Rainbow Electronics LM70 User Manual
February 2005
LM70
SPI/MICROWIRE 10-Bit plus Sign Digital Temperature
Sensor
LM70 SPI/MICROWIRE
General Description
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.
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.
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.
Applications
n System Thermal Management
n Personal Computers
n Disk Drives
n Office Electronics
n Electronic Test Equipment
Features
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
Key Specifications
j
Supply Voltage 2.65V to 5.5V
j
Supply Current operating 260 µA (typ)
490 µA (max)
shutdown 12 µA (typ)
j
Temperature
Accuracy
−40˚C to 85˚C
−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)
±
2˚C(max)
™
10-Bit plus Sign Digital Temperature Sensor
Simplified Block Diagram
10122301
© 2005 National Semiconductor Corporation DS101223 www.national.com
Connection Diagrams
LM70
MSOP-8 LLP-8
TOP VIEW
NS Package Number MUA08A
10122302
10122325
TOP VIEW
NS Package Number LDA08A
Ordering Information
Order Number
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
Package
Marking
NS Package
Number
Supply Voltage Transport Media
Pin Descriptions
Label SOP-8
Pin #
SI/O 1 1 Input/Output - Serial bus bi-directional data line.
SC 2 3 Clock - Serial bus clock Schmitt trigger input
GND 4 7 Power Supply Ground Ground
+
V
CS 7 8 Chip Select input. From Controller
NC 3, 6, 8 2, 4, 6 No Connect These pins are not connected to the
5 5 Positive Supply Voltage Input DC Voltage from 2.65V to 5.5V. Bypass
LLP-8
Pin #
Function Typical Connection
From and to Controller
Schmitt trigger input.
From Controller
line.
with a 0.1 µF ceramic capacitor.
LM70 die in any way.
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Typical Application
LM70
10122303
FIGURE 1. COP Microcontroller Interface
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Absolute Maximum Ratings (Note 1)
LM70
Supply Voltage −0.3V to 6.0V
Voltage at any Pin −0.3V to V
+
+ 0.3V
ESD Susceptibility (Note 4)
Human Body Model 3000V
Machine Model 300V
Input Current at any Pin (Note 2) 5 mA
Package Input Current (Note 2) 20 mA
Storage Temperature −65˚C to +150˚C
Soldering Information, Lead Temperature
MSOP-8 and LLP-8 Packages
(Note 3)
Vapor Phase (60 seconds)
Infrared (15 seconds)
215˚C
220˚C
Operating Ratings
Specified Temperature Range T
(Note 5) −55˚C to +150˚C
Supply Voltage Range (+V
) +2.65V to +5.5V
S
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 T
A=TJ=TMIN
to T
Parameter Conditions
Temperature Error (Note 6) T
= −10˚C to +65˚C +1.5/−2.0 +1.5/−2.0 ˚C (max)
A
T
= −40˚C to +85˚C
A
T
= −55˚C to +125˚C +3.0/−2.0 +3.0/−2.0 ˚C (max)
A
T
= −55˚C to +150˚C +3.5/−2.0 +3.5/−2.0 ˚C (max)
A
Resolution 11
Temperature Conversion
(Note 9) 140 210 210 ms (max)
Time
Quiescent Current Serial Bus Inactive 260 490 490 µA (max)
Serial Bus Active 260 µA
Shutdown Mode 12 µA
; all other limits TA=TJ=+25˚C, unless otherwise noted.
MAX
Typical
(Note 7)
LM70-5
Limits
(Note 8)
±
2.0
LM70-3
Limits
(Note 8)
±
2.0 ˚C (max)
0.25
(Limit)
MIN
Units
Bits
˚C
to T
MAX
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 T
A=TJ=TMIN
to T
Symbol Parameter Conditions
V
IN(1)
V
IN(0)
Logical “1” Input Voltage V+x 0.7 V (min)
Logical “0” Input Voltage −0.3 V (min)
Input Hysteresis Voltage V
V
I
IN(1)
I
IN(0)
C
IN
V
OH
V
OL
I
O_TRI-STATE
Logical “1” Input Current VIN=V
Logical “0” Input Current VIN= 0V −0.005 −3.0 µA (min)
All Digital Inputs 20 pF
High Level Output Voltage IOH= −400 µA 2.4 V (min)
Low Level Output Voltage IOL=+2mA 0.4 V (max)
TRI-STATE Output Leakage
Current
VO= GND
V
; all other limits TA=TJ=+25˚C, unless otherwise noted.
MAX
Typical
(Note 7)
+
= 2.65V to 3.6V 0.8 0.27 V (min)
+
= 4.5V to 5.5V 0.8 0.35 V (min)
+
0.005 3.0 µA (max)
Limits
(Note 8)
+
V
+ 0.3 V (max)
+
V
x 0.3 V (max)
−1
+
=V
O
+1
Units
(Limit)
µA (min)
µA (max)
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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, C
to T
MAX
Symbol Parameter Conditions
t
1
(load capacitance) on output lines = 100 pF unless otherwise specified. Boldface limits apply for TA=TJ=T
L
; all other limits TA=TJ= +25˚C, unless otherwise noted.
Typical
(Note 7)
Limits
(Note 8)
SC (Clock) Period 0.16
DC
t
2
t
3
t
4
t
5
t
6
t
7
CS Low to SC (Clock) High Set-Up Time 100 ns (min)
CS Low to Data Out (SO) Delay 70 ns (max)
SC (Clock) Low to Data Out (SO) Delay 70 ns (max)
CS High to Data Out (SO) TRI-STATE 200 ns (min)
SC (Clock) High to Data In (SI) Hold Time 60 ns (min)
Data In (SI) Set-Up Time to SC (Clock) High 30 ns (min)
Timing Diagrams
LM70
MIN
Units
(Limit)
µs (min)
(max)
FIGURE 2. Data Output Timing Diagram
FIGURE 3. TRI-STATE Data Output Timing Diagram
10122304
10122305
FIGURE 4. Data Input Timing Diagram
10122306
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