
BATT
GND 2
MAX6364
5
OUT
RESET IN 3 SOT23-6
4
VCC
Chip Information
TRANSISTOR COUNT: 720
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 (c) 2000 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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