19-1819; Rev 0; 10/00
Low-Cost, Remote SOT Temperature Switches
General Description
The MAX6511/MAX6512/MAX6513 are fully integrated,
remote temperature switches that use an external P-N
junction (typically a diode-connected transistor) as the
sensing element to measure the remote temperature.
These devices assert a logic signal when the tempera-
ture crosses a factory-programmed threshold. Available
trip thresholds are from +45°C to +125°C in 10°C incre-
ments. Accuracy is within ±3°C (T
A
= -5°C to +55°C) or
±5°C (T
A
= -40°C to +85°C). Hysteresis is pin selec-
table to 5°C or 10°C.
The MAX6511 has an active-low CMOS output and the
MAX6513 has an active-high CMOS output. The
MAX6512 has an open-drain output. The output is
asserted when the temperature exceeds the threshold
value. The active-low open-drain output is intended to
interface with a microprocessor (µP) reset or interrupt
input. The active-high CMOS output can directly drive a
power FET to control a cooling fan.
The MAX6511/MAX6512/MAX6513 operate from a
+3.0V to +5.5V supply and typically consume 400µA of
supply current. They are available in a small 6-pin
SOT23 package.
Features
o
Continuously Measure External Junction
Temperature
o
Factory-Programmed Temperature Threshold
from +45°C to +125°C in 10°C Increments
o
Insensitive to Series Parasitic Resistance
o
Active-Low CMOS Output (MAX6511) or Open-
Drain Output for Overtemperature Alarm
(MAX6512) or Active-High Output (MAX6513) for
Direct Fan Control
o
<100ms Response Time
o
Accuracy
±3°C (T
REMOTE =
+45°C to +125°C, T
A
= -5°C to +55°C)
±5°C (T
REMOTE =
+45°C to +125°C, T
A
= -40°C to +85°C)
o
Pin-Selectable 5°C or 10°C Hysteresis
o
400µA Average Current Consumption
o
+3.0V to +5.5V Supply Range
o
6-Pin SOT23 Package
MAX6511/MAX6512/MAX6513
________________________Applications
CPU Temperature Monitoring in High-Speed
Computers
Multichip Modules
Battery Packs
Temperature Control
Temperature Alarms
Fan Control
PART*
Ordering Information
TEMP. RANGE
PIN-
OUTPUT
PACKAGE
CMOS
(Active-Low)
MAX6511EUT_
_ _ -T -40°C to +85°C 6 SOT23-6
MAX6512EUT_
_ _ -T -40°C to +85°C 6 SOT23-6 Open-Drain
MAX6513EUT_
_ _ -T -40°C to +85°C 6 SOT23-6
CMOS
(Active-High)
Pin Configuration
TOP VIEW
V
DD
1
6
DXP
*These parts are offered in nine standard temperature versions
with a minimum order of 2500 pieces. To complete the suffix infor-
mation, select an available trip point in degrees centigrade from
the device marking codes table. For example, the
MAX6511UT065-T describes a MAX6511 in a SOT23-6 package
with a +65°C threshold.
GND
2
MAX6511
MAX6512
MAX6513
5
DXN
HYST
3
4
TOVER (TOVER)
( ) ARE FOR MAX6513 SOT23 ONLY.
Typical Operating Circuit appears at end of data sheet.
________________________________________________________________
Maxim Integrated Products
1
For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Low-Cost, Remote SOT Temperature Switches
MAX6511/MAX6512/MAX6513
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (V
DD
) ...............................................-0.3V to +6V
DXP, DXN, HYST, TOVER (MAX6513),
TOVER
(MAX6511/MAX6512) ................-0.3V to (V
DD
+ 0.3V)
TOVER (MAX6513),
TOVER
(MAX6511)
Output Current ....................................................-1mA/+50mA
DXN Input Current...................................................-1mA/+50mA
Current (all other pins)......................................................±20mA
Continuous Power Dissipation (T
A
= +70°C)
6-Pin SOT23-6 (derate 9.1mW/°C above +70°C) ........727mW
Operating Temperature Range ...........................-40°C to +85°C
Storage Temperature Range .............................-65°C to +150°C
Junction Temperature ......................................................+150°C
Lead Temperature
Vapor Phase (60s) .......................................................+215°C
Infrared (15s) ...............................................................+220°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
DD
= +3.0V to +5.5V, C
S
= 2200pF, T
A
= -40°C to +85°C, T
REMOTE
= +45°C to +125°C (Note 1), unless otherwise noted. Typical
values are at T
A
= +25°C.) (Note 2)
PARAMETER
Supply Voltage Range
Supply Current
Temperature Threshold
Accuracy (Note 3)
Power-Supply Sensitivity for
Temperature Trip Point
Temperature Threshold
Hysteresis
Response Time
Input Voltage High
Input Voltage Low
Output Voltage High
Output Voltage Low
Maximum DXP Source
Current
Minimum DXP Source
Current
V
IH
V
IL
V
OH
V
OL
MAX6511/MAX6513, I
OUT
= 1mA
I
OUT
= 1mA
0.4V
≤
V
DXP
≤
2V,
DXN = GND
0.4V
≤
V
DXP
≤
2V,
DXN = GND
270
9
V
DD
- 0.2
0.2
V
DD
-
0.2
0.2
T
HYST
HYST = V
IL
HYST = V
IH
SYMBOL
V
DD
I
DD
∆T
TH
T
A
= -5°C to +55°C
T
A
= -40°C to +85°C
-3.0
-5.0
-0.6
5
10
70
120
CONDITIONS
MIN
3.0
400
TYP
MAX
5.5
600
+3.0
+5.0
UNITS
V
µA
°C
°C/V
°C
ms
V
V
V
V
µA
µA
Note 1:
T
REMOTE
refers to the temperature of the remote-sensing junction. T
A
refers to the temperature of the MAX6511/MAX6512/
MAX6513 package.
Note 2:
All parameters are 100% production tested at T
A
= +25°C. Specifications over temperature limits are guaranteed by design.
Note 3:
This parameter is guaranteed by design to ±3.5 sigma.
2
_______________________________________________________________________________________
Low-Cost, Remote SOT Temperature Switches
Typical Operating Characteristics
(V
DD
= +3.3V, C
S
= 2200pF, T
A
= +25°C, unless otherwise noted.)
MAX6511/MAX6512/MAX6513
SUPPLY CURRENT
vs. AMBIENT TEMPERATURE
MAX6511 toc01
TEMPERATURE TRIP THRESHOLD ERROR
vs. AMBIENT TEMPERATURE T
A
MAX6511 toc02
TEMPERATURE TRIP THRESHOLD ERROR
vs. C
S
CAPACITANCE
TEMPERATURE TRIP THRESHOLD ERROR (°C)
12
10
8
6
4
2
0
-2
-4
0
10
20
30
40
50
60
MAX6511 toc03
TEMPERATURE TRIP THRESHOLD ERROR (°C)
440
420
SUPPLY CURRENT (µA)
400
380
360
340
320
300
-40
-15
10
35
60
(NOTE: SUPPLY CURRENT
INCLUDES EXTERNAL
DIODE-CONNECTED
TRANSISTOR)
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
-1.2
-1.4
-1.6
-60 -40 -20 0
14
85
20 40 60 80 100 120 140
AMBIENT TEMPERATURE T
A
(°C)
AMBIENT TEMPERATURE T
A
(°C)
C
S
CAPACITANCE (nF)
TEMPERATURE TRIP THRESHOLD ERROR
vs. SERIES RESISTANCE
TEMPERATURE TRIP THRESHOLD ERROR (°C)
MAX6511 toc04
TEMPERATURE TRIP THRESHOLD
vs. SUPPLY VOLTAGE
TEMPERATURE TRIP THRESHOLD ERROR (°C)
0.2
0
-0.2
-0.4
-0.6
-0.8
-1.0
-1.2
-1.4
-1.6
-1.8
3.0
3.5
4.0
4.5
5.0
5.5
MAX6511 toc05
1.0
0.5
0
-0.5
-1.0
-1.5
-2.0
0
0.4
20 40 60 80 100 120 140 160 180 200
SERIES RESISTANCE (Ω)
SUPPLY VOLTAGE (V)
_______________________________________________________________________________________
3
Low-Cost, Remote SOT Temperature Switches
MAX6511/MAX6512/MAX6513
Pin Description
PIN
MAX6511
MAX6512
1
2
3
NAME
MAX6513
1
2
3
V
DD
GND
HYST
Power-Supply Input, +3.0V to +5.5V. Bypass V
DD
to GND with a 0.1µF
capacitor.
Ground
Hysteresis Selection. Hysteresis is 10°C for HYST = V
DD
, 5°C for HYST = GND.
CMOS Active-Low Output (MAX6511) or Open-Drain Active-Low Output
(MAX6512).
TOVER
goes low when the temperature exceeds the factory-
programmed temperature threshold. This pin can only sink current in the
MAX6512.
CMOS Active-High Output (MAX6513). TOVER goes high when the temperature
exceeds the factory-programmed temperature threshold.
This pin connects to the negative (cathode) terminal of the external P-N sense
junction. DXN must be connected to GND.
This pin connects to the positive (anode) terminal of the external P-N sense
junction.
FUNCTION
4
—
TOVER
—
5
6
4
5
6
TOVER
DXN
DXP
Detailed Description
The MAX6511/MAX6512/MAX6513 fully integrated tem-
perature switches incorporate a precision bandgap ref-
erence, a conversion block, a current source, and a
comparator (Figure 1). These devices use an external
P-N junction as the temperature-sensing element. They
steer bias currents through the external diode, measure
the forward voltages, and compute the temperature
using a precision chopper stabilized amplifier.
Resistance values of less than 100Ω in series with the
external sense junction will result in trip-point errors
<1°C. The MAX6511/MAX6512/MAX6513 provide noise
immunity by integration and oversampling of the diode
voltage, but good design practice includes routing the
DXP and DXN lines away from noise sources, such as
high-speed digital lines, switching regulators, induc-
tors, and transformers. The DXP and DXN traces
should be paired together and surrounded by ground
plane whenever possible.
In applications where the temperature changes rapidly,
the measured temperature will be approximately equal
to the average value of the temperature during the
measurement period.
The MAX6512 has an active-low, open-drain output struc-
ture that can only sink current. The MAX6511 has an active-
low CMOS output structure, and the MAX6513 has an
active-high CMOS output.
The MAX6511/MAX6512/MAX6513 are available with
preset temperature thresholds from +45°C to +125°C in
10°C increments.
DXP
DXN
TEMPERATURE
CONVERSION
COMPAR-
ATOR
LATCH
TOVER
BANDGAP
VOLTAGE
REFERENCE
Figure 1. Functional Block Diagram
4
_______________________________________________________________________________________
Low-Cost, Remote SOT Temperature Switches
MAX6511/MAX6512/MAX6513
Table 1. Sensor Transistor Manufacturers
MANUFACTURER
Central Semiconductor (USA)
ON (USA)
Rohm Semiconductor (Japan)
Samsung (Korea)
Siemens (Germany)
Zetex (England)
MODEL NUMBER
CMPT3904
MMBT3904
SST3904
KST3904-TF
SMBT3904
FMMT3904CT-ND
TOVER (MAX6511)
TIME
TRIP TEMPERATURE
TRIP TEMPERATURE HYSTERESIS
Note:
Transistors must be diode connected (base shorted to
collector).
Figure 2. Temperature Trip Threshold Hysteresis
Hysteresis Input
The HYST pin is a CMOS-compatible input that selects
hysteresis at either a high level (10°C for HYST = V
DD
)
or a low level (5°C for HYST = GND). Hysteresis pre-
vents the output from chattering when the temperature
is near the trip point. The HYST pin must not float.
The output asserts when the temperature exceeds the
trip point and deasserts when the temperature falls
back below the trip point minus the hysteresis. For
example, if the trip point is 105°C, the output will assert
at 105°C and will not deassert until temperature falls
below 105°C minus the hysteresis (e.g., 95°C if 10°C
hysteresis is chosen) (Figure 2).
cate the manufacturer has good process controls and
that the devices have consistent V
be
characteristics.
The MAX6511/MAX6512/MAX6513 can also measure
the die temperature of CPUs and other integrated cir-
cuits having on-board temperature-sensing diodes.
Use the monitor’s output to reset the µP, assert an inter-
rupt, activate a cooling fan, or trigger an external alarm.
Noise Filtering Capacitors
A quality ceramic capacitor must be connected across
the DXP/DXN inputs to maintain temperature threshold
accuracy by filtering out noise. The capacitor should be
located physically close to the DXP/DXN pins and
should typically have a value of 2200pF. Larger capaci-
tor values can cause temperature measurement errors.
A 50% variation from the recommended capacitor
value can cause up to ±1°C error.
Applications Information
Remote-Diode Selection
To ensure best accuracy, use a good-quality diode-
connected transistor. Suggested devices are listed in
Table 1. Large power transistors are not recommend-
ed. Tight specifications for forward current gain indi-
_______________________________________________________________________________________
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