National Semiconductor LM74A Technical data
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LM74A
LM74A SPI/MICROWIRE 12-Bit Plus Sign Temperature Sensor (LM74 in Die Form)
December 2001
SPI/MICROWIRE
™
12-Bit Plus Sign Temperature Sensor
(LM74 in Die Form)
General Description
The LM74A is a temperature sensor, Delta-Sigma
analog-to-digital converter with an SPI and MICROWIRE
compatible interface in die form. The host can query the
LM74A 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.
This particular data sheet applies to the LM74 in die form.
The LM74 is available in the SO-8 package as well as an
5-Bump micro SMD package please refer to LM74 data
sheet for detailed specifictions pertaining to the packaged
parts.
The LM74A 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 LM74Aaccuracy of
specified over a temperature range of 0˚C to +150˚C.
The LM74A’s 4.5V 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
±
3.5˚C is
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 LM74 is available in a 5-Bump micro SMD and 8-pin
SOP
Key Specifications
j
Supply Voltage 4.5V to 5.5V
j
Supply Current operating 310µA (typ)
520µA (max)
shutdown 8µA (typ)
j
Temperature
Accuracy
0˚C to 140˚C
140˚C to 150˚C
±
3.0˚C(max)
±
3.5˚C(max)
Simplified Block Diagram
20017701
MICROWIRE®is a registered trademark of National Semiconductor Corporation.
© 2001 National Semiconductor Corporation DS200177 www.national.com
Connection Diagram
LM74A
LM74A
Bond Pad Layout
1.40mm x 1.57 mm (55 x 62 mils)
Bond Pad Mechanical Dimensions
Dimensions of bond pad coordinates are in millimeters.
Origin of coordinates: center of die.
X-Direction is in the longitudinal axis of the die.
Coordinates refer to center of Bond Pad.
#
Pin
1 -0.569 mm +0.585 mm
2 -0.537 mm +0.314 mm
3 -0.569 mm -0.554 mm
4 n/a n/a
5 +0.537 mm +0.277 mm
6 +0.569 mm +0.569 mm
Back
XY
Ordering Information
Order Number
LM74A MDA No Package, Die 4.5V to 5.5V 7k unit surftape tape-and-reel
NS Package
Number
TOP VIEW
20017727
Supply Voltage Transport Media
Pin Descriptions
Label Pin
SI/O 1 Slave Input/Output - Serial bus bi-directional data line.
SC 2 Slave Clock - Serial bus clock Shmitt trigger input
GND 3 Power Supply Ground Ground
NC 4 No Connection No Connection
CS
+
V
Back (Backside) Can go to GND connection
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#
Shmitt trigger input.
line.
5 Chip Select input. From Controller
6 Positive Supply Voltage Input DC Voltage from 4.5V to 5.5V. Bypass with a
Function Typical Connection
From and to Controller
From Controller
0.1 µF ceramic capacitor.
Typical Application
LM74A
20017703
FIGURE 1. COP Microcontroller Interface
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Absolute Maximum Ratings (Note 1)
LM74A
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
+
+ 0.3V
Operating Ratings
Operating Temperature Range 0˚C to +150˚C
Specified Temperature Range T
(Note 5)
LM74A 0˚C to +150˚C
Supply Voltage Range (+V
) +4.5V to +5.5V
S
ESD Susceptibility (Note 4)
Human Body Mode
Machine Model
2000V
200V
Temperature-to-Digital Converter Characteristics
Unless otherwise noted, these specifications apply for V+= 4.5V to 5.5V (Note 6). Boldface limits apply for TA=TJ=T
to T
Temperature Error (Note 6) T
Resolution 13 Bits
Temperature Conversion Time (Note 9) 280 425 ms (max)
Quiescent Current Serial Bus
; all other limits TA=TJ=+25˚C, unless otherwise noted.
MAX
Parameter Conditions
= 0˚C to
A
+140˚C
T
= +140˚C
A
to +150˚C
Inactive
Serial Bus
Active
Shutdown
Mode, V
+
=
5V
Typical
(Note 7)
Limits
(Note 8)
±
3.0
±
3.5 ˚C (max)
310 520 µA (max)
310 µA
8µA
to T
MIN
Units
(Limit)
˚C (max)
MAX
MIN
Logic Electrical Characteristics
DIGITAL DC CHARACTERISTICS
Unless otherwise noted, these specifications apply for V
to T
; all other limits TA=TJ=+25˚C, unless otherwise noted.
MAX
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 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
+
= 4.5V to 5.5V (Note 6). Boldface limits apply for TA=TJ=T
+
= 4.5V to 5.5V 0.8 0.33 V (min)
+
VO= GND
+
=V
V
O
Typical
(Note 7)
Limits
(Note 8)
+
V
+ 0.3 V (max)
+
V
x 0.3 V (max)
Units
(Limit)
0.005 3.0 µA (max)
−1
+1
µA (min)
µA
(max)
MIN
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