Electronic Components Datasheet Search
  English  ▼
ALLDATASHEET.COM

X  

LM74CITP-5 Datasheet(PDF) 9 Page - National Semiconductor (TI)

[Old version datasheet] Texas Instruments acquired National semiconductor.
Part # LM74CITP-5
Description  SPI/MICROWIRE??12-Bit Plus Sign Temperature Sensor
Download  15 Pages
Scroll/Zoom Zoom In 100%  Zoom Out
Manufacturer  NSC [National Semiconductor (TI)]
Direct Link  http://www.national.com
Logo NSC - National Semiconductor (TI)

LM74CITP-5 Datasheet(HTML) 9 Page - National Semiconductor (TI)

Back Button LM74CITP-5 Datasheet HTML 5Page - National Semiconductor (TI) LM74CITP-5 Datasheet HTML 6Page - National Semiconductor (TI) LM74CITP-5 Datasheet HTML 7Page - National Semiconductor (TI) LM74CITP-5 Datasheet HTML 8Page - National Semiconductor (TI) LM74CITP-5 Datasheet HTML 9Page - National Semiconductor (TI) LM74CITP-5 Datasheet HTML 10Page - National Semiconductor (TI) LM74CITP-5 Datasheet HTML 11Page - National Semiconductor (TI) LM74CITP-5 Datasheet HTML 12Page - National Semiconductor (TI) LM74CITP-5 Datasheet HTML 13Page - National Semiconductor (TI) Next Button
Zoom Inzoom in Zoom Outzoom out
 9 / 15 page
background image
1.0 Functional Description (Continued)
munication will consist of 32 serial clocks. The first 16 clocks
comprise the transmit phase of communication, while the
second 16 clocks are the receive phase.
When CS is high SI/O will be in TRI-STATE®. Communica-
tion should be initiated by taking chip select (CS) low. This
should not be done when SC is changing from a low to high
state. Once CS is low the serial I/O pin (SI/O) will transmit
the first bit of data. The master can then read this bit with the
rising edge of SC. The remainder of the data will be clocked
out by the falling edge of SC. Once the 14 bits of data (one
sign bit, twelve temperature bits and 1 high bit) are transmit-
ted the SI/O line will go into TRI-STATE. CS can be taken
high at any time during the transmit phase. If CS is brought
low in the middle of a conversion the LM74 will complete the
conversion and the output shift register will be updated after
CS is brought back high.
The receive phase of a communication starts after 16 SC
periods. CS can remain low for 32 SC cycles. The LM74 will
read the data available on the SI/O line on the rising edge of
the serial clock. Input data is to an 8-bit shift register. The
part will detect the last eight bits shifted into the register. The
receive phase can last up to 16 SC periods. All ones must be
shifted in order to place the part into shutdown. A zero in any
location will take the LM74 out of shutdown. The following
codes should only be transmitted to the LM74:
00 hex
01 hex
03 hex
07 hex
0F hex
1F hex
3F hex
7F hex
FF hex
any others may place the part into a Test Mode. Test Modes
are used by National Semiconductor to thoroughly test the
function of the LM74 during production testing. Only eight
bits have been defined above since only the last eight trans-
mitted are detected by the LM74, before CS is taken HIGH.
The following communication can be used to determine the
Manufacturer’s/Device ID and then immediately place the
part into continuous conversion mode. With CS continuously
low:
Read 16 bits of temperature data
Write 16 bits of data commanding shutdown
Read 16 bits of Manufacture’s/Device ID data
Write 8 to 16 bits of data commanding Conversion Mode
Take CS HIGH.
Note that one complete temperature conversion period will
have to pass before the LM74 Temperature register will
contain the new temperature data. Until then, it will contain a
"stale" temperature (the data that was in the register before
going into shutdown mode).
1.3 TEMPERATURE DATA FORMAT
Temperature data is represented by a 13-bit, two’s comple-
ment word with an LSB (Least Significant Bit) equal to
0.0625˚C:
Temperature
Digital Output
Binary
Hex
+150˚C
0100 1011 0000 0111
4B 07h
+125˚C
0011 1110 1000 0111
3E 87h
+25˚C
0000 1100 1000 0111
0C 87h
+0.0625˚C
0000 0000 0000 1111
00 0Fh
0˚C
0000 0000 0000 0111
00 07h
−0.0625˚C
1111 1111 1111 1111
FF FFh
−25˚C
1111 0011 1000 0111
F3 87h
−55˚C
1110 0100 1000 0111
E4 87h
Note: The last two bits are TRI-STATE® and depicted as one
in the table.
The first data byte is the most significant byte with most
significant bit first, permitting only as much data as neces-
sary to be read to determine temperature condition. For
instance, if the first four bits of the temperature data indicate
an overtemperature condition, the host processor could im-
mediately take action to remedy the excessive tempera-
tures.
1.4 SHUTDOWN MODE/MANUFACTURER’S ID
Shutdown mode is enabled by writing XX FF to the LM74 as
shown in Figure 7c. The serial bus is still active when the
LM74 is in shutdown. Current draw drops to less than 10 µA
between serial communications. When in shutdown mode
the LM74 always will output 1000 0000 0000 00XX. This is
the manufacturer’s/Device ID information. The first 5-bits of
the field (1000 0XXX) are reserved for manufacturer’s ID. As
mentioned in Section 1.2, writing a zero to the LM74 con-
figuration register will take it out of shutdown mode and
place it in conversion mode. In other words, any valid code
listed in Section 1.2 other than XX FF will put it in conversion
mode. After leaving shutdown, but before the first tempera-
ture conversion is complete, the temperature register will
contain the last measured temperature which resided in the
temperature register before entering shutdown mode. After
the completion of the first conversion, the temperature reg-
ister will be updated with the new temperature data.
www.national.com
9


Similar Part No. - LM74CITP-5

ManufacturerPart #DatasheetDescription
logo
Texas Instruments
LM74CITP-3/NOPB TI1-LM74CITP-3/NOPB Datasheet
1Mb / 22P
[Old version datasheet]   LM74 SPI/Microwire12-Bit Plus Sign Temperature Sensor
More results

Similar Description - LM74CITP-5

ManufacturerPart #DatasheetDescription
logo
Texas Instruments
LM71 TI-LM71_15 Datasheet
1Mb / 21P
[Old version datasheet]    SPI/MICROWIRE 13-Bit Plus Sign Temperature Sensor
logo
National Semiconductor ...
LM71 NSC-LM71 Datasheet
249Kb / 13P
   SPI/MICROWIRE??13-Bit Plus Sign Temperature Sensor
LM71 NSC-LM71_05 Datasheet
627Kb / 13P
   SPI/MICROWIRE 13-Bit Plus Sign Temperature Sensor
logo
Texas Instruments
LM95071 TI1-LM95071_15 Datasheet
1,010Kb / 20P
[Old version datasheet]   SPI/MICROWIRE 13-Bit Plus Sign Temperature Sensor
logo
National Semiconductor ...
LM70 NSC-LM70 Datasheet
285Kb / 13P
   SPI/MICROWIRE??10-Bit plus Sign Digital Temperature Sensor
LM74A NSC-LM74A Datasheet
605Kb / 12P
   SPI/MICROWIRE 12-Bit Plus Sign Temperature Sensor (LM74 in Die Form)
logo
Texas Instruments
LM70CILD-3NOPB TI1-LM70CILD-3NOPB Datasheet
1Mb / 21P
[Old version datasheet]   LM70 SPI/MICROWIRE 10-Bit plus Sign Digital Temperature Sensor
LM70 TI-LM70_15 Datasheet
1Mb / 22P
[Old version datasheet]   LM70 SPI/MICROWIRE 10-Bit plus Sign Digital Temperature Sensor
logo
National Semiconductor ...
LM70 NSC-LM70_06 Datasheet
691Kb / 14P
   SPI/MICROWIRE 10-Bit plus Sign Digital Temperature
logo
Texas Instruments
LM74A TI-LM74A_15 Datasheet
395Kb / 15P
[Old version datasheet]   LM74A SPI/MICROWIRE 12-Bit Plus Sign Temperature Sensor (LM74 in Die Form)
More results


Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ] 

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Link Exchange   |   Manufacturer List
All Rights Reserved©Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn
Indian : Alldatasheet.in  |   Mexican : Alldatasheet.com.mx  |   British : Alldatasheet.co.uk  |   New Zealand : Alldatasheet.co.nz
Family Site : ic2ic.com  |   icmetro.com