NSC LM74CIM-5, LM74CIM-3 Datasheet
LM74
SPI/MICROWIRE
General Description
The LM74 is a temperature sensor, Delta-Sigma
analog-to-digital converter with an SPI and MICROWIRE
compatible interface. The host can query the LM74 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 LM74 has 12-bit plus sign temperature resolution
(0.0625˚C per LSB) while operating over a temperature
range of −55˚C to +150˚C.
The LM74’s 3.0V 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 diskdrives,printers,electronic test equipment, and office electronics.
Applications
n System Thermal Management
n Personal Computers
n Disk Drives
n Office Electronics
™
Digital Temperature Sensor
December 1999
n Electronic Test Equipment
Features
n 0.0625˚C temperature resolution.
n Shutdown mode conserves power between temperature
reading
n SPI and MICROWIRE Bus interface
n SO-8 package saves space
Key Specifications
n Supply Voltage 3.0V to 5.5V
n Supply Current operating 310 µA (typ)
520 µA (max)
shutdown 7 µA (typ)
n Temperature
Accuracy
−10˚C to 65˚C
−25˚C to 110˚C
−55˚C to 125˚C
±
1.25˚C(max)
±
2.1˚C(max)
±
3˚C(max)
LM74 SPI/MICROWIRE Digital Temperature Sensor
Simplified Block Diagram
DS100909-1
MICROWIRE®is a registeredtrademark of National Semiconductor Corporation.
© 1999 National Semiconductor Corporation DS100909 www.national.com
Connection Diagram
LM74
Ordering Information
Order Number
LM74CIM-3 SO-8, M08A 3.0V to 3.6V 95 Units in Rail
LM74CIMX-3 SO-8, M08A 3.0V to 3.6V 2500 Units in Tape and Reel
LM74CIM-5 SO-8, M08A 4.5V to 5.5V 95 Units in Rail
LM74CIMX-5 SO-8, M08A 4.5V to 5.5V 2500 Units in Tape and Reel
Pin Descriptions
NS Package
Number
SO-8
DS100909-2
TOP VIEW
NS Package Number M08A
Supply Voltage Transport Media
Label Pin
SI/O 1 Slave Input/Output - Serial bus bi-directional data
SC 2 Slave Clock - Serial bus clock Shmitt trigger input
NC 3 No Connection No Connection
GND 4 Power Supply Ground Ground
NC 5 No Connection No Connection
NC 6 No Connection No Connection
CS
+
V
#
line. Shmitt trigger input.
line.
7 Chip Select input. From Controller
8 Positive Supply Voltage Input DC Voltage from 3.0V to 5.5V. Bypass with
Function Typical Connection
From and to Controller
From Controller
a 0.1 µF ceramic capacitor.
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Typical Application
LM74
DS100909-3
FIGURE 1. COP Microcontroller Interface
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Absolute Maximum Ratings (Note 1)
LM74
Supply Voltage −0.3V to 6.0V
Voltage at any Pin −0.3V to V
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
SOP Package (Note 3)
Vapor Phase (60 seconds)
Infrared (15 seconds)
+
+ 0.3V
215˚C
220˚C
ESD Susceptibility (Note 4)
Human Body Model 2000V
Machine Model 200V
Operating Ratings
Specified Temperature Range T
(Note 5) −55˚C to +150˚C
Supply Voltage Range (+V
) +3.0V to +5.5V
S
MIN
to T
MAX
Temperature-to-Digital Converter Characteristics
Unless otherwise noted, these specifications apply for V
LM74CIM-5 (Note 6). Boldface limits apply for T
noted.
Parameter Conditions
=
Temperature Error (Note 6) T
−10˚C to +65˚C
A
=
T
−25˚C to +110˚C
A
=
T
−40˚C to +85˚C +2.65/−1.65
A
=
T
−40˚C to +110˚C +2.65/
A
=
−55˚C to +125˚C
T
A
=
T
−55˚C to +150˚C
A
+
=
3.0V to 3.6V for the LM74CIM-3 and V
=
=
to T
T
A
T
J
MIN
; all other limits T
MAX
Typical
(Note 7)
LM74-5
Limits
(Note 8)
±
1.25
±
2.1 +2.65/−2.15 ˚C (max)
+
=
=
A
4.5V to 5.5V for the
=
T
+25˚C, unless otherwise
J
LM74-3
Limits
(Note 8)
±
1.25 ˚C (max)
±
2.15 ˚C (max)
Units
(Limit)
+2.65/−2.15 ˚C (max)
−2.0
±
3.0
±
5.0
±
3.5 ˚C (max)
±
5.0 ˚C (max)
Resolution 13 Bits
Temperature Conversion Time (Note 9) 280 425 425 ms (max)
Quiescent Current Serial Bus Inactive 310 520 520 µA (max)
Serial Bus Active 310 µA
+
Shutdown Mode, V
Shutdown Mode, V
=
3.3V 7 µA
+
=
5V 8 µA
Logic Electrical Characteristics
DIGITAL DC CHARACTERISTICS
Unless otherwise noted, these specifications apply for V
LM74CIM-5. Boldface limits apply for T
=
T
A
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
I
IN(1)
I
IN(0)
C
IN
V
OH
V
OL
I
O_TRI-STATE
Logical “1” Input Current V
Logical “0” Input Current V
All Digital Inputs 20 pF
High Level Output Voltage I
Low Level Output Voltage I
TRI-STATE Output Leakage
Current
+
=
=
J
3.0V to 3.6V for the LM74CIM-3 and V
to T
T
MIN
+
+
V
IN
IN
OH
OL
V
O
V
O
; all other limits T
MAX
=
3.0V to 3.6V 0.8 0.35 V (min)
=
4.5V to 5.5V 0.8 0.33 V (min)
+
=
V
=
0V −0.005 −3.0 µA (min)
=
−400 µA 2.4 V (min)
=
+2 mA 0.4 V (max)
=
GND
+
=
V
=
=
T
A
J
Typical
(Note 7)
0.005 3.0 µA (max)
+
=
+25˚C, unless otherwise noted.
4.5V to 5.5V for the
Limits
(Note 8)
+
V
+ 0.3 V (max)
+
V
x 0.3 V (max)
−1
+1
Units
(Limit)
µA (min)
µA(max)
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