MAX823TEUK-T ,5-Pin Microprocessor Supervisory Circuits with Watchdog Timer and Manual ResetApplications MAX823_EXK-T-40°C to +85°CMAX823_EUK-T 5 SOT23-5-40°C to +125°CComputers and Controlle ..
MAX823TEXK+T ,5-Pin Microprocessor Supervisory Circuits with Watchdog Timer and Manual ResetApplications MAX823_EXK-T-40°C to +85°CMAX823_EUK-T 5 SOT23-5-40°C to +125°CComputers and Controlle ..
MAX824L ,5-Pin Microprocessor Supervisory Circuits with Watchdog Timer and Manual ResetApplications MAX823_EXK-T-40°C to +85°CMAX823_EUK-T 5 SOT23-5-40°C to +125°CComputers and Controlle ..
MAX824LEUK+T ,5-Pin Microprocessor Supervisory Circuits with Watchdog Timer and Manual ResetMAX823/MAX824/MAX82519-0487; Rev 5; 12/055-Pin Microprocessor Supervisory Circuits WithWatchdog Tim ..
MAX824LEXK+T ,5-Pin Microprocessor Supervisory Circuits with Watchdog Timer and Manual ResetApplications MAX823_EXK-T-40°C to +85°CMAX823_EUK-T 5 SOT23-5-40°C to +125°CComputers and Controlle ..
MAX824MEUK ,Microprocessor supervisory circuit. Reset threshold 4.38V. Active-low reset. Active-high reset. Watchdog input.General Description ________
MB81C81A-35 ,CMOS 256K-BIT HIGH-SPEED SRAMMay 1990 00
Edition1.0 FUJITSU
M38 1 C8 1A-25/-35
CMOS 256K-BI T HIGH-SPEED SRAM
256K Words ..
MB81F643242C-10FN ,4 x 512K x 32 bit synchronous dynamic RAMFUJITSU SEMICONDUCTORADVANCED INFO. AE0.1EDATA SHEETMEMORYCMOS4 · 512 K · 32 BITSYNCHRONOUS DYNAMIC ..
MB81F643242C-10FN ,4 x 512K x 32 bit synchronous dynamic RAMfeatures a fully synchronous operation referenced to a positive edge clock whereby all operations a ..
MB81N643289-60FN ,8 x 256K x 32 bit double data rate FCRAMapplications where large memory density and high effective bandwidth arerequired and where a simple ..
MB8264A-10 , MOS 65536-BIT DYNAMIC RANDOM ACCESS MEMORY
MB8264A-10 , MOS 65536-BIT DYNAMIC RANDOM ACCESS MEMORY
MAX823LEUK+T-MAX823LEUK-T-MAX823MEUK+-MAX823MEUK+T-MAX823MEUK-T-MAX823R-MAX823REUK+-MAX823REUK+T-MAX823REXK+T-MAX823SEUK+T-MAX823SEUK-T-MAX823SEXK+-MAX823SEXK+T-MAX823T-MAX823TEUK+T-MAX823TEUK-T-MAX823TEXK+T-MAX824L-MAX824LEUK+T-MAX824LEXK+T-MAX824REUK+T-MAX824R
5-Pin Microprocessor Supervisory Circuits with Watchdog Timer and Manual Reset
________________General DescriptionThe MAX823/MAX824/MAX825* microprocessor (µP)
supervisory circuits combine reset output, watchdog,
and manual reset input functions in 5-pin SOT23 and
SC70 packages. They significantly improve system relia-
bility and accuracy compared to separate ICs or discrete
components. The MAX823/MAX824/MAX825 are specifi-
cally designed to ignore fast transients on VCC.
Seven preprogrammed reset threshold voltages are
available (see Reset Threshold Table). All three devices
have an active-low reset output, which is guaranteed to
be in the correct state for VCCdown to 1V. The MAX823
also offers a watchdog input and manual reset input.
The MAX824 offers a watchdog input and a comple-
mentary active-high reset. The MAX825 offers a manual
reset input and a complementary active-high reset. The
Selector Guide explains the functions offered in this
series of parts.
________________________ApplicationsComputers and Controllers
Embedded Controllers
Intelligent Instruments
Automotive Systems
Critical µP Monitoring
Portable/Battery-Powered Equipment
FeaturesPrecision Monitoring of +2.5V, +3V, +3.3V, and
+5V Power SuppliesOperating Current:6µA (MAX823L/M) (SC70)
2µA (MAX825T/S/R/Z/Y) (SC70)Fully Specified Over Temperature140ms min Power-On ResetGuaranteed RESETValid to VCC= 1V Power-Supply Transient ImmunityWatchdog Timer with 1.6s Timeout
(MAX823/MAX824)Manual Reset Input (MAX823/MAX825)No External Components
MAX823/MAX824/MAX825
5-Pin Microprocessor Supervisory Circuits With
Watchdog Timer and Manual Reset545454
GND
WDI
VCC
MAX823
SOT23/SC70TOP VIEW
RESET
GND
WDIRESET
VCC
MAX824
SOT23/SC70RESET
GNDRESET
VCC
MAX825
SOT23/SC70RESET
______________________Selector Guide19-0487; Rev 5; 12/05
†Insert the desired suffix letter (from the Reset Threshold table) into
the blank to complete the part number. All devices are available in
tape-and-reel only. There is a 2500 piece minimum order increment.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
MAX823Active-Low Reset✔
Active-High Reset—
FUNCTIONWatchdog Input✔
MAX824
MAX825Manual Reset Input✔—✔
SUFFIXRESET
THRESHOLD (V)4.634.383.082.932.63
Typical Operating Circuit appears at end of data sheet.
Marking Information appears at end of data sheet.
Ordering InformationPART†
TEMP. RANGE PIN-PACKAGE
MAX823_EXK-T-40°C to +85°C5 SC70-5
MAX823_EUK-T-40°C to +125°C5 SOT23-5
MAX824_EXK-T-40°C to +85°C5 SC70-5
Ordering Information continued at end of data sheet.Reset Threshold TableZ (SC70 only)2.32
Y (SC70 only)2.19
Pin Configurations*Pg
MAX823/MAX824/MAX825
5-Pin Microprocessor Supervisory Circuits With
Watchdog Timer and Manual Reset
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VCC= +4.75V to +5.5V for MAX82_L, VCC= +4.5V to +5.5V for MAX82_M, VCC= +3.15V to +3.6V for MAX82_T, VCC= +3V
to +3.6V for MAX82_S, VCC= +2.7V to +3.6V for MAX82_R, VCC= +2.38V to +2.75V for MAX82_Z, VCC= +2.25V to +2.75V for
MAX82_Y, TA= TMINto TMAX, TA= -40°C to +85°C (SC70), TA= -40°C to +125°C (SOT23), unless otherwise noted. Typical values
are at TA= +25°C.) (Note 1)
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.
VCC........................................................................-0.3V to +6.0V
All Other Pins..............................................-0.3V to (VCC+ 0.3V)
Input Current, All Pins Except RESET and RESET..............20mA
Output Current, RESET, RESET..........................................20mA
Continuous Power Dissipation (TA= +70°C)
5-Pin SC70 (derate 3.1mW/°C above +70°C)...............247mW
5-Pin SOT23 (derate 7.1mW/°C above +70°C).............571mW
Operating Temperature Range
MAX82_EXK......................................................-40°C to +85°C
MAX82_EUK...................................................-40°C to +125°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
MAX825T/S/R/Z/Y
PARAMETERSYMBOLMINTYPMAXUNITSSupply Current
(SOT23 Only)ISUPPLY
Operating Voltage Range
MAX825L/M
MAX823L/M
MAX824L/M
1.05.5VCC1.2V
512MAX823T/S/R/Z/Y
MAX824T/S/R/Z/Y
2.552.70TA= TMINto TMAX= +25°CMAX82_R
3.003.15TA= TMINto TMAX= +25°CMAX82_T
2.853.00TA= TMINto TMAX= +25°C
CONDITIONSMAX82_Sunconnected= TMINto TMAX= +25°CMAX82_L
4.314.384.45= 0°C to +70°C= TMINto TMAX
WDI and MR
unconnected= TMINto TMAX= +25°CMAX82_M
MAX825T/S/R/Z/Y
Supply Current
(SC70 Only)ISUPPLY
MAX825L/M
MAX823L/M
MAX824L/M
412MAX823T/S/R/Z/Y
MAX824T/S/R/Z/Yunconnected
WDI and MR
unconnected
Reset ThresholdV= TMINto TMAX= +25°CMAX82_Z
(SC70 only)
2.132.25TA= TMINto TMAX= +25°CMAX82_Y
(SC70 only)
VRST
MAX823/MAX824/MAX825
5-Pin Microprocessor Supervisory Circuits With
Watchdog Timer and Manual Reset
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSMAX82_L/M10Reset Threshold HysteresisMAX82_T/S/R/Z/Y5mV
Reset Threshold Temperature
Coefficient40ppm/°C
Reset Timeout PeriodtRP140200280ms
VCC to RESET DelayVRST - VCC = 100mV20μs
MAX82_L/M, VCC = VRST max,
ISOURCE = 120μAVCC - 1.5
VOHMAX82_T/S/R/Z/Y, VCC = VRST max,
ISOURCE = 30μA0.8 ✕ VCC
MAX82_L/M, VCC = VRST min,
ISINK = 3.2mA0.4
MAX82_T/S/R/Z/Y VCC = VRST min,
ISINK = 1.2mA0.3
TA = 0°C to +70°C, VCC = 1V,
VCC falling, ISINK = 50μA0.3
RESET Output Voltage
VOL
TA = TMIN to TMAX, VCC = 1.2V,
VCC falling, VBATT = 0V, ISINK = 100μA
MAX82_L/M, RESET = 0V, VCC = 5.5V800RESET Output Short-Circuit
Current (Note 2)ISOURCEMAX82_T/S/R/Z/Y, RESET = 0V, VCC = 3.6V400μA
VOHVCC > 1.8V, ISOURCE = 150μA0.8 ✕ VCC
MAX824L/M, MAX825L/M,
VCC = VRST max, ISINK = 3.2mA0.4RESET Output VoltageVOL
MAX824T/S/R/Z/Y, MAX825T/S/R/Z/Y,
VCC = VRST max, ISINK = 1.2mA0.3
WATCHDOG INPUT (MAX823/MAX824)Watchdog Timeout PeriodtWD1.121.602.40s
WDI Pulse WidthtWDIVIL = 0.4V, VIH = 0.8 ✕ VCC50ns
VIL 0.3 ✕ VCCWDI Input Voltage (Note 3)VIH0.7 ✕ VCCV
WDI = VCC, time average120160WDI Input Current (Note 4)WDI = 0, time average-20-15μA
ELECTRICAL CHARACTERISTICS (continued)(VCC= +4.75V to +5.5V for MAX82_L, VCC= +4.5V to +5.5V for MAX82_M, VCC= +3.15V to +3.6V for MAX82_T, VCC= +3V
to +3.6V for MAX82_S, VCC= +2.7V to +3.6V for MAX82_R, VCC= +2.38V to +2.75V for MAX82_Z, VCC= +2.25V to +2.75V for
MAX82_Y, TA= TMINto TMAX, TA= -40°C to +85°C (SC70), TA= -40°C to +125°C (SOT23), unless otherwise noted. Typical values
are at TA= +25°C.) (Note 1)
MAX823/MAX824/MAX825
5-Pin Microprocessor Supervisory Circuits With
Watchdog Timer and Manual Reset
Note 1:Over-temperature limits are guaranteed by design and not production tested.
Note 2:The RESETshort-circuit current is the maximum pullup current when RESETis driven low by a µP bidirectional reset pin.
Note 3:WDI is internally serviced within the watchdog period if WDI is left unconnected.
Note 4:The WDI input current is specified as the average input current when the WDI input is driven high or low. The WDI input is
designed to drive a three-stated output device with a 10µA maximum leakage current and a maximum capacitive load of
200pF. This output device must be able to source and sink at least 200µA when active.
PARAMETERSYMBOLCONDITIONSMINTYPMAXU N IT S
MANUAL RESET INPUT (MAX823/MAX825)VIL 0.3 ✕ VCCMR Input VoltageVIH0.7 ✕ VCCV
MR Pulse Width1.0μs
MR Noise Immunity (pulse width
with no reset)100ns
MR to Reset Delay500ns
MR Pullup Resistance
(internal)355275kΩ
ELECTRICAL CHARACTERISTICS (continued)(VCC= +4.75V to +5.5V for MAX82_L, VCC= +4.5V to +5.5V for MAX82_M, VCC= +3.15V to +3.6V for MAX82_T, VCC= +3V
to +3.6V for MAX82_S, VCC= +2.7V to +3.6V for MAX82_R, VCC= +2.38V to +2.75V for MAX82_Z, VCC= +2.25V to +2.75V for
MAX82_Y, TA= TMINto TMAX, TA= -40°C to +85°C (SC70), TA= -40°C to +125°C (SOT23), unless otherwise noted. Typical values
are at TA= +25°C.) (Note 1)
MAX823/MAX824/MAX825
5-Pin Microprocessor Supervisory Circuits With
Watchdog Timer and Manual Reset
__________________________________________Typical Operating CharacteristicsMAX823_, VCC= +5V, TA= +25°C, unless otherwise noted.)
MAX823/4/5 toc01
TEMPERATURE (°C)
SUPPLY CURRENT (
VCC SUPPLY CURRENT
vs. TEMPERATUREMAX823L
(SC70 ONLY)
MAX824Y
MAX825R
RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX823/4/5 toc02
TEMPERATURE (°C)
RESET TIMEOUT PERIOD (ms)
RESET COMPARATOR PROPAGATION DELAY
vs. TEMPERATURE
MAX823/4/5 toc03
TEMPERATURE (°C)
PROPAGATION DELAY (
VCC FALLING
WATCHDOG TIMEOUT PERIOD
vs. TEMPERATURE
MAX823/4/5 toc04
TEMPERATURE (°C)
WATCHDOG TIMEOUT PERIOD (s)
NORMALIZED RESET THRESHOLD
VOLTAGE vs. TEMPERATURE
MAX823/4/5 toc05
TEMPERATURE (°C)
NORMALIZED RESET THRESHOLD (V)
MAX823/4/5 toc06
RESET THRESHOLD OVERDRIVE (mV), VRST - VCC
TRANSIENT DURATION (
(SC70 ONLY)
MAXIMUM VCC TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVERESET OCCURS
ABOVE CURVE
MAX82_Y
MAX82_R
MAX82_L
MAX823/MAX824/MAX825
5-Pin Microprocessor Supervisory Circuits With
Watchdog Timer and Manual Reset
Pin DescriptionMAX823
MAX824
MAX825
VCC
VCC
WDI
(MAX823/MAX824
ONLY)
1.25V
GND
RESET
(MAX824/MAX825
ONLY)
RESET
(MAX823/MAX825
ONLY)
RESET
GENERATOR
WATCHDOG
TIMER
WATCHDOG
TRANSITION
DETECTOR
FUNCTION1
Active-Low Reset Output. Pulses low for 200ms when triggered, and remains
low whenever VCCis below the reset threshold or when MRis a logic low. It
remains low for 200ms after one of the following occurs: VCCrises above the
reset threshold, the watchdog triggers a reset, or MRgoes low to high.2Ground—
Manual Reset Input. A logic low on MRasserts reset. Reset remains asserted as
long as MRis held low and for 200ms after MRreturns high. The active-low input
has an internal 52kΩpullup resistor. It can be driven from a CMOS logic line or
shorted to ground with a switch. Leave open or connect to VCCif unused.3Active-High Reset Output. Inverse of RESET.5Supply Voltage4
Watchdog Input. If WDI remains either high or low for longer than the watch-
dog timeout period, the internal watchdog timer runs out and a reset is trig-
gered. The internal watchdog timer clears whenever reset is asserted, or
whenever WDI sees a rising or falling edge. If WDI is left unconnected or is
connected to a three-stated buffer output, the watchdog feature is disabled.
NAMERESETGNDMRRESETVCCWDI
Figure 1. Functional Diagram
MAX824MAX823MAX825
PIN
