MAX708SCSA-T ,+3V Voltage Monitoring, Low-Cost, µP Supervisory CircuitsELECTRICAL CHARACTERISTICS(MAX70_P/R, MAX706AP/AR: V = 2.7V to 5.5V; MAX70_S, MAX706AS: V = 3.0V to ..
MAX708SCSA-T ,+3V Voltage Monitoring, Low-Cost, µP Supervisory CircuitsFeaturesThe MAX706P/R/S/T, MAX706AP/AR/AS/AT, and♦ µMAX Package, Small 8-Pin SOMAX708R/S/T micropro ..
MAX708SCUA ,+3V Voltage Monitoring, Low-Cost, レP Supervisory CircuitsFeatures
The MAX706P/R/S/T and MAX708R/S/T microprocessor t pMAX Package: Smallest 8-Pin SO
( ..
MAX708SCUA ,+3V Voltage Monitoring, Low-Cost, レP Supervisory CircuitsELECTRICAL CHARACTERISTICS
(MAX/CLP/R: Vcc = 2.70V10 5.5V, MAX70_S: VCC = 3.00V to 5EV, MAX10_T: ..
MAX708SCUA ,+3V Voltage Monitoring, Low-Cost, レP Supervisory CircuitsFeatures
The MAX706P/R/S/T and MAX708R/S/T microprocessor t pMAX Package: Smallest 8-Pin SO
( ..
MAX708SCUA+ ,+3V Voltage Monitoring, Low-Cost, µP Supervisory CircuitsApplicationsUNREGULATEDBattery-Powered EquipmentDC-DCDCCONVERTERMAX639Portable Instruments+3V/+3.3V ..
MB47358 ,DUAL OPERATIONAL AMPLIFIERFUJITSU SEMICONDUCTORDS04-11104-3EDATA SHEETLINEAR ICDUAL OPERATIONAL AMPLIFIERMB47358DUAL OPERATIO ..
MB47393 ,DUAL COMPARATORFUJITSU SEMICONDUCTORDS04-12103-4EDATA SHEETASSPDUAL COMPARATORMB47393n DESCRIPTIONThe Fujitsu MB47 ..
MB47393P ,Dual comparatorFUJITSU SEMICONDUCTORDS04-12103-4EDATA SHEETASSPDUAL COMPARATORMB47393n DESCRIPTIONThe Fujitsu MB47 ..
MB47393P ,Dual comparatorFUJITSU SEMICONDUCTORDS04-12103-4EDATA SHEETASSPDUAL COMPARATORMB47393n DESCRIPTIONThe Fujitsu MB47 ..
MB47393PF ,Dual comparatorFUJITSU SEMICONDUCTORDS04-12103-4EDATA SHEETASSPDUAL COMPARATORMB47393n DESCRIPTIONThe Fujitsu MB47 ..
MB4752A ,SUBSCRIBER LINE INTERFACE IC" mm;
gr T$544-A874
'j?itl,'l,lllill,ililill MB4752A April 1987
'llllllllllllllllllllllllill ..
MAX706PCPA+-MAX706PCSA+-MAX706PEPA+-MAX706PESA+-MAX706RCPA+-MAX706RCSA+-MAX706RCSA+T-MAX706RCUA+-MAX706REPA+-MAX706RESA+-MAX706RESA+T-MAX706SCPA+-MAX706SCSA+-MAX706SCSA+T-MAX706SCSA-T-MAX706SCUA+-MAX706SEPA+-MAX706SESA+-MAX706SESA+T-MAX706SESA-T-MAX706TCSA+-
+3V Voltage Monitoring, Low-Cost, µP Supervisory Circuits
General DescriptionThe MAX706P/R/S/T, MAX706AP/AR/AS/AT, and
MAX708R/S/T microprocessor (µP) supervisory circuits
reduce the complexity and number of components
required to monitor +3V power-supply levels in +3V to
+5V µP systems. These devices significantly improve
system reliability and accuracy compared to separate
ICs or discrete components.
The MAX706P/R/S/T and MAX706AP/AR/AS/AT supervi-
sory circuits provide the following four functions:A reset output during power-up, power-down, and
brownout conditions.An independent watchdog output that goes low if the
watchdog input has not been toggled within 1.6s.A 1.25V threshold detector for power-fail warning,
low-battery detection, or for monitoring a power
supply other than the main supply.An active-low, manual-reset input.
The only difference between the MAX706R/AR,
MAX706S/AS, and MAX706T/AT is the reset-threshold
voltage levels, which are 2.63V, 2.93V, and 3.08V,
respectively. All have active-low reset output signals.
The MAX706P/AP are identical to the MAX706R/AR,
except the reset output signal is active-high. The watch-
dog timer function for the MAX706AP/AR/AS/AT dis-
ables when the WDI input is left open or connected to a
high-impedance state of a low-leakage tri-state output.
The MAX708R/S/T provide the same functions as the
MAX706R/S/T and MAX706AR/AS/AT except they do
not have a watchdog timer. Instead, they provide both
RESETand RESET outputs. As with the MAX706,
devices with R, S, and T suffixes have reset thresholds
of 2.63V, 2.93V, and 3.08V, respectively.
These devices are available in 8-pin SO, DIP, and
µMAX®packages and are fully specified over the oper-
ating temperature range.
ApplicationsBattery-Powered Equipment
Portable Instruments
Computers
Controllers
Intelligent Instruments
Critical µP Power Monitoring
FeaturesµMAX Package, Small 8-Pin SOPrecision Supply-Voltage Monitors
2.63V (MAX706P/R, MAX706AP/AR, and MAX708R)
2.93V (MAX706S, MAX706AS, and MAX708S)
3.08V (MAX706T, MAX706AT, and MAX708T)200ms Reset Time DelayDebounced TTL/CMOS-Compatible Manual Reset
Input100µA Quiescent CurrentWDI Disable Feature (MAX706AP/AR/AS/AT)Watchdog Timer: 1.6s TimeoutReset Output Signal:
Active-High Only (MAX706P, MAX706AP)
Active-Low Only (MAX706R/S/T, MAX706AR/AS/AT)
Active-High and Active-Low (MAX708R/S/T)Voltage Monitor for Power-Fail or Low-Battery
Warning8-Pin Surface-Mount PackageGuaranteed RESETAssertion to VCC = 1V
MAX706P/R/S/T
, MAX706AP/AR/AS/A
, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
Ordering Information19-0099; Rev 5; 4/06
Ordering Information continued at end of data sheet.
Pin Configurations appear at end of data sheet.µMAX is a registered trademark of Maxim Integrated Products, Inc.
PART†TEMP
RANGE
PIN-
PACKAGE
PKG
CODE
MAX706PCPA0°C to +70°C8 PDIPP8-1
MAX706PCSA0°C to +70°C8 SOS8-2
MAX706PCUA0°C to +70°C8 µMAXU8-1
MAX706PEPA-40°C to +85°C8 PDIPP8-1
†SO, µMAX, and PDIP packages are available in lead-free.
VCC
PFI
GNDPFO
WDO
RESET
UNREGULATED
PUSHBUTTON
SWITCH
WDII/O LINE
INTERRUPT
MAX639
DC-DC
CONVERTER
+3V/+3.3V
MAX706R/S/T
MAX706AR/AS/AT
VCC
RESET
NMI
Typical Operating Circuits
MAX706P/R/S/T
, MAX706AP/AR/AS/A
, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(MAX70_P/R, MAX706AP/AR: VCC= 2.7V to 5.5V; MAX70_S, MAX706AS: VCC = 3.0V to 5.5V; MAX70_T, MAX706AT: VCC = 3.15V to
5.5V; TJ= TA= TMINto TMAX, unless otherwise noted. Typical values are at TJ= TA= +25°C.) (Note 2)
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.
Terminal Voltage (with respect to GND)
VCC........................................................................-0.3V to +6V
All Other Inputs (Note 1)..........................-0.3V to (VCC+ 0.3V)
Input Current
VCC..................................................................................20mA
GND.................................................................................20mA
Output Current (all outputs)................................................20mA
Continuous Power Dissipation (TA= +70°C)
8-Pin CERDIP (derate 8mW/°C above +70°C)..............640mW
8-Pin PDIP (derate 9.1mW/°C above +70°C).............727.3mW
8-Pin SO (derate 5.9mW/°C above +70°C)................470.6mW
8-Pin µMAX (derate 4.5mW/oC above +70°C)..............362mW
Operating Temperature Range
MAX70_C.............................................................0°C to +70°C
MAX70_E..........................................................-40°C to +85°C
MAX70_M.......................................................-55°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
Note 1:The input-voltage limits on PFI, WDI, and MRcan be exceeded if the input current is less than 10mA.
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSMAX70_C1.05.5Supply Voltage RangeVCCMAX70_E/M1.25.5V
MAX706_C90200
MAX706_E/M90300
MAX708_C50200VCC < 3.6V
MAX708_E/M50300
MAX706_C135350
MAX706_E/M135500
MAX708_C65350
Supply CurrentISUPPLY
VCC < 5.5V
MAX708_E/M65500
MAX70_P/R, MAX706AP/AR2.552.632.70
MAX70_S, MAX706AS2.852.933.00Reset Threshold (Note 3)
(VCC Falling)VRST
MAX70_T, MAX706AT3.003.083.15
Reset Threshold Hysteresis
(Note 3)VHYS20mV
MAX70_P/R, MAX706AP/AR VCC = 3.0V140200280
MAX70_S, MAX706AS, VCC = 3.3V140200280Reset Pulse Width (Note 3)tRST
VCC = 5V200
RESET OUTPUTVOHVRST(MAX) < VCC < 3.6VISOURCE = 500µA0.8 x
VCC
VOLVRST(MAX) < VCC < 3.6VISINK = 1.2mA0.3
VOH4.5V < VCC < 5.5VIRSOURCE =
800µA
VCC -
VOL4.5V < VCC < 5.5VISINK = 3.2mA0.4
MAX70_C VCC = 1.0V, ISINK = 50µA0.3
Output-Voltage High
(MAX70_R/S/T)
(MAX706AR/AS/AT)
VOL
MAX706P/R/S/T
, MAX706AP/AR/AS/A
, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
ELECTRICAL CHARACTERISTICS (continued)(MAX70_P/R, MAX706AP/AR: VCC= 2.7V to 5.5V; MAX70_S, MAX706AS: VCC = 3.0V to 5.5V; MAX70_T, MAX706AT: VCC = 3.15V to
5.5V; TJ= TA= TMINto TMAX, unless otherwise noted. Typical values are at TJ= TA= +25°C.) (Note 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSVOHVRST(MAX) < VCC < 3.6VISOURCE = 215µAVCC –
VOLVRST(MAX) < VCC < 3.6VISINK = 1.2mA0.3
VOH4.5 < VCC < 5.5VISOURCE = 800µAVCC -
Output-Voltage High
(MAX706P) (MAX706AP)
VOL4.5V < VCC < 5.5VISINK = 3.2mA0.4
VOHVRST(MAX) < VCC < 3.6VISOURCE = 500µA0.8 x VCC
VOLVRST(MAX) < VCC < 3.6VISINK = 500µA0.3
VOH4.5V < VCC < 5.5VISOURCE = 800µAVCC -
Output-Voltage High
(MAX708_)
VOL4.5V < VCC < 5.5VISINK = 1.2mA0.4
WATCHDOG INPUTMAX706P/R, MAX706AP/AR, VCC = 3.0V1.001.62.25Watchdog Timeout PeriodtWDMAX706S/T, MAX706AS/AT, VCC = 3.3V1.001.62.25s
VIL = 0.4VVRST(MAX) < VCC
< 3.6V100WDI Pulse Width
(MAX706_, MAX706A_)tWP
VIH = 0.8V x VCC4.5V < VCC <
5.5V50
VILVRST(MAX) < VCC < 3.6V0.6
VIHVRST(MAX) < VCC < 3.6V0.7 x
VCC
VILVCC = 5.0V0.8
Watchdog Input Threshold
(MAX706_, MAX706A_)
VIHVCC = 5.0V3.5
MAX706_-1.0+0.02+1.0WDI Input CurrentWDI = 0V or VCCMAX706A_-5+5µA
MAX706P/R/S/T
, MAX706AP/AR/AS/A
, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
ELECTRICAL CHARACTERISTICS (continued)(MAX70_P/R, MAX706AP/AR: VCC= 2.7V to 5.5V; MAX70_S, MAX706AS: VCC = 3.0V to 5.5V; MAX70_T, MAX706AT: VCC = 3.15V to
5.5V; TJ= TA= TMINto TMAX, unless otherwise noted. Typical values are at TJ= TA= +25°C.) (Note 2)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITS
WATCHDOG OUTPUTVOHVRST(MAX) < VCC < 3.6VISOURCE = 500µA0.8 x
VCC
VOLVRST(MAX) < VCC < 3.6VISINK = 500µA0.3
VOH4.5V < VCC < 5.5VISOURCE = 800µAVCC -
WDO Output Voltage
(MAX706_, MAX706A_)
VOL4.5V < VCC < 5.5VISINK = 1.2mA0.4
MANUAL RESET INPUTVRST(MAX) < VCC
< 3.6V2570250
MR Pullup CurrentMR = 0
4.5V < VCC <
5.5V100250600
VRST(MAX) < VCC < 3.6V500MR Pulse WidthtMR4.5V < VCC < 5.5V150ns
VILVRST(MAX) < VCC < 3.6V0.6
VIHVRST(MAX) < VCC < 3.6V0.7 x
VCC
VIL4.5V < VCC < 5.5V0.8
MR Input Threshold
VIH4.5V < VCC < 5.5V2.0
VRST(MAX) < VCC < 3.6V750MR to Reset Output DelaytMD4.5V < VCC < 5.5V250ns
POWER-FAILURE COMPARATOR(MAX70_P/R, MAX706AP/AR) PFI falling
VCC = 3.0V1.21.251.3
PFI Input Threshold
(MAX70_S/T, MAX706AS/AT) PFI falling,
VCC = 3.3V1.21.251.3
PFI Input Current-25+0.01+25nA
VOHVRST(MAX) < VCC < 3.6VISOURCE = 500µA0.8 x
VCC
VOLVRST(MAX) < VCC < 3.6VISINK = 1.2mA0.3
VOH4.5V < VCC < 5.5VISOURCE = 800µAVCC -
PFO Output Voltage
VOL4.5V < VCC < 5.5VISINK = 3.2mA0.4
Note 2:All devices 100% production tested at TA= +85°C. Limits over temperature are guaranteed by design.
Note 3:Applies to both RESETin the MAX70_R/S/T and MAX706AR/AS/AT, and RESET in the MAX706P/MAX706AP.
MAX706P/R/S/T
, MAX706AP/AR/AS/A
, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
Typical Operating Characteristics(TA = +25°C, unless otherwise noted.)
Typical Operating Characteristics
MAX706P/R/S/T
, MAX706AP/AR/AS/A
, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
Pin Description
MAX706P
MAX706AP
MAX706R/S/T,
MAX706AR/AS/ATMAX708R/S/T
SO/DIPµMAXSO/DIPµMAXSO/DIPµMAX
NAMEFUNCTION1313MR
Acti ve-Low , M anual -Reset Inp ut. P ull M R b el ow 0.6V to tr i gg er aeset pul se. M R i s TTL/C M OS com p ati b l e w hen V C C = 5V and cane shorted to GN D wi th a swi tch. M R i s i nter nal l y connected to a
70µA sour ce curr ent. C onnect to V C C or l eave unconnected .2424V C C S upp l y V ol tag e Inp ut53535GNDGround64646PFI
Adjustable Power-Fail Comparator Input. Connect PFI to a
resistive divider to set the desired PFI threshold. When PFI is
less than 1.25V, PFO goes low and sinks current; otherwise,
PFO remains high. Connect PFI to GND if not used.5757PFO
Active-Low, Power-Fail Comparator Output. PFO asserts when
PFI is below the internal 1.25V threshold. PFO deasserts when
PFI is above the internal 1.25V threshold. Leave PFO
unconnected if not used.868——WDI
Watchdog Input. A falling or rising transition must occur at
WDI within 1.6s to prevent WDO from asserting (see Figure 4).
The internal watchdog timer is reset to zero when reset is
asserted or when transition occurs at WDI. The watchdog
function for the MAX706P/R/S/T can not be disabled. The
watchdog timer for the MAX706AP/AR/AS/AT disables when
WDI input is left open or connected to a tri-state output in its
high-impedance state with a leakage current of less than
600nA.1——82RESET
Active-High Reset Output. RESET remains high when VCC is
below the reset threshold or MR is held low. It remains low for
200ms after the reset conditions end (Figure 3).82——WDO
Active-Low Watchdog Output. WDO goes low when a
transition does not occur at WDI within 1.6s and remains low
until a transition occurs at WDI (indicating the watchdog
interrupt has been serviced). WDO also goes low when VCC
falls below the reset threshold; however, unlike the reset
output signal, WDO goes high as soon as VCC rises above
the reset threshold.7171RESET
Active-Low Reset Output. RESET remains low when VCC is
below the reset threshold or MR is held low. It remains low for
200ms after the reset conditions end (Figure 3).———68N.C.No Connection. Not internally connected.
MAX706P/R/S/T
, MAX706AP/AR/AS/A
, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory Circuits
RESET and RESETOutputsA microprocessor’s (µP’s) reset input starts in a known
state. When the µP is in an unknown state, it should be
held in reset. The MAX706P/R/S/T and the MAX706AP/
AR/AS/AT assert reset when VCCis low, preventing
code execution errors during power-up, power-down,
or brownout conditions.
On power-up once VCCreaches 1V, RESETis guaran-
teed to be logic-low and RESET is guaranteed to be
logic-high. As VCCrises, RESETand RESET remain
asserted. Once VCCexceeds the reset threshold, the
internal timer causes RESETand RESET to be
deasserted after a time equal to the reset pulse width,
which is typically 200ms (Figure 3).
If a power-fail or brownout condition occurs (i.e., VCC
drops below the reset threshold), RESETand RESET
are asserted. As long as VCCremains below the reset
threshold, the internal timer is continually reset, causing
the RESETand RESET outputs to remain asserted.
Thus, a brownout condition that interrupts a previously
initiated reset pulse causes an additional 200ms delay
from the time the latest interruption occurred. On
power-down once VCCdrops below the reset threshold,
RESETand RESET are guaranteed to be asserted for
VCC≥1V.
The MAX706P/MAX706AP provide a RESET signal, and
the MAX706R/S/T and MAX706AR/AS/AT provide a
RESETsignal. The MAX708R/S/T provide both RESET
and RESET.
Watchdog TimerThe MAX706P/R/S/T and the MAX706AP/AR/AS/AT
watchdog circuit monitor the µP’s activity. If the µP
does not toggle the watchdog input (WDI) within 1.6s,
the watchdog output (WDO) goes low (Figure 4). If the
reset signal is asserted, the watchdog timer will be
reset to zero and disabled. As soon as reset is
released, the timer starts counting. WDI can detect puls-
es as narrow as 100ns with a 2.7V supply and 50ns with a
4.5V supply. The watchdog timer for the MAX706P/R/S/T
cannot be disabled.The watchdog timer for the
MAX706AP/AR/AS/AT operates similarly to the
MAX706P/R/S/T. However, the watchdog timer for the
MAX706AP/AR/AS/AT disables when the WDI input is
left open or connected to a tri-state output in its high-
impedance state and with a leakage current of less
than 600nA. The watchdog timer can be disabled any-
RESET
GENERATOR
VCC
70μARESET
RESETPFO
GND3
1.25V
2.63V MAX708R
2.93V MAX708S
3.08V MAX708TMRVCCPFI
MAX708R/S/T
Figure 1. MAX706_ Functional DiagramFigure 2. MAX708_ Functional Diagram
WATCHDOG
TRANSITION
DETECTOR
WATCHDOG
TIMER
TIMEBASE FOR
RESET AND
WATCHDOG
RESET
GENERATOR
VCC
70μAWDORESET
(RESET)PFO
GND3
1.25V
2.63V MAX706P/R
2.93V MAX706S
3.08V MAX706T
( ) ARE FOR MAX706P/AP.WDIMRVCCPFI
MAX706P/R/S/T
MAX706AP/AR/AS/AT
MAX706P/R/S/T
, MAX706AP/AR/AS/A
, MAX708R/S/T
+3V Voltage Monitoring, Low-Cost µP
Supervisory CircuitsWDOcan be connected to the nonmaskable interrupt
(NMI) input of a µP. When VCCdrops below the reset
threshold, WDOimmediately goes low, even if the
watchdog timer has not timed out (Figure 3). Normally,
this would trigger an NMI, but since reset is asserted
simultaneously, the NMI is overridden. The WDO
should not be connected to RESETdirectly. Instead,
connect WDOto MRto generate a reset pulse when it
times out.
Manual ResetThe manual reset (MR) input allows RESETand RESET
to be activated by a pushbutton switch. The switch is
effectively debounced by the 140ms minimum reset
pulse width. MRcan be driven by an external logic line
since it is TTL/CMOS compatible. The minimum MR
input pulse width is 500ns when VCC= +3V and 150ns
when VCC= +5V. Leave MRunconnected or connect
to VCC when not used.
Power-Fail ComparatorThe power-fail comparator can be used for various pur-
poses because its output and noninverting input are
not internally connected. The inverting input is internally
connected to a 1.25V reference. The power-fail com-
parator has 10mV of hysteresis, which prevents repeat-
ed triggering of the power-fail output (PFO).
tRSTtRST
+3.3V
+3.3V
+1V
RESET
RESET
WDO*
+3.3V
MR*
tMR
*NOTE: MR EXTERNALLY DRIVEN LOW.
WDO TIMING SHOWN FOR MAX706P/R/S/T.
+3.3V
VCCVRSTVRST
tMD
tWP
tWDtWDtWD
+3V/+3.3V
WDI
+3V/+3.3VWDO
+3V/+3.3VRESET
tRSTRESET EXTERNALLY
TRIGGERED BY MR
MAX706_
MAX708R/S/T
RESET
(RESET)
130kΩ
PARAMETERMINTYPMAXUNIT+12V RESET
THRESHOLD AT +25°C10.2410.8711.50V
1MΩ
+3V/+3.3V+12V
VCC
PFI
( ) ARE FOR MAX706P/AP
GND
PFO
TO μP
MAX706R/S/T
MAX708R/S/T
MAX706AR/AS/AT
RESETFigure 4. MAX706AP/AR/AS/AT Watchdog Timing
Figure 3. RESET, RESET, MR, and WDOTiming
Figure 5. Monitoring Both +3V/+3.3V and +12V
Figure 6. RESETValid to GND Circuit
