MAX807NEWE+ ,Full-Featured µP Supervisory Circuit with ±1.5% Reset AccuracyMAX807L/M/N19-0433; Rev 4; 11/05Full-Featured µP Supervisory Circuit with±1.5% Reset Accuracy
MAX807NEWE+ ,Full-Featured µP Supervisory Circuit with ±1.5% Reset AccuracyFeaturesThe MAX807 microprocessor (µP) supervisory circuit♦ Precision 4.675V (MAX807L), 4.425V (MAX ..
MAX807NEWE+ ,Full-Featured µP Supervisory Circuit with ±1.5% Reset AccuracyFeaturesThe MAX807 microprocessor (µP) supervisory circuit♦ Precision 4.675V (MAX807L), 4.425V (MAX ..
MAX807NEWE+T ,Full-Featured µP Supervisory Circuit with ±1.5% Reset AccuracyApplicationsV BATTCC 314ComputersWDI4 MAX807 13 BATT ONControllersGND CE IN5 12Intelligent Instrume ..
MAX808LCSA ,Supervisory circuit with +-1.5% reset accuracy. Reset threshold(typ) 4.675V. CMOS RAM write protection..MAX801L/M/N, MAX808L/M/N19-1086; Rev 0; 6/968-Pin µP Supervisory Circuitswith ±1.5% Reset Accuracy_ ..
MAX808LCSA ,Supervisory circuit with +-1.5% reset accuracy. Reset threshold(typ) 4.675V. CMOS RAM write protection..ELECTRICAL CHARACTERISTICS(V = 4.6V to 5.5V for the MAX80_L, V = 4.5V to 5.5V for the MAX80_N, V = ..
MB71A38-25 , PROGRAMMABLE SCHOTTKY 16384-BIT READ ONLY MEMORY
MB8117800A-60 ,2 M X 8 BIT FAST PAGE MODE DYNAMIC RAMapplications where very low power dissipation and high bandwidth are basic requirements of the desi ..
MB81464- ,MOS 262144 Bit DRAMfeatures page mode which allows high speed
random access of up to 256 bits within the same tow.
..
MAX807LCPE+-MAX807LCUE+-MAX807LCWE+-MAX807MCWE+-MAX807MEWE+-MAX807NCWE+-MAX807NEUE-MAX807NEUE+-MAX807NEWE+-MAX807NEWE+T
Full-Featured µP Supervisory Circuit with ±1.5% Reset Accuracy
General DescriptionThe MAX807 microprocessor (µP) supervisory circuit
reduces the complexity and number of components
needed to monitor power-supply and battery-control func-
tions in µP systems. A 70µA supply current makes the
MAX807 ideal for use in portable equipment, while a 2ns
chip-enable propagation delay and 250mA output current
capability (20mA in battery-backup mode) make it suit-
able for larger, higher-performance equipment.
The MAX807 comes in 16-pin DIP, SO, and TSSOP pack-
ages, and provides the following functions:
•µP reset. The active-low RESEToutput is asserted dur-
ing power-up, power-down, and brownout conditions,
and is guaranteed to be in the correct state for VCCdown to 1V.Active-high RESET output.Manual-reset input.Two-stage power-fail warning. A separate low-line
comparator compares VCCto a threshold 52mV above
the reset threshold. This low-line comparator is more
accurate than those in previous µP supervisors.Backup-battery switchover for CMOS RAM, real-time
clocks, µPs, or other low-power logic.Write protection of CMOS RAM or EEPROM.2.275V threshold detector provides for power-fail
warning and low-battery detection, or monitors a
power supply other than +5V.BATT OK status flag indicates that the backup-battery
voltage is above +2.275V.Watchdog-fault output—asserted if the watchdog input
has not been toggled within a preset timeout period.
ApplicationsComputers
Controllers
Intelligent Instruments
Critical µP Power Monitoring
Portable/Battery-Powered Equipment
FeaturesPrecision 4.675V (MAX807L), 4.425V (MAX807M),
or 4.575V (MAX807N) Voltage Monitoring200ms Power-OK/Reset Time DelayRESETand RESET OutputsIndependent Watchdog Timer1µA Standby CurrentPower Switching
250mA in VCCMode
20mA in Battery-Backup ModeOn-Board Gating of Chip-Enable Signals;
2ns CE Gate Propagation DelayMaxCap®and SuperCap®CompatibleVoltage Monitor for Power Fail Backup-Battery MonitorGuaranteed RESETValid to VCC= 1V±1.5% Low-Line Threshold Accuracy 52mV above
Reset Threshold
MAX807L/M/N
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy19-0433; Rev 4; 11/05RESETRESET
WDO
CE INGND
VCC
OUT
BATT
TOP VIEW
MAX807
CE OUT
WDI
LOW LINE
BATT OK
PFI
PFO
BATT ON
DIP/SO/TSSOP
Pin Configuration
Ordering Information and Typical Operating Circuit appear at end of data sheet.SuperCap is a registered trademark of Baknor Industries. MaxCap is a registered trademark of Cesiwid, Inc.
MAX807L/M/N
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VCC= 4.60V to 5.5V for the MAX807L, VCC= 4.50V to 5.5V for the MAX807N, VCC= 4.35V to 5.5V for the MAX807M,
VBATT= 2.8V, VPFI= 0V, TA= TMINto TMAX. Typical values are tested with VCC= 5V and TA= +25°C, unless otherwise noted.)
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.
Input Voltages (with respect to GND)
VCC..........................................................................-0.3V to 6V
VBATT.......................................................................-0.3V to 6V
All Other Inputs......................................-0.3V to (VOUT+ 0.3V)
Input Current
VCCPeak...........................................................................1.0A
VCCContinuous.............................................................500mA
IBATTPeak......................................................................250mA
IBATTContinuous.............................................................50mA
GND.................................................................................50mA
All Other Inputs................................................................50mA
Continuous Power Dissipation (TA= +70°C)
Plastic DIP (derate 10.53mW/°C above +70°C)..........842mW
Wide SO (derate 9.52mW/°C above +70°C)................762mW
CERDIP (derate 10.00mW/°C above +70°C)...............800mW
TSSOP (derate 6.70 mW/°C above +70°C).................533mW
Operating Temperature Ranges
MAX807_C_E......................................................0°C to +70°C
MAX807_E_E...................................................-40°C to +85°C
MAX807_MJE................................................-55°C to +125°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10s).................................+300°C
VBATT= 2.8V, VCC = 3.0V
VCC= 0V, VBATT= 2.8V
VCC= 3V, IOUT= 100mA
VCC= 4.5V,
IOUT= 250mA
VBATT= 2.0V, IOUT= 5mA, VCC= 0V
VBATT= 2.8V, IOUT= 10mA, VCC= 0V
VBATT= 4.5V, IOUT= 20mA, VCC= 0V
CONDITIONSBATT Standby Current (Note 3)
Supply Current in Battery-
Backup Mode (excludes IOUT)
(Note 2)
0.4170110Supply Current in Normal
Operating Mode (excludes IOUT)
VBATT- 0.20VBATT- 0.08
VOUTin Battery-Backup ModeVBATT- 0.25VBATT- 0.12
VBATT- 0.17
VCCto OUT On-Resistance1.8
UNITSMINTYPMAXSYMBOLPARAMETER05.5Operating Voltage Range
VBATT, VCC(Note 1)
MAX807C/E
MAX807M
VBATT= 2.0V, IOUT= 5mA
VBATT= 2.8V, IOUT= 10mA
VBATT= 4.5V, IOUT= 20mA40
BATT to OUT On-Resistance1225
8.5= +25°C
MAX807C/E
MAX807M= +25°C= TMINto
TMAX
VBATT= 2.8VPower up
Power downVVBATTBattery-Switchover ThresholdVBATT+ 0.05
VCC= 3V, VBATT= 2.8V, IOUT= 100mA
VCC= 4.5V
VCC- 0.02IOUT= 25mA
IOUT= 250mA,
MAX807C/E
IOUT= 250mA,
MAX807M
VOUTin Normal Operating
ModeV
VCC- 0.25VCC- 0.12
VCC- 0.35VCC- 0.22
VCC- 0.45
Battery-Switchover Hysteresis50
BATT ON Output, Low VoltageVRST (max), ISINK= 3.2mAV2.7BATT ON Output, High VoltageVCC= 0V, ISOURCE= 0.1mA, VBATT= 2.8VV
MAX807L/M/N
Full-Featured µP Supervisory Circuit with
±1.5% Reset AccuracyVIH
ELECTRICAL CHARACTERISTICS (continued)(VCC= 4.60V to 5.5V for the MAX807L, VCC= 4.50V to 5.5V for the MAX807N, VCC= 4.35V to 5.5V for the MAX807M,
VBATT= 2.8V, VPFI= 0V, TA= TMINto TMAX. Typical values are tested with VCC= 5V and TA= +25°C, unless otherwise noted.)
CONDITIONSUNITSMINTYPMAXSYMBOLPARAMETERSink current70
BATT ON Output
Short-Circuit CurrentSource current, VCC= 0V, VBATT= 2.8V
LOW LINEto RESET
Threshold VoltageVLR
Reset Threshold Hysteresis
VCCfalling305270mVmV
4.5004.5754.650VRSTReset ThresholdVCCrising and falling
4.634.71MAX807N
VCCto LOW LINEDelayVCCfalling at 1mV/µs24µs26VCCto RESETDelayVCCfalling at 1mV/µs
4.484.56MAX807M
Minimum Watchdog Input
Pulse Width
Watchdog-Timeout Period
VIL= 0.8V, VIH= 0.75 x VCC
tWD
100ns
1.121.62.24s140200280tRPRESETActive-Timeout PeriodVCCrising
4.734.81MAX807L
MAX807L
MAX807N
MAX807M
ISINK= 50µA,
VBATT= 0V, VCCfalling
VCC- 1.5VCC- 0.1
RESETOutput Voltage
ISOURCE= 0.1mA
0.10.4ISINK= 3.2mA, VCC= 4.25V60Output sink current, VCC= 4.25V
1.6ISCRESETOutput
Short-Circuit CurrentOutput source current
VCC= 1V,
MAX807_C
VCC= 1.2V,
MAX807_E/M0.4ISINK= 3.2mA
VCC- 1.5RESET Output VoltageISOURCE= 5mA0.4ISINK= 3.2mA, VCC= 4.25V
VCC- 1.5LOW LINEOutput VoltageISOURCE= 5mA60Output sink currentISCRESET Output
Short-Circuit CurrentOutput source current, VCC= 4.25V28Output sink current, VCC= 4.25VISCLOW LINEOutput
Short-Circuit CurrentOutput source current0.4ISINK= 3.2mA
VCC- 1.5WDOOutput VoltageISOURCE= 5mA35Output sink currentISCWDOOutput
Short-Circuit CurrentOutput source current
VLLVLOW LINEThreshold,
VCCRising0.75 x VCC
VIHWDI Threshold Voltage
(Note 4)VIL-50-10Reset deasserted, WDI = 0V50WDI Input CurrentReset deasserted, WDI = VCC
RESET, LOW LINE, AND WATCHDOG TIMER
MAX807L/M/N
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
Note 1:Either VCCor VBATTcan go to 0 if the other is greater than 2.0V.
Note 2:The supply current drawn by the MAX807 from the battery (excluding IOUT) typically goes to 15µA when (VBATT- 0.1V)
< VCC< VBATT. In most applications, this is a brief period as VCCfalls through this region (see Typical Operating Characteristics).
Note 3:“+”= battery discharging current, “-”= battery charging current.
Note 4:WDI is internally connected to a voltage-divider between VCCand GND. If unconnected, WDI is driven to 1.8V (typical),
disabling the watchdog function.
Note 5:Overdrive (VOD) is measured from center of hysteresis band.
Note 6:The chip-enable resistance is tested with VCEIN= VCC/2, and ICEIN= 1mA.
Note 7:The chip-enable propagation delay is measured from the 50% point at CEIN to the 50% point at CEOUT.
ELECTRICAL CHARACTERISTICS (continued)(VCC= 4.60V to 5.5V for the MAX807L, VCC= 4.50V to 5.5V for the MAX807N, VCC= 4.35V to 5.5V for the MAX807M,
VBATT= 2.8V, VPFI= 0V, TA= TMINto TMAX. Typical values are tested with VCC= 5V and TA= +25°C, unless otherwise noted.)
CONDITIONSUNITSMINTYPMAXSYMBOLPARAMETERPFI Leakage Current±0.005±40nA20PFI Hysteresis±0.00002±1CEIN Leakage CurrentDisabled mode, MR= 0V14PFI to PFODelay (Note 5)
PFI Input ThresholdVPFTVPFIfalling
2.222.2852.35V2.202.2652.33
RESETto CEOUT DelayVCCfalling28µs75150CEIN to CEOUT Resistance
(Note 6)Enabled mode, VCC= VRST(max)Minimum Pulse Input1µs170MR-to-RESETPropagation
Delay17CEOUT Short-Circuit Current
(RESET Active)
VCC= 5V, disabled mode, OUT = 0, MR= 0V28CEIN to CEOUT
Propagation Delay (Note 7)
VCC= 5V, CLOAD= 50pF,
50Ωsource impedance driver
3.5CEOUT Output Voltage High
(RESETActive)Disabled mode, MR= 0VThresholdVIH2.4V
BATT OK ThresholdVBOK2.2002.2652.350V
BATT OK Hysteresis20mV
Output Voltage
(PFO, BATT OK)
VOLISINK= 3.2mA0.4V
Output Short-Circuit CurrentISCOutput sink current35mA
VPFIrising
VBATT- 0.1VBATT
VCC= 5V,
IOUT= 2mA
VCC= 0V,
IOUT= 10µA
VIL0.8
VOHISOURCE= 5mAVCC- 1.5
Output source current20
VOD= 30mV, VPFIfallingPullup CurrentMR= 0V50100200µA
CHIP-ENABLE GATING
MANUAL RESET INPUT
BATT OK COMPARATOR
LOGIC OUTPUTS
MAX807L/M/N
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
__________________________________________Typical Operating Characteristics(VCC= 5V, VBATT= 2.8V, PFI = 0, no load, TA= +25°C, unless otherwise noted.)
VCC SUPPLY CURRENT vs. TEMPERATURE
(NORMAL OPERATING MODE)
MAX807-01
TEMPERATURE (°C)
SUPPLY CURRENT (100-4040120080
BATTERY SUPPLY CURRENT vs.
TEMPERATURE (BATTERY-BACKUP MODE)
MAX807-02
TEMPERATURE (°C)
BATTERY SUPPLY CURRENT (100-4040120080
CHIP-ENABLE PROPAGATION DELAY
vs. TEMPERATURE
MAX807-03
TEMPERATURE (°C)
PROPAGATION DELAY (ns)100-4040120080
BATT-TO-OUT ON-RESISTANCE
vs. TEMPERATURE
MAX807-04
TEMPERATURE (°C)
BATT-TO-OUT ON-RESISTANCE (100-4040120080
VBATT = 2.0V
VBATT = 2.8V
VBATT = 4.5V
VCC = 0V
IOUT = 10mA
RESET THRESHOLD
vs. TEMPERATURE
MAX807-07
TEMPERATURE (°C)
RESET THRESHOLD (V)100-4040120080
MAX807L
MAX807N
MAX807M
VCC-TO-OUT ON-RESISTANCE
vs. TEMPERATURE
MAX807-05
TEMPERATURE (°C)
-TO-OUT ON-RESISTANCE (100-4040120080
IOUT = 250mA
PFI THRESHOLD
vs. TEMPERATURE (VPFI FALLING)
MAX807-06
TEMPERATURE (°C)
PFI THRESHOLD (V)100-4040120080
RESET TIMEOUT PERIOD
vs. TEMPERATURE (VCC RISING)
MAX807-08
TEMPERATURE (°C)
RESET TIMEOUT PERIOD (ms)100-4040120080
LOW LINE -TO-RESET THRESHOLD
vs. TEMPERATURE (VCC FALLING)
MAX807-09
TEMPERATURE (°C)
LOW LINE-TO-RESET THRESHOLD (mV)100-4040120080
MAX807L/M/N
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
Typical Operating Characteristics (contiued)(VCC= 5V, VBATT= 2.8V, PFI = 0, no load, TA= +25°C, unless otherwise noted.)
4.40
LOW LINE THRESHOLD
vs. TEMPERATURE (VCC RISING)
MAX807-10
TEMPERATURE (°C)
LOW LINE THRESHOLD (V)100-4040120080
L VERSION
N VERSION
M VERSION
LOW LINE COMPARATOR PROPAGATION
DELAY vs. TEMPERATURE (VCC FALLING)
MAX807-11
TEMPERATURE (°C)
LOW LINE COMPARATOR PROP DELAY (100-4040120080
VCC FALLING AT 1mV/μs
RESET COMPARATOR PROPAGATION
DELAY vs. TEMPERATURE (VCC FALLING)
MAX807-12
TEMPERATURE (°C)
RESET COMPARATOR PROP DELAY (100-4040120080
VCC FALLING AT 1mV/μs
BATTERY CURRENT
vs. INPUT SUPPLY VOLTAGE
MAX807-13
VCC (V)
BATTERY CURRENT (
VCC-TO-OUT vs.
OUTPUT CURRENT
MAX807-16
IOUT (mA)
CC
- VOUT (mV)
SLOPE = 1.0Ω
50Ω DRIVER
CHIP-ENABLE PROPAGATION DELAY
vs. CE OUT LOAD CAPACITANCE
MAX807-14
CLOAD (pF)
PROPAGATION DELAY (ns)
BATT-TO-OUT vs.
OUTPUT CURRENT
MAX807-15
IOUT (mA)
BATT-TO-OUT (mV)
VCC = 0V
SLOPE = 12Ω
MAXIMUM TRANSIENT DURATION vs.
RESET COMPARATOR OVERDRIVE
MAX807-17
RESET COMPARATOR OVERDRIVE (mV)
MAXIMUM TRANSIENT DURATION (
RESET OCCURS
MAX807L/M/N
Full-Featured µP Supervisory Circuit with
±1.5% Reset Accuracy
Pin DescriptionActive-Low Reset Output. RESETis triggered and stays low when VCCis below the reset threshold or
when MRis low. It remains low 200ms after VCCrises above the reset threshold or MRreturns high.
RESEThas a strong pulldown but a relatively weak pullup, and can be wire-OR connected to logic gates.
Valid for VCC≥1V. RESETswings between VCCand GND.
RESET9
Watchdog Output. This CMOS-logic output goes low if WDI remains high or low longer than the watch-
dog-timeout period (tWD), and remains low until the next transition of WDI. WDOremains high if WDI is
unconnected. WDOis high during reset. WDOswings between VCCand GND. Connect WDOto MRto
generate resets during watchdog faults.
WDO10
Chip-Enable Output. Output to the chip-enable gating circuit. CEOUT is pulled up to the higher of VCC
or VBATT, when the chip-enable gate is disabled.CEOUT11
Chip-Enable InputCEIN12
Battery-On Output. CMOS-logic output/external bypass switch driver. High when OUT is connected to
BATT and low when OUT is connected to VCC. Connect the base of a PNP transistor or gate of a PMOS
transistor to BATT ON for IOUTrequirements exceeding 250mA. BATT ON swings between the higher of
VCCand VBATTand GND.
BATT ON13
GroundGND5
Manual-Reset Input. A logic low on MRasserts reset. Reset remains asserted as long as MRremains low
and for 200ms after MRreturns high. MRis an active-low input with an internal pullup to VCC. It can be
driven using TTL or CMOS logic, or shorted to ground with a switch. Connect to VCC, or leave uncon-
nected if not used.6
Low-Line Comparator Output. This CMOS-logic output goes low when VCCfalls to 52mV above the reset
threshold. Use this output to generate an NMI to initiate an orderly shutdown routine when VCCis falling.
LOW LINEswings between VCCand GND.
LOW LINE7
Active-High Reset Output. RESET is the inverse of RESET. It is a CMOS output that sources and sinks
current. RESET swings between VCCand GND.RESET8
Watchdog Input. If WDI remains high or low longer than the watchdog-timeout period (1.6s, typ), WDO
goes low. Leave unconnected to disable the watchdog function.WDI4
Input Supply Voltage, nominally +5V. Bypass with a 0.1µF capacitor to GND.VCC3
PINPower-Fail Output. This CMOS-logic output goes low when PFI is less than VPFT(2.265V). Valid for
VCC ≥4V. PFOswings between VCCand GND.PFO2
Power-Fail Input. When PFI is less than VPFT(2.265V), PFOgoes low. Connect to ground when unused.PFI1
FUNCTIONNAMEBackup-Battery Input. When VCCfalls below the reset threshold and VBATT, OUT switches from VCCto
BATT. VBATTmay exceed VCC. The battery can be removed while the MAX807 is powered-up, provided
BATT is bypassed with a 0.1µF capacitor to GND. If no battery is used, connect BATT to ground, and
connect VCCand OUT together.
BATT14
Battery-OK Signal Output. High in normal operating mode when VBATTexceeds VBOK(2.265V). Valid for
VCC≥4V.BATT OK15
Output Supply Voltage to CMOS RAM. When VCCexceeds the reset threshold or VCC> VBATT, OUT is
connected to VCC. When VCCfalls below the reset threshold and VBATT, OUT connects to BATT. Bypass
OUT with a 0.1µF capacitor to GND.
OUT16
Detailed DescriptionThe MAX807 µP supervisory circuit provides power-
supply monitoring, backup-battery switchover, and pro-
gram execution watchdog functions in µP systems
(Figure 1). Use of BiCMOS technology results in an
improved 1.5% reset-threshold precision, while keeping
supply currents typically below 70µA. The MAX807 is
intended for battery-powered applications that require
high reset-threshold precision, allowing a wide power-
supply operating range while preventing the system
from operating below its specified voltage range.
RESETand RESET OutputsThe MAX807’s RESEToutput ensures that the µP pow-
ers up in a known state, and prevents code execution
errors during power-down and brownout conditions. It
accomplishes this by resetting the µP, terminating pro-
gram execution when VCCdips below the reset thresh-
old or MRis pulled low. Each time RESETis asserted it
stays low for the 200ms reset timeout period, which is
set by an internal timer to ensure the µP has adequate
time to return to an initial state. Any time VCCgoes
below the reset threshold before the reset-timeout peri-
od is completed, the internal timer restarts. The watch-
dog timer can also initiate a reset if WDOis connected
to MR(see the Watchdog Inputsection).
MAX807L/M/N
Full-Featured µP Supervisory Circuit with
±1.5% Reset AccuracyMAX807
CE IN
PFI
GND
VCC
BATT
VCC
THE HIGHER
OF VCC OR VBATT
BATTERY-BACKUP
COMPARATOR
RESET
COMPARATOR
LOW-LINE
COMPARATOR
BATTERY-OK
COMPARATOR
POWER-FAIL
COMPARATOR
2.275V
OUT
BATT ON
LOW LINE
BATT OK
PFO
WDI
50kΩ
RESET
RESET
WDO
CE OUT
WATCHDOG
TRANSITION
DETECTOR
STATE
MACHINE
OSCILLATOR
Figure 1. Block Diagram
