LM27CIM5-2HJ [NSC]
SOT-23, 3 Degree Celcious Accurate, 120-150 Degree Celcious Factory Preset Thermostat; SOT - 23 , 3度Celcious准确, 120-150度Celcious出厂预设恒温器型号: | LM27CIM5-2HJ |
厂家: | National Semiconductor |
描述: | SOT-23, 3 Degree Celcious Accurate, 120-150 Degree Celcious Factory Preset Thermostat |
文件: | 总9页 (文件大小:202K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
August 2002
LM27
SOT-23, 3˚C Accurate, 120˚C-150˚C Factory Preset
Thermostat
n Portable Battery Powered Systems
n Fan Control
The LM27 is a precision, single digital-output, low-power
n Industrial Process Control
General Description
thermostat comprised of an internal reference, DAC, tem-
perature sensor and comparator. Utilizing factory program-
ming, it can be manufactured with different trip points as well
as different digital output functionality. The trip point (TOS
n HVAC Systems
n Electronic System Protection
)
can be preset at the factory to any temperature in the range
of +120˚C to +150˚C in 1˚C increments. The LM27 has one
digital output (OS/OS/US/US), one digital input (HYST) and
one analog output (VTEMP). The digital output stage can be
preset as either open-drain or push-pull. In addition, it can be
factory programmed to be active HIGH or LOW. The digital
output can be factory programmed to indicate an over tem-
perature shutdown event (OS or OS) or an under tempera-
ture shutdown event (US or US). When preset as an over-
temperature shutdown (OS) it will go LOW to indicate that
the die temperature is over the internally preset TOS and go
HIGH when the temperature goes below (TOS–THYST). Simi-
larly, when preprogrammed as an undertemperature shut-
down (US) it will go HIGH to indicate that the temperature is
below TUS and go LOW when the temperature is above
(TUS+THYST). The typical hysteresis, THYST, can be set to
2˚C or 10˚C and is controlled by the state of the HYST pin. A
VTEMP analog output provides a voltage that is proportional
to temperature and has a −10.7mV/˚C output slope.
Features
n Internal comparator with pin selectable 2˚C or 10˚C
hysteresis
n No external components required
n Open-drain or push-pull digital output; supports CMOS
logic levels
n Internal temperature sensor with VTEMP output pin
n VTEMP output allows after-assembly system testing
n Internal voltage reference and DAC for trip-point setting
n Currently available in 5-pin SOT-23 plastic package
n Excellent power supply noise rejection
Key Specifications
j
Power Supply Voltage
2.7V to 5.5V
40µA(max)
j
Power Supply Current
15µA(typ)
j
j
Hysteresis Temperature
2˚C or 10˚C(typ)
3˚C (max)
Currently, there are several standard parts available, see
ordering information for details. For other part options, con-
tact a National Semiconductor Distributor or Sales Repre-
sentative for information on minimum order qualification. The
LM27 is currently available in a 5-lead SOT-23 package.
Temperature Trip Point Accuracy
Applications
n Microprocessor Thermal Management
n Appliances
LM27CIM5-2HJ Simplified Block Diagram and Connection Diagram
20030701
The LM27CIM5-2HJ has a fixed trip point of 140˚C.
For other trip point and output function availability,
please see ordering information or contact National Semiconductor.
© 2002 National Semiconductor Corporation
DS200307
www.national.com
Ordering Information
For more detailed information on the suffix meaning see the part number template at the end of the Electrical Characteris-
tics Section. Contact National Semiconductor for other set points and output options.
Order Number
3000 Units in Tape & Reel
NS Package
Number
MA05B
Bulk Rail
LM27CIM5-1HJ
LM27CIM5-2HJ
Top Mark
T1HJ
Trip Point Setting Output Function
LM27CIM5X-1HJ
LM27CIM5X-2HJ
130˚C
140˚C
Open Drain OS
Open Drain OS
T2HJ
MA05B
Connection Diagram
20030702
Pin Description
Pin Number
Pin Name
Function
Connection
GND for 10˚C or V+ for 2˚C
1
HYST
Hysteresis control, digital
input
2
GND
Ground, connected to the
back side of the die through
lead frame.
System GND
3
4
VTEMP
V+
Analog output voltage
proportional to temperature
Supply input
Leave floating or connect to a high impedance
node.
2.7V to 5.5V with a 0.1µF bypass capacitor.
For PSRR information see Section Titled
NOISE CONSIDERATIONS.
5
OS
OS
US
US
Overtemperature Shutdown
open-drain active low
Controller interrupt, system or power supply
shutdown; pull-up resistor ≥ 10kΩ
thermostat digital output
Overtemperature Shutdown
totem-pull active high
Controller interrupt, system or power supply
shutdown
thermostat digital output
Undertemperature Shutdown
open-drain active low
System or power supply shutdown; pull-up
resistor ≥ 10kΩ
thermostat digital output
Undertemperature Shutdown
totem-pull active high
System or power supply shutdown
thermostat digital output
Note: pin 5 functionality and trip point setting are programmed during LM27 manufacture.
www.national.com
2
Absolute Maximum Ratings (Note 1)
Storage Temperature
ESD Susceptibility (Note 4)
Human Body Model
Machine Model
−65˚C to + 150˚C
Input Voltage
6.0V
2500V
250V
Input Current at any pin (Note 2)
Package Input Current(Note 2)
Package Dissipation at TA = 25˚C
(Note 3)
5mA
20mA
Operating Ratings(Note 1)
500mW
Soldering Information
SOT23 Package
Specified Temperature Range
TMIN ≤ TA ≤ TMAX
−40˚C ≤ TA ≤ +150˚C
+2.7V to +5.5V
+5.5V
LM27CIM
Vapor Phase (60 seconds)
Infrared (15 seconds)
215˚C
220˚C
Positive Supply Voltage (V+)
Maximum VOUT
LM27 Electrical Characteristics
The following specifications apply for V+ = 2.7VDC to 5.5VDC, and VTEMP load current = 0µA unless otherwise specified. Bold-
face limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25˚C unless otherwise specified.
Typical
LM27CIM
Limits
Units
Symbol
Parameter
Conditions
(Note 6)
(Limits)
(Note 7)
Temperature Sensor
<
<
Trip Point Accuracy (Includes
REF, DAC, Comparator Offset,
+120˚C TA +150˚C
3
˚C (max)
V
and Temperature Sensitivity
errors)
Trip Point Hysteresis
HYST = GND
HYST = V+
10
2
˚C
˚C
VTEMP Output Temperature
Sensitivity
−10.82
mV/˚C
VTEMP Temperature Sensitivity
Error to Equation:
VO = (−3.552x10−6x(T−30)2+
(−10.695x10−3x(T−30))+
1.8386V
−30˚C ≤ TA ≤ 150˚C,
2.7V ≤ V+ ≤ 5.5V
−55˚C ≤ TA ≤ 150˚C,
4.5V ≤ V+ ≤ 5.5V
TA = 25˚C
3
3
˚C (max)
˚C (max)
2.5
0.7
˚C (max)
mV
VTEMP Load Regulation
VTEMP Line Regulation
Supply Current
−1µA ≤ IL ≤ 0
0.070
−0.2
15
0 ≤ IL ≤ +40µA
+2.7V ≤ V+ ≤ +5.5V,
−30˚C ≤ TA ≤ +120˚C
mV (max)
mV/V
IS
22
µA (max)
µA (max)
40
Digital Output and Input
IOUT(“1”)
Logical “1” Output Leakage
V+ = +5.0V
0.001
1
µA (max)
V (max)
Current (Note 9)
VOUT(“0”)
Logical “0” Output Voltage
IOUT = +1.2mA and
V+≥2.7V;
0.4
IOUT = +3.2mA and
V+≥4.5V; (Note 8)
ISOURCE = 500µA, V+
≥ 2.7V
VOUT(“1”)
Logical “1” Push-Pull Output
Voltage
0.8 x V+
V+ − 1.5
0.8 x V+
0.2 x V+
V (min)
V (min)
V (min)
V (max)
ISOURCE = 800µA,
V+≥4.5V
VIH
VIL
HYST Input Logical ”1“ Threshold
Voltage
HYST Input Logical ”0“ Threshold
Voltage
3
www.national.com
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed
specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test
conditions.
+
<
>
V ), the current at that pin should be limited to 5mA. The 20mA
Note 2: When the input voltage (V ) at any pin exceeds the power supply (V
GND or V
I
I
I
maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5mA to four. Under normal
operating conditions the maximum current that pins 2, 4 or 5 can handle is limited to 5mA each.
Note 3: The maximum power dissipation must be derated at elevated temperatures and is dictated by T
(maximum junction temperature), θ (junction to
JA
Jmax
ambient thermal resistance) and T (ambient temperature). The maximum allowable power dissipation at any temperature is P = (T
–T )/θ or the number
A
D
Jmax
A JA
given in the Absolute Maximum Ratings, whichever is lower. For this device, T
= 150˚C. For this device the typical thermal resistance (θ ) of the different
Jmax
JA
package types when board mounted follow:
Package Type
θJA
SOT23-5, MA05B
250˚C/W
Note 4: The human body model is a 100pF capacitor discharge through a 1.5kΩ resistor into each pin. The machine model is a 200pF capacitor discharged directly
into each pin.
Note 5: See the URL ”http://www.national.com/packaging/“ for other recommendations and methods of soldering surface mount devices.
Note 6: Typicals are at T = T = 25˚C and represent most likely parametric norm.
J
A
Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 8: Care should be taken to include the effects of self heating when setting the maximum output load current. The power dissipation of the LM27 would increase
by 1.28mW when I
=3.2mA and V
=0.4V. With a thermal resistance of 250˚C/W, this power dissipation would cause an increase in the die temperature of
OUT
OUT
about 0.32˚C due to self heating. Self heating is not included in the trip point accuracy specification.
Note 9: The 1µA limit is based on a testing limitation and does not reflect the actual performance of the part. Expect to see a doubling of the current for every 15˚C
increase in temperature. For example, the 1nA typical current at 25˚C would increase to 16nA at 85˚C.
Part Number Template
The series of digits labeled xyz in the part number LM27CIM-xyz, describe the set point value and the function of the output as
follows:
The place holders xy describe the set point temperature as shown in the following table.
x (10x)
y (1x)
Temperature (˚C)
x (10x)
y (1x)
Temperature (˚C)
-
-
-
-
-
-
-
H
J
0
1
2
3
4
5
6
-
-
S
T
V
-
7
8
K
L
-
9
Z
1
2
3
12
13
14
15
N
P
R
-
-
-
The value of z describes the assignment/function of the output as shown in the following table:
Open-Drain/
Active-Low/High
Push-Pull
OS/US
Value of z
Digital Output Function
0
0
1
1
0
0
1
1
0
1
0
1
J
K
L
Active-Low, Open-Drain, OS output
Active-Low, Open-Drain, US output
Active-High, Push-Pull, OS output
Active-High, Push-Pull, US output
N
For example:
•
the part number LM27CIM5-2SJ has TOS = 147˚C, and programmed as an active-low open-drain overtemperature shutdown
output.
•
the part number LM27CIM5-ZLN has TUS = 123˚C, and programmed as an active-high, push-pull undertemperature shutdown
output.
Active-high open-drain and active-low push-pull options are available, please contact National Semiconductor for more informa-
tion.
www.national.com
4
Functional Description
LM27 OPTIONS
20030712
20030713
LM27-_ _J
LM27-_ _K
20030714
20030715
LM27-_ _L
LM27-_ _N
FIGURE 1. Output Pin Options Block Diagrams
The LM27 can be factory programmed to have a trip point
anywhere in-between 120˚C to 150˚C.
board temperature not the ambient temperature (see
Section Titled Mounting Considerations)
3.
4.
5.
Applications Hints
A. Observe that OS is high.
B. Drive VTEMP to ground.
AFTER-ASSEMBLY PCB TESTING
C. Observe that OS is now low.
D. Release the VTEMP pin.
E. Observe that OS is now high.
The LM27’s VTEMP output allows after-assembly PCB testing
by following a simple test procedure. Simply measuring the
VTEMP output voltage will verify that the LM27 has been
assembled properly and that its temperature sensing cir-
cuitry is functional. The VTEMP output has very weak drive
capability that can be overdriven by 1.5mA. Therefore, one
can simply force the VTEMP voltage to cause the digital
output to change state, thereby verifying that the comparator
and output circuitry function after assembly. Here is a
sample test procedure that can be used to test the
LM27CIM5X-2HJ which has a 140˚C trip point.
A. Observe that OS is high.
B. Drive VTEMP voltage down gradually.
C. When OS goes low, note the VTEMP voltage.
>
D. VTEMPTrig = VTEMP at OS trigger (HIGH- LOW)
E. Calculate Ttrig using Equation (2).
1. Turn on V+ and measure VTEMP. Then calculate the
temperature reading of the LM27 using the equation:
A. Gradually raise VTEMP until OS goes HIGH. Note
VTEMP
.
VO = (−3.552x10−6x(T−30)2) +
B. Calculate THYST using Equation (2).
(−10.69576x10−3x(T−30)) + 1.8386V
(1)
or
VTEMP LOADING
The VTEMP output has very weak drive capability (40µA
source, 1µA sink). So care should be taken when attaching
circuitry to this pin. Capacitive loading may cause the VTEMP
output to oscillate. Simply adding a resistor in series as
shown in Figure 2 will prevent oscillations from occurring. To
determine the value of the resistor follow the guidelines
given in Table 1. The same value resistor will work for either
placement of the resistor. If an additional capacitive load is
placed directly on the LM27 output, rather than across
CLOAD, it should be at least a factor of 10 smaller than
(2)
2. Verify that the temperature measured in step one is
within ( 3˚C + error of reference temperature sensor) of
the ambient/board temperature. The ambient/board tem-
perature (reference temperature) should be measured
using an extremely accurate calibrated temperature sen-
sor, which is in close proximity to and mounted on the
same PCB as the LM27 perhaps even touching the GND
lead of the LM27 if possible. The LM27 will sence the
CLOAD
.
5
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MOUNTING CONSIDERATIONS
Applications Hints (Continued)
The LM27 can be applied easily in the same way as other
integrated-circuit temperature sensors. It can be glued or
cemented to a surface. The temperature that the LM27 is
sensing will be within about +0.06˚C of the surface tempera-
ture to which the LM27’s leads are attached to.
TABLE 1. Resistive compensation for capacitive
loading of VTEMP
CLOAD
≤100pF
1nF
R (Ω)
0
This presumes that the ambient air temperature is almost the
same as the surface temperature; if the air temperature were
much higher or lower than the surface temperature, the
actual temperature measured would be at an intermediate
temperature between the surface temperature and the air
temperature.
8200
3000
1000
430
10nF
100nF
≥1µF
To ensure good thermal conductivity, the backside of the
LM27 die is directly attached to the GND pin (pin 2). The
temperatures of the lands and traces to the other leads of the
LM27 will also affect the temperature that is being sensed.
Alternatively, the LM27 can be mounted inside a sealed-end
metal tube, and can then be dipped into a bath or screwed
into a threaded hole in a tank. As with any IC, the LM27 and
accompanying wiring and circuits must be kept insulated and
dry, to avoid leakage and corrosion. This is especially true if
the circuit may operate at cold temperatures where conden-
sation can occur. Printed-circuit coatings and varnishes such
as Humiseal and epoxy paints or dips are often used to
ensure that moisture cannot corrode the LM27 or its connec-
tions.
20030717
a) R in series with capacitor
The junction to ambient thermal resistance (θJA) is the pa-
rameter used to calculate the rise of a part’s junction tem-
perature due to its power dissipation. For the LM27 the
equation used to calculate the rise in the die junction tem-
perature is as follows:
(3)
where TA is the ambient temperature, V+ is the power supply
voltage, IQ is the quiescent current, IL_TEMP is the load
current on the VTEMP output, VDO is the voltage on the digital
output, and IDO is the load current on the digital output. Since
the LM27’s junction temperature is the actual temperature
being measured, care should be taken to minimize the load
current that the LM27 is required to drive.
20030718
b) R in series with signal path
FIGURE 2. Resistor placement for capacitive loading
compensation of VTEMP
The tables shown in Figure 3 summarize the thermal resis-
tance for different conditions and the rise in die temperature
of the LM27 without any loading on VTEMP and a 10k pull-up
resistor on an open-drain digital output with a 5.5V power
supply.
NOISE CONSIDERATIONS
The LM27 has excellent power supply noise rejection. Listed
below is a variety of signals used to test the LM27 power
supply rejection. False triggering of the output was not ob-
served when these signals where coupled into the V+ pin of
the LM27.
SOT23-5
SOT23-5
no heat sink
small heat sink
θJA
(˚C/W)
250
TJ−TA
θJA
(˚C/W)
TBD
TJ−TA
(˚C)
•
•
•
square wave 400kHz, 1Vp-p
(˚C)
0.11
TBD
square wave 2kHz, 200mVp-p
sine wave 100Hz to 1MHz, 200mVp-p
Still Air
TBD
TBD
Moving Air
TBD
TBD
Testing was done while maintaining the temperature of the
LM27 one degree centigrade way from the trip point with the
output not activated.
FIGURE 3. Thermal resistance (θJA) and temperature
rise due to self heating (TJ−TA)
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6
Typical Applications
20030703
Note: The fan’s control pin has internal pull-up. The 10k pull-down sets a slow fan speed. When the output of the LM27 goes low, the fan will speed up.
FIGURE 4. Two Speed Fan Speed Control
20030720
FIGURE 5. Fan High Side Drive
20030721
FIGURE 6. Fan Low Side Drive
7
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Typical Applications (Continued)
20030722
FIGURE 7. Audio Power Amplifier Thermal Protection
20030723
FIGURE 8. Simple Thermostat
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8
Physical Dimensions inches (millimeters)
unless otherwise noted
5-Lead Molded SOT-23 Plastic Package, JEDEC
Order Number LM27CIM5 or LM27CIM5X
NS Package Number MA05B
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
1. Life support devices or systems are devices or
systems which, (a) are intended for surgical implant
into the body, or (b) support or sustain life, and
whose failure to perform when properly used in
accordance with instructions for use provided in the
labeling, can be reasonably expected to result in a
significant injury to the user.
2. A critical component is any component of a life
support device or system whose failure to perform
can be reasonably expected to cause the failure of
the life support device or system, or to affect its
safety or effectiveness.
National Semiconductor
Corporation
Americas
National Semiconductor
Europe
National Semiconductor
Asia Pacific Customer
Response Group
Tel: 65-2544466
Fax: 65-2504466
National Semiconductor
Japan Ltd.
Tel: 81-3-5639-7560
Fax: 81-3-5639-7507
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Email: support@nsc.com
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Email: ap.support@nsc.com
www.national.com
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.
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