MAX837 Fast Delivery |IC PHOENIX CO.,LIMITED

MAX837 ,4-Pin Micropower Voltage MonitorsApplications_______________Ordering InformationPrecision Battery MonitorPIN- TOPPART* TEMP RANGELoa ..
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MAX837EUS+T ,4-Pin Micropower Voltage MonitorsApplications_______________Ordering InformationPrecision Battery MonitorPIN- TOPPART* TEMP RANGELoa ..
MAX837EUS-T ,4-Pin Micropower Voltage MonitorsMAX836/MAX83719-1137; Rev 0; 9/964-Pin Micropower Voltage Monitors_______________
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MAX837
4-Pin Micropower Voltage Monitors
MAX836/MAX837
4-Pin Micropower Voltage Monitors
TOP VIEW
OUTVCC
GND
SOT143
MAX836
MAX837
___________________Pin Configuration
GND
1.204V
REF
OUT
MAX836
ONLY
MAX836
MAX837
VCCVCC
VCC
0.1μF
__________Typical Operating Circuit
19-1137; Rev 3; 5/08
______________General Description
The MAX836/MAX837 micropower voltage monitors
contain a 1.204V precision bandgap reference and a
comparator in a SOT143 package. The MAX836 has an
open-drain, n-channel output driver, while the MAX837
has a push-pull output driver. Two external resistors set
the trip threshold voltage.
________________________Applications
Precision Battery Monitor
Load Switching
Battery-Powered Systems
Threshold Detectors
____________________________Features±1.25% Precision Voltage ThresholdSOT143 PackageLow Cost< 5µA Typical Supply CurrentOpen-Drain Output (MAX836)
Push-Pull Output (MAX837)
_______________Ordering Information
*All devices available in tape-and-reel only. Contact factory for
availability.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
PART*TEMP RANGEPIN-
PACKAGE
TOP
MARK
MAX836EUS-T-40°C to +85°C4 SOT143-4EQAA
MAX837EUS-T-40°C to +85°C4 SOT143-4ERAA
MAX836/MAX837
4-Pin Micropower Voltage Monitors
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC= +2.5V to +11.0V, TA= TMINto TMAX, unless otherwise noted. Typical values are at TA= +25°C.)
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, OUT to GND (MAX836)....................................-0.3V to 12V
IN, OUT to GND (MAX837).........................-0.3V to (VCC+ 0.3V)
Input Current
VCC.................................................................................20mA
IN.....................................................................................10mA
Output Current, OUT...........................................................20mA
Rate of Rise, VCC............................................................100V/µs
Continuous Power Dissipation
4-Pin SOT143 (derate 4mW/°C above +70°C).............320mW
Operating Temperature Range...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +150°C
Lead Temperature (soldering, 10s).................................+300°CNoottee 11::The voltage-detector output remains in the direct state for VCCdown to 1.2V when VIN≤VCC/2.Noottee 22::Supply current has a monotonic dependence on VCC(see the Typical Operating Characteristics).Noottee 33::IN leakage current has a monotonic dependence on VCC(see the Typical Operating Characteristics).Noottee 44::The MAX836 open-drain output can be pulled up to a voltage greater than VCC, but may not exceed 11V.= -40°C to +85°C
VCC= full operating range
VIN= 1.25V,
OUT = high
TA= TMINto TMAX8.0VCC= 3.6VTA= +25°C2.05.0
VCC= full operating rangeICC
VIN= 1.16V,
OUT = lowSupply Current (Note 2)
3.56.5= +25°C
CONDITIONS
VCC= 5.0V, 50mV overdrive= +25°C
VCC= 5.0V, 100mV overdrive
VCC= 5V, IN = low to high
VCC= 5.0V, no load (MAX837 only)
VCC= 5.0V, no load (MAX836 pull-up = 10kΩ)
VIN= VTH
VIN> VTHMAX(MAX836 only)
VIN> VTHMAX, ISOURCE= 500µA (MAX837 only)
VIN< VTHMIN, ISINK= 500µA
TA= TMINto TMAX
VINfallingVCC= 3.6V
PARAMETERSYMBOLMINTYPMAXUNITS
1.1691.2041.231Trip Threshold VoltageVTH1.1851.2041.215V
Trip Threshold Voltage
HysteresisVHYST6mV
IN Operating Voltage Range
(Note 1)VINVCC-1V
IN Leakage Current (Note 3)IINnA±3±12
Operating Voltage Range
(Note 1)VCC2.511.0V
Propagation DelaytPL80µs
Glitch Immunity35µs
OUT Rise TimetRT260ns
OUT Fall TimetFT680ns
Output Leakage Current
(Note 4)ILOUT±1µA
Output-Voltage HighVOHVCC- 0.5V
Output-Voltage LowVOL0.4V
MAX836/MAX837
4-Pin Micropower Voltage Monitors
TRIP THRESHOLD VOLTAGE
vs. TEMPERATURE
MAX836/7 01
TEMPERATURE (°C)
TRIP THRESHOLD VOLTAGE (V)0-20-40-60100806040
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX836/7 02
VCC (V)
SUPPLY CURRENT (
VIN = 1.22V6
SUPPLY CURRENT vs. IN VOLTAGE
MAX836/7 03
VIN (V)
SUPPLY CURRENT (13759101112
VCC = 11V
VCC = 3.6V6
IN LEAKAGE CURRENT vs. IN VOLTAGE
MAX836/7 04
VIN (V)
IN LEAKAGE CURRENT (nA)137591011
VCC = 11V
TA = +85°C
TA = -40°C
TA = +25°C
10,000
1,000
OUTPUT VOLTAGE
vs. OUTPUT SINK CURRENT
MAX836/7-06B
OUTPUT SINK CURRENT (mA)
OUTPUT VOLTAGE (mV)
TA = +85°C
TA = -40°C
TA = +25°C
IN LEAKAGE CURRENT
vs. SUPPLY VOLTAGE
MAX836/7 05
VCC (V)
IN LEAKAGE CURRENT (nA)
TA = -40°C
TA = +85°C
TA = +25°C
VIN = 1.2V
MAX837 OUTPUT VOLTAGE
vs. OUTPUT SOURCE CURRENT
MAX836/7-06A
OUTPUT SOURCE CURRENT (mA)
OUTPUT VOLTAGE (V)
TA = +25°C
TA = -40°C
TA = +85°C
OUTPUT LOW VOLTAGE
vs. SUPPLY VOLTAGE
MAX836/7 07
VCC (V)
OUTPUT LOW VOLTAGE (mV)3597101112
ISINK = 500μA8
SHORT-CIRCUIT SINK CURRENT vs.
SUPPLY VOLTAGE
MAX836/7 08
VCC (V)
SHORT-CIRCUIT SINK CURRENT (mA)
TA = +85°C
TA = -40°C
TA = +25°C
__________________________________________Typical Operating Characteristics
(VCC= +5V, RLOAD= 1MΩ, RPULLUP= 10kΩ(MAX836 only), TA = +25°C, unless otherwise noted.)
Detailed Description
The MAX836/MAX837 micropower voltage monitors
contain a 1.204V precision bandgap reference and a
comparator (see the Typical Operating Circuit). The
only difference between the two parts is the structure of
the comparator output driver. The MAX836 has an
open-drain n-channel output driver that can be pulled
up to a voltage higher than VCC, but under 11V. The
MAX837’s output is push-pull, and can both source
and sink current.
Programming the Trip Voltage
Two external resistors set the trip voltage, VTRIP (Figure 1).
VTRIPis the point at which the applied voltage (typically
VCC) toggles OUT. The MAX836/MAX837’s high input
impedance allows large-value resistors without compro-
mising trip-voltage accuracy. To minimize current con-
sumption, select a value for R2 between 500kΩand
1MΩ, then calculate R1 as follows:
where VTRIP= desired trip voltage (in volts), VTH=
threshold trip voltage (1.204V).
Applications Information
Adding Hysteresis
Hysteresis adds noise immunity to the MAX836/MAX837
and prevents repeated triggering when VINis near the
threshold trip voltage. Figure 2 shows how to add hys-
R1 = R2 V-1TRIP⎜⎟
MAX836/MAX837
4-Pin Micropower Voltage Monitors
_____________________________Typical Operating Characteristics (continued)
(VCC= +5V, RLOAD= 1MΩ, RPULLUP= 10kΩ(MAX836 only), TA = +25°C, unless otherwise noted.)
_____________________Pin Description
NAMEFUNCTIONGNDSystem GroundVCCSystem Supply Input
PININ
Noninverting Input to the Comparator.
The inverting input connects to the
internal 1.204V bandgap reference.OUTOpen-Drain (MAX836) or
Push-Pull (MAX837) Output
GND
RPULLUP
OUT
MAX836
VCCVCC
VCCR1 + R2VTRIP = (1.204)
NOTE: UNITS ARE OHMS AND VOLTS
0.1μF
OUT RISE/FALL-TIME
vs. SUPPLY VOLTAGE
MAX836/7 10
VCC (V)
TIME (ns)
FALL TIME
RISE TIME
MAX837 ONLY
VCC FALLING PROPAGATION DELAY
vs. TEMPERATURE
MAX836/7 09
TEMPERATURE (°C)
PROPAGATION DELAY (-4008040100
1mV/μs
10mV/μs
VTRIP = 3.0V
VTRIP = 3.0V
VTRIP = 4.63V
VTRIP = 4.63V
both parts. For the MAX836, select the ratio of resistors
R1 and R2 so that IN sees 1.204V when the monitor volt-
age falls to or rises above the desired trip point (VTRIP).
R3 adds hysteresis and is typically an order of magni-
tude larger than R1 or R2. The current through R1 and
R2 should be at least 500nA to ensure that the 12nA
maximum input current does not shift the trip point sig-
nificantly. Capacitor C1 adds additional noise rejection.
Monitoring Voltages Other than VCC
The MAX836/MAX837 can monitor voltages other than
VCC(Figure 3). Calculate VTRIPas shown in the
Programming the Trip Voltage section. The monitored
voltage (VMON) is independent of VCC. VINmust be 1V
less than VCC.
Heater Temperature Control
Figure 4 shows a basic heater temperature-control cir-
cuit. Upon power-up, OUT is high and the n-channel
MOSFET turns on. Current flows through the heating
element (R4), warming the surrounding area. R2 is a
negative-temperature-coefficient thermistor and as tem-
perature increases, its resistance decreases. As the
thermistor heats up and its resistance decreases, the
MAX837’s voltage at IN decreases until it reaches the
1.204V threshold voltage. At this point, OUT goes low,
turning off the heating element. The thermistor cools
and the voltage at IN rises until it overcomes the
MAX837’s hysteresis (6mV). OUT returns high when this
point is reached, turning on the heating element again.
This cycle repeats as long as power is applied.
Determine the thermistor’s resistance (R2) at the
desired temperature. Then, using R2’s resistance and
half the resistance of R3, calculate R1’s value with the
following formula:
R1 = (R2 + R3) V
1.204-1CC⎛⎜⎟
MAX836/MAX837
4-Pin Micropower Voltage Monitors
GND
NOTE: C1 ADDS ADDITIONAL NOISE IMMUNITY
OUTOUTVCCVCC0.1μF
MAX837
Figure 2. Adding Hysteresis to the Comparator
GNDOUTVCC
VMON
VCC
0.1μF
MAX837
Figure 3. Monitoring Voltages Other than VCC
THERMISTOR
WITH
NEGATIVE
COEFFICIENT
HEATING
ELEMENT
OUTGND
VCC
VCC
VCC
0.1μF
R1 = (R2 + R3)(- 1 Ω) 1.204
MAX837
Figure 4. Heater Temperature Control
MAX836/MAX837
4-Pin Micropower Voltage Monitors
Package Information
For the latest package outline information and land patterns, go
to /packages.
PACKAGE TYPEPACKAGE CODEDOCUMENT NO.
4 SOT143U4-121-0052
Chip Information
TRANSISTOR COUNT:54

Partno	Mfg	Dc	Qty	Available	Descript
MAX837		N/a	40	avai	4-Pin Micropower Voltage Monitors