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PDF LM76 Data sheet ( Hoja de datos )
| Número de pieza | LM76 | |
| Descripción | 0.5C/ 1C/ 12-Bit Sign Digital Temperature Sensor and Thermal Window Comparator with Two-Wire Interface | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
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Hay una vista previa y un enlace de descarga de LM76 (archivo pdf) en la parte inferior de esta página. Total 15 Páginas | ||
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January 2000
LM76
±0.5˚C, ±1˚C, 12-Bit + Sign Digital Temperature Sensor
and Thermal Window Comparator with Two-Wire
Interface
General Description
The LM76 is a digital temperature sensor and thermal win-
dow comparator with an I2C™ Serial Bus interface with an
accuracy of ±1˚C. This accuracy for the LM76CHM is speci-
fied for a −10˚C to 45˚C temperature range, while for the
LM76CNM the temperature range is 70˚C to 100˚C. The
LM76CHM is specified with an accuracy ±0.5˚C at 25˚C. The
window-comparator architecture of the LM76 eases the de-
sign of temperature control systems conforming to the ACPI
(Advanced Configuration and Power Interface) specification
for personal computers. The open-drain Interrupt (INT) out-
put becomes active whenever temperature goes outside a
programmable window, while a separate Critical Tempera-
ture Alarm (T_CRIT_A) output becomes active when the
temperature exceeds a programmable critical limit. The INT
output can operate in either a comparator or event mode,
while the T_CRIT_A output operates in comparator mode
only.
The host can program both the upper and lower limits of the
window as well as the critical temperature limit. Program-
mable hysterisis as well as a fault queue are available to
minimize false tripping. Two pins (A0, A1) are available for
address selection. The sensor powers up with default thresh-
olds of 2˚C THYST, 10˚C TLOW, 64˚C THIGH, and 80˚C
T_CRIT.
The LM76’s 3.3V and 5.0V supply voltage, Serial Bus inter-
face, 12-bit + sign output, and full-scale range of over 127˚C
make it ideal for a wide range of applications. These include
thermal management and protection applications in personal
computers, electronic test equipment, office electronics and
bio-medical applications.
Features
n Window comparison simplifies design of ACPI
compatible temperature monitoring and control.
n Serial Bus interface
n Separate open-drain outputs for Interrupt and Critical
Temperature shutdown
n Shutdown mode to minimize power consumption
n Up to 4 LM76s can be connected to a single bus
n 12-bit + sign output; full-scale reading of over 127˚C
Key Specifications
n Supply Voltage
n Supply Current
n Temperature
Accuracy
n Resolution
operating
shutdown
+25˚C
−10˚C to +45˚C
70˚C to 100˚C
3.3V or 5.0V
250 µA (typ)
450 µA (max)
8 µA (max)
±0.5˚C(max)
±1.0˚C(max)
±1.0˚C(max)
0.0625˚C
Applications
n System Thermal Management
n Personal Computers
n Office Electronics
n HVAC
I2C® is a registered trademark of Philips Corporation.
© 2000 National Semiconductor Corporation DS101015
www.national.com
1 page  
Logic Electrical Characteristics (Continued)
DIGITAL DC
LM76CNM-3
CHARACTERISTICS Unless
and for +VS=+5.0 Vdc ±10%
footrhethrwe iLseM7n6oCteHd,Mt-h5e.s.eBsopledcfiaficceatlioimnsitsapapplyplfyorfoforrT+AV=S=T+J3.=3
Vdc
TMIN
±5% for the
to TMAX; all
other limits TA= TJ=+25˚C, unless otherwise noted.
Symbol
Parameter
Conditions
Typical
(Note 8)
Limits
(Note 9)
Units
(Limit)
VIN(0)
SDA and SCL Logical “0” Input
Voltage
−0.3 V (min)
VIN(HYST)
SDA and SCL Digital Input
Hysteresis
+VS x 0.3
V (max)
500 250 mV (min)
VIN(1)
A0 and A1 Logical “1” Input
Voltage
2.0 V (min)
VIN(0)
A0 and A1 Logical “0” Input
Voltage
+VS+0.3
−0.3
V (max)
V (min)
0.8 V (max)
IIN(1)
IIN(0)
CIN
IOH
VOL
Logical “1” Input Current
Logical “0” Input Current
Capacitance of All Digital Inputs
High Level Output Current
Low Level Output Voltage
T_CRIT_A Output Saturation
Voltage
VIN = + VS
VIN = 0V
VOH = + VS
IOL = 3 mA
IOUT = 4.0 mA
(Note 12)
0.005
−0.005
20
1.0 µA (max)
−1.0
µA (max)
pF
10 µA (max)
0.4 V (max)
0.8 V (max)
T_CRIT_A Delay
1 Conversions
(max)
tOF Output Fall Time
CL = 400 pF
250 ns (max)
IO = 3 mA
SERIAL BUS DIGITAL SWITCHING CHARACTERISTICS Unless
Vdc ±5% for the LM76CNM-3 and for +VS=+5.0 Vdc ±10% for the
otherwise noted, these
LM76CHM-5, CL (load
specifications
capacitance)
apply for
on output
+VS=
lines
+3.3
= 80
pF unless otherwise specified. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = +25˚C, unless oth-
erwise noted.
The switching characteristics of the LM76 fully meet or exceed the published specifications of the I2C bus. The following pa-
rameters are the timing relationship between SCL and SDA signal related to the LM76. They are not the I2C bus specifica-
tions.
Symbol
Parameter
Conditions
Typical
(Note 8)
Limits
(Note 9)
Units
(Limit)
t1 SCL (Clock) Period
t2 Data in Set-Up Time to SCL High
t3 Data Out Stable after SCL Low
t4 SDA Low Set-Up Time to SCL Low (Start Condition)
t5 SDA High Hold Time after SCL High (Stop Condition)
2.5 µs(min)
100 ns(min)
0 ns(min)
100 ns(min)
100 ns(min)
DS101015-4
5 www.national.com
5 Page 
2.0 I2C Timing Diagrams
DS101015-9
Typical 2-Byte Read From Preset Pointer Location Such as Temp or Comparison Registers
DS101015-10
Typical Pointer Set Followed by Immediate Read for 2-Byte Register such as Temp or Comparison Registers
DS101015-11
Typical 1-Byte Read from Configuration Register with Preset Pointer
Typical Pointer Set Followed by Immediate Read from Configuration Register
DS101015-12
Configuration Register Write
Comparison Register Write
FIGURE 6. Timing Diagrams
DS101015-13
DS101015-14
11 www.national.com
11 Page | ||
| Páginas | Total 15 Páginas | |
| PDF Descargar | [ Datasheet LM76.PDF ] | |
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