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Ultra-Low-Voltage SC70 Voltage Detectors and µP Reset Circuits
MAX6832–MAX6840
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
General DescriptionThe MAX6832–MAX6840 are microprocessor (µP)
supervisory circuits used to monitor low-voltage power
supplies in µP and digital systems. They provide excel-
lent circuit reliability and low cost by eliminating exter-
nal components and adjustments when used with
+1.2V to +1.8V powered circuits.
These devices assert a reset signal whenever the VCC
supply voltage declines below a preset threshold or
whenever manual reset (MR) is asserted. Reset remains
asserted for a fixed timeout delay after VCChas risen
above the reset threshold or when manual reset is
deasserted. Five different timeout periods are available:
70µs (voltage detector), 1.5ms, 30ms, 210ms, and 1.68s.
Reset thresholds suitable for operation with a variety of
supply voltages are available.
The MAX6832/MAX6835/MAX6838 have a push-pull
active-low reset output (RESET). The MAX6833/
MAX6836/MAX6839 have a push-pull active-high reset
output (RESET) and the MAX6834/MAX6837/MAX6840
have an open-drain active-low reset output (RESET). The
open-drain active-low reset output requires a pullup resis-
tor that can be connected to a voltage higher than VCC.
The MAX6835/MAX6836/MAX6837 feature a debounced
manual reset input (MR), while the MAX6838/MAX6839/
MAX6840 provide a RESET-IN input allowing the user to
externally adjust the reset threshold. The reset compara-
tor is designed to ignore fast transients on VCC.
Low supply current of 7.5µA makes the MAX6832–
MAX6840 ideal for use in portable equipment. These
devices are available in 3- and 4-pin SC70 packages.
ApplicationsComputers
Controllers
Intelligent Instruments
Critical µP and µC Power Monitoring
Portable/Battery-Powered Equipment
FeaturesFactory-Set Reset Threshold Voltages for
Nominal Supplies from 1.2V to 1.8VLow Power Consumption: 7.5µA (typ) Space-Saving 3- and 4-Pin SC70 Packages±2.5% Reset Threshold Accuracy Over
Temperature Five Different Timeout Periods Available: 70µs
(voltage detector), 1.5ms, 30ms, 210ms, and 1.68sThree Reset Output Configurations
Push-Pull RESET
Push-Pull RESET
Open-Drain RESETGuaranteed Reset Valid to VCC=
0.55V—Active-Low
0.75V—Active-HighAdjustable Threshold Reset-In Option Manual Reset Input OptionImmune to Short Negative VCCTransientsPin Compatible with MAX803/MAX809/MAX810,
MAX6711/MAX6712/MAX6713, and
MAX6381–MAX6390 Series
Ordering Information
Pin Configurations, Typical Operating Circuit, and Selector
Guide appear at end of data sheet.
PARTTEMP RANGEPIN-PACKAGE
MAX6832_XRD_-T-40°C to +85°C3 SC70-3
MAX6833_XRD_-T-40°C to +85°C3 SC70-3
MAX6834_XRD_-T-40°C to +85°C3 SC70-3
MAX6835_XSD_-T-40°C to +85°C4 SC70-4
MAX6836_XSD_-T-40°C to +85°C4 SC70-4
MAX6837_XSD_-T-40°C to +85°C4 SC70-4
MAX6838XSD_-T-40°C to +85°C4 SC70-4
MAX6839XSD_-T-40°C to +85°C4 SC70-4
MAX6840XSD_-T-40°C to +85°C4 SC70-4
Insert the desired suffix letter from the Threshold Suffix Guide
(MAX6832–MAX6837) and the Active Timeout Period Guide
tables into the blanks to complete the part number. Sample
stock is generally available on standard versions only (see
Standard Versions table). Standard versions require a minimum
order increment of 2.5k units. Nonstandard versions must be
ordered in 10k unit increments. Contact factory for availability.
All parts are offered in tape-and-reel only.
Devices are available in both leaded and lead-free packaging.
Visit www.maximintegrated.com/products/patentsfor
product patent marking information.
MAX6832–MAX6840
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VCC= +0.55V to +3.6V, TA= TMINto TMAX, 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)
VCC........................................................................-0.3V to +6.0V
Open-Drain RESET, MR.......................................-0.3V to +6.0V
RESET-IN, Push-Pull RESET
and RESET..............................................-0.3V to (VCC+ 0.3V)
Input/Output Current (all pins)............................................20mA
Continous Power Dissipation (TA= +70°C)
3-Pin SC70 (derate 2.9mW/°C above +70°C)...............235mW
4-Pin SC70 (derate 3.1mW/°C above +70°C)...............245mW
Operating Temperature Range...........................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°C
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSTA = -40°C to +85°C
MAX6832/MAX6835/MAX6838
MAX6834/MAX6837/MAX6840
TA = -40°C to +85°C
MAX6833/MAX6836/MAX68390.853.6Supply Voltage RangeVCC
TA = 0°C to +85°C
MAX6833/MAX6836/MAX68390.753.6
VCC = 1.2V, no load, reset not asserted7.513
VCC = 1.8V, no load, reset not asserted916Supply CurrentICC
VCC = 3.6V, no load, reset not asserted16251.6201.6651.7101.5301.5751.6201.3501.3881.4251.2751.3131.3501.0801.1101.140
Reset ThresholdVTH
F (Note 2)1.0201.0501.080
1.1V ≤ VCC ≤ 3.3V, 0°C to +85°C-2.5%444+2.5%RESET-IN ThresholdVRSTIN1.1V ≤ VCC ≤ 3.3V, -40°C to +85°C-3.0%444+3.0%mV
RESET-IN Leakage CurrentIRSTIN-25+25nA
Reset Threshold HysteresisVHYS0.75%VTH
VCC or RESET-IN to Reset DelayVCC falling, step signal from
(VTH + 100mV) to (VTH - 100mV)60µs0.0711.52203040140210280
Reset Active Timeout PeriodtRP112016802240
MAX6832–MAX6840
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
ELECTRICAL CHARACTERISTICS (continued)(VCC= +0.55V to +3.6V, TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.) (Note 1)
PARAMETERSYMBOLCONDITIONSMINTYPMAXUNITSPropagation Delay (D0 only)tPVCC rising, step signal
from (VTH - 100mV) to (VTH + 100mV)70µs
Startup Time (D0 only)VCC rising from 0 to 1.1V (tR < 1µs)150µs
VIL 0.3 x VCCMR Input VoltageVIH0.7 x VCCV
MR Minimum Input Pulse WidthMR driven from VCC to 02µs
MR Glitch RejectionMR driven from VCC to 0100ns
MR to Reset DelayMR driven from VCC to 0500ns
MR Pullup Resistance To VCC142026kΩ
VCC ≥ 0.55V, ISINK =15µA, reset asserted0.15
VCC ≥ 1.0V, ISINK = 80µA, reset asserted0.15Open-Drain RESET Output
VoltageVOL
VCC ≥ 1.5V, ISINK = 200µA, reset asserted0.2
Open-Drain RESET Output
Leakage CurrentILKGVCC > VTH, reset not asserted1.0µA
VCC ≥ 0.55V, ISINK = 15µA, reset asserted0.2 x VCC
VCC ≥ 1.0V, ISINK = 80µA, reset asserted0.2 x VCCVOL
VCC ≥ 1.5V, ISINK = 200µA, reset asserted0.2 x VCC
VCC ≥ 1.1V, ISOURCE = 50µA, reset not
asserted0.8 x VCC
Push-Pull RESET Output
Voltage
VOH
VCC ≥ 1.5V, ISOURCE = 150µA, reset asserted0.8 x VCC
VCC ≥ 0.75V, ISOURCE = 10µA, reset asserted
(Note 2)0.8 x VCC
VCC ≥ 0.85V, ISOURCE = 10µA, reset asserted0.8 x VCC
VCC ≥ 1.0V, ISOURCE = 50µA, reset asserted0.8 x VCC
VOH
VCC ≥ 1.5V, ISOURCE = 150µA, reset asserted0.8 x VCC
VCC ≥ 1.1V, ISINK = 80µA, reset not asserted0.2 x VCC
Push-Pull RESET Output
Voltage
VOLVCC ≥ 1.5V, ISINK = 200µA, reset not asserted0.2 x VCC
Note 1:100% production tested at +25°C. Over temperature limits are guaranteed by design.
Note 2:Temperature range is from 0°C to +85°C.
Typical Operating Characteristics(VCC= full range and TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C).
SUPPLY CURRENT vs. TEMPERATUREMAX6832-40 toc01
SUPPLY CURRENT (
TEMPERATURE (°C)
VCC = 3.6V
VCC = 3.0V
VCC = 2.5V
VCC = 1.8V
VCC = 1.5V
VCC = 0.55V
POWER-DOWN RESET DELAY
vs. TEMPERATURE
MAX6832-40 toc02
TEMPERATURE (°C)
POWER-DOWN RESET DELAY (
VOD = OVERDRIVE (mV)
VOD = 10mV
VOD = 20mV
VOD = 100mV
VOD = 200mV
NORMALIZED RESET THRESHOLD
vs. TEMPERATURE
MAX6832-40 toc04
TEMPERATURE (°C)
NORMALIZED RESET THRESHOLD
VTH = 1.665V
NORMALIZED POWER-UP RESET
TIMEOUT vs. TEMPERATURE
MAX6832-40 toc03
TEMPERATURE (°C)
NORMALIZED RESET TIMEOUT PERIOD
D1 OPTION
D2 OPTION
MAX6832–MAX6840
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
MAX6832–MAX6840
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
Pin Description—MAX6832–MAX6837
PIN
MAX6833
SC70-3
MAX6832/
MAX6834
SC70-3
MAX6836
SC70-4
MAX6835/
MAX6837
SC70-4
NAMEFUNCTION111GNDGround—2RESET
Reset Output, Open-Drain or Push-Pull, Active-Low. RESET
changes from HIGH to LOW when VCC drops below the
selected reset threshold or MR is pulled low. RESET remains
LOW for the reset timeout period after VCC exceeds the device
reset threshold and MR is released high.—2—RESET
Reset Output, Push-Pull, Active-High. RESET changes from
LOW to HIGH when the VCC input drops below the selected
reset threshold or MR is pulled low. RESET remains HIGH for
the reset timeout period after VCC exceeds the device reset
threshold and MR is released high.33MR
Active-Low Manual Reset Input. Internal 20kΩ pullup to VCC.
Pull LOW to force a reset. Reset remains active as long as MR is
LOW and for the reset timeout period after MR goes HIGH.
Leave unconnected or connect to VCC if unused.44VCCSupply Voltage and Monitored Supply
Pin Description—MAX6838/MAX6839/MAX6840
PIN
MAX6839
SC70-4
MAX6838/
MAX6840
SC70-4
NAMEFUNCTION1RESET-IN
Adjustable Reset Threshold Input. High-impedance input for reset comparator. Connect
this pin to an external resistive-divider network to set the reset threshold voltage; the
typical threshold is 444mV. Reset is asserted when RESET-IN is below the threshold (VCC
is not monitored).VCCSupply Voltage (1.1V to 3.3V)3GNDGround—RESET
Reset Output, Push-Pull, Active-High. RESET changes from LOW to HIGH when the
RESET-IN input drops below the typical reset threshold (444mV). RESET remains HIGH for
the reset timeout period after RESET-IN exceeds the reset threshold.RESET
Reset Output, Open-Drain or Push-Pull, Active-Low. RESET changes from HIGH to LOW
when RESET-IN drops below the typical reset threshold (444mV). RESET remains LOW for
the reset timeout period after RESET-IN exceeds the reset threshold.
MAX6832–MAX6840
Ultra-Low-Voltage SC70 Voltage Detectors
and µP Reset Circuits
Detailed Description
Reset OutputA microprocessor’s (µP’s) reset input starts the µP in a
known state. The MAX6832–MAX6840 assert a reset to
prevent code-execution errors during power-up, power-
down, or brownout conditions. They also assert a reset
signal whenever the VCCsupply voltage falls below a
preset threshold (MAX6832–MAX6837) or RESET-IN
falls below the adjustable threshold (MAX6838/
MAX6839/MAX6840), keeping reset asserted for a fixed
timeout delay (Table 2) after VCCor RESET-IN has risen
above the reset threshold. The MAX6832/MAX6835/
MAX6838 use a push-pull active-low output, the
MAX6833/MAX6836/MAX6839 have a push-pull active-
high output, and the MAX6834/MAX6837/MAX6840
have an open-drain active-low output stage. Connect a
pullup resistor on the MAX6834/MAX6837/MAX6840’s
RESEToutput to any supply between 0 and 6V.
Manual Reset InputMany µP-based systems require manual reset capabili-
ty, allowing the operator, a test technician, or external
logic circuitry to initiate a reset. Reset remains asserted
while MRis low, and for a fixed timeout delay after MR
returns high. This input has an internal 20kΩpullup
resistor, so it can be left open if it is not used. MRcan
be driven with CMOS logic level, or with open-drain/col-
lector outputs. To create a manual reset function, con-
nect a normally open momentary switch from MRto
ground; external debounce circuitry is not required. Ifis driven from long cables or if the device is used in
a noisy environment, connecting a 0.1µF capacitor fromto ground provides additional noise immunity.
RESET-IN InformationThe MAX6838/MAX6839/MAX6840 feature a RESET-IN
input for monitoring supply voltages down to 0.44V. An
external resistive-divider network can be used to set
voltage monitoring thresholds as shown in Figure 1. As
the monitored voltage falls, the voltage at RESET-IN
decreases and asserts a reset when it falls below the
RESET-IN threshold (VRSTIN). The low-leakage current
MAX6838/
MAX6839/
MAX6840
RESET
TIMEOUT
PERIOD
RESET
OUTPUT
VREF = 444mV
RESET-IN
RESET/
RESET
GND
VCCVCC
MAX6832–
MAX6837
RESET
TIMEOUT
PERIOD
MANUAL
RESET
DETECT
RESET
OUTPUT
VREF = 444mV
RESET/
RESET
GND
MR (MAX6835/MAX6836/MAX6837 ONLY)
PULLUP
Functional DiagramsVMONITORED
RESET-IN
GND
RESET
(RESET)
VCC
( ) ARE FOR MAX6839
MAX6838/
MAX6839/
MAX6840
R1 = R2 [(VMONITORED/VREF) -1]
WHERE VMONITORED IS THE DESIRED TRIP LEVEL,
VREF = 444mV
