LM74
SPI/MICROWIRE
™
12-Bit Plus Sign Temperature Sensor
General Description
The LM74 is a temperature sensor, Delta-Sigma analog-todigital 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 disk drives, printers, electronic test equipment, and office electronics. The LM74 is
available in the SO-8 package as well as an 5-Bump micro
SMD package.
Applications
n System Thermal Management
n Personal Computers
n Disk Drives
n Office Electronics
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 5-Bump micro SMD package saves space
Key Specifications
j
Supply Voltage 3.0V or 2.65V to
5.5V
j
Supply Current operating 265µA (typ)
520µA (max)
shutdown 3µA (typ)
j
Temperature
Accuracy −10˚C to 65˚C
±
1.25˚C(max)
−25˚C to 110˚C
±
2.1˚C(max)
−55˚C to 125˚C
±
3˚C(max)
Simplified Block Diagram
10090901
MICROWIRE®is a registered trademark of National Semiconductor Corporation.
TRI-STATE
®
is a registered trademark of National Semiconductor Corporation.
April 2003
LM74 SPI/MICROWIRE 12-Bit Plus Sign Temperature Sensor
© 2003 National Semiconductor Corporation DS100909 www.national.com
Connection Diagrams
SO-8 5-Bump micro SMD
10090902
TOP VIEW
NS Package Number M08A
10090924
Note:
- Pin numbers are referenced to the package marking text orientation. Pin
1 is designated by the square.
- Reference JEDEC Registration MO-211, variation BC
- The top 4 characters designate the date code. The bottom 3 characters
designate the device type (see ordering information).
TOP VIEW
NS Package Number BPD05MPB
Ordering Information
Order Number
Package
Marking
NS Package
Number
Supply Voltage Transport Media
LM74CIM-3 LM74CIM-3 SO-8, M08A 3.0V to 3.6V 95 Units in Rail
LM74CIMX-3 LM74CIM-3 SO-8, M08A 3.0V to 3.6V 2500 Units in Tape and Reel
LM74CIM-5 LM74CIM-5 SO-8, M08A 4.5V to 5.5V 95 Units in Rail
LM74CIMX-5 LM74CIM-5 SO-8, M08A 4.5V to 5.5V 2500 Units in Tape and Reel
LM74CIBP-3 T8 micro SMD,
BPD05MPB
2.65V to 3.6V 250 Units in Tape and Reel
LM74CIBPX-3 T8 micro SMD,
BPD05MPB
2.65V to 3.6V 3000 Units in Tape and Reel
LM74CIBP-5 T9 micro SMD,
BPD05MPB
4.5V to 5.5V 250 Units in Tape and Reel
LM74CIBPX-5 T9 micro SMD,
BPD05MPB
4.5V to 5.5V 3000 Units in Tape and Reel
LM74
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Pin Descriptions
Label SO-8
Pin
#
micro
SMD
Pin
#
Function Typical Connection
SI/O 1 1 Slave Input/Output - Serial bus bi-directional data
line. Schmitt trigger input.
From and to Controller
SC 2 5 Slave Clock - Serial bus clock Schmitt trigger input
line.
From Controller
NC 3 No Connection No Connection
GND 4 4 Power Supply Ground Ground
NC 5 No Connection No Connection
NC 6 No Connection No Connection
CS
7 3 Chip Select input. From Controller
V
+
8 2 Positive Supply Voltage Input DC Voltage from 3.0V to 5.5V for the
LM74CIM and 2.65V to 5.5V for the
LM74CIBP. Bypass with a 0.1 µF ceramic
capacitor.
Typical Application
10090903
FIGURE 1. COP Microcontroller Interface
LM74
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Absolute Maximum Ratings (Note 1)
Supply Voltage −0.3V to 6.0V
Voltage at any Pin −0.3V to V
+
+ 0.3V
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
SO-8 Package (Note 3)
Vapor Phase (60 seconds)
Infrared (15 seconds)
215˚C
220˚C
ESD Susceptibility (Note 4)
Human Body Mode
LM74CIBP SC, pin 5 1900V
LM74CIM and LM74CIBP all
other pins
2000V
Machine Model 200V
Operating Ratings
Specified Temperature Range T
MIN
to T
MAX
(Note 5)
LM74CIBP
LM74CIM
−40˚C to +125˚C
−55˚C to +150˚C
Supply Voltage Range (+V
S
)
LM74CIBP +2.65V to +5.5V
LM74CIM +3.0V to +5.5V
Temperature-to-Digital Converter Characteristics
Unless otherwise noted, these specifications apply for V+= 2.65V to 3.6V for the LM74CIBP -3, V+= 3.0V to 3.6V for the
LM74CIM -3 and V
+
= 4.5V to 5.5V for the LM74 -5 (Note 6). Boldface limits apply for TA=TJ=T
MIN
to T
MAX
; all other lim-
its T
A=TJ
=+25˚C, unless otherwise noted.
Parameter Conditions
Typical
(Note 7)
LM74-5
Limits
(Note 8)
LM74-3
Limits
(Note 8)
Units
(Limit)
Temperature Error (Note 6) T
A
= −10˚C to +65˚C
±
1.25
±
1.25 ˚C (max)
T
A
= −25˚C to +110˚C
±
2.1 +2.65/−2.15 ˚C (max)
T
A
= −40˚C to +85˚C +2.65/−1.65
±
2.15 ˚C (max)
T
A
= −40˚C to +110˚C +2.65/
−2.0
+2.65/−2.15 ˚C (max)
T
A
= −55˚C to +125˚C
±
3.0
±
3.5 ˚C (max)
T
A
= −55˚C to +150˚C
±
5.0
±
5.0 ˚C (max)
Resolution 13 Bits
Temperature
Conversion Time
SO-8 (Note 9) 280 425 425 ms (max)
micro SMD (Note 9) 611 925 925 ms (max)
Quiescent Current SO-8 Serial Bus Inactive 310 520 520 µA (max)
micro SMD 265 470 470 µA (max)
SO-8 Serial Bus Active 310 µA
micro SMD 310 µA
SO-8 Shutdown Mode,
V
+
= 3.3V
7µA
micro SMD 3 µA
SO-8 Shutdown Mode,
V
+
=5V
8µA
micro SMD 4 µA
Logic Electrical Characteristics
DIGITAL DC CHARACTERISTICS Unless otherwise noted, these specifications apply for V+= 2.65V to 3.6V for the
LM74CIBP -3, V
+
= 3.0V to 3.6V for the LM74CIM -3 and V+= 4.5V to 5.5V for the LM74 -5 (Note 6). Boldface limits apply
for T
A=TJ=TMIN
to T
MAX
; all other limits TA=TJ=+25˚C, unless otherwise noted.
Symbol Parameter Conditions
Typical
(Note 7)
Limits
(Note 8)
Units
(Limit)
V
IN(1)
Logical “1” Input Voltage V+x 0.7 V (min)
V
+
+ 0.3 V (max)
V
IN(0)
Logical “0” Input Voltage −0.3 V (min)
V
+
x 0.3 V (max)
Input Hysteresis Voltage V
+
= 3.0V to 3.6V 0.8 0.35 V (min)
V
+
= 4.5V to 5.5V 0.8 0.33 V (min)
I
IN(1)
Logical “1” Input Current VIN=V
+
0.005 3.0 µA (max)
LM74
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Logic Electrical Characteristics (Continued)
DIGITAL DC CHARACTERISTICS Unless otherwise noted, these specifications apply for V+= 2.65V to 3.6V for the
LM74CIBP -3, V
+
= 3.0V to 3.6V for the LM74CIM -3 and V+= 4.5V to 5.5V for the LM74 -5 (Note 6). Boldface limits apply
for T
A=TJ=TMIN
to T
MAX
; all other limits TA=TJ=+25˚C, unless otherwise noted.
Symbol Parameter Conditions
Typical
(Note 7)
Limits
(Note 8)
Units
(Limit)
I
IN(0)
Logical “0” Input Current VIN= 0V −0.005 −3.0 µA (min)
C
IN
All Digital Inputs 20 pF
V
OH
High Level Output Voltage IOH= −400 µA 2.4 V (min)
V
OL
Low Level Output Voltage IOL=+2mA 0.4 V (max)
I
O_TRI-STATE
TRI-STATE Output Leakage
Current
VO= GND
V
O
=V
+
−1
+1
µA (min)
µA
(max)
SERIAL BUS DIGITAL SWITCHING CHARACTERISTICS Unless otherwise noted, these specifications apply for V+= 2.65V
to 3.6V for the LM74CIBP -3, V
+
= 3.0V to 3.6V for the LM74CIM -3 and V+= 4.5V to 5.5V for the LM74 -5 (Note 6); CL(load
capacitance) on output lines = 100 pF unless otherwise specified. Boldface limits apply for T
A=TJ=TMIN
to T
MAX
; all other
limits T
A=TJ
= +25˚C, unless otherwise noted.
Symbol Parameter Conditions
Typical
(Note 7)
Limits
(Note 8)
Units
(Limit)
t
1
SC (Clock) Period 0.16
DC
µs (min)
(max)
t
2
CS Low to SC (Clock) High Set-Up Time 100 ns (min)
t
3
CS Low to Data Out (SO) Delay 70 ns (max)
t
4
SC (Clock) Low to Data Out (SO) Delay 100 ns (max)
t
5
CS High to Data Out (SO) TRI-STATE 200 ns (max)
t
6
SC (Clock) High to Data In (SI) Hold Time 50 ns (min)
t
7
Data In (SI) Set-Up Time to SC (Clock) High 30 ns (min)
10090904
FIGURE 2. Data Output Timing Diagram
LM74
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