NSC LM70CILDX-3 Spi/microwire 10-bit plus sign digital temperature Datasheet

LM70
SPI/MICROWIRE 10-Bit plus Sign Digital Temperature
Sensor
General Description
Features
The LM70 is a temperature sensor, Delta-Sigma analog-todigital converter with an SPI and MICROWIRE compatible
interface available in LLP and MSOP 8-pin packages. The
host can query the LM70 at any time to read temperature. A
shutdown mode decreases power consumption to less than
10 µA. This mode is useful in systems where low average
power consumption is critical.
n 0.25˚C temperature resolution.
n Shutdown mode conserves power between temperature
reading
n SPI and MICROWIRE Bus interface
n MSOP-8 and LLP-8 packages save space
n UL Recognized Component
The LM70 has 10-bit plus sign temperature resolution
(0.25˚C per LSB) while operating over a temperature range
of −55˚C to +150˚C.
Key Specifications
The LM70’s 2.65V to 5.5V supply voltage range, low supply
current and simple SPI interface make it ideal for a wide
range of applications. These include thermal management
and protection applications in hard disk drives, printers, electronic test equipment, and office electronics.
j Supply Current
System Thermal Management
Personal Computers
Disk Drives
Office Electronics
Electronic Test Equipment
2.65V to 5.5V
operating
260 µA (typ)
490 µA (max)
j Temperature
Accuracy
Applications
n
n
n
n
n
j Supply Voltage
shutdown
12 µA (typ)
−40˚C to 85˚C
± 2˚C(max)
−10˚C to 65˚C
+1.5/−2˚C(max)
−55˚C to 125˚C
+3/−2˚C(max)
−55˚C to 150˚C
+3.5/−2˚C(max)
Simplified Block Diagram
10122301
© 2006 National Semiconductor Corporation
DS101223
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LM70 SPI/MICROWIRE™10-Bit plus Sign Digital Temperature Sensor
February 2006
LM70
Connection Diagrams
MSOP-8
LLP-8
10122302
TOP VIEW
NS Package Number MUA08A
10122325
TOP VIEW
NS Package Number LDA08A
Ordering Information
Package
Marking
Order Number
NS Package
Number
Supply Voltage
Transport Media
LM70CILD-3
T33
LLP-8, LDA08A
2.65V to 3.6V
1000 Units in Tape and Reel
LM70CILDX-3
T33
LLP-8, LDA08A
2.65V to 3.6V
4500 Units in Tape and Reel
LM70CILD-5
T35
LLP-8, LDA08A
4.5V to 5.5V
1000 Units in Tape and Reel
LM70CILDX-5
T35
LLP-8, LDA08A
4.5V to 5.5V
4500 Units in Tape and Reel
LM70CIMM-3
T04C
MSOP-8, MUA08A
2.65V to 3.6V
1000 Units in Tape and Reel
LM70CIMMX-3
T04C
MSOP-8, MUA08A
2.65V to 3.6V
3500 Units in Tape and Reel
LM70CIMM-5
T03C
MSOP-8, MUA08A
4.5V to 5.5V
1000 Units in Tape and Reel
LM70CIMMX-5
T03C
MSOP-8, MUA08A
4.5V to 5.5V
3500 Units in Tape and Reel
Pin Descriptions
Label
SOP-8
Pin #
LLP-8
Pin #
Function
SI/O
1
1
Input/Output - Serial bus bi-directional data line.
Schmitt trigger input.
From and to Controller
SC
2
3
Clock - Serial bus clock Schmitt trigger input
line.
From Controller
GND
4
7
Power Supply Ground
Ground
5
5
Positive Supply Voltage Input
DC Voltage from 2.65V to 5.5V. Bypass
with a 0.1 µF ceramic capacitor.
+
V
CS
NC
7
3, 6, 8
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8
2, 4, 6
Typical Connection
Chip Select input.
From Controller
No Connect
These pins are not connected to the
LM70 die in any way.
2
LM70
Typical Application
10122303
FIGURE 1. COP Microcontroller Interface
3
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LM70
Absolute Maximum Ratings (Note 1)
Supply Voltage
ESD Susceptibility (Note 4)
Human Body Model
−0.3V to 6.0V
Voltage at any Pin
−0.3V to V + 0.3V
Input Current at any Pin (Note 2)
3000V
Machine Model
+
300V
5 mA
20 mA
Operating Ratings
−65˚C to +150˚C
Specified Temperature Range
Package Input Current (Note 2)
Storage Temperature
Soldering Information, Lead Temperature
MSOP-8 and LLP-8 Packages
(Note 3)
Vapor Phase (60 seconds)
Infrared (15 seconds)
TMIN to TMAX
(Note 5)
−55˚C to +150˚C
Supply Voltage Range (+VS)
+2.65V to +5.5V
215˚C
220˚C
Temperature-to-Digital Converter Characteristics
Unless otherwise noted, these specifications apply for V+ = 2.65V to 3.6V for the LM70-3 and V+ = 4.5V to 5.5V for the LM70-5
(Note 6). Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ=+25˚C, unless otherwise noted.
LM70-5
Limits
(Note 8)
LM70-3
Limits
(Note 8)
TA = −10˚C to +65˚C
+1.5/−2.0
+1.5/−2.0
˚C (max)
TA = −40˚C to +85˚C
± 2.0
± 2.0
˚C (max)
TA = −55˚C to +125˚C
+3.0/−2.0
+3.0/−2.0
˚C (max)
TA = −55˚C to +150˚C
+3.5/−2.0
+3.5/−2.0
˚C (max)
Parameter
Temperature Error (Note 6)
Typical
(Note 7)
Conditions
Resolution
11
0.25
Units
(Limit)
Bits
˚C
Temperature Conversion
Time
(Note 9)
140
210
210
ms (max)
Quiescent Current
Serial Bus Inactive
260
490
490
µA (max)
Serial Bus Active
260
µA
Shutdown Mode
12
µA
Logic Electrical Characteristics
Digital DC Characteristics
Unless otherwise noted, these specifications apply for V+ = 2.65V to 3.6V for the LM70-3 and V+ = 4.5V to 5.5V for the
LM70-5. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ=+25˚C, unless otherwise noted.
Symbol
VIN(1)
VIN(0)
Parameter
Conditions
Typical
(Note 7)
Logical “1” Input Voltage
Logical “0” Input Voltage
Input Hysteresis Voltage
Limits
(Note 8)
Units
(Limit)
V+ x 0.7
V (min)
V+ + 0.3
V (max)
−0.3
V (min)
V+ x 0.3
V (max)
V+ = 2.65V to 3.6V
0.8
0.27
V (min)
V+ = 4.5V to 5.5V
0.8
0.35
V (min)
0.005
3.0
µA (max)
−0.005
−3.0
µA (min)
+
IIN(1)
Logical “1” Input Current
VIN = V
IIN(0)
Logical “0” Input Current
VIN = 0V
CIN
All Digital Inputs
20
pF
VOH
High Level Output Voltage
IOH = −400 µA
2.4
V (min)
VOL
Low Level Output Voltage
IOL = +2 mA
0.4
V (max)
IO_TRI-STATE
TRI-STATE Output Leakage
Current
VO = GND
V O = V+
−1
+1
µA (min)
µA (max)
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4
LM70
Logic Electrical Characteristics
(Continued)
Serial Bus Digital Switching Characteristics
Unless otherwise noted, these specifications apply for V+ = 2.65V to 3.6V for the LM70-3 and V+ = 4.5V to 5.5V for the
LM70-5, CL (load capacitance) on output lines = 100 pF unless otherwise specified. Boldface limits apply for TA = TJ = TMIN
to TMAX; all other limits TA = TJ = +25˚C, unless otherwise noted.
Symbol
Parameter
Typical
(Note 7)
Conditions
Limits
(Note 8)
Units
(Limit)
µs (min)
(max)
t1
SC (Clock) Period
0.16
DC
t2
CS Low to SC (Clock) High Set-Up Time
100
ns (min)
t3
CS Low to Data Out (SO) Delay
70
ns (max)
t4
SC (Clock) Low to Data Out (SO) Delay
70
ns (max)
t5
CS High to Data Out (SO) TRI-STATE
200
ns (min)
t6
SC (Clock) High to Data In (SI) Hold Time
60
ns (min)
t7
Data In (SI) Set-Up Time to SC (Clock) High
30
ns (min)
Timing Diagrams
10122304
FIGURE 2. Data Output Timing Diagram
10122305
FIGURE 3. TRI-STATE Data Output Timing Diagram
10122306
FIGURE 4. Data Input Timing Diagram
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LM70
Electrical Characteristics
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating
the device beyond its rated operating conditions.
Note 2: When the input voltage (VI) at any pin exceeds the power supplies (VI < GND or VI > +VS) 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.
Note 3: See the section titled “Surface Mount” found in a current National Semiconductor Linear Data Book for other methods of soldering surface mount devices.
Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pin.
Note 5: The life expectancy of the LM70 will be reduced when operating at elevated temperatures. LM70 θJA (thermal resistance, junction-to-ambient) when
attached to a printed circuit board with 2 oz. foil is summarized in the table below:
NS Package
Number
Thermal
Resistance (θJA)
LM70CILD
LDA08A
51.3˚C/W
LM70CIMM
MUA08A
200˚C/W
Device Number
Note 6: Both part numbers of the LM70 will operate properly over the V+ supply voltage range of 2.65V to 5.5V. The temperature error for temperature ranges of
−10˚C to +65˚C, −40˚C to +85˚C, −55˚C to +125˚C and −55˚C to +150˚C include error induced by power supply variation of ± 5% from the nominal value.
Temperature error will increase by ± 0.3˚C for a power supply voltage (V+) variation of ± 10% from the nominal value.
Note 7: Typicals are at TA = 25˚C and represent most likely parametric norm.
Note 8: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).
Note 9: This specification is provided only to indicate how often temperature data is updated. The LM70 can be read at any time without regard to conversion state
(and will yield last conversion result). A conversion in progress will not be interrupted. The output shift register will be updated at the completion of the read and a
new conversion restarted.
Note 10: For best accuracy, minimize output loading. Higher sink currents can affect sensor accuracy with internal heating. This can cause an error of 0.64˚C at full
rated sink current and saturation voltage based on junction-to-ambient thermal resistance.
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6
LM70
Electrical Characteristics
(Continued)
10122308
FIGURE 5. Temperature-to-Digital Transfer Function (Non-linear scale for clarity)
TRI-STATE Test Circuit
10122307
FIGURE 6.
7
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LM70
Typical Performance Characteristics
Average Power-On Reset Voltage vs Temperature
Static Supply Current vs Temperature
10122323
10122321
Temperature Error
10122322
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8
The LM70 temperature sensor incorporates a band-gap type
temperature sensor and 10-bit plus sign ∆Σ ADC (DeltaSigma Analog-to-Digital Converter). Compatibility of the
LM70’s three wire serial interface with SPI and MICROWIRE
allows simple communications with common microcontrollers and processors. Shutdown mode can be used to optimize current drain for different applications. A manufacture’s
ID register identifies the LM70 as National Semiconductor
product.
1.1 POWER UP AND POWER DOWN
The LM70 always powers up in a known state. The power up
default condition is continuous conversion mode. Immediatly
after power up the LM70 will output an erroneous code until
the first temperature conversion has completed.
When the supply voltage is less than about 1.6V (typical),
the LM70 is considered powered down. As the supply voltage rises above the nominal 1.6V power up threshold, the
internal registers are reset to the power up default state
described above.
1.2 SERIAL BUS INTERFACE
The LM70 operates as a slave and is compatible with SPI or
MICROWIRE bus specifications. Data is clocked out on the
falling edge of the serial clock (SC), while data is clocked in
on the rising edge of SC. A complete transmit/receive communication will consist of 32 serial clocks. The first 16 clocks
comprise the transmit phase of communication, while the
second 16 clocks are the receive phase.
When CS is high SI/O will be in TRISTATE ® . Communication
should be initiated by taking chip select (CS) low. This
should not be done when SC is changing from a low to high
state. Once CS is low the serial I/O pin (SI/O) will transmit
the first bit of data. The master can then read this bit with the
rising edge of SC. The remainder of the data will be clocked
out by the falling edge of SC. Once the 14 bits of data (one
sign bit, ten temperature bits and 3 high bits) are transmitted
the SI/O line will go into TRI-STATE. CS can be taken high at
any time during the transmit phase. If CS is brought low in
the middle of a conversion the LM70 will complete the conversion and the output shift register will be updated after CS
is brought back high.
The receive phase of a communication starts after 16 SC
periods. CS can remain low for 32 SC cycles. The LM70 will
read the data available on the SI/O line on the rising edge of
the serial clock. Input data is to an 8-bit shift register. The
part will detect the last eight bits shifted into the register. The
receive phase can last up to 16 SC periods. All ones must be
shifted in order to place the part into shutdown. A zero in any
location will take the LM70 out of shutdown. The following
codes only should be transmitted to the LM70:
• 00 hex (normal operation)
• 01 hex (normal operation)
• 03 hex (normal operation)
•
•
•
•
1.3 TEMPERATURE DATA FORMAT
Temperature data is represented by a 11-bit, two’s complement word with an LSB (Least Significant Bit) equal to
0.25˚C:
Temperature
Digital Output
Binary
Hex
+150˚C
0100 1011 0001 1111
4B 1Fh
+125˚C
0011 1110 1001 1111
3E 9Fh
+25˚C
0000 1100 1001 1111
0B 9Fh
+0.25˚C
0000 0000 0011 1111
00 3Fh
0˚C
0000 0000 0001 1111
00 1Fh
−0.25˚C
1111 1111 1111 1111
FF FFh
−25˚C
1111 0011 1001 1111
F3 9Fh
−55˚C
1110 0100 1001 1111
E4 9Fh
Note: The last two bits are TRI-STATE and depicted as one
in the table.
The first data byte is the most significant byte with most
significant bit first, permitting only as much data as necessary to be read to determine temperature condition. For
instance, if the first four bits of the temperature data indicate
an overtemperature condition, the host processor could immediately take action to remedy the excessive temperatures.
1.4 SHUTDOWN MODE/MANUFACTURER’S ID
Shutdown mode is enabled by writing XX FF to the LM70 as
shown in Figure 7c and discussed in Section 1.2. The serial
bus is still active when the LM70 is in shutdown. Current
draw drops to less than 10 µA between serial communications. When in shutdown mode the LM70 always will output
1000 0001 0000 00XX. This is the manufacturer’s ID/Device
ID information. The first 5-bits of the field (1000 0XXX) are
reserved for manufacturer’s ID.
07 hex (normal operation)
0F hex (normal operation)
1F hex (normal operation)
3F hex(normal operation)
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LM70
• 7F hex(normal operation)
• FF hex (Shutdown, transmit manufacturer’s ID)
.
any others may place the part into a Test Mode. Test Modes
are used by National Semiconductor to thoroughly test the
function of the LM70 during production testing. Only eight
bits have been defined above since only the last eight transmitted, before CS is taken HIGH, are detected by the LM70
The following communication can be used to determine the
Manufacturer’s/Device ID and then immediately place the
part into continuous conversion mode. With CS continuously
low:
• Read 16 bits of temperature data
• Write 16 bits of data commanding shutdown
• Read 16 bits of Manufacture’s/Device ID data
• Write 8 to 16 bits of data commanding Conversion Mode
• Take CS HIGH.
Note that 250 ms will have to pass for a conversion to
complete before the LM70 actually transmits temperature
data.
1.0 Functional Description
LM70
1.0 Functional Description
(Continued)
1.5 INTERNAL REGISTER STRUCTURE
The LM70 has three registers, the temperature register, the
configuration register and the manufacturer’s/device identification register. The temperature and manufacturer’s/device
identification registers are read only. The configuration register is write only.
1.5.1 CONFIGURATION REGISTER
(Selects shutdown or continuous conversion modes):
(Write Only):
D15
D14
D13
D12
D11
D10
D9
D8
X
X
X
X
X
X
X
X
D7
D6
D5
D4
D3
D2
D1
D0
Shutdown
D0-D15 set to XX FF hex enables shutdown mode.
D0-D15 set to XX 00 hex enables continuous conversion
mode.
Note: setting D0-D15 to any other values may place the
LM70 into a manufacturer’s test mode, upon which the LM70
will stop responding as described. These test modes are to
be used for National Semiconductor production testing only.
See Section 1.2 Serial Bus Interface for a complete discussion.
1.5.2 TEMPERATURE REGISTER
(Read Only):
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
MSB
Bit 9
Bit 8
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
LSB
1
1
1
X
X
D0–D1: Undefined. TRI-STATE will be output on SI/0.
D2–D4: Always set high.
D5–D15: Temperature Data. One LSB = 0.25˚C. Two’s
complement format.
1.5.3 MANUFACTURER’S/DEVICE ID REGISTER
(Read Only):
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
X
X
D0–D1: Undefined. TRI-STATE will be output on SI/0.
D2-D4: Always set LOW.
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D5–D15: Manufacturer’s ID Data. This register is accessed
whenever the LM70 is in shutdown mode.
10
LM70
2.0 Serial Bus Timing Diagrams
10122314
a) Reading Continuous Conversion - Single Eight-Bit Frame
10122315
b) Reading Continuous Conversion - Two Eight-Bit Frames
10122318
c) Writing Shutdown Control
FIGURE 7. Timing Diagrams
between the plastic package and the LM70 die. If the ambient air temperature is significantly different from the printed
circuit board temperature, it will have a small effect on the
measured temperature.
In probe-type applications, the LM70 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
LM70 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 insure that moisture cannot corrode the LM70
or its connections.
3.0 Application Hints
To get the expected results when measuring temperature
with an integrated circuit temperature sensor like the LM70,
it is important to understand that the sensor measures its
own die temperature. For the LM70, the best thermal path
between the die and the outside world is through the LM70’s
pins. In the MSOP-8 package the ground pin is connected to
the back side of the LM70 die and thus has the most effect
on the die temperature. Although the other pins will also
have some effect on the LM70die temperature and therefore
should not be discounted. The LM70 will provide an accurate
measurement of the temperature of the printed circuit board
on which it is mounted, because the pins represent a good
thermal path to the die. A less efficient thermal path exists
11
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LM70
4.0 Typical Applications
10122320
FIGURE 8. Temperature monitor using Intel 196 processor
10122319
FIGURE 9. LM70 digital input control using micro-controller’s general purpose I/O.
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12
LM70
Physical Dimensions
inches (millimeters) unless otherwise noted
8-Lead Molded Mini Small Outline Package (MSOP)
(JEDEC REGISTRATION NUMBER M0-187)
Order Number LM70CIMM-3, LM70CIMMX-3, LM70CIMM-5 or LM70CIMMX-5
NS Package Number MUA08A
8-Lead Molded Leadless Leadframe Package
Order Number LM70CILD-3, LM70CILDX-3, LM70CILD-5 or LM70CILDX-5
NS Package Number LDA08A
13
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LM70 SPI/MICROWIRE™10-Bit plus Sign Digital Temperature Sensor
Notes
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.
For the most current product information visit us at www.national.com.
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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.
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National Semiconductor manufactures products and uses packing materials that meet the provisions of the Customer Products
Stewardship Specification (CSP-9-111C2) and the Banned Substances and Materials of Interest Specification (CSP-9-111S2) and contain
no ‘‘Banned Substances’’ as defined in CSP-9-111S2.
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