19-1280; Rev 6; 2/11
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
________________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
Ordering Information
PART
MAX6501UK_
_ _ _+T
MAX6502UK_
_ _ _+T
MAX6503UK_
_ _ _+T
MAX6504UK_
_ _ _+T
TEMP RANGE
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
-55°C to +125°C
PIN-PACKAGE
5 SOT23
5 SOT23
5 SOT23
5 SOT23
Typical Operating Circuit
+2.7V TO +5.5V
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.
V
CC
MAX6502
TOVER
GND
GND
HYST
V
CC
μP
________________________Applications
µP Temperature Monitoring in High-Speed
Computers
Temperature Control
Temperature Alarms
Fan Control
INT
GND
Selector Guide and Pin Configurations appear at end of
data sheet.
________________________________________________________________
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, Micropower
Temperature Switches in SOT23
MAX6501–MAX6504
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
CC
) Range....................................-0.3V to +7V
TOVER
(MAX6501) ...................................................-0.3V to +7V
TOVER (MAX6502) .....................................-0.3V to (V
CC
+ 0.3V)
TUNDER
(MAX6503) ................................................-0.3V to +7V
TUNDER (MAX6504) ..................................-0.3V to (V
CC
+ 0.3V)
All Other Pins..............................................-0.3V to (V
CC
+ 0.3V)
Input Current (all pins) ........................................................20mA
Output Current (all pins) .....................................................20mA
Continuous Power Dissipation (T
A
= +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
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 (MAX6501/MAX6503 only), T
A
= T
MIN
to T
MAX
, unless otherwise noted. Typical values are
at T
A
= +25°C.) (Note 1)
PARAMETER
Supply Voltage Range
Supply Current
Temperature Threshold
Accuracy (Note 2)
SYMBOL
V
CC
I
CC
-45°C to -25°C
ΔT
TH
-15°C to +15°C
+35°C to +65°C
+75°C to +125°C
Temperature Threshold
Hysteresis
HYST Input Threshold
(Note 3)
T
HYST
V
IH
V
IL
I
SOURCE
= 500µA, V
CC
> 2.7V
(MAX6502/MAX6504 only)
I
SOURCE
= 800µA, V
CC
> 4.5V
(MAX6502/MAX6504 only)
I
SINK
= 1.2mA, V
CC
> 2.7V
I
SINK
= 3.2mA, V
CC
> 4.5V
V
CC
= 2.7V, V
TUNDER
= 5.5V (MAX6503),
V
TOVER
= 5.5V (MAX6501)
10
0.8 x V
CC
V
V
CC
- 1.5
0.3
0.4
V
nA
HYST = GND
HYST = V
CC
0.8 x V
CC
0.2 x V
CC
-6
-4
-4
-6
CONDITIONS
MIN
2.7
30
±0.5
±0.5
±0.5
±0.5
2
10
TYP
MAX
5.5
85
+6
+4
+4
+6
°C
V
°C
UNITS
V
µA
Output Voltage High
V
OH
Output Voltage Low
Open-Drain Output Leakage
Current
V
OL
Note 1:
100% production tested at T
A
= +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.
2
_______________________________________________________________________________________
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
__________________________________________Typical Operating Characteristics
(V
CC
= +5V, R
PULLUP
= 100kΩ (MAX6501/MAX6503), T
A
= +25°C, unless otherwise noted.)
SUPPLY CURRENT
vs. TEMPERATURE
MAX6501 TOC-A
MAX6501 TOC01
MAX6501–MAX6504
TRIP THRESHOLD ACCURACY
60
SAMPLE SIZE = 300
PERCENTAGE OF PARTS SAMPLED (%)
50
40
30
20
10
0
-5 -4
-3
-2
-1
0
1
2
3
4
5
ACCURACY (°C)
40
35
SUPPLY CURRENT (μA)
30
25
20
15
10
5
0
-55
-25
MAX6502/MAX6504
OUTPUT SOURCE RESISTANCE
vs. TEMPERATURE
700
600
500
400
300
200
100
0
V
CC
= 5.0V
V
CC
= 3.3V
V
CC
= 2.7V
MAX6501 TOC02
800
OUTPUT SOURCE RESISTANCE (Ω)
5
35
65
95
125
-55
-25
5
35
65
95
125
TEMPERATURE (°C)
TEMPERATURE (°C)
OUTPUT SINK RESISTANCE
vs. TEMPERATURE
140
OUTPUT SINK RESISTANCE (Ω)
120
100
V
CC
= 3.3V
80
V
CC
= 2.7V
MAX6501 TOC03
SOT23 THERMAL STEP RESPONSE
IN PERFLUORINATED FLUID
MAX6501 TOC4
SOT23 THERMAL STEP RESPONSE
IN STILL AIR
MAX6501 TOC5
160
+100°C
+100°C
+15°C/div
60
40
20
0
-55
-25
5
35
65
95
125
V
CC
= 5.0V
+12.5°C/div
MOUNTED ON 0.75in
2
OF 2 oz. COPPER
+25°C
5sec/div
MOUNTED ON 0.75in
2
OF 2 oz. COPPER
+25°C
20sec/div
TEMPERATURE (°C)
HYSTERESIS
vs. TRIP TEMPERATURE
14
12
HYSTERESIS (°C)
10
8
6
4
2
0
-45
-25
-5
15
35
55
75
95
115
TRIP TEMPERATURE (°C)
MAX6503
MAX6504
HYST = GND
MAX6501
MAX6502
HYST = GND
MAX6503
MAX6504
HYST = V
CC
MAX6501
MAX6502
HYST = V
CC
MAX6501 TOC8
MAX6501 STARTUP AND POWER-DOWN
(T
<
T
TH
)
MAX6501 TOC07
MAX6501 STARTUP DELAY
(T
>
T
TH
)
MAX6501 TOC07A
16
A
A
B
B
TRACE A: TOVER VOLTAGE, R
PULLUP
= 100kΩ
TRACE B: V
CC
PULSE DRIVEN FROM 3.3V CMOS LOGIC OUTPUT
TRACE A: TOVER VOLTAGE, R
PULLUP
= 100kΩ
TRACE B: V
CC
PULSE DRIVEN FROM 3.3V CMOS LOGIC OUTPUT
_______________________________________________________________________________________
3
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
MAX6501–MAX6504
Pin Description
PIN
NAME
MAX6501
1, 2
MAX6502
1, 2
MAX6503
1, 2
MAX6504
1, 2
GND
Ground. Not internally connected. Connect both ground pins
together close to the chip. Pin 2 provides the lowest thermal
resistance to the die.
Hysteresis Input. Connect HYST to GND for 2°C hysteresis, or
connect to V
CC
for 10°C hysteresis.
Supply Input (+2.7V to +5.5V)
Open-Drain, Active-Low Output.
TOVER
goes low when the die
temperature exceeds the factory-programmed temperature
threshold. Connect to a 100kΩ pullup resistor. May be pulled
up to a voltage higher than V
CC
.
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 100kΩ pullup resistor. May be
pulled up to a voltage higher than V
CC
.
Push-Pull Active-High Output. TUNDER goes high when the die tem-
perature falls below the factory-programmed temperature threshold.
FUNCTION
3
4
3
4
3
4
3
4
HYST
V
CC
5
—
—
—
TOVER
—
5
—
—
TOVER
—
—
5
—
TUNDER
—
—
—
5
TUNDER
________________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
T
TH
= +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).
Table 1. Factory-Programmed Threshold
Range
PART
MAX6501
MAX6502
MAX6503
MAX6504
THRESHOLD (T
TH
) RANGE
+35°C < T
TH
< +125°C
+35°C < T
TH
< +125°C
-45°C < T
TH
< +15°C
-45°C < T
TH
< +15°C
Hysteresis Input
The HYST pin is a CMOS-compatible input that selects
hysteresis at either a high level (10°C for HYST = V
CC
)
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 V
CC
.
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).
4
_______________________________________________________________________________________
Low-Cost, +2.7V to +5.5V, Micropower
Temperature Switches in SOT23
MAX6501–MAX6504
TOVER
POSITIVE
TEMPCO
REFERENCE
NEGATIVE
TEMPCO
REFERENCE
HYST
NETWORK
V
TOVER
MAX6501
WITH 100kΩ PULLUP
HYST
COLD
+25°C
T
TH
HOT
TEMP
MAX6501
V
TOVER
POSITIVE
TEMPCO
REFERENCE
NEGATIVE
TEMPCO
REFERENCE
HYST
NETWORK
TOVER
MAX6502
HYST
COLD
+25°C
T
TH
HOT
TEMP
MAX6502
MAX6503
WITH 100kΩ PULLUP
TUNDER
POSITIVE
TEMPCO
REFERENCE
NEGATIVE
TEMPCO
REFERENCE
HYST
NETWORK
V
TUNDER
HYST
COLD
T
TH
+25°C
HOT
TEMP
MAX6503
V
TUNDER
POSITIVE
TEMPCO
REFERENCE
NEGATIVE
TEMPCO
REFERENCE
HYST
NETWORK
TUNDER
MAX6504
HYST
COLD
T
TH
+25°C
HOT
TEMP
MAX6504
Figure 1. Block and Functional Diagrams
_______________________________________________________________________________________
5
