NSC LM26NV

LM26NV
SOT-23, ±3°C Accurate, Factory Preset Thermostat
(LM26 without VTEMP output)
General Description
The LM26NV is a precision, single digital-output, low-power
thermostat comprised of an internal reference, DAC, temperature sensor and comparator. Utilizing factory programming,
it can be manufactured with different trip points as well as
different digital output functionality. The trip point (TOS) can
be preset at the factory to any temperature in the range of
−55°C to +110°C in 1°C increments. The LM26NV has one
digital output (OS/OS/US/US) and one digital input (HYST).
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 temperature shutdown event
(OS or OS) or an under temperature shutdown event (US or
US). When preset as an overtemperature 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). Similarly, when preprogrammed as
an undertemperature shutdown (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.
Available parts are detailed in the ordering information. For
other part options, contact a National Semiconductor Distributor or Sales Representative for information on minimum
order qualification. The LM26NV is currently available in a 5lead SOT-23 package.
■
■
■
■
■
■
Portable Battery Powered Systems
Fan Control
Industrial Process Control
HVAC Systems
Remote Temperature Sensing
Electronic System Protection
Features
■ Internal comparator with pin programmable 2°C or 10°C
hysteresis
■ No external components required
■ Open Drain or push-pull digital output; supports CMOS
■
■
■
■
logic levels
Internal temperature sensor
Internal voltage reference and DAC for trip-point setting
Currently available in 5-pin SOT-23 plastic package
Excellent power supply noise rejection
Key Specifications
■ Power Supply Voltage
2.7V to 5.5V
■ Power Supply Current
40µA(max)
20µA(typ)
■ Hysteresis Temperature
2°C or 10°C(typ)
Temperature Trip Point Accuracy
Applications
■ Microprocessor Thermal Management
■ Appliances
Temperature Range
LM26NV
−55°C to +110°C
±3°C (max)
+120°C
±4°C (max)
Connection Diagram
30075102
© 2008 National Semiconductor Corporation
300751
www.national.com
LM26NV SOT-23, ±3°C Accurate, Factory Preset Thermostat (LM26 without VTEMP output)
August 5, 2008
LM26NV
Pin Descriptions
Pin
Number
Pin
Name
Function
Connection
1
HYST
Hysteresis control, digital input
GND for 10°C or V+ for 2°C
2
GND
Ground, connected to the back side of the die
through lead frame.
System GND
3
NC
Not Connected Inside Part
Ground or No Connect
4
V+
Supply input
2.7V to 5.5V with a 0.1µF bypass capacitor. For PSRR
information see Section Titled NOISE CONSIDERATIONS.
5
OS
Overtemperature Shutdown open-drain active
low thermostat digital output
Controller interrupt, system or power supply shutdown; pull-up
OS
Overtemperature Shutdown push-pull active
high thermostat digital output
Controller interrupt, system or power supply shutdown
US
Undertemperature Shutdown open-drain active System or power supply shutdown; pull-up resistor ≥ 10kΩ
low thermostat digital output
US
Undertemperature Shutdown push-pull active
high thermostat digital output
resistor ≥ 10kΩ
System or power supply shutdown
Note: Pin 5 functionality and trip point setting are programmed during LM26NV manufacture.
Ordering Information
For more detailed information on the suffix meaning see the part number template at the end of the Electrical Characteristics
Section. Contact National Semiconductor for other set points and output options.
Order Number
Bulk Rail
LM26CIM5-YPE
3000 Units in Tape &
Reel
LM26CIM5X-YPE
NS Package
Number
Trip Point Setting
Output Function
MA05B
115°C
Active-Low, Open
Drain, OS Output
Top Mark
YPE
LM26CIM5-YPE Simplified Block Diagram and Connection Diagram
30075101
The LM26CIM5-YPE has a fixed trip point of 115°C.
For other trip point and output function availability,
please see ordering information or contact National Semiconductor.
www.national.com
2
Input Voltage
Input Current at any pin (Note 2)
Package Input Current(Note 2)
Package Dissipation at TA = 25°C
(Note 3)
Soldering Information
SOT23 Package
Vapor Phase (60 seconds)
Infrared (15 seconds)
6.0V
5mA
20mA
Operating Ratings
500mW
−65°C to + 150°C
2500V
250V
(Note 1)
TMIN ≤ TA ≤ TMAX
Specified Temperature Range
−55°C ≤ TA ≤ +125°C
LM26NV
Positive Supply Voltage (V+)
Maximum VOUT
215°C
220°C
+2.7V to +5.5V
+5.5V
LM26NV Electrical Characteristics
The following specifications apply for V+ = 2.7VDC to 5.5VDC, and VTEMP load current = 0µA unless otherwise specified. Boldface
limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = 25°C unless otherwise specified.
Symbol
Parameter
Conditions
Typical
(Note 6)
LM26NV
Limits
Units
(Limits)
(Note 7)
Temperature Sensor
Trip Point Accuracy (Includes VREF, DAC, -55°C ≤ TA ≤ +110°C
Comparator Offset, and Temperature
+120°C
Sensitivity errors)
Trip Point Hysteresis
HYST = GND
HYST =
IS
V+
Supply Current
±3
°C (max)
±4
°C (max)
11
°C
°C
2
16
20
40
µA (max)
µA (max)
0.001
1
µA (max)
0.4
V (max)
ISOURCE = 500µA, V+ ≥
2.7V
0.8 × V+
V (min)
ISOURCE = 800µA, V
V+ − 1.5
V (min)
Digital Output and Input
IOUT(“1”)
Logical “1” Output Leakage Current
(Note 9)
V+ = +5.0V
VOUT(“0”)
Logical “0” Output Voltage
IOUT = +1.2mA and
V+≥2.7V; IOUT = +3.2mA
and V+≥4.5V; (Note 8)
VOUT(“1”)
Logical “1” Push-Pull Output Voltage
≥4.5V
+
VIH
HYST Input Logical ”1“ Threshold
Voltage
0.8 × V+
V (min)
VIL
HYST Input Logical ”0“ Threshold
Voltage
0.2 × V+
V (max)
3
www.national.com
LM26NV
Storage Temperature
ESD Susceptibility (Note 4)
Human Body Model
Machine Model
Absolute Maximum Ratings (Note 1)
LM26NV
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.
Note 2: When the input voltage (VI) at any pin exceeds the power supply (VI < GND or VI > V+), the current at that pin should be limited to 5mA. The 20mA
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 TJmax (maximum junction temperature), θJA (junction to
ambient thermal resistance) and TA (ambient temperature). The maximum allowable power dissipation at any temperature is PD = (TJmax–TA)/θJA or the number
given in the Absolute Maximum Ratings, whichever is lower. For this device, TJmax = 150°C. For this device the typical thermal resistance (θJA) of the different
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 TJ = TA = 25°C and represent most likely parametric norm.
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 LM26NV would
increase by 1.28mW when IOUT=3.2mA and VOUT=0.4V. With a thermal resistance of 250°C/W, this power dissipation would cause an increase in the die
temperature of 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.
www.national.com
4
x (10x)
y (1x)
Temperature (°C)
The series of characters labeled "xyz" in the part number
LM26CIM5-xyz, describe the set point value and the function
of the output. The character at "x" and "y" define the set point
temperature (at which the digtal output will go active). The "z"
character defines the type and function of the digital output.
These place holders are defined in the following tables.
H
H
0
J
J
1
K
K
2
L
L
3
N
N
4
The place holders xy describe the set point temperature as
shown in the following table.
P
P
5
x (10x)
A
y (1x)
R
R
6
Temperature (°C)
S
S
7
−5
T
T
8
V
9
-
B
-
−4
V
C
-
−3
X
-
10
−2
Y
-
11
Z
-
12
D
-
E
-
−1
F
-
−0
The value of z describes the assignment/function of the output as shown in the following table:
Active-Low/High
Open-Drain/ PushPull
OS/US
Value of z
0
0
0
E
Active-Low, Open-Drain, OS output
0
0
1
F
Active-Low, Open-Drain, US output
1
1
0
G
Active-High, Push-Pull, OS output
1
1
1
H
Active-High, Push-Pull, US output
Digital Output Function
output will be an active-low, open-drain, over-temperature
output.
Many active-high open-drain and active-low push-pull options
are available, please contact National Semiconductor for
more information.
EXAMPLE:
• The part number LM26CIM5-YPE has TOS = 115°C, and
has an active-low open-drain overtemperature shutdown
output. The "Y" represents the tens value "11", the "P"
represents the ones value "5", and the "E" means that the
5
www.national.com
LM26NV
Part Number Template
LM26NV
Functional Description
LM26NV OPTIONS
The LM26NV can be factory programmed to have a trip point anywhere in the range of −55°C to +110°C. It is also available in any
of four output options, as indicated by the last letter in the part number.
30075112
30075113
LM26CIM5 - _ _ E: The "E" indicates that the digital
output is Active-Low Open-Drain and
will trip as temperature is rising (OS)
LM26CIM5 - _ _ F: The "F" indicates that the digita
l output is Active-Low Open-Drain
and will trip as temperature is falling (US)
30075114
30075115
LM26CIM5 - _ _G: The "G" indicates that the digital
output is Active-High Push-Pull and
will trip as temperature is rising (OS)
LM26CIM5 - _ _H: The "H" indicates that the digital
output is Active-High Push-Pull and
will trip as temperature is falling (US)
FIGURE 1. Output Pin Options Block Diagrams
www.national.com
6
NOISE CONSIDERATIONS
The LM26NV has excellent power supply noise rejection.
Listed below is a variety of signals used to test the LM26NV
power supply rejection. False triggering of the output was not
observed when these signals where coupled into the V+ pin
of the LM26NV.
• square wave 400kHz, 1Vp-p
• square wave 2kHz, 200mVp-p
• sine wave 100Hz to 1MHz, 200mVp-p
Testing was done while maintaining the temperature of the
LM26NV one degree centigrade way from the trip point with
the output not activated.
(1)
MOUNTING CONSIDERATIONS
The LM26NV 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 LM26NV is
sensing will be within about +0.06°C of the surface temperature to which the LM26NV's leads are attached to.
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.
To ensure good thermal conductivity, the backside of the
LM26NV die is directly attached to the GND pin (pin 2). The
temperatures of the lands and traces to the other leads of the
LM26NV will also affect the temperature that is being sensed.
Alternatively, the LM26NV can be mounted inside a sealedend metal tube, and can then be dipped into a bath or screwed
where TA is the ambient temperature, V+ is the power supply
voltage, IQ is the quiescent current, VDO is the voltage on the
digital output, and IDO is the load current on the digital output.
The tables shown in Figure 2 summarize the thermal resistance for different conditions and the rise in die temperature
of the LM26NV and a 10k pull-up resistor on an open-drain
digital output with a 5.5V power supply.
SOT23-5
no heat sink
θJA
(°C/W)
SOT23-5
small heat sink
θJA
TJ−TA
(°C)
(°C/W)
TJ−TA
(°C)
Still Air
250
0.11
TBD
TBD
Moving Air
TBD
TBD
TBD
TBD
FIGURE 2. Thermal resistance (θJA) and temperature rise
due to self heating (TJ−TA)
Typical Applications
30075103
FIGURE 3. Two Speed Fan Speed Control: The fan's control pin has an internal pull-up. The 10 kOhm pull-down sets a
slow fan speed. When the output of the LM26NV goes low, the fan will speed up.
7
www.national.com
LM26NV
into a threaded hole in a tank. As with any IC, the LM26NV
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 condensation 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 LM26NV or its connections.
The junction to ambient thermal resistance (θJA) is the parameter used to calculate the rise of a part's junction temperature due to its power dissipation. For the LM26NV the
equation used to calculate the rise in the die junction temperature is as follows:
Applications Hints
LM26NV
30075120
FIGURE 4. Fan High Side Drive: The LM26NV switches the fan on when the measured temperature exceeds the trip
temperatue.
30075121
FIGURE 5. Fan Low Side Drive: The LM26LV sinks causes the switch to sink the fan current when the measured
temperature exceeds the trip temperature.
30075122
FIGURE 6. Audio Power Amplifier Thermal Protection: By thermally coupling the LM26NV to the audio power amplifier,
the LM26NV safeguards the amplifier from overheating, turning on the fan when it temperature exceeds the trip
temperature.
www.national.com
8
LM26NV
30075123
FIGURE 7. Simple Thermostat: When the measured temperature is below the trip temperature of the LM26NV, the OS
output will be high, causing the switch and relay to close. When the temperature exceeds the trip point, OS goes low and
shuts off the relay and heater.
9
www.national.com
LM26NV
Physical Dimensions inches (millimeters) unless otherwise noted
5-Lead Molded SOT-23 Plastic Package, JEDEC
Order Number LM26CIM5-_ _ E or LM26CIM5X-_ _ E;
LM26CIM5-_ _ F or LM26CIM5X-_ _ F; LM26CIM5-_ _ G or LM26CIM5X-_ _ G;
LM26CIM5-_ _ H or LM26CIM5X-_ _ H
NS Package Number MA05B
www.national.com
10
LM26NV
Notes
11
www.national.com
LM26NV SOT-23, ±3°C Accurate, Factory Preset Thermostat (LM26 without VTEMP output)
Notes
For more National Semiconductor product information and proven design tools, visit the following Web sites at:
Products
Design Support
Amplifiers
www.national.com/amplifiers
WEBENCH
www.national.com/webench
Audio
www.national.com/audio
Analog University
www.national.com/AU
Clock Conditioners
www.national.com/timing
App Notes
www.national.com/appnotes
Data Converters
www.national.com/adc
Distributors
www.national.com/contacts
Displays
www.national.com/displays
Green Compliance
www.national.com/quality/green
Ethernet
www.national.com/ethernet
Packaging
www.national.com/packaging
Interface
www.national.com/interface
Quality and Reliability
www.national.com/quality
LVDS
www.national.com/lvds
Reference Designs
www.national.com/refdesigns
Power Management
www.national.com/power
Feedback
www.national.com/feedback
Switching Regulators
www.national.com/switchers
LDOs
www.national.com/ldo
LED Lighting
www.national.com/led
PowerWise
www.national.com/powerwise
Serial Digital Interface (SDI)
www.national.com/sdi
Temperature Sensors
www.national.com/tempsensors
Wireless (PLL/VCO)
www.national.com/wireless
THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION
(“NATIONAL”) PRODUCTS. NATIONAL MAKES NO REPRESENTATIONS OR WARRANTIES WITH RESPECT TO THE ACCURACY
OR COMPLETENESS OF THE CONTENTS OF THIS PUBLICATION AND RESERVES THE RIGHT TO MAKE CHANGES TO
SPECIFICATIONS AND PRODUCT DESCRIPTIONS AT ANY TIME WITHOUT NOTICE. NO LICENSE, WHETHER EXPRESS,
IMPLIED, ARISING BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS IS GRANTED BY THIS
DOCUMENT.
TESTING AND OTHER QUALITY CONTROLS ARE USED TO THE EXTENT NATIONAL DEEMS NECESSARY TO SUPPORT
NATIONAL’S PRODUCT WARRANTY. EXCEPT WHERE MANDATED BY GOVERNMENT REQUIREMENTS, TESTING OF ALL
PARAMETERS OF EACH PRODUCT IS NOT NECESSARILY PERFORMED. NATIONAL ASSUMES NO LIABILITY FOR
APPLICATIONS ASSISTANCE OR BUYER PRODUCT DESIGN. BUYERS ARE RESPONSIBLE FOR THEIR PRODUCTS AND
APPLICATIONS USING NATIONAL COMPONENTS. PRIOR TO USING OR DISTRIBUTING ANY PRODUCTS THAT INCLUDE
NATIONAL COMPONENTS, BUYERS SHOULD PROVIDE ADEQUATE DESIGN, TESTING AND OPERATING SAFEGUARDS.
EXCEPT AS PROVIDED IN NATIONAL’S TERMS AND CONDITIONS OF SALE FOR SUCH PRODUCTS, NATIONAL ASSUMES NO
LIABILITY WHATSOEVER, AND NATIONAL DISCLAIMS ANY EXPRESS OR IMPLIED WARRANTY RELATING TO THE SALE
AND/OR USE OF NATIONAL PRODUCTS INCLUDING LIABILITY OR WARRANTIES RELATING TO FITNESS FOR A PARTICULAR
PURPOSE, MERCHANTABILITY, OR INFRINGEMENT OF ANY PATENT, COPYRIGHT OR OTHER INTELLECTUAL PROPERTY
RIGHT.
LIFE SUPPORT POLICY
NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR
SYSTEMS WITHOUT THE EXPRESS PRIOR WRITTEN APPROVAL OF THE CHIEF EXECUTIVE OFFICER AND GENERAL
COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein:
Life support devices or systems are devices 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. A critical component is any component in 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 and the National Semiconductor logo are registered trademarks of National Semiconductor Corporation. All other
brand or product names may be trademarks or registered trademarks of their respective holders.
Copyright© 2008 National Semiconductor Corporation
For the most current product information visit us at www.national.com
National Semiconductor
Americas Technical
Support Center
Email: [email protected]
Tel: 1-800-272-9959
www.national.com
National Semiconductor Europe
Technical Support Center
Email: [email protected]
German Tel: +49 (0) 180 5010 771
English Tel: +44 (0) 870 850 4288
National Semiconductor Asia
Pacific Technical Support Center
Email: [email protected]
National Semiconductor Japan
Technical Support Center
Email: [email protected]