19-3147; Rev 1; 2/11
Low-Cost, 2.7V to 5.5V Temperature Switches
in a SOT23
General Description
The MAX6514/MAX6515 low-cost, fully integrated temper-
ature switches assert a logic signal when their die tem-
perature crosses a factory-programmed threshold.
Operating from a 2.7V to 5.5V supply, these devices fea-
ture a fixed voltage reference, an analog temperature
sensor, and a comparator. They are available with facto-
ry-trimmed temperature trip thresholds from -45°C to
+15°C and +35°C to +115°C in 10°C increments, and are
accurate to ±1°C (typ). These devices require no external
components and typically consume 22µA of supply cur-
rent. Hysteresis is pin selectable at 2°C or 10°C.
The MAX6514/MAX6515 are offered with hot-tempera-
ture thresholds (+35°C to +115°C), asserting when the
temperature is above the threshold or with cold-temper-
ature thresholds (-45°C to +15°C), asserting when the
temperature is below the threshold. The MAX6514/
MAX6515 can be used over a -35°C to +125°C range
with a supply voltage of 2.7V to 5.5V. For applications
sensing temperature down to -45°C, a supply voltage
above 4.5V is required.
The MAX6514 has an active-high, push-pull output. The
MAX6515 has an active-low, open-drain output. These
devices are available in a space-saving 5-pin SOT23
package and operate over the -55°C to +125°C tem-
perature range.
Features
♦
High-Accuracy ±1.5°C (max) over -15°C to +65°C
Temperature Range
♦
Low-Power Consumption: 22µA Typical Current
♦
Factory-Programmed Thresholds from -45°C to
+115°C in 10°C Increments
♦
Open-Drain or Push-Pull Outputs
♦
Pin-Selectable 2°C or 10°C Hysteresis
MAX6514/MAX6515
Ordering Information
PART
MAX6514UK_
_ _ _+T
MAX6515UK_
_ _ _+T
TEMP RANGE
-55°C to +125°C
-55°C to +125°C
PIN-
PACKAGE
5 SOT23
5 SOT23
Applications
Over/Undertemperature Protection
Fan Control
Test Equipment
Temperature Control
Temperature Alarms
Notebook, Desktop PCs
RAID
Servers
Note:
These parts are offered in 16 standard temperature ver-
sions with a minimum order of 2500 pieces. To complete the
suffix information, add P or N for positive or negative trip tem-
perature, and select an available trip point in degrees centi-
grade. For example, the MAX6514UKP065+T describes a
MAX6514 in a 5-pin SOT23 package with a +65°C threshold in
tape and reel (2.5k minimum order). Contact the factory for
pricing and availability.
+Denotes
a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Typical Operating Circuit
V
CC
100kΩ
V
CC
TOVER
INT
V
CC
0.1μF
MAX6515
MICROCONTROLLER
Pin Configurations and Functional Diagram appear at end of
data sheet.
GND GND HYST
GND
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Low-Cost, 2.7V to 5.5V Temperature Switches
in a SOT23
MAX6514/MAX6515
ABSOLUTE MAXIMUM RATINGS
All Voltages Are Referenced to GND
V
CC
..........................................................................-0.3V to +6V
TOVER, TUNDER
(open drain)................................ -0.3V to +6V
TOVER, TUNDER (push-pull)....................... -0.3V to V
CC
+ 0.3V
HYST .............................................................-0.3V to V
CC
+ 0.3V
Continuous Power Dissipation
SOT23 (derate 3.1mW/°C above +70°C) .....................247mW
Operating Temperature Range ........................-55°C to +125°C
Junction Temperature ..................................................... +150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) ................................ +300°C
Soldering Temperature ....................................................+260°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.
ELECTRICAL CHARACTERISTICS
(V
CC
= 2.7V to 5.5V, R
PULLUP
= 100kΩ, (open-drain output only), T
A
= -55°C to +125°C, unless otherwise noted. Typical values are
at T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage Range
SYMBOL
V
CC
Hot-temperature thresholds
(+35°C to +115°C)
Supply Current
I
CC
Cold-temperature thresholds
(-45°C to +15°C)
-15°C to +65°C
Temperature Threshold Accuracy
(Note 2)
Temperature Threshold
Hysteresis
HYST Input Threshold (Note 4)
Logic Output Voltage High
(Push-Pull)
Logic Output Voltage Low
(Push-Pull and Open Drain)
Open-Drain Output Leakage
Current
ΔT
TH
+75°C to +115°C
-45°C to -25°C (Note 3)
T
HYST
V
IH
V
IL
V
OH
V
OL
I
SOURCE
= 500µA, V
CC
> 2.7V
I
SOURCE
= 800µA, V
CC
> 4.5V
I
SINK
= 1.2mA, V
CC
> 2.7V
I
SINK
= 3.2mA, V
CC
> 4.5V
V
CC
= 2.7V, open-drain output = 5.5V
10
0.8 x V
CC
V
CC
- 1.5
0.3
0.4
HYST = V
CC
HYST = GND
0.8 x V
CC
0.2 x V
CC
-1.5
-2.5
-3
2
10
CONDITIONS
MIN
2.7
22
40
+1.5
+2.5
+3
°C
V
V
V
nA
°C
TYP
MAX
5.5
40
µA
UNITS
V
Note 1:
100% production tested at T
A
= +25°C. Specifications over temperature are guaranteed by design.
Note 2:
The MAX6514/MAX6515 are available with internal factory-programmed temperature trip thresholds from -45°C to +15°C
and +35°C to +115°C in 10°C increments.
Note 3:
V
CC
must be greater than 4.5V for a switching threshold of -45°C.
Note 4:
Guaranteed by design.
2
_______________________________________________________________________________________
Low-Cost, 2.7V to 5.5V Temperature Switches
in a SOT23
Typical Operating Characteristics
(V
CC
= 4.5V, T
A
= +25°C, unless otherwise noted.)
MAX6514/MAX6515
TRIP THRESHOLD ACCURACY
SAMPLE SIZE = 147
PERCENTAGE OF PARTS SAMPLED (%)
40
MAX6514 toc01
50
SUPPLY CURRENT
vs. TEMPERATURE
MAX6514 toc02
30
25
SUPPLY CURRENT (μA)
20
15
10
5
30
20
10
0
-1.25 TO -0.75 TO -0.25 TO 0.25 TO 0.75 TO 1.25 TO
-1.5
0.5
1.0
1.5
-1.0
-0.5
ACCURACY (°C)
0
-55 -35 -15
5
25
45
65
85 105 125
TEMPERATURE (°C)
TOVER/TUNDER OUTPUT VOLTAGE HIGH
vs. SOURCE CURRENT
MAX6514 toc03
TOVER/TUNDER OUTPUT VOLTAGE LOW
vs. SINK CURRENT
MAX6514 toc04
5
500
4
400
V
OH
(V)
2
V
OL
(V)
0
10
3
300
200
1
100
0
1
2
3
4
5
6
7
8
9
I
SINK
(mA)
0
0
1
2
3
4
5
6
7
8
9
10
I
SINK
(mA)
STARTUP AND POWER-DOWN (TEMP < T
TH
)
MAX6514 toc05
STARTUP DELAY (TEMP > T
TH
)
MAX6514 toc06
V
CC
(2V/div)
V
CC
(2V/div)
TOVER
(2V/div)
TOVER
(2V/div)
TIME (400μs/div)
TIME = 100μs
_______________________________________________________________________________________
3
Low-Cost, 2.7V to 5.5V Temperature Switches
in a SOT23
MAX6514/MAX6515
Pin Description
PIN
MAX6514
1, 2
3
4
5
MAX6515
1, 2
3
4
—
NAME
GND
HYST
V
CC
TOVER
Ground
Hysteresis Input. Connect to V
CC
for 2°C of hysteresis or to GND for 10°C hysteresis.
Input Supply. Bypass to ground with a 0.1µF capacitor.
Push-Pull Active-High Output (Hot Threshold). TOVER goes high when the die temperature
exceeds the factory-programmed hot-temperature threshold.
Open-Drain, Active-Low Output (Hot Threshold).
TOVER
goes low when the die temperature
exceeds the factory-programmed hot-temperature threshold. Connect to a 100kΩ pullup
resistor. Can be pulled up to a voltage higher than V
CC
.
Push-Pull Active-High Output (Cold Threshold). TUNDER goes high when the die temperature
falls below the factory-programmed cold-temperature threshold.
Open-Drain, Active-Low Output (Cold Threshold).
TUNDER
goes low when the die
temperature goes below the factory-programmed cold-temperature threshold. Connect to a
100kΩ pullup resistor. Can be pulled up to a voltage higher than V
CC
.
FUNCTION
—
5
TOVER
5
—
TUNDER
—
5
TUNDER
Detailed Description
The MAX6514/MAX6515 fully integrated temperature
switches incorporate a fixed reference, an analog tem-
perature sensor, and a comparator. Pin-selectable 2°C
or 10°C hysteresis keeps the digital output from oscil-
lating when the die temperature approaches the
threshold temperature. The MAX6514 has an active-
high, push-pull output structure that can sink or source
current. The MAX6515 has an active-low, open-drain
output structure that can only sink current. The internal
power-on reset circuit guarantees the logic output is at
its +25°C state for at least 50µs.
Logic Temperature Indicators
Overtemperature Indicator (Hot Thresholds)
TOVER and
TOVER
designations apply to thresholds
above T
A
= +25°C (+35°C, +45°C, +55°C, +65°C,
+75°C, +85°C, +95°C, +105°C, and +115°C). All “hot”
thresholds are positive temperatures.
The overtemperature indicator output is open drain
active low (TOVER) or push-pull active high (TOVER).
TOVER
goes low when the die temperature exceeds
the factory-programmed temperature threshold.
TOVER
should be pulled up to a voltage no greater than 5.5V
with a 100kΩ pullup resistor. TOVER is a push-pull
active-high CMOS output that goes high when the die
temperature exceeds the factory-programmed temper-
ature threshold.
Undertemperature Indicator (Cold Thresholds)
TUNDER and
TUNDER
designations apply to thresh-
olds below T
A
= +25°C (+15°C, +5°C, -5°C, -15°C,
-25°C, -35°C, -45°C). The undertemperature indicator
output is open-drain, active low (TUNDER) or push-pull,
active high (TUNDER).
TUNDER
goes low when the die
temperature goes below the factory-programmed tem-
perature threshold.
TUNDER
should be pulled up to a
voltage no greater than 5.5V with a 100kΩ pullup resis-
tor. TUNDER is a push-pull active-high CMOS output
that goes high when the die temperature falls below the
factory-programmed temperature threshold.
Hysteresis Input
The HYST input selects the devices’ temperature hys-
teresis and prevents the output from oscillating when the
temperature approaches the trip point. Connect HYST to
V
CC
for 2°C hysteresis or to GND for 10°C hysteresis.
4
_______________________________________________________________________________________
Low-Cost, 2.7V to 5.5V Temperature Switches
in a SOT23
Applications Information
Temperature-Window Alarm
The MAX6515 logic output asserts when the die tem-
perature is outside the factory-programmed range.
Combining the outputs of two devices creates an
over/undertemperature alarm. Two MAX6515s are used
to form two complementary pairs, containing one cold
trip-point output and one hot trip-point output. The
assertion of either output alerts the system to an out-of-
range temperature (Figure 1).
The thermal overrange signal can be used to assert a
thermal shutdown, power-up, recalibration, or other
temperature-dependent function.
The typical thermal resistance is +140°C/W for the 5-
pin SOT23 package. To limit the effects of self-heating,
minimize the output current. For example, if the
MAX6514/MAX6515 sink 1mA, the open-drain output
voltage is guaranteed to be less than 0.3V. Therefore,
an additional 0.3mW of power is dissipated within the
IC. This corresponds to a 0.042°C shift in the die tem-
perature in the 5-pin SOT23 package.
+5V
100kΩ
OUT OF RANGE
V
CC
TOVER
TUNDER
V
CC
MAX6514/MAX6515
Low-Cost, Fail-Safe Temperature
In high-performance/high-reliability applications, multi-
ple temperature monitoring is important. The high-level
integration and low cost of the MAX6514/MAX6515
facilitate the use of multiple temperature monitors to
increase system reliability. The Figure 2 application
uses two MAX6514s with different hot-temperature
thresholds to ensure that fault conditions that can over-
heat the monitored device cause no permanent dam-
age. The first temperature monitor activates the fan
when the die temperature exceeds +45°C. The second
MAX6514 triggers a system shutdown if the die temper-
ature reaches +75°C, preventing damage from a wide
variety of destructive fault conditions, including
latchups, short circuits, and cooling-system failures.
MAX6515UKP075
MAX6515UKN005
GND GND HYST
GND GND HYST
Figure 1. Temperature-Window Alarms Using the MAX6515
+5V
Thermal Considerations
The MAX6514/MAX6515 supply current is typically
22µA. When used to drive high-impedance loads, the
devices dissipate negligible power and self-heating
effects are minimized.
Accurate temperature monitoring depends on the ther-
mal resistance between the device being monitored
and the MAX6514/MAX6515 die. Heat flows in and out
of plastic packages, primarily through the leads. Pin 2
of the 5-pin SOT23 package provides the lowest ther-
mal resistance to the die. Short, wide copper traces
between the MAX6514/MAX6515 and the objects
whose temperature is being monitored ensure heat
transfers occur quickly and reliably. The rise in die tem-
perature due to self-heating is given by the following
formula:
ΔT
J
= P
DISSIPATION
x
θ
JA
where P
DISSIPATION
is the power dissipated by the
MAX6514/MAX6515, and
θ
JA
is the thermal resistance
of the package.
HEAT
V
CC
TOVER
SYSTEM
SHUTDOWN
MAX6514UKP075
GND GND HYST
μP
V
CC
HYST
TOVER
FAN
CONTROL
GND
MAX6514UKP045
HEAT
GND GND
Figure 2. Low-Power, High-Reliability, Fail-Safe Temperature
Monitor
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5
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