________________General Description
The MAX6501–MAX6504 low-cost, fully integrated tem-
perature switches assert a logic signal when their die
temperature crosses a factory-programmed threshold.
Operating from a +2.7V to +5.5V supply, these devices
feature two on-chip, temperature-dependent voltage
references and a comparator. They are available with
factory-trimmed temperature trip thresholds from -45°C
to +125°C in 10°C increments, and are accurate to
±0.5°C (typ) or ±6°C (max). These devices require no
external components and typically consume 30µA sup-
ply current. Hysteresis is pin-selectable at 2°C or 10°C.
The MAX6501/MAX6503 have an active-low, open-drain
output intended to interface with a microprocessor (µP)
reset input. The MAX6502/MAX6504 have an active-
high, push-pull output intended to directly drive fan-
control logic. The MAX6501/MAX6502 are offered with
hot-temperature thresholds (+35°C to +125°C), assert-
ing when the temperature is above the threshold. The
MAX6503/MAX6504 are offered with cold-temperature
thresholds (-45°C to +15°C), asserting when the tem-
perature is below the threshold.
The MAX6501–MAX6504 are offered in eight standard
temperature versions; contact the factory for pricing
and availability of nonstandard temperature versions.
They are available in a 5-pin SOT23 package.
____________________________Features
♦♦±0.5°C (typical) Threshold Accuracy Over
Full Temperature Range
♦♦No External Components Required
♦♦Low Cost
♦♦30µA Supply Current
♦♦Factory-Programmed Thresholds from
-45°C to +125°C in 10°C Increments
♦♦Open-Drain Output (MAX6501/MAX6503)
Push-Pull Output (MAX6502/MAX6504)
♦♦Pin-Selectable 2°C or 10°C Hysteresis
♦♦SOT23-5 Package
MAX6501–MAX6504
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
________________________________________________________________
Maxim Integrated Products
1
19-1280; Rev 6; 2/11
Ordering Information
Selector Guide and Pin Configurations appear at end of
data sheet.
MAX6502
+2.7V TO +5.5V
GND HYST
TOVER μP
INT
GND GND
VCC VCC
Typical Operating Circuit
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.
PART TEMP RANGE PIN-PACKAGE
MAX6501UK_ _ _ _+T -55°C to +125°C 5 SOT23
MAX6502UK_ _ _ _+T -55°C to +125°C 5 SOT23
MAX6503UK_ _ _ _+T -55°C to +125°C 5 SOT23
MAX6504UK_ _ _ _+T -55°C to +125°C 5 SOT23
Note: These parts are offered in eight standard temperature
versions with a minimum order of 2,500 pieces. To complete
the suffix information, add P or N for positive or negative trip
temperature, and select an available trip point in degrees
centigrade. For example, the MAX6501UKP065+T describes a
MAX6501 in a SOT23 package with a +65°C threshold.
Contact the factory for pricing and availability of nonstandard
temperature versions (minimum order 10,000 pieces).
+
Denotes a lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
________________________Applications
µP Temperature Monitoring in High-Speed
Computers
Temperature Control
Temperature Alarms
Fan Control
MAX6501–MAX6504
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VCC = +2.7V to +5.5V, RPULLUP = 100kΩ(MAX6501/MAX6503 only), TA= TMIN to 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.
Note 1: 100% production tested at TA= +25°C. Specifications over temperature limits are guaranteed by design.
Note 2: The MAX6501–MAX6504 are available with internal, factory-programmed temperature trip thresholds from -45°C to +125°C
in +10°C increments
(
see
Selector Guide).
Note 3: Guaranteed by design.
Supply Voltage (VCC) Range....................................-0.3V to +7V
TOVER (MAX6501) ...................................................-0.3V to +7V
TOVER (MAX6502).....................................-0.3V to (VCC + 0.3V)
TUNDER (MAX6503) ................................................-0.3V to +7V
TUNDER (MAX6504) ..................................-0.3V to (VCC + 0.3V)
All Other Pins..............................................-0.3V to (VCC + 0.3V)
Input Current (all pins) ........................................................20mA
Output Current (all pins) .....................................................20mA
Continuous Power Dissipation (TA= +70°C)
SOT23 (derate 3.1mW/°C above +70°C)......................247mW
Operating Temperature Range .........................-55°C to +135°C
Storage Temperature Range .............................-65°C to +165°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature (reflow) .......................................+260°C
-45°C to -25°C
VCC = 2.7V, VTUNDER = 5.5V (MAX6503),
VTOVER = 5.5V (MAX6501)
-15°C to +15°C
HYST = GND
ISOURCE = 500µA, VCC > 2.7V
(MAX6502/MAX6504 only)
ISINK = 1.2mA, VCC > 2.7V
CONDITIONS
-6 ±0.5 +6
µA30 85ICC
V2.7 5.5VCC
Supply Voltage Range
Supply Current
nA10
Open-Drain Output Leakage
Current
-4 ±0.5 +4
2
THYST
Temperature Threshold
Hysteresis
V
0.8 x VCC
0.3
UNITSMIN TYP MAXSYMBOLPARAMETER
+35°C to +65°C
+75°C to +125°C
-4 ±0.5 +4 °C
-6 ±0.5 +6
ΔTTH
Temperature Threshold
Accuracy (Note 2)
V
0.2 x VCC
VIL
HYST Input Threshold
(Note 3)
0.8 x VCC
VIH
ISINK = 3.2mA, VCC > 4.5V V
0.4
VOL
Output Voltage Low
HYST = VCC 10 °C
ISOURCE = 800µA, VCC > 4.5V
(MAX6502/MAX6504 only) VCC - 1.5
VOH
Output Voltage High
MAX6501–MAX6504
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
_______________________________________________________________________________________
3
0
5
10
15
20
25
30
35
40
-55 5-25 35 65 95 125
SUPPLY CURRENT
vs. TEMPERATURE
MAX6501 TOC01
TEMPERATURE (°C)
SUPPLY CURRENT (μA)
0
100
200
300
400
500
600
700
800
-55 5-25 35 65 95 125
MAX6502/MAX6504
OUTPUT SOURCE RESISTANCE
vs. TEMPERATURE
MAX6501 TOC02
TEMPERATURE (°C)
OUTPUT SOURCE RESISTANCE (Ω)
VCC = 2.7V
VCC = 5.0V
VCC = 3.3V
0
20
40
60
80
100
120
140
160
-55 5-25 35 65 95 125
OUTPUT SINK RESISTANCE
vs. TEMPERATURE
MAX6501 TOC03
TEMPERATURE (°C)
OUTPUT SINK RESISTANCE (Ω)
VCC = 2.7V
VCC = 5.0V
VCC = 3.3V
+15°C/div
+100°C
+25°C
SOT23 THERMAL STEP RESPONSE
IN PERFLUORINATED FLUID
MAX6501 TOC4
5sec/div
MOUNTED ON 0.75in2
OF 2 oz. COPPER
0
4
2
8
6
10
12
14
16
-5 15-25-45 35 55 75 95 115
HYSTERESIS
vs. TRIP TEMPERATURE
MAX6501 TOC8
TRIP TEMPERATURE (°C)
HYSTERESIS (°C)
MAX6503
MAX6504
HYST = VCC
MAX6501
MAX6502
HYST = VCC
MAX6501
MAX6502
HYST = GND
MAX6503
MAX6504
HYST = GND
+12.5°C/div
+100°C
+25°C
SOT23 THERMAL STEP RESPONSE
IN STILL AIR
MAX6501 TOC5
20sec/div
MOUNTED ON 0.75in2
OF 2 oz. COPPER
TRACE A: TOVER VOLTAGE, RPULLUP = 100kΩ
TRACE B: VCC PULSE DRIVEN FROM 3.3V CMOS LOGIC OUTPUT
MAX6501 STARTUP AND POWER-DOWN
(T < TTH)
B
A
MAX6501 TOC07
TRACE A: TOVER VOLTAGE, RPULLUP = 100kΩ
TRACE B: VCC PULSE DRIVEN FROM 3.3V CMOS LOGIC OUTPUT
MAX6501 STARTUP DELAY
(T > TTH)
B
A
MAX6501 TOC07A
__________________________________________Typical Operating Characteristics
(VCC = +5V, RPULLUP = 100kΩ(MAX6501/MAX6503), TA= +25°C, unless otherwise noted.)
0
10
20
30
40
50
60
-5 -4 -3 -2 -1 0 1 2 3 4 5
TRIP THRESHOLD ACCURACY
MAX6501 TOC-A
ACCURACY (°C)
PERCENTAGE OF PARTS SAMPLED (%)
SAMPLE SIZE = 300
MAX6501–MAX6504
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
4 _______________________________________________________________________________________
Pin Description
1, 2 1, 2
Ground. Not internally connected. Connect both ground pins
together close to the chip. Pin 2 provides the lowest thermal
resistance to the die.
1, 2
PIN
1, 2 GND
3 3 Hysteresis Input. Connect HYST to GND for 2°C hysteresis, or
connect to VCC for 10°C hysteresis.
3 3 HYST
4 4 Supply Input (+2.7V to +5.5V)
5 —
Open-Drain, Active-Low Output. TOVER goes low when the die
temperature exceeds the factory-programmed temperature
threshold. Connect to a 100kΩpullup resistor. May be pulled
up to a voltage higher than VCC.
— — TOVER
4 4 VCC
— 5
Push-Pull Active-High Output. TOVER goes high when the die tem-
perature exceeds the factory-programmed temperature threshold.
— —
Open-Drain, Active-Low Output. TUNDER goes low when the
die temperature goes below the factory-programmed tempera-
ture threshold. Connect to a 100kΩpullup resistor. May be
pulled up to a voltage higher than VCC.
5 — TUNDER
— —
Push-Pull Active-High Output. TUNDER goes high when the die tem-
perature falls below the factory-programmed temperature threshold.
— 5 TUNDER
— — TOVER
MAX6502MAX6501 MAX6503 MAX6504
NAME FUNCTION
________________General Description
The MAX6501–MAX6504 fully integrated temperature
switches incorporate two temperature-dependent refer-
ences and a comparator. One reference exhibits a pos-
itive temperature coefficient and the other a negative
temperature coefficient (Figure 1). The temperature at
which the two reference voltages are equal determines
the temperature trip point. Pin-selectable 2°C or 10°C
hysteresis keeps the output from oscillating when the
die temperature approaches the threshold temperature.
The MAX6501/MAX6503 have an active-low, open-
drain output structure that can only sink current. The
MAX6502/MAX6504 have an active-high, push-pull out-
put structure that can sink or source current. The inter-
nal power-on reset circuit guarantees the output is at
TTH = +25°C state at startup for 50µs.
The MAX6501–MAX6504 are available with factory-
preset temperature thresholds from -45°C to +125°C in
10°C increments. Table 1 lists the available temperature
threshold ranges. The MAX6501/MAX6503 outputs are
intended to interface with a microprocessor (µP) reset
input (Figure 2). The MAX6502/MAX6504 outputs are
intended for applications such as driving a fan control
(Figure 3).
Hysteresis Input
The HYST pin is a CMOS-compatible input that selects
hysteresis at either a high level (10°C for HYST = VCC)
or a low level (2°C for HYST = GND). Hysteresis pre-
vents the output from oscillating when the temperature
approaches the trip point. The HYST pin should not be
left unconnected. Drive HYST close to ground or VCC.
Other input voltages cause increased supply current.
The actual amount of hysteresis depends on the part’s
programmed trip threshold (see the
Typical Operating
Characteristics
).
Table 1. Factory-Programmed Threshold
Range
+35°C < TTH < +125°C
+35°C < TTH < +125°C
THRESHOLD (TTH) RANGE
-45°C < TTH < +15°C
-45°C < TTH < +15°C
MAX6503
MAX6504
MAX6501
MAX6502
PART
MAX6501–MAX6504
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
_______________________________________________________________________________________ 5
POSITIVE
TEMPCO
REFERENCE
NEGATIVE
TEMPCO
REFERENCE
HYST
NETWORK
TOVER
HYST
TOVER
TEMP
COLD +25°CT
TH
V
MAX6501
POSITIVE
TEMPCO
REFERENCE
NEGATIVE
TEMPCO
REFERENCE
HYST
NETWORK
TOVER
HYST
TOVER
TEMP
COLD +25°CT
TH
HOT
HOT
V
POSITIVE
TEMPCO
REFERENCE
NEGATIVE
TEMPCO
REFERENCE
HYST
NETWORK
TUNDER
HYST
TUNDER
TEMP
COLD TTH +25°C HOT
V
POSITIVE
TEMPCO
REFERENCE
NEGATIVE
TEMPCO
REFERENCE
HYST
NETWORK
TUNDER
HYST
TUNDER
TEMP
COLD TTH +25°C HOT
V
MAX6502
MAX6503
MAX6504
MAX6501
WITH 100kΩ PULLUP
MAX6504
MAX6503
WITH 100kΩ PULLUP
MAX6502
Figure 1. Block and Functional Diagrams
MAX6501–MAX6504
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
6 _______________________________________________________________________________________
Applications Information
Thermal Considerations
The MAX6501–MAX6504 supply current is typically
30µA. When used to drive high-impedance loads, the
devices dissipate negligible power. Therefore, the die
temperature is essentially the same as the package
temperature. The key to accurate temperature monitor-
ing is good thermal contact between the MAX6501–
MAX6504 package and the device being monitored. In
some applications, the SOT23 package may be small
enough to fit underneath a socketed µP, allowing the
device to monitor the µP’s temperature directly. Use the
monitor’s output to reset the µP, assert an interrupt, or
trigger an external alarm.
Accurate temperature monitoring depends on the ther-
mal resistance between the device being monitored
and the MAX6501–MAX6504 die. Heat flows in and out
of plastic packages, primarily through the leads. Pin 2
of the SOT23-5 package provides the lowest thermal
resistance to the die. Short, wide copper traces leading
to the temperature monitor ensure that heat transfers
quickly and reliably.
The rise in die temperature due to self-heating is given
by the following formula:
ΔTJ= PDISSIPATION x θJA
where PDISSIPATION is the power dissipated by the
MAX6501–MAX6504, and θJA is the package’s thermal
resistance.
The typical thermal resistance is 140°C/W for the
SOT23 package. To limit the effects of self-heating,
minimize the output currents. For example, if the
MAX6501 or MAX6503 sink 1mA, the output voltage is
guaranteed to be less than 0.3V. Therefore, an addi-
tional 0.3mW of power is dissipated within the IC. This
corresponds to a 0.042°C shift in the die temperature in
the SOT23.
Temperature-Window Alarm
The MAX6501–MAX6504 temperature switch outputs
assert when the die temperature is outside the factory-
programmed range. Combining the outputs of two
devices creates an over/undertemperature alarm. The
MAX6501/MAX6503 and the MAX6502/MAX6504 are
designed to form two complementary pairs, each con-
taining 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. The MAX6502/MAX6504
push/pull output stages can be ORed to produce a ther-
mal out-of-range alarm. More favorably, a MAX6501/
MAX6503 can be directly wire-ORed with a single exter-
nal resistor to accomplish the same task (Figure 4).
The temperature window alarms shown in Figure 4 can
be used to accurately determine when a device’s tem-
perature falls out of the -5°C to +75°C range. The ther-
mal-overrange signal can be used to assert a thermal
shutdown, power-up, recalibration, or other temperature-
dependent function.
Low-Cost, Fail-Safe
Temperature Monitor
In high-performance/high-reliability applications, multi-
ple temperature monitoring is important. The high-level
integration and low cost of the MAX6501–MAX6504
facilitate the use of multiple temperature monitors to in-
crease system reliability. Figure 5’s application uses
two MAX6502s with different temperature thresholds to
ensure that fault conditions that can overheat the moni-
tored device cause no permanent damage. The first
temperature monitor activates the fan when the die
temperature exceeds +45°C. The second MAX6502
triggers a system shutdown if the die temperature
reaches +75°C. The second temperature monitor’s out-
put asserts when a wide variety of destructive fault con-
ditions occur, including latchups, short circuits, and
cooling-system failures.
MAX6502
+5V
TOVERGNDGND
VCC HYST
μP FAN
HEAT
VCC
Figure 3. Overtemperature Fan Control
MAX6501
+3.3V
GNDHYST GND
VCC
μP
HEAT
VCC RPULLUP
100kΩ
TOVER
INT
SHUTDOWN
OR
RESET
Figure 2. Microprocessor Alarm/Reset
MAX6501–MAX6504
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
_______________________________________________________________________________________ 7
MAX6503_ _N005MAX6501_ _P075
+5V
HYSTHYST GND
GND
VCC
GNDGND
VCC
RPULL-UP
100k
TOVER TUNDER
OUT OF RANGE
MAX6502_ _P075
HYST
GND
GND
+5V
MAX6504_ _N005
GND
GND
HYST
VCC
VCC
TOVER
TUNDER
OUT OF RANGE
OVERTEMP
UNDERTEMP
Figure 4. Temperature-Window Alarms
MAX6502_ _P075
GND
GND HYST
+5V
MAX6502_ _P045
GND GND
HYST
VCC
VCC
TOVER
TOVER
TEMPERATURE
FAULT
FAN
CONTROL
μP
HEAT
HEAT
Figure 5. Low-Power, High-Reliability, Fail-Safe Temperature
Monitor
Table 2. Device Marking Codes
MAX6502UKP115 2.5kACFY
MAX6502UKP105 10kACFZ
MAX6504UKP015 10kADKE
MAX6504UKP005 2.5kABZY
MAX6504UKN005 10kADVX
MAX6504UKN015 2.5kACGD
MAX6504UKN025 10kADVT
MAX6504UKN035 10kADVU
MAX6504UKN045 10kACAX
DEVICE MINIMUM
ORDER
CODE
MAX6503UKP015 10kADPN
MAX6503UKP005 2.5kABZX
MAX6503UKN005 10kADNZ
MAX6503UKN015 2.5kACFX
MAX6503UKN025 10kADVR
MAX6503UKN035 10kADVS
MAX6503UKN045 10kADIZ
MAX6502UKP095 2.5kABZW
MAX6502UKP085 2.5kACGA
MAX6502UKP075 2.5kACGB
MAX6502UKP065 2.5kABZV
MAX6502UKP055 2.5kACGC
MAX6502UKP045 2.5kABZU
MAX6502UKP035 10kABZG
MAX6501UKP115 2.5kACAG
MAX6501UKP105 10kACFU
MAX6501UKP095 2.5kABZT
MAX6501UKP085 2.5kACDP
MAX6501UKP075 2.5kACFV
MAX6501UKP065 2.5kABZS
MAX6501UKP055 2.5kACFW
MAX6501UKP045 2.5kABZR
MAX6501UKP035 10kABZF
DEVICE MINIMUM
ORDER
CODE
MAX6501UKP125 25kADQK
MAX6502UKP125 25kADUD
MAX6501–MAX6504
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
8 _______________________________________________________________________________________
GND
VCC
HYST
( ) ARE FOR MAX6502.
15TOVER
(TOVER)
GND
MAX6501
MAX6502
SOT23
TOP VIEW
2
34
GND
VCC
HYST
( ) ARE FOR MAX6504.
15TUNDER
(TUNDER)
GND
MAX6503
MAX6504
SOT23
2
34
Pin Configurations
Chip Information
SUBSTRATE CONNECTED TO GND
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maxim-ic.com/packages. Note that a
“+”, “#”, or “-” in the package code indicates RoHS status only.
Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
PART MAX6501 MAX6502 MAX6503 MAX6504
OUTPUT
STAGE
Open-
Drain Push-Pull Open-
Drain Push-Pull
TRIP TEMP
THRESHOLD Hot Hot Cold Cold
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
✓ ✓
Selector Guide
-45
-35
-25
-15
-5
+5
+15
+35
+45
+55
+65
+75
+85
+95
+105
+115
+125 ✓ ✓
STANDARD TEMPERATURE THRESHOLDS (°C)
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
5 SOT23 U5+2 21-0057 90-0174
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 _____________________
9
© 2011 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products, Inc.
MAX6501–MAX6504
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
5 10/06
In Table 2 updated the device marking codes for MAX6503UKN035,
MAX6503UKN025, MAX6503UKN005, MAX6503UKP015, MAX6504UKN035,
MAX6504UKN025, and MAX6504UKN005
7
6 2/11
Removed the TO-220 package from entire data sheet; changed all leaded parts to
lead(Pb)-free parts in the Ordering Information table; in the Absolute Maximum Ratings
section changed the continuous power dissipation numbers (7.1mW/°C to 3.1mW/°C
and 571mW to 247mW) and added the soldering temperature; added the Package
Information table
All
