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LMT87
SNIS170E – JANUARY 2014 – REVISED OCTOBER 2017
LMT87 2.7-V, SC70/TO-92/TO-92S,
Analog Temperature Sensors With Class-AB Output
1 Features
3 Description
•
The LMT87 device is a precision CMOS temperature
sensor with ±0.4°C typical accuracy (±2.7°C
maximum) and a linear analog output voltage that is
inversely proportional to temperature. The 2.7-V
supply voltage operation, 5.4-μA quiescent current,
and 0.7-ms power-on time enable effective powercycling architectures to minimize power consumption
for battery-powered applications such as drones and
sensor nodes. The LMT87LPG through-hole TO-92S
package fast thermal time constant supports offboard time-temperature sensitive applications such
as smoke and heat detectors. The accuracy over the
wide operating range and other features make the
LMT87 an excellent alternative to thermistors.
1
•
•
•
•
•
•
•
•
•
LMT87LPG (TO-92S package) has a Fast
Thermal Time Constant, 10-s Typical (1.2 m/s
Airflow)
Very Accurate: ±0.4°C Typical
Low 2.7-V Operation
Average Sensor Gain of -13.6 mV/°C
Low 5.4-µA Quiescent Current
Wide Temperature Range: –50°C to 150°C
Output is Short-Circuit Protected
Push-Pull Output With ±50-µA Drive Capability
Footprint Compatible With the Industry-Standard
LM20/19 and LM35 Temperature Sensors
Cost-Effective Alternative to Thermistors
2 Applications
•
•
•
•
•
•
Automotive
Infotainment and Cluster
Powertrain Systems
Smoke and Heat Detectors
Drones
Appliances
For devices with different average sensor gains and
comparable
accuracy,
refer
to
Comparable
Alternative Devices for alternative devices in the
LMT8x family.
Device Information (1)
PART NUMBER
LMT87
(1)
PACKAGE
BODY SIZE (NOM)
SOT (5)
2.00 mm × 1.25 mm
TO-92 (3)
4.30 mm × 3.50 mm
TO-92S (3)
4.00 mm × 3.15 mm
For all available packages, see the orderable addendum
addendum at the end of the data sheet.
Thermal Time Constant
Output Voltage vs Temperature
VDD (+2.7V to +5.5V)
100%
FINAL TEMPERATURE
90%
80%
VDD
70%
60%
LMT87
50%
CBP
OUT
40%
30%
20%
GND
LMT8xLPG
Thermistor
10%
0
0
20
40
60
TIME (s)
80
100
D003
Copyright © 2016, Texas Instruments Incorporated
* Fast thermal response NTC
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.
LMT87
SNIS170E – JANUARY 2014 – REVISED OCTOBER 2017
www.ti.com
Table of Contents
1
2
3
4
5
6
7
8
Features ..................................................................
Applications ...........................................................
Description .............................................................
Revision History.....................................................
Device Comparison Tables...................................
Pin Configuration and Functions .........................
Specifications.........................................................
1
1
1
2
3
4
5
7.1
7.2
7.3
7.4
7.5
7.6
7.7
5
5
5
5
6
6
7
Absolute Maximum Ratings ......................................
ESD Ratings..............................................................
Recommended Operating Conditions.......................
Thermal Information ..................................................
Accuracy Characteristics...........................................
Electrical Characteristics ..........................................
Typical Characteristics .............................................
Detailed Description .............................................. 9
8.1 Overview ................................................................... 9
8.2 Functional Block Diagram ......................................... 9
8.3 Feature Description................................................... 9
8.4 Device Functional Modes........................................ 11
9
Application and Implementation ........................ 13
9.1 Application Information............................................ 13
9.2 Typical Applications ............................................... 13
10 Power Supply Recommendations ..................... 14
11 Layout................................................................... 15
11.1 Layout Guidelines ................................................. 15
11.2 Layout Example .................................................... 15
12 Device and Documentation Support ................. 16
12.1
12.2
12.3
12.4
12.5
Receiving Notification of Documentation Updates
Community Resources..........................................
Trademarks ...........................................................
Electrostatic Discharge Caution ............................
Glossary ................................................................
16
16
16
16
16
13 Mechanical, Packaging, and Orderable
Information ........................................................... 16
4 Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Revision D (June 2017) to Revision E
Page
•
Moved the automotive device to a standalone data sheet (SNIS202) .................................................................................. 1
•
Changed TO-92 GND pin number from: 1 to: 3 .................................................................................................................... 4
•
Changed TO-92 VDD pin number from: 3 to: 1 ...................................................................................................................... 4
Changes from Revision C (October 2015) to Revision D
Page
•
Updated data sheet text to the latest documentation and translations standards ................................................................. 1
•
Added AEC-Q100 automotive qualification bullets to Features ............................................................................................. 1
•
Added Time Constant graph................................................................................................................................................... 1
•
Removed disk drivers, games, wireless transceivers, and cell phones from Applications..................................................... 1
•
Added LPG (TO-92S) package .............................................................................................................................................. 4
•
Added Figure 10 to Typical Characteristics............................................................................................................................ 7
Changes from Revision B (May 2014) to Revision C
Page
•
Deleted all mentions of TO-126 package .............................................................................................................................. 1
•
Added TO-92 LPM pin configuration graphic ......................................................................................................................... 4
•
Changed Handling Ratings to ESD Ratings and moved Storage Temperature to Absolute Maximum Ratings table........... 5
•
Changed KV to V ................................................................................................................................................................... 5
•
Added layout recommendation for TO-92 LP and LPM packages....................................................................................... 15
Changes from Revision A (June 2013) to Revision B
Page
•
Added data sheet flow and layout to conform with new TI standards. Added the following sections: Application and
Implementation, Power Supply Recommendations, Layout, Device and Documentation Support, Mechanical,
Packaging, and Orderable Information .................................................................................................................................. 1
•
Added TO-92 and TO-126 package information. .................................................................................................................. 1
2
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SNIS170E – JANUARY 2014 – REVISED OCTOBER 2017
•
Changed from 450°C/W to 275 °C/W. New specification is derived using TI ' s latest methodology. .................................. 5
•
Deleted Note: The input current is leakage only and is highest at high temperature. It is typically only 0.001 μA. The
1 μA limit is solely based on a testing limitation and does not reflect the actual performance of the part............................. 6
5 Device Comparison Tables
Table 1. Available Device Packages
ORDER NUMBER
(1)
PACKAGE
PIN
BODY SIZE (NOM)
MOUNTING TYPE
LMT87DCK
SOT (AKA (2): SC70, DCK)
5
2.00 mm × 1.25 mm
Surface Mount
LMT87LP
TO-92 (AKA (2): LP)
3
4.30 mm × 3.50 mm
Through-hole; straight leads
(2)
LMT87LPG
TO-92S (AKA
3
4.00 mm × 3.15 mm
Through-hole; straight leads
LMT87LPM
TO-92 (AKA (2): LPM)
3
4.30 mm × 3.50 mm
Through-hole; formed leads
LMT87DCK-Q1
SOT (AKA (2): SC70, DCK)
5
2.00 mm × 1.25 mm
Surface Mount
(1)
(2)
: LPG)
For all available packages and complete order numbers, see the Package Option addendum at the end of the data sheet.
AKA = Also Known As
Table 2. Comparable Alternative Devices
DEVICE NAME
AVERAGE OUTPUT SENSOR GAIN
POWER SUPPLY RANGE
LMT84
–5.5 mV/°C
1.5 V to 5.5 V
LMT85
–8.2 mV/°C
1.8 V to 5.5 V
LMT86
–10.9 mV/°C
2.2 V to 5.5 V
LMT87
–13.6 mV/°C
2.7 V to 5.5 V
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SNIS170E – JANUARY 2014 – REVISED OCTOBER 2017
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6 Pin Configuration and Functions
DCK Package
5-Pin SOT (SC70)
Top View
1
LP Package
3-Pin TO-92
(Top View)
5
VDD
VDD
2
LMT87
GND
3
4
OUT
VDD
1
D
VD
LPG Package
3-Pin TO-92S
(Top View)
G
3 D
N
2 T
U
O
1
Scale: 4:1
2
3
LPM Package
3-Pin TO-92
(Top View)
1 T
U
O
3
D
VD
2 D
N
G
Scale: 4:1
1
D
VD
2 T
U
O
3 D
N
G
Scale: 4:1
Pin Functions
PIN
NAME
GND
SOT (SC70)
TO-92
TO-92S
2 (1)
3
2
TYPE
DESCRIPTION
EQUIVALENT CIRCUIT
Ground
N/A
FUNCTION
Power Supply Ground
VDD
OUT
3
2
1
Analog
Output
VDD
1, 4, 5
1
3
Power
Outputs a voltage that is inversely
proportional to temperature
GND
(1)
4
N/A
Positive Supply Voltage
Direct connection to the back side of the die
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SNIS170E – JANUARY 2014 – REVISED OCTOBER 2017
7 Specifications
7.1 Absolute Maximum Ratings
See
(1) (2)
MIN
MAX
UNIT
Supply voltage
–0.3
6
V
Voltage at output pin
–0.3
(VDD + 0.5)
V
Output current
–7
7
mA
Input current at any pin (3)
–5
5
mA
150
°C
150
°C
Maximum junction temperature (TJMAX)
Storage temperature Tstg
(1)
(2)
(3)
–65
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.
Soldering process must comply with Reflow Temperature Profile specifications. Refer to www.ti.com/packaging.
When the input voltage (VI) at any pin exceeds power supplies (VI < GND or VI > V), the current at that pin should be limited to 5 mA.
7.2 ESD Ratings
VALUE
UNIT
LMT87LP in TO-92 package
V(ESD)
Electrostatic
discharge
Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001 (1) (2)
±2500
Charged-device model (CDM), per JEDEC specification JESD22-C101 (3)
±1000
Human-body model (HBM), per JESD22-A114 (2)
±2500
Charged-device model (CDM), per JEDEC specification JESD22-C101 (3)
±1000
V
LMT87DCK in SC70 package
V(ESD)
(1)
(2)
(3)
Electrostatic
discharge
V
JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
The human-body model is a 100-pF capacitor discharged through a 1.5-kΩ resistor into each pin.
JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.
7.3 Recommended Operating Conditions
MIN
Specified temperature
MAX
UNIT
TMIN ≤ TA ≤ TMAX
°C
−50 ≤ TA ≤ 150
°C
Supply voltage (VDD)
2.7
5.5
V
7.4 Thermal Information (1)
THERMAL METRIC (2)
(3) (4)
LMT87
LMT87LP
LMT87LPG
DCK (SOT/SC70)
LP/LPM (TO-92)
LPG (TO-92S)
5 PINS
3 PINS
3 PINS
UNIT
RθJA
Junction-to-ambient thermal resistance
275
167
130.4
°C/W
RθJC(top)
Junction-to-case (top) thermal resistance
84
90
64.2
°C/W
RθJB
Junction-to-board thermal resistance
56
146
106.2
°C/W
ψJT
Junction-to-top characterization parameter
1.2
35
14.6
°C/W
ψJB
Junction-to-board characterization parameter
55
146
106.2
°C/W
(1)
(2)
(3)
(4)
For information on self-heating and thermal response time see section Mounting and Thermal Conductivity.
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report.
The junction to ambient thermal resistance (RθJA) under natural convection is obtained in a simulation on a JEDEC-standard, High-K
board as specified in JESD51-7, in an environment described in JESD51-2. Exposed pad packages assume that thermal vias are
included in the PCB, per JESD 51-5.
Changes in output due to self-heating can be computed by multiplying the internal dissipation by the thermal resistance.
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7.5 Accuracy Characteristics
These limits do not include DC load regulation. These stated accuracy limits are with reference to the values in Table 3.
PARAMETER
CONDITIONS
70°C to 150°C; VDD = 3.0 V to 5.5 V
MIN (1)
TYP
MAX (1)
–2.7
±0.4
2.7
20°C to 40°C; VDD = 2.7 V to 5.5 V
±0.6
20°C to 40°C; VDD = 3.4 V to 5.5 V
±0.3
Temperature accuracy (2) 0°C; VDD = 3.0 V to 5.5 V
–2.7
0°C; VDD = 3.6 V to 5.5 V
–2.7
–50°C; VDD = 4.2 V to 5.5 V
(1)
(2)
°C
°C
°C
±0.6
2.7
±0.3
–50°C; VDD = 3.6 V to 5.5 V
UNIT
°C
°C
±0.6
2.7
±0.3
°C
°C
Limits are specific to TI's AOQL (Average Outgoing Quality Level).
Accuracy is defined as the error between the measured and reference output voltages, tabulated in the Transfer Table at the specified
conditions of supply gain setting, voltage, and temperature (expressed in °C). Accuracy limits include line regulation within the specified
conditions. Accuracy limits do not include load regulation; they assume no DC load.
7.6 Electrical Characteristics
Unless otherwise noted, these specifications apply for +VDD = 2.7 V to 5.5 V. MIN and MAX limits apply for TA = TJ = TMIN to
TMAX ; typical limits apply for TA = TJ = 25°C.
PARAMETER
TEST CONDITIONS
MIN (1)
Sensor gain (output transfer
function slope)
Load regulation (3)
Supply current
CL
Output load capacitance
(1)
(2)
(3)
(4)
(5)
6
(2)
MAX
(1)
–13.6
Source ≤ 50 μA, (VDD – VOUT) ≥ 200 mV
–1
Sink ≤ 50 μA, VOUT ≥ 200 mV
mV
1
200
TA = 30°C to 150°C, (VDD – VOUT) ≥ 100 mV
TA = –50°C to 150°C, (VDD – VOUT) ≥ 100 mV
CL= 0 pF to 1100 pF
Output drive
TA = TJ = 25°C
5.4
8.1
μA
5.4
9
μA
1.9
ms
50
μA
0.7
–50
mV
μV/V
1100
Power-on time (5)
UNIT
mV/°C
–0.22
0.26
Line regulation (4)
IS
TYP
pF
Limits are specific to TI's AOQL (Average Outgoing Quality Level).
Typicals are at TJ = TA = 25°C and represent most likely parametric norm.
Source currents are flowing out of the LMT87. Sink currents are flowing into the LMT87.
Line regulation (DC) is calculated by subtracting the output voltage at the highest supply voltage from the output voltage at the lowest
supply voltage. The typical DC line regulation specification does not include the output voltage shift discussed in Output Voltage Shift.
Specified by design and characterization.
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7.7 Typical Characteristics
4
TEMPERATURE ERROR (ºC)
3
2
1
0
-1
-2
-3
-4
-50
-25
0
25
50
75
100 125 150
TEMPERATURE (ºC)
Figure 1. Temperature Error vs Temperature
Figure 2. Minimum Operating Temperature vs
Supply Voltage
Figure 3. Supply Current vs Temperature
Figure 4. Supply Current vs Supply Voltage
Figure 5. Load Regulation, Sourcing Current
Figure 6. Load Regulation, Sinking Current
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Typical Characteristics (continued)
Figure 7. Change in VOUT vs Overhead Voltage
Figure 8. Supply-Noise Gain vs Frequency
100%
FINAL TEMPERATURE
90%
80%
70%
60%
50%
40%
30%
20%
LMT8xLPG
Thermistor
10%
0
0
Figure 9. Output Voltage vs Supply Voltage
8
20
40
60
TIME (s)
80
100
D003
Figure 10. LMT87LPG Thermal Response vs Common
Leaded Thermistor With 1.2-m/s Airflow
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8 Detailed Description
8.1 Overview
The LMT87 is an analog output temperature sensor. The temperature-sensing element is comprised of a simple
base emitter junction that is forward biased by a current source. The temperature-sensing element is then
buffered by an amplifier and provided to the OUT pin. The amplifier has a simple push-pull output stage thus
providing a low impedance output source.
8.2 Functional Block Diagram
Full-Range Celsius Temperature Sensor (−50°C to +150°C)
VDD
OUT
Thermal Diodes
GND
8.3 Feature Description
8.3.1 LMT87 Transfer Function
The output voltage of the LMT87, across the complete operating temperature range, is shown in Table 3. This
table is the reference from which the LMT87 accuracy specifications (listed in the Accuracy Characteristics
section) are determined. This table can be used, for example, in a host processor look-up table. A file containing
this data is available for download at the LMT87 product folder under Tools and Software Models.
Table 3. LMT87 Transfer Table
TEMP
(°C)
VOUT
(mV)
TEMP
(°C)
VOUT
(mV)
TEMP
(°C)
VOUT
(mV)
TEMP
(°C)
VOUT
(mV)
TEMP
(°C)
VOUT
(mV)
–50
3277
–10
2767
30
2231
70
1679
110
1115
–49
3266
–9
2754
31
2217
71
1665
111
1101
–48
3254
–8
2740
32
2204
72
1651
112
1087
–47
3243
–7
2727
33
2190
73
1637
113
1073
–46
3232
–6
2714
34
2176
74
1623
114
1058
–45
3221
–5
2700
35
2163
75
1609
115
1044
–44
3210
–4
2687
36
2149
76
1595
116
1030
–43
3199
–3
2674
37
2136
77
1581
117
1015
–42
3186
–2
2660
38
2122
78
1567
118
1001
–41
3173
–1
2647
39
2108
79
1553
119
987
–40
3160
0
2633
40
2095
80
1539
120
973
–39
3147
1
2620
41
2081
81
1525
121
958
–38
3134
2
2607
42
2067
82
1511
122
944
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Feature Description (continued)
Table 3. LMT87 Transfer Table (continued)
TEMP
(°C)
VOUT
(mV)
TEMP
(°C)
VOUT
(mV)
TEMP
(°C)
VOUT
(mV)
TEMP
(°C)
VOUT
(mV)
TEMP
(°C)
VOUT
(mV)
–37
3121
3
2593
43
2054
83
1497
123
929
–36
3108
4
2580
44
2040
84
1483
124
915
–35
3095
5
2567
45
2026
85
1469
125
901
–34
3082
6
2553
46
2012
86
1455
126
886
–33
3069
7
2540
47
1999
87
1441
127
872
–32
3056
8
2527
48
1985
88
1427
128
858
–31
3043
9
2513
49
1971
89
1413
129
843
–30
3030
10
2500
50
1958
90
1399
130
829
–29
3017
11
2486
51
1944
91
1385
131
814
–28
3004
12
2473
52
1930
92
1371
132
800
–27
2991
13
2459
53
1916
93
1356
133
786
–26
2978
14
2446
54
1902
94
1342
134
771
–25
2965
15
2433
55
1888
95
1328
135
757
–24
2952
16
2419
56
1875
96
1314
136
742
–23
2938
17
2406
57
1861
97
1300
137
728
–22
2925
18
2392
58
1847
98
1286
138
713
–21
2912
19
2379
59
1833
99
1272
139
699
–20
2899
20
2365
60
1819
100
1257
140
684
–19
2886
21
2352
61
1805
101
1243
141
670
–18
2873
22
2338
62
1791
102
1229
142
655
–17
2859
23
2325
63
1777
103
1215
143
640
–16
2846
24
2311
64
1763
104
1201
144
626
–15
2833
25
2298
65
1749
105
1186
145
611
–14
2820
26
2285
66
1735
106
1172
146
597
–13
2807
27
2271
67
1721
107
1158
147
582
–12
2793
28
2258
68
1707
108
1144
148
568
–11
2780
29
2244
69
1693
109
1130
149
553
150
538
Although the LMT87 is very linear, the response does have a slight umbrella parabolic shape. This shape is very
accurately reflected in Table 3. The transfer table can be calculated by using the parabolic equation (Equation 1).
mV
mV
ª
º ª
VTEMP mV = 2230.8mV - «13.582
T - 30°C » - «0.00433 2 T - 30°C
°C
¬
¼ ¬
°C
2º
»
¼
(1)
The parabolic equation is an approximation of the transfer table and the accuracy of the equation degrades
slightly at the temperature range extremes. Equation 1 can be solved for T resulting in:
T
13 .582
13 .582
2
4 u 0.00433 u 2230 .8 VTEMP mV
2 u ( 0.00433 )
30
(2)
For an even less accurate linear transfer function approximation, a line can easily be calculated over the desired
temperature range from Table 3 using the two-point equation (Equation 3):
·
¹
V - V1 =
V2 - V1
T2 - T1
· u (T - T1)
¹
where
•
•
•
•
10
V is in mV,
T is in °C,
T1 and V1 are the coordinates of the lowest temperature,
and T2 and V2 are the coordinates of the highest temperature.
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For example, if the user wanted to resolve this equation, over a temperature range of 20°C to 50°C, they would
proceed as follows:
1958 mV - 2365 mV·
u (T - 20oC)
50oC - 20oC
¹
·
¹
V - 2365 mV =
(4)
o
o
V - 2365 mV = (-13.6 mV / C) u (T - 20 C)
(5)
o
V = (-13.6 mV / C) u T + 2637 mV
(6)
Using this method of linear approximation, the transfer function can be approximated for one or more
temperature ranges of interest.
8.4 Device Functional Modes
8.4.1 Mounting and Thermal Conductivity
The LMT87 can be applied easily in the same way as other integrated-circuit temperature sensors. It can be
glued or cemented to a surface.
To ensure good thermal conductivity, the backside of the LMT87 die is directly attached to the GND pin. The
temperatures of the lands and traces to the other leads of the LMT87 will also affect the temperature reading.
Alternatively, the LMT87 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 LMT87 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. If moisture creates a short circuit from the output to ground or VDD,
the output from the LMT87 will not be correct. Printed-circuit coatings are often used to ensure that moisture
cannot corrode the leads or circuit traces.
The thermal resistance junction to ambient (RθJA or θJA) is the parameter used to calculate the rise of a device
junction temperature due to its power dissipation. Use Equation 7 to calculate the rise in the LMT87 die
temperature:
TJ = TA + TJA ª¬(VDDIS ) + (VDD - VOUT ) IL º¼
where
•
•
•
•
TA is the ambient temperature,
IS is the supply current,
ILis the load current on the output,
and VO is the output voltage.
(7)
For example, in an application where TA = 30°C, VDD = 5 V, IS = 5.4 μA, VOUT = 2231 mV, and IL = 2 μA, the
junction temperature would be 30.014°C, showing a self-heating error of only 0.014°C. Because the junction
temperature of the LMT87 is the actual temperature being measured, take care to minimize the load current that
the LMT87 is required to drive. Thermal Information (1) shows the thermal resistance of the LMT87.
8.4.2 Output Noise Considerations
A push-pull output gives the LMT87 the ability to sink and source significant current. This is beneficial when, for
example, driving dynamic loads like an input stage on an analog-to-digital converter (ADC). In these applications
the source current is required to quickly charge the input capacitor of the ADC. The LMT87 is ideal for this and
other applications which require strong source or sink current.
The LMT87 supply-noise gain (the ratio of the AC signal on VOUT to the AC signal on VDD) was measured during
bench tests. The typical attenuation is shown in Figure 8 found in the Typical Characteristics section. A load
capacitor on the output can help to filter noise.
For operation in very noisy environments, some bypass capacitance should be present on the supply within
approximately 5 centimeters of the LMT87.
(1)
For information on self-heating and thermal response time see section Mounting and Thermal Conductivity.
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Device Functional Modes (continued)
8.4.3 Capacitive Loads
The LMT87 handles capacitive loading well. In an extremely noisy environment, or when driving a switched
sampling input on an ADC, it may be necessary to add some filtering to minimize noise coupling. Without any
precautions, the LMT87 can drive a capacitive load less than or equal to 1100 pF, as shown in Figure 11. For
capacitive loads greater than 1100 pF, a series resistor may be required on the output, as shown in Figure 12.
VDD
LMT87
OPTIONAL
BYPASS
CAPACITANCE
OUT
GND
CLOAD ” 1100 pF
Figure 11. LMT87 No Decoupling Required for Capacitive Loads Less Than 1100 pF
VDD
RS
LMT87
OUT
OPTIONAL
BYPASS
CAPACITANCE
GND
CLOAD > 1100 pF
Figure 12. LMT87 with Series Resistor for Capacitive Loading Greater Than 1100 pF
Table 4. Recommended Series Resistor Values
CLOAD
MINIMUM RS
1.1 nF to 99 nF
3 kΩ
100 nF to 999 nF
1.5 kΩ
1 μF
800 Ω
8.4.4 Output Voltage Shift
The LMT87 is very linear over temperature and supply voltage range. Due to the intrinsic behavior of an
NMOS/PMOS rail-to-rail buffer, a slight shift in the output can occur when the supply voltage is ramped over the
operating range of the device. The location of the shift is determined by the relative levels of VDD and VOUT. The
shift typically occurs when VDD- VOUT = 1 V.
This slight shift (a few millivolts) takes place over a wide change (approximately 200 mV) in VDD or VOUT.
Because the shift takes place over a wide temperature change of 5°C to 20°C, VOUT is always monotonic. The
accuracy specifications in the Accuracy Characteristics table already include this possible shift.
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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 LMT87 features make it suitable for many general temperature-sensing applications. It can operate down to
2.7-V supply with 5.4-µA power consumption. Package options like the through-hole TO-92 package also allow
the LMT87 to be mounted onboard, off-board, to a heat sink, or on multiple unique locations in the same
application.
9.2 Typical Applications
9.2.1 Connection to ADC
Simplified Input Circuit of
SAR Analog-to-Digital Converter
+2.7V to +5.5V
Reset
Input
Pin
LMT87
VDD
CBP
RMUX
RSS
Sample
OUT
GND
CMUX
CFILTER
CSAMPLE
Figure 13. Suggested Connection to a Sampling Analog-to-Digital Converter Input Stage
9.2.1.1 Design Requirements
Most CMOS ADCs found in microcontrollers and ASICs have a sampled data comparator input structure. When
the ADC charges the sampling cap, it requires instantaneous charge from the output of the analog source such
as the LMT87 temperature sensor and many op amps. This requirement is easily accommodated by the addition
of a capacitor (CFILTER).
9.2.1.2 Detailed Design Procedure
The size of CFILTER depends on the size of the sampling capacitor and the sampling frequency. Because not all
ADCs have identical input stages, the charge requirements will vary. This general ADC application is shown as
an example only.
9.2.1.3 Application Curve
3.5
OUTPUT VOLTAGE (V)
3.0
2.5
2.0
1.5
1.0
0.5
0.0
±50
0
50
100
150
TEMPERATURE (ƒC)
C001
Figure 14. Analog Output Transfer Function
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Typical Applications (continued)
9.2.2 Conserving Power Dissipation With Shutdown
VDD
SHUTDOWN
VOUT
LMT87
Any logic
device output
Figure 15. Simple Shutdown Connection of the LMT87
9.2.2.1 Design Requirements
Because the power consumption of the LMT87 is less than 9 µA, it can simply be powered directly from any logic
gate output and therefore not require a specific shutdown pin. The device can even be powered directly from a
microcontroller GPIO. In this way, it can easily be turned off for cases such as battery-powered systems where
power savings are critical.
9.2.2.2 Detailed Design Procedure
Simply connect the VDD pin of the LMT87 directly to the logic shutdown signal from a microcontroller.
9.2.2.3 Application Curves
Time: 500 μs/div; Top trace: VDD 1 V/div;
Bottom trace: OUT 1 V/div
Figure 16. Output Turnon Response Time Without a
Capacitive Load and VDD = 3.3 V
Time: 500 μs/div; Top trace: VDD 1 V/div;
Bottom trace: OUT 1 V/div
Figure 17. Output Turnon Response Time With a 1.1-nF
Capacitive Load and VDD = 3.3 V
Time: 500 μs/div; Top trace: VDD 2 V/div;
Bottom trace: OUT 1 V/div
Figure 18. Output Turnon Response Time Without a
Capacitive Load and VDD = 5 V
Time: 500 μs/div; Top trace: VDD 2 V/div;
Bottom trace: OUT 1 V/div
Figure 19. Output Turnon Response Time With a 1.1-nF
Capacitive Load and VDD = 5 V
10 Power Supply Recommendations
The low supply current and supply range (2.7 V to 5.5 V) of the LMT87 allow the device to easily be powered
from many sources. Power supply bypassing is optional and is mainly dependent on the noise on the power
supply used. In noisy systems it may be necessary to add bypass capacitors to lower the noise that is coupled to
the output of the LMT87.
14
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11 Layout
11.1 Layout Guidelines
The LMT87 is extremely simple to layout. If a power-supply bypass capacitor is used, it should be connected as
shown in the Layout Example.
11.2 Layout Example
VIA to ground plane
VIA to power plane
VDD
VDD
VDD
GND
0.01 µ F
OUT
VDD
Figure 20. SC70 Package Recommended Layout
GND
OUT
VDD
Figure 21. TO-92 LP Package Recommended Layout
GND
OUT
VDD
Figure 22. TO-92 LPM Package Recommended Layout
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12 Device and Documentation Support
12.1 Receiving Notification of Documentation Updates
To receive notification of documentation updates, navigate to the device product folder on ti.com. In the upper
right corner, click on Alert me to register and receive a weekly digest of any product information that has
changed. For change details, review the revision history included in any revised document.
12.2 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.
12.3 Trademarks
E2E is a trademark of Texas Instruments.
All other trademarks are the property of their respective owners.
12.4 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.
12.5 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.
16
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PACKAGE OPTION ADDENDUM
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10-Dec-2020
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)
LMT87DCKR
ACTIVE
SC70
DCK
5
3000
RoHS & Green
SN
Level-1-260C-UNLIM
-50 to 150
BUA
LMT87DCKT
ACTIVE
SC70
DCK
5
250
RoHS & Green
SN
Level-1-260C-UNLIM
-50 to 150
BUA
LMT87LP
ACTIVE
TO-92
LP
3
1800
RoHS & Green
SN
N / A for Pkg Type
-50 to 150
LMT87
LMT87LPG
ACTIVE
TO-92
LPG
3
1000
RoHS & Green
SN
N / A for Pkg Type
-50 to 150
LMT87
LMT87LPGM
ACTIVE
TO-92
LPG
3
3000
RoHS & Green
SN
N / A for Pkg Type
-50 to 150
LMT87
LMT87LPM
ACTIVE
TO-92
LP
3
2000
RoHS & Green
SN
N / A for Pkg Type
-50 to 150
LMT87
(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
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