Sample &
Buy
Product
Folder
Support &
Community
Tools &
Software
Technical
Documents
LM26
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
LM26 SOT-23, ±3°C Accurate, Factory-Preset Thermostat
1 Features
3 Description
•
The LM26 is a precision, single digital-output, lowpower 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 LM26 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 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. A VTEMP analog output provides a voltage
that is proportional to temperature and has a −10.82
mV/°C output slope.
1
•
•
•
•
•
•
•
•
•
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 With VTEMP Output
Pin
VTEMP Output Allows After-Assembly System
Testing
Internal Voltage Reference and DAC for Trip-Point
Setting
Currently Available in 5-pin SOT-23 Plastic
Package
Excellent Power Supply Noise Rejection
UL Recognized Component
Key Specifications
– Power Supply Voltage 2.7 V to 5.5 V
– Power Supply Current
40 μA (Maximum) 16 μA (Typical)
– Hysteresis Temperature 2°C or 10°C (Typical)
2 Applications
•
•
•
•
•
•
•
•
Microprocessor Thermal Management
Appliances
Portable Battery Powered Systems
Fan Control
Industrial Process Control
HVAC Systems
Remote Temperature Sensing
Electronic System Protection
Available parts are detailed in the Device Comparison
Table. For other part options, contact a Texas
Instruments Distributor or Sales Representative for
information on minimum order qualification. The
LM26 is currently available in a 5-lead SOT-23
package.
Device Information(1)
PART NUMBER
LM26
PACKAGE
BODY SIZE (NOM)
SOT-23 (5)
2.90 mm × 1.60 mm
(1) For all available packages, see the orderable addendum at
the end of the datasheet.
LM26CIM5-TPA Simplified Block Diagram and Connection Diagram
TOS
HYST
OS
HYST
REF
Temp. of
Leads
+
GND
TEMP
SENSOR
VTEMP
TOS - THYST
-
LM26TPA
OS
V+ = 2.7V
to 5.5V
HYST=GND for 10°C Hysteresis
HYST = V+ for 2°C Hysteresis
VTEMP = (-3.479 x 10-6 x (T-30)2) + (-1.082 x 10-2 x (T-30)) + 1.8015V
The LM26CIM5-TPA has a fixed trip point of 85°C. For other trip point and output function availability, please see the
Device Comparison Table or contact Texas Instruments.
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.
LM26
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Device Comparison Table.....................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
4
7.1
7.2
7.3
7.4
7.5
7.6
4
5
5
5
5
6
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Electrical Characteristics ..........................................
Typical Characteristics ..............................................
Detailed Description .............................................. 7
8.1 Overview ................................................................... 7
8.2 Functional Block Diagrams ....................................... 7
8.3 Feature Description................................................... 8
8.4 Device Functional Modes.......................................... 9
9
Application and Implementation ........................ 10
9.1 Application Information............................................ 10
9.2 Typical Application .................................................. 10
9.3 System Examples ................................................... 11
10 Power Supply Recommendations ..................... 12
11 Layout................................................................... 12
11.1
11.2
11.3
11.4
Layout Guidelines .................................................
Layout Example ....................................................
Thermal Considerations ........................................
Part Number Template..........................................
12
12
13
14
12 Device and Documentation Support ................. 15
12.1
12.2
12.3
12.4
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
15
15
15
15
13 Mechanical, Packaging, and Orderable
Information ........................................................... 15
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision R (February 2013) to Revision S
Page
•
Added Pin Configuration and Functions section, Handling Rating table, Feature Description section, Device
Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout
section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information
section ................................................................................................................................................................................... 1
•
Removed Part Number Template table ................................................................................................................................. 6
•
Removed Temperature Trip Point Accuracy table ................................................................................................................ 6
Changes from Revision Q (September 2011) to Revision R
•
2
Page
Changed layout of National Data Sheet to TI format ........................................................................................................... 11
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
LM26
www.ti.com
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
5 Device Comparison Table
Order Number
Top Mark
Trip Point
Setting
Output Function
LM26CIM5X-BPB
TBPB
-45°C
Active-Low, Open-Drain, US output
LM26CIM5-DPB
LM26CIM5X-DPB
TDPB
-25°C
Active-Low, Open-Drain, US output
LM26CIM5-HHD
LM26CIM5X-HHD
THHD
0°C
Active-High, Push-Pull, US output
LM26CIM5-NPA
LM26CIM5X-NPA
TNPA
45°C
Active-Low, Open-Drain, OS output
LM26CIM5-RPA
LM26CIM5X-RPA
TRPA
65°C
Active-Low, Open-Drain, OS output
LM26CIM5-SHA
LM26CIM5X-SHA
TSHA
75°C
Active-Low, Open-Drain, OS output
LM26CIM5-SPA
LM26CIM5X-SPA
TSPA
70°C
Active-Low, Open-Drain, OS output
LM26CIM5-TPA
LM26CIM5X-TPA
TTPA
85°C
Active-Low, Open-Drain, OS output
LM26CIM5-VHA
LM26CIM5X-VHA
TVHA
90°C
Active-Low, Open-Drain, OS output
LM26CIM5-VPA
LM26CIM5X-VPA
TVPA
95°C
Active-Low, Open-Drain, OS output
LM26CIM5-XHA
LM26CIM5X-XHA
TXHA
100°C
Active-Low, Open-Drain, OS output
LM26CIM5-XPA
LM26CIM5X-XPA
TXPA
105°C
Active-Low, Open-Drain, OS output
LM26CIM5-YHA
LM26CIM5X-YHA
TYHA
110°C
Active-Low, Open-Drain, OS output
LM26CIM5-YPA
LM26CIM5X-YPA
TYPA
115°C
Active-Low, Open-Drain, OS output
LM26CIM5-ZHA
LM26CIM5X-ZHA
TZHA
120°C
Active-Low, Open-Drain, OS output
Bulk Rail (1000 Units)
Tape & Reel (3000 Units)
LM26CIM5-BPB
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
3
LM26
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
www.ti.com
6 Pin Configuration and Functions
DBV Package
5-Pin SOT-23
(Top View)
Pin Functions
PIN
NO.
NAME
1
HYST
2
GND
3
VTEMP
4
V+
TYPE
Input
(1)
Hysteresis control, digital input; connect to GND for 10°C or V+ for 2°C
Power
Ground, connected to the back side of the die through lead frame; connect to
system ground
Output
Analog output voltage proportional to temperature; leave floating or connect to a
high impedance node.
Power
Supply input; connect to 2.7 V to 5.5 V with a 0.1-μF bypass capacitor.
Output
Overtemperature Shutdown open-drain active low thermostat digital output;
connect to controller interrupt, system/power supply shutdown; pullup resistor ≥ 10
kΩ
OS
Output
Overtemperature Shutdown push-pull active high thermostat digital output;
connect to controller interrupt, system/power supply shutdown
US
Output
Undertemperature Shutdown open-drain active low thermostat digital output;
connect to controller interrupt, system/power supply shutdown; pullup resistor ≥ 10
kΩ
US
Output
Undertemperature Shutdown push-pull active high thermostat digital output;
connect to controller interrupt, system/power supply shutdown
OS
5
DESCRIPTION
(1)
Pin 5 functionality and trip point setting are programmed during LM26 manufacture.
7 Specifications
7.1 Absolute Maximum Ratings
over operating free-air temperature range (unless otherwise noted)
(1)
MIN
Input Voltage
Input Current at any pin
Package Input Current
(2)
(2)
Package Dissipation at TA = 25°C
Soldering
Information (4)
(3)
SOT-23 Package
(2)
(3)
(4)
4
V
5
mA
20
mA
500
mW
215
Infrared (15 seconds)
220
−65
UNIT
6
Vapor Phase (60 seconds)
Storage Temperature, Tstg
(1)
MAX
150
°C
°C
Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings
only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended
Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
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 5 mA.
The 20-mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input
current of 5 mA to four. Under normal operating conditions the maximum current that pins 2, 4 or 5 can handle is limited to 5 mA each.
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:
See the URL http://www.ti.com/packaging for other recommendations and methods of soldering surface mount devices.
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
LM26
www.ti.com
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
7.2 ESD Ratings
VALUE
V(ESD)
(1)
Electrostatic discharge (1)
Human body model (HBM)
±2500
Machine Model
±250
UNIT
V
The human body model is a 100-pF capacitor discharge through a 1.5-kΩ resistor into each pin. The machine model is a 200-pF
capacitor discharged directly into each pin.
7.3 Recommended Operating Conditions
over operating free-air temperature range (unless otherwise noted) (1)
Specified Temperature Range (TMIN ≤ TA ≤ TMAX)
Positive Supply Voltage (V+)
MIN
MAX
UNIT
−55
125
°C
2.7
5.5
V
5.5
V
Maximum VOUT
(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.
7.4 Thermal Information
LM26
THERMAL METRIC (1)
DBV (SOT-23)
UNIT
5 PINS
RθJA
(1)
Junction-to-ambient thermal resistance
250
°C/W
For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application
report, SPRA953.
7.5 Electrical Characteristics
The following specifications apply for V+ = 2.7 VDC to 5.5 VDC, and VTEMP load current = 0 µA unless otherwise specified. All
limits apply for TA = TJ = TMIN to TMAX unless otherwise specified.
PARAMETER
TEST CONDITIONS
MIN (1)
TYP (2)
MAX (1)
UNIT
TEMPERATURE SENSOR
Trip Point Accuracy (Includes VREF, DAC,
Comparator Offset, and Temperature
Sensitivity errors)
Trip Point Hysteresis
–55°C ≤ TA ≤ +110°C
±3
°C
TA = +120°C
±4
°C
HYST = GND
HYST = V+
VO = (−3.479 × 10−6 × (T − 30)2) +
(−1.082 × 10−2 × (T − 30)) + 1.8015 V
VTEMP Load Regulation
VTEMP Line Regulation
IS
(1)
(2)
Supply Current
°C
2
°C
−10.82
VTEMP Output Temperature Sensitivity
VTEMP Temperature Sensitivity Error to
Equation:
11
mV/°C
−30°C ≤ TA ≤ 120°C
±3
°C
−55°C ≤ TA ≤
120°C,
±3
°C
±2.5
°C
4.5 V ≤ V+ ≤ 5.5 V
TA = 30°C
Source ≤ 1 μA
0.070
Sink ≤ 40 μA
+2.7 V ≤ V+ ≤ +5.5 V,
−30°C ≤ TA ≤ +120°C
TA = 25°C
mV
0.7
−0.2
16
mV
mV/V
20
µA
40
Limits are guaranteed to TI's AOQL (Average Outgoing Quality Level).
Typicals are at TJ = TA = 25°C and represent most likely parametric norm.
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
5
LM26
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
www.ti.com
Electrical Characteristics (continued)
The following specifications apply for V+ = 2.7 VDC to 5.5 VDC, and VTEMP load current = 0 µA unless otherwise specified. All
limits apply for TA = TJ = TMIN to TMAX unless otherwise specified.
PARAMETER
MIN (1)
TEST CONDITIONS
TYP (2)
MAX (1)
UNIT
DIGITAL OUTPUT AND INPUT
IOUT(1)
Logical 1 Output Leakage Current
(3)
Logical 0 Output Voltage
VOUT(1)
Logical 1 Push-Pull Output Voltage
VIH
HYST Input Logical 1 Threshold Voltage
VIL
HYST Input Logical 0 Threshold Voltage
(4)
0.001
IOUT = +1.2 mA and V+ ≥ 2.7 V;
IOUT = +3.2 mA and V+ ≥ 4.5 V (4)
VOUT(0)
(3)
V+ = +5.0 V
TA = 25°C
ISOURCE = 500 µA, V+ ≥ 2.7 V
+
ISOURCE = 800 µA, V ≥ 4.5 V
1
µA
0.4
V
0.8 × V+
V
V+ − 1.5
V
0.8 × V+
V
0.2 × V+
V
The 1-µA 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 1-nA typical current at 25°C would increase to 16 nA at 85°C.
Take care to include the effects of self heating when setting the maximum output load current. The power dissipation of the LM26 would
increase by 1.28 mW when IOUT = 3.2 mA and VOUT = 0.4 V. 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.
7.6 Typical Characteristics
100
Supply Current (µA)
80
60
40
20
0
±60
±40
±20
0
20
40
60
80
Temperature (°C)
100
120
140
C001
Figure 1. Power Supply Current Temperature Dependence
6
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
LM26
www.ti.com
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
8 Detailed Description
8.1 Overview
The LM26 is a factory preset thermostat (temperature switch) that includes an integrated temperature sensor,
reference voltage, DAC and comparator. The LM26 can be factory programmed to have a trip point anywhere in
the range of −55°C to +120°C. The output functionality can also be changed during the manufacturing process,
as described in the functional block diagrams. Available options include:
• OS: active low, open drain that indicates an over temperature shutdown event (most common)
• US: active low, open-drain that indicates an under temperature shutdown event
• OS: active high, push-pull that indicates an over temperature shutdown event
• US: active high, push-pull that indicates an under temperature shutdown event
The internal temperature sensor is brought out on the VTEMP pin and can be used to determine the temperature
that the LM26 is reading by monitoring with an ADC. It has a negative temperature coefficient (NTC) of
approximately -10mV/°C. This pin also allows after assembly PCB testing (see section After Assembly PCB
Testing for more details).
The comparator hysteresis is selectable by the state of the HYST. Two values are available 10°C or 2°C.
Comparator hysteresis is essential, as it prevents comparator output chattering when the temperature is at the
comparator threshold set point (REF as shown in the functional block diagrams). Once the comparator trips the
hysteresis function changes the comparator threshold (REF) level such that the output remains locked in the
active state. The threshold is changed by either 10°C or 2°C as programmed by the state of the HYST pin.
8.2 Functional Block Diagrams
HYST
OS
HYST
REF
GND
TEMP
SENSOR
+
+
VTEMP
V
LM26__A
Figure 2. LM26-_ _A Output Pin Block Diagram
US
HYST
HYST
REF
GND
TEMP
SENSOR
+
+
V
VTEMP
LM26__B
Figure 3. LM26-_ _B Output Pin Block Diagram
HYST
HYST
REF
GND
TEMP
SENSOR
VTEMP
V+
OS
+
+
V
LM26__C
Figure 4. LM26-_ _C Output Pin Block Diagram
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
7
LM26
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
www.ti.com
Functional Block Diagrams (continued)
HYST
US
HYST
REF
V+
-
GND
TEMP
SENSOR
+
+
VTEMP
V
LM26__D
Figure 5. LM26-_ _D Output Pin Block Diagram
8.3 Feature Description
8.3.1 Hysteresis
The HYST pin level sets the comparator hysteresis. Setting the HYST pin to GND selects 10°C hysteresis, while
setting it to V+ selects 2°C. A series resistor can be used for protection purposes. The input leakage current of
the pin is less than 10 µA. The value of the resistor will depend on the value of V+ as well as the leakage current.
For example with V+ = 3.3 V the input threshold level for VIH = 0.8 × 3.3 V = 2.64 V, thus the voltage drop across
the resistor should be less than 0.66 V. The 10-µA input leakage current requires the resistor value to be less
than 66 kΩ.
8.3.2 VTEMP Output
The VTEMP output provides an output voltage that can be used to determine the temperature reading of the LM26.
The temperature reading of the LM26 can be calculated using the equation:
VO = ( - 3.47 ´ 10-6 ´ (T - 30)2 ) + (1.082 ´ 10-2 ´ (T - 30)) + 1.8015 V
(1)
or
T = -1525.04 + 2.4182 ´ 106 +
1.8015 - VTEMP
3.479 ´ 10-6
(2)
The VTEMP output has very weak drive capability (1-µA source, 40-µA 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 6 and Figure 7 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 LM26 output, rather than across CLOAD, it should
be at least a factor of 10 smaller than CLOAD.
Table 1. Resistive Compensation for Capacitive Loading of VTEMP
CLOAD
8
R (Ω)
≤100pF
0
1nF
8200
10nF
3000
100nF
1000
≥1µF
430
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
LM26
www.ti.com
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
Heavy Capacitive
Load, Cable/Wiring
HYST
Heavy Capacitive
Load, Cable/Wiring
OS/OS/US/
US
GND LM26
VTEMP
HYST
R
V+
OS/OS/US/
US
GND LM26
VTEMP
V+
CLOAD
R
CLOAD
0.1Pf
Figure 6. Resistor Placement for CapacitiveLoading Compensation of VTEMP With R in Series
With Capacitor
0.1Pf
Figure 7. Resistor Placement for CapacitiveLoading Compensation of VTEMP With R in Series
With Signal Path
8.4 Device Functional Modes
The LM26 after factory programming has two functional modes one with 2°C Hysteresis and the other with 10°C
hysteresis as programmed by the level of the HYST pin. Selection of the level will depend on the system noise
and the temperature transition rate.
8.4.1 After Assembly PCB Testing
The LM26's VTEMP output allows after-assembly PCB testing by following a simple test procedure. Simply
measuring the VTEMP output voltage will verify that the LM26 has been assembled properly and that its
temperature sensing circuitry 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 LM26CIM5-TPA which has an 85°C trip point.
1. Turn on V+ and measure VTEMP. Then calculate the temperature reading of the LM26 using the equation:
VO = ( - 3.47 ´ 10-6 ´ (T - 30)2 ) + (1.082 ´ 10-2 ´ (T - 30)) + 1.8015 V
(3)
or
T = -1525.04 + 2.4182 ´ 106 +
1.8015 - VTEMP
3.479 ´ 10-6
(4)
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 temperature (reference temperature) should be
measured using an extremely accurate calibrated temperature sensor.
3.
(a) Observe that OS is high.
(b) Drive VTEMP to ground.
(c) Observe that OS is now low.
(d) Release the VTEMP pin.
(e) Observe that OS is now high.
4.
(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 Trig using Equation 2.
5.
(a) Gradually raise VTEMP until OS goes HIGH. Note VTEMP.
(b) Calculate THYST using Equation 2.
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
9
LM26
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
www.ti.com
9 Application and Implementation
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
The LM26 thermostat (temperature switch) can be used in applications such as microprocessor thermal
management, appliances, fan control, industrial process control, power supplies for system protection, fan speed
adjust or plain temperature monitoring.
9.2 Typical Application
System Fan
Sanyo Denki
109R0612T4H12
12V
HYST
OS
GND LM26
VTEMP
V+
+5V
10k
0.1Pf
Figure 8. Two-Speed Fan Speed Control
9.2.1 Design Requirements
The requirement is to change speed fo a fan to maximum at 45°C with an accuracy of
Table 2. Design Parameters
DESIGN PARAMETER
EXAMPLE VALUE
Min Fan Speed
1900 RPM
Max Fan Speed
3800 RPM
Temperature Threshold To Switch From Min Speed to Max Speed
45°C
Threshold accuracy
±3°C
9.2.2 Detailed Design Procedure
The design procedure is simple. A fan was selected that has the capability to be controlled by an external NTC
thermistor. The recommended NTC thermistor adjusts the fan speed to maximum at 40°C. The LM26 meets the
threshold accuracy requirements for temperature control of the fan speed and allows setting the max speed
temperature threshold higher as required to 45°C. The resistance of the thermistor for the min fan speed is 6.8
kΩ. Since thermistors have a negative temperature coefficient (NTC), 10 kΩ was chosen to ensure that the fan is
at min speed when the LM26 OS is off. When the OS output goes low at 45°C it simulates the low thermistor
resistance at higher temperatures thus setting fan to max speed.
10
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
LM26
www.ti.com
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
9.2.3 Application Curve
VTEMP Output
(Temp. of Leads)
Trip Point
Trip Point - Hysteresis
OFF
OS
Fan
Speed
ON
3800 RPM
1900 RPM
Figure 9. Temperature Effect on Fan Speed
9.3 System Examples
5V
12V
HYST
OS
GND LM26
VTEMP
V+
1N4001
NDS356P
R1
(100k)
Vout
TOYO
USTF802512HW
1N4001
5V
0.1
HYST
5V Fan
MC05J3
Comair-Rotron
OS
GND LM26
VTEMP
V+
R1
(1k)
5V
0.1
Figure 10. Fan High-Side Drive
Figure 11. Fan Low-Side Drive
5V
5V
THERMALLY COUPLED
+28V
8:
HYST
IC2 OS
GND LM26
VTEMP
V+
+
-
NDS356P
100k
IC1 -28V
LM3886
20k
1k
47k
3.3PF
Audio
Input
0.1Pf
1N4001
5V
10PF
HYST
OS
GND LM26
VTEMP
V+
5V Fan
MC05J3
Comair-Rotron
Figure 12. Audio Power Amplifier Thermal
Protection
Heater
Supply
R1
(10k)
Heater
0.1
5V
Figure 13. Simple Thermostat
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
11
LM26
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
www.ti.com
10 Power Supply Recommendations
The LM26 has excellent power supply noise rejection. Listed below is a variety of signals used to test the LM26
power supply rejection. False triggering of the output was not observed when these signals where coupled into
the V+ pin of the LM26.
• square wave 400 kHz, 1 Vp-p
• square wave 2 kHz, 200 mVp-p
• sine wave 100 Hz to 1 MHz, 200 mVp-p
Testing was done while maintaining the temperature of the LM26 one degree centigrade way from the trip point
with the output not activated.
11 Layout
11.1 Layout Guidelines
The LM26 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 LM26 is sensing will be within about +0.06°C of the surface
temperature to which the LM26'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 LM26 die is directly attached to the GND pin (pin 2).
The temperatures of the lands and traces to the other leads of the LM26 will also affect the temperature that is
being sensed.
Alternatively, the LM26 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 LM26 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 LM26 or its connections.
11.2 Layout Example
VIA to ground plane
VIA to power plane
R only required
for open-drain
R is optional maybe directly
connected to GND or V
+
OS, OS,
US, US
HYST
GND
+
VTEMP
V
0.1 µ F
Figure 14. LM26 Typical Layout
12
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
LM26
www.ti.com
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
11.3 Thermal Considerations
The junction to ambient thermal resistance (RθJA) is the parameter used to calculate the rise of a part's junction
temperature due to its power dissipation. For the LM26 the equation used to calculate the rise in the die junction
temperature is as follows:
TJ = TA + QJA (V + - VTEMP )IL _ TEMP + VDOIDO )
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
(5)
Since the LM26's junction temperature is the actual temperature being measured, care should be taken to
minimize the load current that the LM26 is required to drive.
Table 3 summarizes the thermal resistance for different conditions and the rise in die temperature of the LM26
without any loading on VTEMP and a 10-kΩ pullup resistor on an open-drain digital output with a 5.5-V power
supply.
Table 3. Thermal resistance (RθJA) and Temperature Rise Due to Self Heating (TJ−TA)
SOT-23 5 pin
no heat sink
RθJA
(°C/W)
TJ−TA
(°C)
Still Air
250
0.11
Moving Air
TBD
TBD
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
13
LM26
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
www.ti.com
11.4 Part Number Template
The series of digits labeled xyz in the part number LM26CIM-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)
A
-
−5
B
-
−4
C
-
−3
D
-
−2
E
-
−1
F
-
−0
H
H
0
J
J
1
K
K
2
L
L
3
N
N
4
P
P
5
R
R
6
S
S
7
T
T
8
V
V
9
X
-
10
Y
-
11
Z
-
12
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
A
Active-Low, Open-Drain, OS output
0
0
1
B
Active-Low, Open-Drain, US output
1
1
0
C
Active-High, Push-Pull, OS output
1
1
1
D
Active-High, Push-Pull, US output
Digital Output Function
For example:
• the part number LM26CIM5-TPA has TOS = 85°C, and programmed as an active-low open-drain
overtemperature shutdown output.
• the part number LM26CIM5-FPD has TUS = −5°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 Texas Instruments for more
information.
14
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
LM26
www.ti.com
SNIS115S – MAY 2001 – REVISED SEPTEMBER 2015
12 Device and Documentation Support
12.1 Community Resources
The following links connect to TI community resources. Linked contents are provided "AS IS" by the respective
contributors. They do not constitute TI specifications and do not necessarily reflect TI's views; see TI's Terms of
Use.
TI E2E™ Online Community TI's Engineer-to-Engineer (E2E) Community. Created to foster collaboration
among engineers. At e2e.ti.com, you can ask questions, share knowledge, explore ideas and help
solve problems with fellow engineers.
Design Support TI's Design Support Quickly find helpful E2E forums along with design support tools and
contact information for technical support.
12.2 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
12.3 Electrostatic Discharge Caution
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
12.4 Glossary
SLYZ022 — TI Glossary.
This glossary lists and explains terms, acronyms, and definitions.
13 Mechanical, Packaging, and Orderable Information
The following pages include mechanical, packaging, and orderable information. This information is the most
current data available for the designated devices. This data is subject to change without notice and revision of
this document. For browser-based versions of this data sheet, refer to the left-hand navigation.
Submit Documentation Feedback
Copyright © 2001–2015, Texas Instruments Incorporated
Product Folder Links: LM26
15
PACKAGE OPTION ADDENDUM
www.ti.com
30-Sep-2021
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
LM26CIM5-BPB/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
LM26CIM5-DPB/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TDPB
LM26CIM5-HHD/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
THHD
LM26CIM5-NPA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TNPA
LM26CIM5-PHA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TPHA
LM26CIM5-RPA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TRPA
LM26CIM5-SHA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TSHA
LM26CIM5-SPA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TSPA
LM26CIM5-TPA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TTPA
LM26CIM5-VHA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TVHA
LM26CIM5-VPA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TVPA
LM26CIM5-XHA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TXHA
LM26CIM5-XPA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TXPA
LM26CIM5-YHA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TYHA
LM26CIM5-YPA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TYPA
LM26CIM5-ZHA
NRND
SOT-23
DBV
5
1000
Non-RoHS
& Green
Call TI
Level-1-260C-UNLIM
-55 to 125
TZHA
LM26CIM5-ZHA/NOPB
ACTIVE
SOT-23
DBV
5
1000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TZHA
LM26CIM5X-DPB/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TDPB
LM26CIM5X-HHD/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
THHD
LM26CIM5X-NPA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TNPA
Addendum-Page 1
TBPB
Samples
PACKAGE OPTION ADDENDUM
www.ti.com
Orderable Device
30-Sep-2021
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
LM26CIM5X-PHA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TPHA
LM26CIM5X-SPA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TSPA
LM26CIM5X-TPA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TTPA
LM26CIM5X-VHA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TVHA
LM26CIM5X-VPA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TVPA
LM26CIM5X-XHA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TXHA
LM26CIM5X-XPA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TXPA
LM26CIM5X-YHA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TYHA
LM26CIM5X-YPA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TYPA
LM26CIM5X-ZHA/NOPB
ACTIVE
SOT-23
DBV
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-55 to 125
TZHA
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
工商网监
湘ICP备2023018690号
