MAX6721UTVDD3-T ,Vcc1: 1.575 V, Vcc2: 0.788 V, active timeout period: 140 ms-280 ms, dual/triple ultra-low-voltage SOT23 mP supervisor circuitfeatures are available (see Selector Guide). Select reset Immune to Short V Transientstimeout peri ..
MAX6725AKASHD3+ ,Dual/Triple, Ultra-Low-Voltage, SOT23 µP Supervisory CircuitsApplicationsMAX6718AUK_ _D_+T -40°C to +125°C 5 SOT23● Multivoltage Systems ● Industrial Equipment● ..
MAX6730UTRD3 ,Single-/Dual-/Triple-Voltage µP Supervisory Circuits with Independent Watchdog OutputApplications● Multivoltage SystemsWDO NMIPUSHBUTTON● Telecom/Networking EquipmentMRSWITCH● Computer ..
MAX6730UTRD3 ,Single-/Dual-/Triple-Voltage µP Supervisory Circuits with Independent Watchdog OutputElectrical Characteristics(V 1 = V 2 = +0.8V to +5.5V, T = -40°C to +85°C, unless otherwise noted. ..
MAX6731UTTD3+ ,Single-/Dual-/Triple-Voltage µP Supervisory Circuits with Independent Watchdog Outputfeatures Down to +0.63V (MAX6734/MAX6735 Only)significantly improves system reliability and accurac ..
MAX6733UTSVD3-T ,Vcc1: 2.925 V, Vcc2: 1.575 V, active timeout period: 140 ms-280 ms, single/dual/triple-voltage mP supervisor circuit with independent watchdog outputfeatures significantly improves systemVoltages Down to +0.63V (MAX6734/MAX6735 Only)reliability and ..
MB3775 ,SWITCHING REGULATOR CONTROLLERFUJITSU SEMICONDUCTORDS04-27204-3EDATA SHEETASSPSWITCHING REGULATOR CONTROLLERMB3775LOW VOLTAGE DUA ..
MB3775PF , SWITCHING REGULATOR CONTROLLER
MB3776 ,Switching Regulator ControllerFEATURES• Wide supply voltage range: (2 V to 15 V)• Wide oscillation frequency range, high-frequenc ..
MB3776A ,Switching Regulator ControllerFUJITSU SEMICONDUCTORDS04-27201-3EDATA SHEETASSP For Power Supply
MB3776AP ,Switching Regulator ControllerFEATURES• Wide supply voltage range: (2 V to 15 V)• Wide oscillation frequency range, high-frequenc ..
MB3776APF ,Switching Regulator ControllerFUJITSU SEMICONDUCTORDS04-27201-3EDATA SHEETASSP For Power Supply
MAX6717UKSDD3-T-MAX6717UKTGD3-T-MAX6719UTLTD3-T-MAX6719UTSHD3-T-MAX6721UTVDD3-T
Vcc1 4.625 V,Vcc2 3.075 V, active timeout period: 140 ms-280 ms, dual/triple ultra-low-voltage SOT23 mP supervisor circuit
General DescriptionThe MAX6715–MAX6729 are ultra-low-voltage microproces-
sor (µP) supervisory circuits designed to monitor two or three
system power-supply voltages. These devices assert a sys-
tem reset if any monitored supply falls below its factory-
trimmed or adjustable threshold and maintain reset for a
minimum timeout period after all supplies rise above their
thresholds. The integrated dual/triple supervisory circuits sig-
nificantly improve system reliability and reduce size com-
pared to separate ICs or discrete components.
These devices monitor primary supply voltages (VCC1) from
1.8V to 5.0V and secondary supply voltages (VCC2) from
0.9V to 3.3V with factory-trimmed reset threshold voltage
options (see Reset Voltage Threshold Suffix Guide). An
externally adjustable RSTIN input option allows customers to
monitor a third supply voltage down to 0.62V. These devices
are guaranteed to be in the correct reset output logic state
when either VCC1 or VCC2 remains greater than 0.8V.
A variety of push-pull or open-drain reset outputs along with
watchdog input, manual reset input, and power-fail input/out-
put features are available (see Selector Guide). Select reset
timeout periods from 1.1ms to 1120ms (min) (see Reset
Timeout Period Suffix Guide). The MAX6715–MAX6729 are
available in small 5, 6, and 8-pin SOT23 packages and oper-
ate over the -40°C to +85°C temperature range.
ApplicationsMultivoltage Systems
Telecom/Networking Equipment
Computers/Servers
Portable/Battery-Operated Equipment
Industrial Equipment
Printer/Fax
Set-Top Boxes
FeaturesVCC1 (primary supply) Reset Threshold Voltages
from 1.58V to 4.63VVCC2 (secondary supply) Reset Threshold
Voltages from 0.79V to 3.08VExternally Adjustable RSTIN Threshold for
Auxiliary/Triple-Voltage Monitoring
(0.62V internal reference)Watchdog Timer Option
35s (min) Long Startup Period
1.12s (min) Normal Timeout PeriodManual Reset Input OptionPower-Fail Input/Power-Fail Output Option
(Push-Pull and Open-Drain Active-Low)Guaranteed Reset Valid Down to VCC1 or
VCC2 = 0.8V Reset Output Logic OptionsImmune to Short VCCTransientsLow Supply Current 14µA (typ) at 3.6VSmall 5, 6, and 8-Pin SOT23 Packages
MAX6715–MAX6729
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory Circuits
Ordering Information
Typical Operating Circuit19-2325; Rev 3; 6/03
Pin Configurations appear at end of data sheet.
Selector Guide appears at end of data sheet.
Note:The first “_ _” are placeholders for the threshold voltage
levels of the devices. Desired threshold levels are set by the part
number suffix found in the Reset Voltage Threshold Suffix Guide.
The “_” after the D is a placeholder for the reset timeout delay
time. Desired delay time is set using the timeout period suffix
found in the Reset Timeout Period Suffix Guide. For example the
MAX6716UTLTD3-T is a dual-voltage supervisor VTH1 = 4.625V,
VTH2 = 3.075V, and 210ms (typ) timeout period.
Ordering Information continued at end of data sheet.
MAX6715–MAX6729
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory Circuits
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VCC1 = VCC2 = 0.8V to 5.5V, GND = 0, TA= -40°C to +85°C, 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.
Terminal Voltage (with respect to GND)
VCC1, VCC2..........................................................-0.3V to +6V
Open-Drain RST, RST1, RST2, PFO, RST................-0.3V to +6V
Push-Pull RST, RST1, PFO, RST...............-0.3V to (VCC1 + 0.3V)
Push-Pull RST2.........................................-0.3V to (VCC2 + 0.3V)
RSTIN, PFI, MR, WDI................................................-0.3V to +6V
Input Current/Output Current (all pins)...............................20mA
Continuous Power Dissipation (TA= +70°C)
5-Pin SOT23-5 (derate 7.1mW/°C above +70°C)........571mW
6-Pin SOT23-6 (derate 8.7mW/°C above +70°C)........696mW
8-Pin SOT23-8 (derate 8.9mW/°C above +70°C)........714mW
Operating Temperature Range...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s).................................+300°C
MAX6715–MAX6729
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory Circuits
ELECTRICAL CHARACTERISTICS (continued)(VCC1 = VCC2 = 0.8V to 5.5V, GND = 0, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
MAX6715–MAX6729
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory Circuits
Note 2:Parameter guaranteed by design.
ELECTRICAL CHARACTERISTICS (continued)(VCC1 = VCC2 = 0.8V to 5.5V, GND = 0, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
MAX6715–MAX6729
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory CircuitsSUPPLY CURRENT vs. TEMPERATURE
VCC1 = 5V, VCC2 = 3.3V
MAX6715-29 toc01
TEMPERATURE (°C)
SUPPLY CURRENT (
SUPPLY CURRENT vs. TEMPERATURE
VCC1 = 3.3V, VCC2 = 2.5V
MAX6715-29 toc02
TEMPERATURE (°C)
SUPPLY CURRENT (
SUPPLY CURRENT vs. TEMPERATURE
VCC1 = 2.5V, VCC2 = 1.8V
MAX6715-29 toc03
TEMPERATURE (°C)
SUPPLY CURRENT (
SUPPLY CURRENT vs. TEMPERATURE
VCC1 = 1.8V, VCC2 = 1.2V
MAX6715-29 toc04
TEMPERATURE (°C)
SUPPLY CURRENT (
NORMALIZED RESET/WATCHDOG
TIMEOUT PERIOD vs. TEMPERATURE
MAX6715-29 toc05
TEMPERATURE (°C)
RESET/WATCHDOG PERIOD
10,000
MAXIMUM VCC TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE
MAX6715-29 toc06
RESET THRESHOLD OVERDRIVE (mV)
MAXIMUM V
TRANSIENT DURATION (
NORMALIZED VCC RESET THRESHOLD
vs. TEMPERATURE
MAX6715-29 toc07
TEMPERATURE (°C)
RESET THRESHOLD
RESET INPUT AND POWER-FAIL INPUT
THRESHOLD vs. TEMPERATURE
MAX6715-29 toc08
TEMPERATURE (°C)
THRESHOLD (mV)-153560
VCC TO RESET DELAY
vs. TEMPERATURE
MAX6715-29 toc09
TEMPERATURE (°C)
TO RESET DELAY (
Typical Operating Characteristics(VCC1 = 5V, VCC2 = 3.3V, TA= +25°C, unless otherwise noted.)
MAX6715–MAX6729
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory Circuits
Pin Descriptionypical Operating Characteristics (continued)(VCC1 = 5V, VCC2 = 3.3V, TA= +25°C, unless otherwise noted.)
MAX6715–MAX6729
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory Circuits
MAX6715–MAX6729
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory Circuits
Pin Description (continued)
Detailed Description
Supply VoltagesThe MAX6715–MAX6729 microprocessor (µP) supervi-
sory circuits maintain system integrity by alerting the µP
to fault conditions. These ICs are optimized for systems
that monitor two or three supply voltages. The output-
reset state is guaranteed to remain valid while either
VCC1 or VCC2 is above 0.8V.
Threshold LevelsInput voltage threshold level combinations are indicat-
ed by a two-letter code in the Reset Voltage Threshold
Suffix Guide(Table 1). Contact factory for availability of
other voltage threshold combinations.
Reset OutputsThe MAX6715–MAX6729 provides an active-low reset
output (RST) and the MAX6725/MAX6726 provides
both an active-high (RST) and an active-low reset out-
put (RST). RST, RST, RST1, and RST2are asserted
when the voltage at either VCC1 or VCC2 falls below the
voltage threshold level, RSTIN drops below threshold,
or MRis pulled low. Once reset is asserted it stays low
for the reset timeout period (see Table 2). If VCC1,
VCC2, or RSTIN goes below the reset threshold before
the reset timeout period is completed, the internal timer
MAX6715–MAX6729
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory Circuits
MAX6715–MAX6729restarts. The MAX6715/MAX6717/MAX6719/MAX6721/
MAX6723/MAX6725/MAX6727/MAX6728 contain open-
drain reset outputs, while the MAX6716/MAX6718/
MAX6720/MAX6722/MAX6724/MAX6726/MAX6729
contain push-pull reset outputs. The MAX6727 provides
two separate open-drain RSToutputs driven by the
same internal logic.
Manual Reset InputMany microprocessor-based products require manual
reset capability, allowing the operator, a test techni-
cian, or external logic circuitry to initiate a reset. A logic
low on MRasserts the reset output. Reset remains
asserted while MRis low and for the reset timeout peri-
od (tRP) after MRreturns high. This input has an internal
50kΩpullup resistor to VCC1 and can be left uncon-
nected if not used. MRcan be driven with TTL or
CMOS logic levels, or with open-drain/collector outputs.
Connect a normally open momentary switch from MRto
GND to create a manual reset function; external
debounce circuitry is not required. If MRis driven from
long cables or if the device is used in a noisy environ-
ment, connect a 0.1µF capacitor from MRto GND to
provide additional noise immunity.
Adjustable Input VoltageThe MAX6719/MAX6720 and MAX6723–MAX6727 provide
an additional input to monitor a third system voltage. The
threshold voltage at RSTIN is typically 626mV. Connect a
resistor-divider network to the circuit as shown in Figure 1
to establish an externally controlled threshold voltage,
VEXT_TH.
VEXT_TH= 626mV((R1 + R2)/R2)
Low leakage current at RSTIN allows the use of large-
valued resistors resulting in reduced power consump-
tion of the system.
Watchdog InputThe watchdog monitors µP activity through the watch-
dog input (WDI). To use the watchdog function, con-
nect WDI to a bus line or µP I/O line. When WDI
remains high or low for longer than the watchdog time-
out period, the reset output asserts. Leave WDI floating
to disable the watchdog function.
The MAX6721–MAX6729 include a dual-mode watch-
dog timer to monitor µP activity. The flexible timeout
architecture provides a long period initial watchdog
mode, allowing complicated systems to complete
lengthy boots, and a short period normal watchdog
mode, allowing the supervisor to provide quick alerts
when processor activity fails. After each reset event
(VCCpower-up/brownout, manual reset, or watchdog
reset), there is a long initial watchdog period of 35s
minimum. The long watchdog period mode provides an
extended time for the system to power-up and fully ini-
tialize all µP and system components before assuming
responsibility for routine watchdog updates.
The normal watchdog timeout period (1.12s min)
begins after the first transition on WDI before the con-
clusion of the long initial watchdog period (Figure 2).
During the normal operating mode, the supervisor will
issue a reset pulse for the reset timeout period if the µP
does not update the WDI with a valid transition (high-to-
low or low-to-high) within the standard timeout period
(1.12s min).
Power-Fail ComparatorPFI is the noninverting input to a comparator. If PFI is
less than VPFI(626.5mV), PFOgoes low. Common uses
for the power-fail comparator include monitoring prereg-
ulated input of the power supply (such as a battery) or
Dual/Triple Ultra-Low-Voltage SOT23 µP
Supervisory CircuitsFigure 1. Monitoring a Third Voltage
Figure 2. Normal Watchdog Startup Sequence
