National Semiconductor LM74 Technical data

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LM74

LM74 SPI/MICROWIRE 12-Bit Plus Sign Temperature Sensor

April 2003

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

−25˚C to 110˚C

−55˚C to 125˚C

1.25˚C(max)

±

2.1˚C(max)

±

3˚C(max)

Simplified Block Diagram

10090901

MICROWIRE®is a registered trademark of National Semiconductor Corporation.

®

TRI-STATE

© 2003 National Semiconductor Corporation DS100909 www.national.com

is a registered trademark of National Semiconductor Corporation.

Connection Diagrams

LM74

SO-8 5-Bump micro SMD

TOP VIEW

10090902

NS Package Number M08A

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

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,

LM74CIBPX-3 T8 micro SMD,

LM74CIBP-5 T9 micro SMD,

LM74CIBPX-5 T9 micro SMD,

NS Package

Number

BPD05MPB

BPD05MPB

BPD05MPB

BPD05MPB

Supply Voltage Transport Media

2.65V to 3.6V 250 Units in Tape and Reel

2.65V to 3.6V 3000 Units in Tape and Reel

4.5V to 5.5V 250 Units in Tape and Reel

4.5V to 5.5V 3000 Units in Tape and Reel

10090924

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Pin Descriptions

LM74

Label SO-8

Pin

SI/O 1 1 Slave Input/Output - Serial bus bi-directional data

SC 2 5 Slave Clock - Serial bus clock Schmitt trigger input

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

+

V

micro

#

SMD

#

Pin

line. Schmitt trigger input.

line.

7 3 Chip Select input. From Controller

8 2 Positive Supply Voltage Input DC Voltage from 3.0V to 5.5V for the

Function Typical Connection

From and to Controller

From Controller

LM74CIM and 2.65V to 5.5V for the
LM74CIBP. Bypass with a 0.1 µF ceramic
capacitor.

Typical Application

FIGURE 1. COP Microcontroller Interface

10090903

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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

+

+ 0.3V

LM74CIM and LM74CIBP all

other pins

Machine Model 200V

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

Operating Ratings

Specified Temperature Range T

(Note 5)
LM74CIBP
LM74CIM

Supply Voltage Range (+V

)

S

LM74CIBP +2.65V to +5.5V

LM74CIM +3.0V to +5.5V

MIN

−40˚C to +125˚C

−55˚C to +150˚C

LM74CIBP SC, pin 5 1900V

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
its T

=+25˚C, unless otherwise noted.

A=TJ

Temperature Error (Note 6) T

Resolution 13 Bits

Temperature
Conversion Time

Quiescent Current SO-8 Serial Bus Inactive 310 520 520 µA (max)

+

= 4.5V to 5.5V for the LM74 -5 (Note 6). Boldface limits apply for TA=TJ=T

Parameter Conditions

= −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

SO-8 (Note 9) 280 425 425 ms (max)

micro SMD (Note 9) 611 925 925 ms (max)

micro SMD 265 470 470 µA (max)

SO-8 Serial Bus Active 310 µA

micro SMD 310 µA

SO-8 Shutdown Mode,

+

V

micro SMD 3 µA

= 3.3V

SO-8 Shutdown Mode,

+

V

micro SMD 4 µA

=5V

Typical

(Note 7)

to T

MIN

LM74-5

Limits

(Note 8)

±

1.25

±

2.1 +2.65/−2.15 ˚C (max)

LM74-3

Limits

(Note 8)

±

1.25 ˚C (max)

±

2.15 ˚C (max)

; all other lim-

MAX

+2.65/−2.15 ˚C (max)

−2.0

±

3.0

±

5.0

±

3.5 ˚C (max)

±

5.0 ˚C (max)

7µA

8µA

2000V

to T

Units

(Limit)

MAX

Logic Electrical Characteristics

DIGITAL DC CHARACTERISTICS Unless otherwise noted, these specifications apply for V+= 2.65V to 3.6V for the

LM74CIBP -3, V

for T

A=TJ=TMIN

Symbol Parameter Conditions

V

IN(1)

V

IN(0)

I

IN(1)

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+

= 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

to T

; all other limits TA=TJ=+25˚C, unless otherwise noted.

MAX

Typical

(Note 7)

Limits

(Note 8)

Logical “1” Input Voltage V+x 0.7 V (min)

+

V

+ 0.3 V (max)

Logical “0” Input Voltage −0.3 V (min)

+

V

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)

Logical “1” Input Current VIN=V

+

0.005 3.0 µA (max)

x 0.3 V (max)

Units

(Limit)

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

for T

A=TJ=TMIN

Symbol Parameter Conditions

I

IN(0)

C

IN

V

OH

V

OL

I

O_TRI-STATE

SERIAL BUS DIGITAL SWITCHING CHARACTERISTICS Unless otherwise noted, these specifications apply for V+= 2.65V
to 3.6V for the LM74CIBP -3, V
capacitance) on output lines = 100 pF unless otherwise specified. Boldface limits apply for T
limits T

A=TJ

Symbol Parameter Conditions

t

1

t

2

t

3

t

4

t

5

t

6

t

7

+

= 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

to T

; all other limits TA=TJ=+25˚C, unless otherwise noted.

MAX

Typical

(Note 7)

Limits

(Note 8)

Units

(Limit)

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

V

O

−1
+1

µA (min)

µA

(max)

+

= 3.0V to 3.6V for the LM74CIM -3 and V+= 4.5V to 5.5V for the LM74 -5 (Note 6); CL(load

A=TJ=TMIN

to T

MAX

; all other

= +25˚C, unless otherwise noted.

Typical

(Note 7)

SC (Clock) Period 0.16

Limits

(Note 8)

DC

Units

(Limit)

µs (min)

(max)

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 100 ns (max)

CS High to Data Out (SO) TRI-STATE 200 ns (max)

SC (Clock) High to Data In (SI) Hold Time 50 ns (min)

Data In (SI) Set-Up Time to SC (Clock) High 30 ns (min)

LM74

FIGURE 2. Data Output Timing Diagram

10090904

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