LM86
0.75C Accurate, Remote Diode and Local Digital
Temperature Sensor with Two-Wire Interface
General Description
The LM86 is an 11-bit digital temperature sensor with a
2-wire System Management Bus (SMBus) serial interface.
The LM86 accurately measures its own temperature as well
as the temperature of an external device, such as processor
thermal diode or diode connected transistor such as the
2N3904. The temperature of any ASIC can be accurately
determined using the LM86 as long as a dedicated diode
(semiconductor junction) is available on the target die. The
LM86 remote sensor accuracy of
0.75C is factory trimmed
for the 1.008 typical non-ideality factor of the mobile Pen-
tium
TM
III thermal diode. The LM86 has an Offset
register
to
allow
measuring
other
diodes
without
requiring
continuous
software
management.
Contact
hardware.monitor.team
@
nsc.com to obtain the latest data for
new processors.
Activation of the ALERT output occurs when any tempera-
ture goes outside a preprogrammed window set by the HIGH
and LOW temperature limit registers or exceeds the T_CRIT
temperature limit. Activation of the T_CRIT_A occurs when
any temperature exceeds the T_CRIT programmed limit.
The LM86 is pin and register compatible with the the Analog
Devices ADM1032 and Maxim MAX6657/8.
Features
n
Accurately senses die temperature of remote ICs or
diode junctions
n
Offset register allows sensing a variety of thermal
diodes accurately
n
On-board local temperature sensing
n
10 bit plus sign remote diode temperature data format,
0.125 C resolution
n
T_CRIT_A output useful for system shutdown
n
ALERT output supports SMBus 2.0 protocol
n
SMBus 2.0 compatible interface, supports TIMEOUT
n
8-pin MSOP and SOIC packages
Key Specifications
j
Supply Voltage
3.0V to 3.6V
j
Supply Current
0.8mA (typ)
j
Local Temp Accuracy (includes quantization error)
T
A
=25C to 125C
3.0C (max)
j
Remote Diode Temp Accuracy (includes quantization
error)
T
A
=30C, T
D
=80C
0.75C (max)
T
A
=30C to 50C, T
D
=60C to 100C
1.0C (max)
T
A
=0C to 85C, T
D
=25C to 125C
3.0C (max)
Applications
n
Computer System Thermal Management
(e.g. Laptop, Desktop, Workstations, Server)
n
Electronic Test Equipment
n
Office Electronics
Simplified Block Diagram
10130301
Pentium
TM
is a trademark of Intel Corporation.
April 2003
LM86
0.75C
Accurate,
Remote
Diode
and
Local
Digital
T
emperature
Sensor
with
T
wo-W
ire
Interface
2003 National Semiconductor Corporation
DS101303
www.national.com
Connection Diagram
MSOP-8 or SOIC-8
10130302
TOP VIEW
Ordering Information
Package
Marking
NS Package
Number
Transport
Media
LM86CIMM
T10C
MUA08A
(MSOP-8)
1000 Units on
Tape and Reel
LM86CIMMX
T10C
MUA08A
(MSOP-8)
3500 Units on
Tape and Reel
LM86CIM
LM86CIM
M08A
(SOIC-8)
95 Units in Rail
LM86CIMX
LM86CIM
M08A
(SOIC-8)
2500 Units on
Tape and Reel
Pin Descriptions
Label
Pin #
Function
Typical Connection
V
DD
1
Positive Supply Voltage
Input
DC Voltage from 3.0 V to 3.6 V
D+
2
Diode Current Source
To Diode Anode. Connected to remote discrete
diode conected transistor junction or to the diode
connected transistor junction on a remote IC whose
die temperature is being sensed.
D-
3
Diode Return Current Sink
To Diode Cathode.
T_CRIT_A
4
T_CRIT Alarm Output,
Open-Drain, Active-Low
Pull-Up Resistor, Controller Interrupt or Power
Supply Shutdown Control
GND
5
Power Supply Ground
Ground
ALERT
6
Interrupt Output,
Open-Drain, Active-Low
Pull-Up Resistor, Controller Interrupt or Alert Line
SMBData
7
SMBus Bi-Directional Data
Line, Open-Drain Output
From and to Controller, Pull-Up Resistor
SMBCLK
8
SMBus Input
From Controller, Pull-Up Resistor
LM86
www.national.com
2
Typical Application
10130303
LM86
www.national.com
3
Absolute Maximum Ratings
(Note 1)
Supply Voltage
-0.3 V to 6.0 V
Voltage at SMBData, SMBCLK,
ALERT, T_CRIT_A
-0.5V to 6.0V
Voltage at Other Pins
-0.3 V to
(V
DD
+ 0.3 V)
D- Input Current
1 mA
Input Current at All Other Pins (Note
2)
5 mA
Package Input Current (Note 2)
30 mA
SMBData, ALERT, T_CRIT_A Output
Sink Current
10 mA
Storage Temperature
-65C to
+150C
Soldering Information, Lead Temperature
SOIC-8 or MSOP-8 Packages (Note
3)
Vapor Phase (60 seconds)
215C
Infrared (15 seconds)
220C
ESD Susceptibility (Note 4)
Human Body Model
2000 V
Machine Model
200 V
Operating Ratings
(Notes 1, 5)
Operating Temperature Range
0C to +125C
Electrical Characteristics
Temperature Range
T
MIN
T
A
T
MAX
LM86
0C
T
A
+85C
Supply Voltage Range (V
DD
)
+3.0V to +3.6V
Temperature-to-Digital Converter Characteristics
Unless otherwise noted, these specifications apply for V
DD
=+3.0Vdc to 3.6Vdc. Boldface limits apply for T
A
= T
J
=
T
MIN
T
A
T
MAX
; all other limits T
A
= T
J
=+25C, unless otherwise noted.
Parameter
Conditions
Typical
Limits
Units
(Note 6)
(Note 7)
(Limit)
Temperature Accuracy Using Local Diode
T
A
= +25C to +125C, (Note 8)
1
3
C (max)
Temperature Accuracy Using Remote Diode of
mobile Pentium III with typical non-ideality of
1.008. For other processors email
hardware.monitor.team
@
nsc.com to obtain the
latest data. (T
D
is the Remote Diode Junction
Temperature)
T
A
= +30C
T
D
= +80C
0.75
C (max)
T
A
= +30C to
+50C
T
D
= +60C
to +100C
1
C (max)
T
A
= +0C to
+85C
T
D
= +25C
to +125C
3
C (max)
Remote Diode Measurement Resolution
11
Bits
0.125
C
Local Diode Measurement Resolution
8
Bits
1
C
Conversion Time of All Temperatures at the
Fastest Setting
(Note 10)
31.25
34.4
ms (max)
Quiescent Current (Note 9)
SMBus Inactive, 16Hz conversion
rate
0.8
1.7
mA (max)
Shutdown
315
A
D- Source Voltage
0.7
V
Diode Source Current
(D+ - D-)=+ 0.65V; high level
160
315
A (max)
110
A (min)
Low level
13
20
A (max)
7
A (min)
ALERT and T_CRIT_A Output Saturation
Voltage
I
OUT
= 6.0 mA
0.4
V (max)
Power-On Reset Threshold
Measure on V
DD
input, falling
edge
2.4
1.8
V (max)
V (min)
Local and Remote HIGH Default Temperature
settings
(Note 11)
+70
C
Local and Remote LOW Default Temperature
settings
(Note 11)
0
C
LM86
www.national.com
4
Temperature-to-Digital Converter Characteristics
(Continued)
Unless otherwise noted, these specifications apply for V
DD
=+3.0Vdc to 3.6Vdc. Boldface limits apply for T
A
= T
J
=
T
MIN
T
A
T
MAX
; all other limits T
A
= T
J
=+25C, unless otherwise noted.
Parameter
Conditions
Typical
Limits
Units
(Note 6)
(Note 7)
(Limit)
Local and Remote T_CRIT Default
Temperature Setting
(Note 11)
+85
C
Logic Electrical Characteristics
DIGITAL DC CHARACTERISTICS Unless otherwise noted, these specifications apply for V
DD
=+3.0 to 3.6 Vdc. Boldface lim-
its apply for T
A
= T
J
= T
MIN
to T
MAX
; all other limits T
A
= T
J
=+25C, unless otherwise noted.
Symbol
Parameter
Conditions
Typical
Limits
Units
(Note 6)
(Note 7)
(Limit)
SMBData, SMBCLK INPUTS
V
IN(1)
Logical "1" Input Voltage
2.1
V (min)
V
IN(0)
Logical "0"Input Voltage
0.8
V (max)
V
IN(HYST)
SMBData and SMBCLK Digital
Input Hysteresis
400
mV
I
IN(1)
Logical "1" Input Current
V
IN
= V
DD
0.005
10
A (max)
I
IN(0)
Logical "0" Input Current
V
IN
= 0 V
-0.005
10
A (max)
C
IN
Input Capacitance
5
pF
ALL DIGITAL OUTPUTS
I
OH
High Level Output Current
V
OH
= V
DD
10
A (max)
V
OL
SMBus Low Level Output Voltage
I
OL
= 4mA
I
OL
= 6mA
0.4
0.6
V (max)
SMBus DIGITAL SWITCHING CHARACTERISTICS Unless otherwise noted, these specifications apply for V
DD
=+3.0 Vdc to
+3.6 Vdc, C
L
(load capacitance) on output lines = 80 pF. Boldface limits apply for T
A
= T
J
= T
MIN
to T
MAX
; all other limits
T
A
= T
J
= +25C, unless otherwise noted. The switching characteristics of the LM86 fully meet or exceed the published specifi-
cations of the SMBus version 2.0. The following parameters are the timing relationships between SMBCLK and SMBData sig-
nals related to the LM86. They adhere to but are not necessarily the SMBus bus specifications.
Symbol
Parameter
Conditions
Typical
Limits
Units
(Note 6)
(Note 7)
(Limit)
f
SMB
SMBus Clock Frequency
100
10
kHz (max)
kHz (min)
t
LOW
SMBus Clock Low Time
from V
IN(0)
max to
V
IN(0)
max
4.7
25
s (min)
ms (max)
t
HIGH
SMBus Clock High Time
from V
IN(1)
min to V
IN(1)
min
4.0
s (min)
t
R,SMB
SMBus Rise Time
(Note 12)
1
s (max)
t
F,SMB
SMBus Fall Time
(Note 13)
0.3
s (max)
t
OF
Output Fall Time
C
L
= 400pF,
I
O
= 3mA, (Note 13)
250
ns (max)
t
TIMEOUT
SMBData and SMBCLK Time Low for
Reset of Serial Interface (Note 14)
25
35
ms (min)
ms (max)
t
SU;DAT
Data In Setup Time to SMBCLK High
250
ns (min)
t
HD;DAT
Data Out Stable after SMBCLK Low
300
900
ns (min)
ns (max)
t
HD;STA
Start Condition SMBData Low to SMBCLK
Low (Start condition hold before the first
clock falling edge)
100
ns (min)
t
SU;STO
Stop Condition SMBCLK High to SMBData
Low (Stop Condition Setup)
100
ns (min)
t
SU;STA
SMBus Repeated Start-Condition Setup
Time, SMBCLK High to SMBData Low
0.6
s (min)
LM86
www.national.com
5
PDF 
ZIP