LM74
SPI/MICROWIRE ™12-Bit Plus Sign Temperature Sensor
General Description
The LM74is a temperature sensor,Delta-Sigma analog-to-digital converter with an SPI and MICROWIRE compatible interface.The host can query the LM74at any time to read temperature.A shutdown mode decreases power consump-tion to less than 10µA.This mode is useful in systems where low average power consumption is critical.
The LM74has 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,elec-tronic test equipment,and office electronics.The LM74is available in the SO-8package as well as an 5-Bump micro SMD package.
Applications
n System Thermal Management n Personal Computers n Disk Drives
n
vitas 永恒的吻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
LM74SPI/MICROWIRE 12-Bit Plus Sign Temperature Sensor
©2003National Semiconductor Corporation DS100909www.national
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 1is designated by the square.
-Reference JEDEC Registration MO-211,variation BC
-The top 4characters designate the date code.The bottom 3characters 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-3LM74CIM-3SO-8,M08A 3.0V to 3.6V 95Units in Rail
LM74CIMX-3LM74CIM-3SO-8,M08A 3.0V to 3.6V 2500Units in Tape and Reel LM74CIM-5LM74CIM-5SO-8,M08A 4.5V to 5.5V 95Units in Rail
LM74CIMX-5LM74CIM-5
SO-8,M08A 4.5V to 5.5V 2500Units in Tape and Reel LM74CIBP-3T8micro SMD,BPD05MPB 2.65V to 3.6V 250Units in Tape and Reel LM74CIBPX-3T8micro SMD,BPD05MPB 2.65V to 3.6V 3000Units in Tape and Reel LM74CIBP-5T9micro SMD,BPD05MPB 4.5V to 5.5V 250Units in Tape and Reel LM74CIBPX-5
T9
micro SMD,BPD05MPB
4.5V to
5.5V
3000Units in Tape and Reel
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Pin Descriptions
Label SO-8
Pin#micro
SMD
Pin#
Function Typical Connection
SI/O11Slave Input/Output-Serial bus bi-directional data
line.Schmitt trigger input.
From and to Controller
SC25Slave Clock-Serial bus clock Schmitt trigger input
line.兄弟的歌
From Controller
NC3No Connection No Connection
GND44Power Supply Ground Ground
NC5No Connection No Connection
NC6No Connection No Connection
CS73Chip Select input.From Controller
V+82Positive Supply Voltage Input DC Voltage from3.0V to5.5V for the
LM74CIM and2.65V to5.5V for the
LM74CIBP.Bypass with a0.1µF ceramic
capacitor.
Typical Application
10090903
FIGURE1.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)5mA Package Input Current (Note 2)20mA
Storage Temperature −65˚C to +150˚C
Soldering Information,Lead Temperature
SO-8Package (Note 3)
Vapor Phase (60seconds)Infrared (15seconds)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 -3and V +=4.5V to 5.5V for the LM74-5(Note 6).Boldface limits apply for T A =T J =T MIN to T MAX ;all other lim-its T A =T J =+25˚C,unless otherwise noted.
Parameter
Conditions
Typical (Note 7)
LM74-5Limits (Note 8)
LM74-3Limits (Note 8)
默 周杰伦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 13Bits Temperature Conversion Time SO-8(Note 9)280425425ms (max)micro SMD (Note 9)
611925925ms (max)Quiescent Current
SO-8Serial Bus Inactive 310520520µA (max)micro SMD
265470
470
µA (max)SO-8Serial Bus Active 310µA micro SMD
310µA SO-8Shutdown Mode,
V +
=3.3V 7µA micro SMD 3µA SO-8Shutdown Mode,
V +
=5V
8µA micro SMD 4
µA
Logic Electrical Characteristics
刘德华 悟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 -3and V +=4.5V to 5.5V for the LM74-5(Note 6).Boldface limits apply for T A =T J =T MIN to T MAX ;all other limits T A =T J =+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 0.7V (min)V ++0.3V (max)V IN(0)
Logical “0”Input Voltage −0.3V (min)V +x 0.3
V (max)Input Hysteresis Voltage
V +=3.0V to 3.6V 0.80.35V (min)V +=4.5V to 5.5V 0.80.33V (min)I IN(1)
Logical “1”Input Current
V IN =V +
0.005
3.0
µA (max)
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Logic Electrical Characteristics(Continued)
DIGITAL DC CHARACTERISTICS Unless otherwise noted,these specifications apply for V+=2.65V to3.6V for the
LM74CIBP-3,V+=3.0V to3.6V for the LM74CIM-3and V+=4.5V to5.5V for the LM74-5(Note6).Boldface limits apply for T A=T J=T MIN to T MAX;all other limits T A=T J=+25˚C,unless otherwise noted.
Symbol Parameter Conditions Typical
(Note7)
Limits
(Note8)
Units
I IN(0)Logical“0”Input Current V IN=0V−0.005−3.0µA(min) C IN All Digital Inputs20pF
V OH High Level Output Voltage I OH=−400µA 2.4V(min) V OL Low Level Output Voltage I OL=+2mA0.4V(max)
I O_TRI-STATE TRI-STATE Output Leakage
Current V O=GND
V O=V+
nobody but you−1
+1
µA(min)
µA
(max)
SERIAL BUS DIGITAL SWITCHING CHARACTERISTICS Unless otherwise noted,these specifications apply for V+=2.65V to3.6V for the LM74CIBP-3,V+=3.0V to3.6V for the LM74CIM-3and V+=4.5V to5.5V for the LM74-5(Note6);C L(load capacitance)on output lines=100pF unless otherwise specified.Boldface limits apply for T A=T J=T MIN to T MAX;all other limits T A=T J=+25˚C,unless otherwise noted.
Symbol Parameter Conditions Typical
(Note7)
Limits
(Note8)
Units
(Limit)
t1SC(Clock)Period0.16
DC µs(min) (max)
t2CS Low to SC(Clock)High Set-Up Time100ns(min)
t3CS Low to Data Out(SO)Delay70ns(max)
t4SC(Clock)Low to Data Out(SO)Delay100ns(max)
t5CS High to Data Out(SO)TRI-STATE200ns(max)
t6SC(Clock)High to Data In(SI)Hold Time50ns(min)
t7Data In(SI)Set-Up Time to SC(Clock)High30ns(min)
10090904
FIGURE2.Data Output Timing Diagram
LM74
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Logic Electrical Characteristics
(Continued)
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 (V I )at any pin exceeds the power supplies (V I <GND or V I >+V S )the current at that pin should be limited to 5mA.The 20mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5mA to four.
Note 3:See AN-450“Surface Mounting Methods and Their Effect on Product Reliability”or 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,100pF discharged through a 1.5k Ωresistor.Machine model,200pF discharged directly into each pin.
Note 5:The life expectancy of the LM74will be reduced when operating at elevated temperatures.LM74θJA (thermal resistance,junction-to-ambient)when attached to a printed circuit board with 2oz.foil is summarized in the table below:
Device Number NS Package Number
Thermal Resistance (θJA )
LM74CIM M08A 160˚C/W LM74CIBP
BPD05MPB
250˚C/W
Note 6:All SOP (LM74CIM)parts will function over the V +supply voltage range of 3V to 5.5V.All micro SMD (LM74SIBP)parts will function over the V +supply voltage range of 2.65V to 5.5V.The SOP (LM74CIM)parts are tested and specified for rated temperature error at their nominal supply voltage for temperature ranges of −10˚C to +65˚C,−55˚C to +125˚C and −55˚C to +150˚C.For the SOP (LM74CIM)parts the temperature error specifications for temperature ranges of −40˚C to +85˚C,−25˚C to +110˚C and −40˚C to +110˚C include error induced by power supply variation of ±5%from the nominal value.For the LM74CIM (SOP)parts the temperature error will increase by ±0.3˚C for a power supply voltage (V +)variation of ±10%from the nominal value.
For the LM74CIBP-3(micro SMD)parts all accuracies are guaranteed over the supply range of 2.65V to 3.6V,except for the temperature ranges of -55˚C to 125˚C and −55˚C to +150˚C where the accuracy applies for the nominal supply voltage of 3.3V.For the LM74CIBP-5(micro SMD)parts all accuracies are guranteed over the supply range of 4.75V to 5.25V,except for the temperature ranges of -55˚C to 125˚C and −55˚C to +150˚C where the accuracy applies for the nominal supply voltage of 5.0V.For the LM74CIBP over -55˚C to 125˚C and −55˚C to +150˚C,a power supply variation of ±10%will degrade the accuracy by ±0.3˚C.
10090905
FIGURE 3.TRI-STATE Data Output Timing Diagram
10090906
FIGURE 4.Data Input Timing Diagram
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