MAX6804US44D3+T ,4-Pin, Low-Power µP Reset Circuits with Manual ResetApplicationsMAX6805US_ _D_-T -40°C to +125°C 4 SOT143● Computers*These devices are available in fac ..
MAX6806UR23 ,Voltage DetectorsApplicationsMAX6806XR_ _ -T -40°C to +85°C 3 SC70● Computers ● Portable/Battery-MAX6806UR_ _ -T -40 ..
MAX6806UR26-T ,Voltage DetectorsApplicationsPART TEMP. RANGE PIN-PACKAGEComputersMAX6806XR_ _-T -40°C to +85°C 3 SC70ControllersMAX ..
MAX6806US23-T ,Voltage DetectorsFeaturesThe MAX6806/MAX6807/MAX6808 precision voltage' Preset Reset Thresholds: 4.6V and 2.6V detec ..
MAX6807UR46-T ,Voltage detector. Reset output active-high, push-pull. Threshold reset 4.6VApplicationsPART TEMP. RANGE PIN-PACKAGEComputersMAX6806XR_ _-T -40°C to +85°C 3 SC70ControllersMAX ..
MAX6808SA46+ ,Voltage DetectorsElectrical Characteristics(V = +5V, T = -40°C to +85°C, unless otherwise noted. Typical values are ..
MB3782 ,Switching Regulator ControllerFUJITSU SEMICONDUCTORDS04-27205-4EDATA SHEETASSP Power Supplies BIPOLARSwitching Regulator Controll ..
MB3782PF ,Switching Regulator ControllerFUJITSU SEMICONDUCTORDS04-27205-4EDATA SHEETASSP Power Supplies BIPOLARSwitching Regulator Controll ..
MB3785A ,Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)FUJITSU SEMICONDUCTORDS04-27208-1EDATA SHEETASSP BIPOLARSwitching Regulator Controller(4 Channels p ..
MB3785APFV ,Switching Regulator Controller (4 Channels plus High-Precision, High-Frequency Capabilities)FUJITSU SEMICONDUCTORDS04-27208-1EDATA SHEETASSP BIPOLARSwitching Regulator Controller(4 Channels p ..
MB3789 ,Switching Regulator Controller (Supporting External Synchronization)FUJITSU SEMICONDUCTORDS04-27211-3EDATA SHEETASSP For Power Supply
MB3789PFV ,Switching Regulator Controller (Supporting External Synchronization)FUJITSU SEMICONDUCTORDS04-27211-3EDATA SHEETASSP For Power Supply
MAX6804US29D3+T-MAX6804US44D3+T
4-Pin, Low-Power µP Reset Circuits with Manual Reset
General DescriptionThe MAX6803/MAX6804/MAX6805 microprocessor (µP)
supervisory circuits monitor the power supplies in 2.85V
to 5.0V µP and digital systems. They increase cir-
cuit reliability and reduce cost by eliminating external
components and adjustments. They also feature a
debounced manual-reset input.
These devices perform a single function: they assert a
reset signal whenever the VCC supply voltage declines
below a preset threshold or whenever manual reset is
asserted. Reset remains asserted for a preset timeout
period after VCC has risen above the reset threshold or
after manual reset is deasserted. The only difference
among the three devices is their output. The MAX6804
(push/pull) and MAX6805 (open-drain) have an active-
low RESET output, while the MAX6803 (push/pull) has
an active-high RESET output. The MAX6803/MAX6804
are guaranteed to be in the correct state for VCC down
to 0.7V. The MAX6805 is guaranteed to be in the correct
state for VCC down to 1.0V.
The reset comparator in these ICs is designed to ignore
fast transients on VCC. Reset thresholds are factory-
trimmable between 2.63V and 4.80V, in approximately
100mV increments. These devices are available with a
1ms min, 20ms min, or 100ms min reset timeout period.
Ideal for space-critical applications, the MAX6803/
MAX6804/MAX6805 come packaged in a 4-pin SOT143.
For a lower threshold voltage version, see the MAX6335/
MAX6336/MAX6337.
Applications●Computers●Controllers●Intelligent Instruments●Critical µP/µC Power Monitoring●Portable/Battery-Powered Equipment
Features●Ultra-Low 0.7V Operating Supply Voltage●Low 4.0µA Supply Current●Precision Monitoring of 2.85V to 5.0V Power-Supply
Voltages●Reset Thresholds Available from 2.63V to 4.80V,
in Approximately 100mV Increments●Debounced Manual-Reset Input●Fully Specified over Temperature●Three Power-On Reset Timeout Periods Available
(1ms min, 20ms min, 100ms min)●Low Cost●Three Available Output Structures: Push/Pull
RESET, Push/Pull RESET, Open-Drain RESET●Guaranteed RESET/RESET Valid to VCC = 0.7V
(MAX6803/MAX6804)●Power-Supply Transient Immunity●No External Components Required●4-Pin SOT143 Package●Pin Compatible with MAX811/MAX812 and
MAX6314/MAX6315(
*These devices are available in factory-set VCC reset thresh-
olds from 2.63V to 4.80V, in approximately 0.1V increments.
Choose the desired reset threshold suffix from Table 1 and
insert it in the blanks following “US” in the part number.
Factory-programmed reset timeout periods are also available.
Insert the number corresponding to the desired nominal reset
timeout period (1 = 1ms min, 2 = 20ms min, 3 = 100ms min) in
the blank following “D” in the part number. There are 15 stan-
dard versions with a required order increment of 2500 pieces.
Sample stock is generally held on the standard versions only
(see Selector Guide). Contact the factory for availability of non-
standard versions (required order increment is 10,000 pieces).
All devices available in tape-and-reel only.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
PART*TEMP RANGEPIN-PACKAGE
MAX6803US_ _D_-T-40°C to +125°C4 SOT143
MAX6804US_ _D_-T-40°C to +125°C4 SOT143
MAX6805US_ _D_-T-40°C to +125°C4 SOT143
MAX6803/MAX6804/
MAX6805
4-Pin, Low-Power
µP Reset Circuits with Manual Reset
Ordering Information
Selector Guide appears at end of data sheet.
Typical Operating Circuit and Pin Configuration appear
at end of data sheet.
Terminal Voltage (with respect to GND)
VCC ......................................................................-0.3V to +6VPush/Pull RESET or RESET, MR ........-0.3V to (VCC + 0.3V)
Open-Drain RESET .............................................-0.3V to +6V
Input Current (VCC) ............................................................20mA
Output Current (RESET, RESET) ......................................20mA
Continuous Power Dissipation (TA = +70°C)4-Pin SOT143 (derate 4mW/°C above +70°C) ...........320mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature ......................................................+150°C
Storage Temperature Range ............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
(VCC = full range, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VCC = +5.0V and TA = +25°C, reset not
asserted.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSSupply Voltage Range
(Note 1)VCC
TA = 0°C to +125°CMAX6803/MAX68040.75.5MAX68051.05.5
TA = -40°C to +125°CMAX6803/MAX68040.785.5
MAX68051.25.5
Supply CurrentICCNo load
VCC = +3.0V410VCC = +5.0V512
Reset ThresholdVTHMAX680_US_ _D_-T,
Table 1
TA = +25°CVTH
- 1.8%VTHVTH
+ 1.8%
TA = -40°C to +125°CVTH
- 3%VTHVTH
+ 3%
VCC Falling Reset DelayVCC falling at 10V/ms30µs
Reset Active Timeout PeriodtRP
MAX680_US_ _D1-T11.52MAX680_US_ _D2-T203040
MAX680_US_ _D3-T100150200
MR Minimum Pulse Width1µs
MR Glitch Immunity50ns
MR Reset Delay0.1µs
MR Input VoltageVIL0.3 × VCCVVIH0.7 × VCC
MR Pullup Resistance122030kΩ
RESET Output Low Voltage
(MAX6804/MAX6805)VOLReset
asserted
ISINK = 50µA, VCC ≥ 1.0V0.4ISINK = 1.2mA, VCC ≥ 2.5V0.3
ISINK = 3.2mA, VCC ≥ 4.25V0.4
RESET Output High Voltage
(MAX6804)VOHReset not
asserted
ISOURCE = 500µA, VCC ≥ 3.0V0.8 × VCCV
ISOURCE = 800µA, VCC ≥ 5.0V0.8 × VCC
MAX6803/MAX6804/
MAX6805
4-Pin, Low-Power
µP Reset Circuits with Manual Reset
Electrical CharacteristicsStresses 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.
Absolute Maximum Ratings
(Reset not asserted, TA = +25°C, unless otherwise noted.)
Note 1: All parts are production tested at TA = +25°C. Over temperature limits are guaranteed by design and not production tested.
Note 2: ISOURCE for the MAX6803 is 100nA; ISINK for the MAX6804 is 100nA; ISINK for the MAX6805 is 50µA.(VCC = full range, TA = -40°C to +125°C, unless otherwise noted. Typical values are at VCC = +5.0V and TA = +25°C, reset not
asserted.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSRESET Output Voltage
(MAX6803)
VOHReset
asserted
ISOURCE = 1µA, VCC ≥ 1.0V0.8 × VCCISOURCE = 200µA, VCC ≥ 1.8V0.8 × VCC
ISOURCE = 800µA, VCC ≥ 4.25V0.8 × VCC
VOLReset not
asserted
ISINK = 1.2mA, VCC ≥ 3.0V0.3ISINK = 3.2mA, VCC ≥ 5.0V0.4
RESET Output Leakage Current
(MAX6805)VCC > VTH, RESET not asserted0.5µA
VCC FALLING PROPAGATION DELAY
vs. TEMPERATURE
MAX6803/04/05 toc06
POROPAGATION DELAY (
VCC = FALLING AT 1V/ms
VCC = FALLING AT 10V/ms
MAXIMUM TRANSIENT DURATION
vs. RESET COMPARATOR OVERDRIVE
MAX6803/04/05 toc05
MAXIMUM TRANSIENT DURATION (
RESET OCCURS
RESET DOES
NOT OCCUR
OUTPUT-VOLTAGE HIGH
vs. SUPPLY VOLTAGE
MAX6803/04/05 toc04
OUTPUT-VOLTAGE HIGH (V
- V
) (mV)
+25°C
-40°C
+125°C
+85°C
VTH = 2.93V
ISINK = 100µA
RESET ASSERTED
(MAX6803)
OUTPUT-VOLTAGE LOW
vs. SUPPLY VOLTAGE
MAX6803/04/05 toc03
VCC (V)
OUTPUT-VOLTAGE LOW (mV)
+25°C
-40°C
+125°C
+85°C
VTH = 2.93V
ISINK = 500µA
RESET
NORMALIZED RESET TIMEOUT PERIOD
vs. TEMPERATURE
MAX6803/04/05 toc02
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
SUPPLY CURRENT
vs. TEMPERATURE
MAX6803/04/05 toc01
TEMPERATURE (°C)
ICC
VCC = +5.0V
VCC = +3.3V
MAX6803/MAX6804/
MAX6805
4-Pin, Low-Power
µP Reset Circuits with Manual Reset
Typical Operating Characteristics
Electrical Characteristics (continued)
Applications Information
Manual-Reset InputMany µP-based products require manual-reset capability,
allowing the operator, a test technician, or external logic
circuitry to initiate a reset. A logic low on MR asserts reset.
Reset remains asserted while MR is low, and for the reset
active timeout period after MR returns high. MR has an
internal 20kΩ pullup resistor, so it can be left unconnected
if not used. Connect a normally open momentary switch
from MR to GND to create a manual-reset function;
external debounce circuitry is not required.
Interfacing to µPs with
Bidirectional Reset PinsSince the RESET output on the MAX6805 is open-drain,
this device interfaces easily with µPs that have bidirec-
tional reset pins, such as the Motorola 68HC11.
Connecting the µP supervisor’s RESET output directly
to the microcontroller’s (µC’s) RESET pin with a
single pullup resistor allows either device to assert reset
(Figure 1).
Negative-Going VCC TransientsIn addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, these devices
are relatively immune to short-duration, negative-going
VCC transients (glitches). The Typical Operating
Characteristics show the Maximum Transient Duration
shows the maximum pulse width that a negative-going
VCC transient may typically have without issuing a reset
signal. As the amplitude of the transient increases, the
maximum allowable pulse width decreases.
Ensuring a Valid Reset Output Down to
VCC = 0When VCC falls below 1V and approaches the minimum
operating voltage of 0.7V, push/pull-structured reset
sinking (or sourcing) capabilities decrease drastically.
High-impedance CMOS-logic inputs connected to the
RESET pin can drift to indeterminate voltages. This
does not present a problem in most cases, since most
Figure 1. Interfacing to μPs with Bidirectional Reset Pins
PIN
NAMEFUNCTION
MAX6803MAX6804
MAX68051GNDGround2RESET
Active-Low Reset Output. RESET is asserted while VCC is below the reset
threshold, or while MR is asserted. RESET remains asserted for a reset
timeout period (tRP) after VCC rises above the reset threshold or MR is
deasserted. RESET on the MAX6804 is push/pull. RESET on the MAX6805
is open-drain.—RESET
Active-High Reset Output. RESET is asserted high while VCC is below the
reset threshold or while MR is asserted, and RESET remains asserted for a
reset timeout period (tRP) after VCC rises above the reset threshold or MR
is deasserted. RESET on the MAX6803 is push/pull.3MR
Manual-Reset Input. A logic low on MR asserts reset. Reset remains
asserted as long as MR is low, and for the reset timeout period (tRP) after
MR goes high. Leave unconnected or connect to VCC if not used.4VCCSupply Voltage Input
VCC
VCC
GND
MAX6805
RESETMR
VCC
GND
RESET
MOTOROLA
68HCXX
100kΩ
MAX6803/MAX6804/
MAX6805
4-Pin, Low-Power
µP Reset Circuits with Manual Reset
Pin Description
µPs and circuitry do not operate when VCC drops below
1V. For the MAX6804 application where RESET must
be valid down to 0, adding a pulldown resistor between
RESET and GND removes stray leakage currents,
holding RESET low (Figure 2a). The pulldown resistor
value is not critical; 100kΩ is large enough not to load
RESET, and small enough to pull it low. For the MAX6803,
where RESET must be valid to VCC = 0, a 100kΩ pullup
resistor between RESET and VCC will hold RESET high
when VCC falls below 0.7V (Figure 2b).
Since the MAX6805 has an open-drain, active-low
out-put, it typically uses a pullup resistor. With this device,
RESET will most likely not maintain an active condi-
tion, but will drift to a non-active level due to the pullup
resistor and the reduced sinking capability of the open-
drain device. Therefore, this device is not recommend-
ed for applications where the RESET pin is required to
be valid down to VCC = 0.
Figure 2. Ensuring Reset Valid down to VCC = 0
VCC
GND
MAX6804
RESETMR
100kΩ
(a)VCC
GND
MAX6803
RESET
100kΩ*
(b)*ASSUMES HIGH-Z RESET INPUT TO THE µP
MAX6803/MAX6804/
MAX6805
4-Pin, Low-Power
µP Reset Circuits with Manual Reset
MAX6804
VCC
VCC
RESETMRRESET
GND
PUSHBUTTON
SWITCH
VCC
GND
VCC(RESET)
GND
MAX6803
MAX6804
MAX6805
SOT143TOP VIEW
RESET
( ) ARE FOR MAX6803
Typical Operating Circuit
Pin Coniguration
Table 1. Factory-Trimmed Reset Thresholds
RESET
THRESHOLD
SUFFIX
TA = +25°CTA = -40°C to +125°C
MINTYP (VTH)MAXMINMAX4.7144.804.8864.6564.9444.6154.704.7854.5594.8414.5474.634.7134.4914.7694.4194.504.5814.3654.6354.3014.384.4594.2494.5114.2234.304.3774.1714.4294.1244.204.2764.0744.3264.0264.104.1743.9774.2233.9284.004.0723.8804.1204.8303.903.9703.7834.0173.7323.803.8683.6863.9143.6333.703.7673.5893.8113.5353.603.6653.4923.7083.4373.503.5633.3953.6053.3393.403.4613.2983.5023.2413.303.3593.2013.3993.1423.203.2583.1043.2963.0253.083.1352.9883.1722.9463.003.0542.9103.0902.8772.932.9832.8423.0182.7502.802.8502.7162.8842.6512.702.7492.6192.7812.5832.632.6772.5512.709
MAX6803/MAX6804/
MAX6805
4-Pin, Low-Power
µP Reset Circuits with Manual Reset
