|
|
PDF LM91 Data sheet ( Hoja de datos )
| Número de pieza | LM91 | |
| Descripción | Diode Input Digital Temperature Sensor | |
| Fabricantes | National Semiconductor | |
| Logotipo |  |
|
Hay una vista previa y un enlace de descarga de LM91 (archivo pdf) en la parte inferior de esta página. Total 14 Páginas | ||
|
No Preview Available !
November 2001
LM91
Diode Input Digital Temperature Sensor with Two-Wire
Interface
General Description
The LM91 is a remote diode temperature sensor,
Delta-Sigma analog-to-digital converter, and digital
over-temperature detector with an SMBus™ interface. The
LM91 senses its own temperature as well as the tempera-
ture of a target IC with a diode junction, such as a Pentium®
II processor or a diode connected 2N3904. A diode junction
(semiconductor junction) is required on the target IC’s die. A
host can query the LM91 at any time to read the temperature
of this diode as well as the temperature state of the LM91
itself. A T_CRIT_A interrupt output becomes active when the
temperature is greater than a programmable comparator
limit, T_CRIT.
The host can program as well as read back the state of the
T_CRIT register. Power up default values for T_CRIT are as
shown in the ordering information table. Three state logic
inputs allow two pins (ADD0, ADD1) to select up to 9 SMBus
address locations for the LM91.
Features
n Directly senses die temperature of remote ICs
n Senses temperature of remote diodes
n SMBus compatible interface, supports SMBus Timeout
n Register readback capability
n 7 bit plus sign temperature data format
n 2 address select lines enable 9 LM91s to be connected
to a single bus
Key Specifications
j Supply Voltage
j Supply Current
j Local Temperature Accuracy
j Remote Diode Temperature Accuracy
+60˚C to +100˚C
0˚C to +125˚C
3.0V - 3.6V
1 mA (max)
±1.0˚C (typ)
±4˚C (max)
±6˚C (max)
Applications
n System Thermal Management
n Personal Computers
n Electronic Test Equipment
n Office Electronics
n HVAC
Simplified Block Diagram
# Indicates Active Low (”NOT“)
SMBus™ is a trademark of the Intel Corporation.
Pentium® II processor is a registered trademark of the Intel Corporation.
I2C® is a registered trademark of the Philips Corporation.
© 2001 National Semiconductor Corporation DS200343
20034301
www.national.com
1 page  
Logic Electrical Characteristics
DIGITAL DC CHARACTERISTICS
Unless otherwise noted, these specifications apply for VCC=+3.0 to 3.6 Vdc. Boldface limits apply for TA = TJ = TMIN to
TMAX; all other limits TA= TJ=+25˚C, unless otherwise noted.
Symbol
Parameter
Conditions
Typical
LM91D
Units
(Note 6)
Limits
(Note 7)
(Limit)
SMBData, SMBCLK
VIN(1)
VIN(0)
IIN(1)
IIN(0)
ADD0, ADD1
Logical “1” Input Voltage
Logical “0”Input Voltage
Logical “1” Input Current
Logical “0” Input Current
VIN = VCC
VIN = 0V
0.005
−0.005
2.1
0.8
1.0
−1.0
V (min)
V (max)
µA (max)
µA (max)
VIN(1)
Logical “1” Input Voltage
VIN(0)
Logical “0”Input Voltage
IIN(1)
Logical “1” Input Current
IIN(0)
Logical “0” Input Current
ALL DIGITAL INPUTS
VIN = VCC
VIN = 0V
VCC
GND
50
50
1.6 V (min)
0.5 V (max)
600 µA (max)
600 µA (max)
CIN Input Capacitance
ALL DIGITAL OUTPUTS
20 pF
IOH High Level Output Current
VOH = VCC
100 µA (max)
VOL SMBus Low Level Output Voltage
IOL = 3 mA
0.4 V (max)
IOL = 6 mA
0.6
SMBus DIGITAL SWITCHING CHARACTERISTICS
Unless otherwise noted, these specifications apply for VCC=+3.0 Vdc to +3.6 Vdc, CL (load capacitance) on output lines = 80
pF. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = +25˚C, unless otherwise noted.
The switching characteristics of the LM91 fully meet or exceed the published specifications of the SMBus or I2C bus. The fol-
lowing parameters are the timing relationships between SMBCLK and SMBData signals related to the LM91. They are not nec-
essarily the I2C or SMBus bus specifications.
Symbol
Parameter
Conditions
Typical
Limits
Units
(Note 6)
(Note 7)
(Limit)
fSMB
SMBus Clock Frequency
400 kHz (max)
10 kHz (min)
tLOW
SMBus Clock Low Time
10% to 10%
1.3 µs (min)
25 ms (max)
tLOWSEXT
tHIGH
tR;SMB
tF;SMB
tOF
Cumulative Clock Low Extend Time
SMBus Clock High Time
SMBus Rise Time
SMBus Fall Time
Output Fall Time
tTIMEOUT
SMBData and SMBCLK Time Low for
Reset of Serial Interface (Note 12)
90% to 90%
10% to 90%
90% to 10%
CL = 400 pF
IO = 3 mA
25 ms (max)
0.6 µs (min)
1 µs
0.3 µs
250 ns (max)
25 ms (min)
40 ms (max)
t1
t2,
tSU;DAT
t3,
tHD;DAT
t4,
tHD;STA
t5,
tSU;STO
t6,
tSU;STA
SMBCLK (Clock) Period
Data In Setup Time to SMBCLK High
Data Out Stable after SMBCLK Low
SMBData Low Setup Time to SMBCLK
Low
SMBData High Delay Time after SMBCLK
High (Stop Condition Setup)
SMBus Start-Condition Setup Time
2.5 µs (min)
100 ns (min)
0 ns (min)
0.9 µs (max)
100 ns (min)
100 ns (min)
0.6 µs (min)
5 www.national.com
5 Page 
1.0 Functional Description (Continued)
1.8.6 LOCAL AND REMOTE T_CRIT REGISTERS
(Read/Write):
D7 D6 D5
MSB Bit 6 Bit 5
D4
Bit 4
D3
Bit 3
D2
Bit 2
D1
Bit 1
D0
LSB
D7–D0: RT_CRIT and LT_CRIT setpoint temperature data. Power up default is LT_CRIT =127˚C and RT_CRIT = 95˚C.
2.0 SMBus Timing Diagrams
20034310
(a) Serial Bus Write to the internal Command Register followed by a the Data Byte
(b) Serial Bus Write to the internal Command Register
20034311
20034312
(c) Serial Bus Read from a Register with the internal Command Register preset to desired value.
FIGURE 4. Serial Bus Timing Diagrams
3.0 Application Hints
The LM91 can be applied easily in the same way as other
integrated-circuit temperature sensors, and its remote diode
sensing capability allows it to be used in new ways as well.
It can be soldered to a printed circuit board, and because the
path of best thermal conductivity is between the die and the
pins, its temperature will effectively be that of the printed
circuit board lands and traces soldered to the LM91’s pins.
This presumes that the ambient air temperature is almost the
same as the surface temperature of the printed circuit board;
if the air temperature is much higher or lower than the
11 www.national.com
11 Page | ||
| Páginas | Total 14 Páginas | |
| PDF Descargar | [ Datasheet LM91.PDF ] | |
Hoja de datos destacado
| Número de pieza | Descripción | Fabricantes |
| LM90 | LM90 +-3C Accurate Remote Diode Local Dig Temp Sensor w/2-Wire Interface (Rev. A) |  Texas Instruments |
| LM90 | Remote Diode and Local Digital Temperature Sensor | National Semiconductor |
| LM9011 | LM9011 Electronic Ignition Interface (Rev. D) | Texas Instruments |
| LM9011 | Electronic Ignition Interface | National Semiconductor |
| Número de pieza | Descripción | Fabricantes |
| SLA6805M | High Voltage 3 phase Motor Driver IC. |
 Sanken |
| SDC1742 | 12- and 14-Bit Hybrid Synchro / Resolver-to-Digital Converters. |
 Analog Devices |
|
DataSheet.es es una pagina web que funciona como un repositorio de manuales o hoja de datos de muchos de los productos más populares, |
| DataSheet.es | 2020 | Privacy Policy | Contacto | Buscar |