LM83
Triple-Diode Input and Local Digital Temperature Sensor
with Two-Wire Interface
General Description
The LM83 is a digital temperature sensor with a 2 wire serial
interface that senses the voltage and thus the temperature of
three remote diodes using a Delta-Sigma analog-to-digital
converter with a digital over-temperature detector. The LM83
accurately senses its own temperature as well as the tem-
perature of three external devices, such as Pentium II
®
Pro-
cessors or diode connected 2N3904s. The temperature of
any ASIC can be detected using the LM83 as long as a dedi-
cated diode (semiconductor junction) is available on the die.
Using the SMBus interface a host can access the LM83's
registers at any time. Activation of a T_CRIT_A output oc-
curs when any temperature is greater than a programmable
comparator limit, T_CRIT. Activation of an INT output occurs
when any temperature is greater than its corresponding pro-
grammable comparator HIGH limit.
The host can program as well as read back the state of the
T_CRIT register and the four T_HIGH registers. Three state
logic inputs allow two pins (ADD0, ADD1) to select up to 9
SMBus address locations for the LM83. The sensor powers
up with default thresholds of 127°C for T_CRIT and all
T_HIGHs. The LM83 is pin for pin and register compatible
with the LM84 as well as the Maxim MAX1617 and the Ana-
log Devices ADM1021.
Features
n
Accurately senses die temperature of 3 remote ICs, or
diode junctions
n
On-board local temperature sensing
n
SMBus and I
2
C compatible interface, supports
SMBus 1.1 TIMEOUT
n
Two interrupt outputs: INT and T_CRIT_A
n
Register readback capability
n
7 bit plus sign temperature data format, 1 °C resolution
n
2 address select pins allow connection of 9 LM83s on a
single bus
Key Specifications
n
Supply Voltage
3.0V to 3.6V
n
Supply Current
0.8mA (max)
n
Local Temp Accuracy (includes quantization error)
0°C to +85°C
±
3.0°C (max)
n
Remote Diode Temp Accuracy (includes quantization
error)
+25°C to +100°C
±
3°C (max)
0°C to +125°C
±
4°C (max)
Applications
n
System Thermal Management
n
Computers
n
Electronic Test Equipment
n
Office Electronics
n
HVAC
Simplified Block Diagram
SMBus
TM
is a trademark of the Intel Corporation.
Pentium II
®
is a registered trademark of the Intel Corporation.
I2C
®
is a registered trademark of the Philips Corporation.
DS101058-1
November 1999
LM83
T
riple-Diode
Input
and
Local
Digital
T
emperature
Sensor
with
T
wo-W
ire
Interface
© 1999 National Semiconductor Corporation
DS101058
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Connection Diagram
Ordering Information
Order
Number
NS
Package
Number
Transport
Media
LM83CIMQA
MQA16A
(QSOP-16)
95 Units in
Rail
LM83CIMQAX
MQA16A
(QSOP-16)
2500 Units on
Tape and
Reel
Typical Application
Pin Description
Label
Pin #
Function
Typical Connection
D1+, D2+, D3+
1, 3, 5
Diode Current Source
To Diode Anode. Connected to remote discrete
diode junction or to the diode junction on a remote
IC whose die temperature is being sensed. When
not used they should be left floating.
V
CC
2
Positive Supply Voltage
Input
DC Voltage from 3.0 V to 3.6 V
QSOP-16
DS101058-2
TOP VIEW
DS101058-3
LM83
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2
Pin Description
(Continued)
Label
Pin #
Function
Typical Connection
D-
4
Diode Return Current
Sink
To all Diode Junction Cathodes using a star
connection to pin. Must float when not used.
ADD0ADD1
10, 6
User-Set SMBus (I
2
C)
Address Inputs
Ground (Low, "0"), V
CC
(High, "1") or open
("TRI-LEVEL")
GND
7, 8
Power Supply Ground
Ground
NC
9, 13, 15
Manufacturing test pins.
Left floating. PC board traces may be routed
through the pads for these pins, although the
components that drive these traces should share
the same supply as the LM83 so that the Absolute
Maximum Rating, Voltage at Any Pin, is not
violated.
INT
11
Interrupt Output,
open-drain
Pull Up Resistor, Controller Interrupt or Alert Line
SMBData
12
SMBus (I
2
C) Serial
Bi-Directional Data Line,
open-drain output
From and to Controller, Pull-Up Resistor
SMBCLK
14
SMBus (I
2
C) Clock Input
From Controller, Pull-Up Resistor
T_CRIT_A
16
Critical Temperature
Alarm, open-drain output
Pull Up Resistor, Controller Interrupt Line or
System Shutdown
LM83
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Absolute Maximum Ratings
(Note 1)
Supply Voltage
-0.3 V to 6.0 V
Voltage at Any Pin
-0.3 V to
(V
CC
+ 0.3 V)
D- Input Current
±
1 mA
Input Current at All Other Pins (Note
2)
5 mA
Package Input Current (Note 2)
20 mA
SMBData, T_CRIT_A, INT Output
Sink Current
10 mA
SMBCLK, SMBData, T_CRIT_A, INT
Output Voltage
6.0 V
Storage Temperature
-65°C to +150°C
Soldering Information, Lead Temperature
QSOP Package (Note 3)
Vapor Phase (60 seconds)
215°C
Infrared (15 seconds)
220°C
ESD Susceptibility (Note 4)
Human Body Model
2000 V
Machine Model
200 V
Operating Ratings
(Notes 1, 5)
Specified Temperature Range
T
MIN
to T
MAX
LM83
-40°C to +125°C
Supply Voltage Range (V
CC
)
+3.0V to +3.6V
Temperature-to-Digital Converter Characteristics
Unless otherwise noted, these specifications apply for V
CC
=+3.0Vdc to 3.6Vdc. Boldface limits apply for T
A
= T
J
= T
MIN
to
T
MAX
; all other limits T
A
= T
J
=+25°C, unless otherwise noted.
Parameter
Conditions
Typical
Limits
Units
(Note 6)
(Note 7)
(Limit)
Temperature Error using Local
Diode ((Note 8))
T
A
= 0 °C to +85°C,
V
CC
=+3.3V
±
1
±
3
°C (max)
T
A
= -40 °C to +125°C,
V
CC
=+3.3V
±
4
°C (max)
Temperature Error using Remote
Diode ((Note 8))
T
A
= +60 °C to +100°C,
V
CC
=+3.3V
±
3
°C (max)
T
A
= 25 °C to +100°C,
V
CC
=+3.3V
±
3
°C (max)
T
A
= 0 °C to +125°C,
V
CC
=+3.3V
±
4
°C (max)
Diode Channel to Channel Matching
0
°C
Resolution
8
Bits
1
°C
Conversion Time of All
Temperatures
(Note 10)
460
600
ms (max)
Quiescent Current (Note 9)
SMBus (I
2
C) Inactive
0.500
0.80
mA (max)
D- Source Voltage
0.7
V
Diode Source Current
(D+ - D-)=+ 0.65V; high
level
125
µA (max)
60
µA (min)
Low level
15
µA (max)
5
µA (min)
T_CRIT_A and INT Output
Saturation Voltage
I
OUT
= 3.0 mA
0.4
V (max)
Power-On Reset Threshold
On V
CC
input, falling
edge
2.3
1.8
V (max)
V (min)
Local and Remote T_CRIT and
HIGH Default Temperature settings
(Note 11)
+127
°C
LM83
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Logic Electrical Characteristics
DIGITAL DC CHARACTERISTICS
Unless otherwise noted, these specifications apply for V
CC
=+3.0 to 3.6 Vdc. Boldface limits apply for T
A
= T
J
= T
MIN
to
T
MAX
; all other limits T
A
= T
J
=+25°C, unless otherwise noted.
Symbol
Parameter
Conditions
Typical
Limits
Units
(Note 6)
(Note 7)
(Limit)
SMBData, SMBCLK
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
300
mV
I
IN(1)
Logical "1" Input Current
V
IN
= V
CC
0.005
1.5
µA (max)
I
IN(0)
Logical "0" Input Current
V
IN
= 0 V
-0.005
1.5
µA (max)
ADD0, ADD1
V
IN(1)
Logical "1" Input Voltage
V
CC
1.5
V (min)
V
IN(0)
Logical "0"Input Voltage
GND
0.6
V (max)
I
IN(1)
Logical "1" Input Current
V
IN
= V
CC
2
µA (max)
I
IN(0)
Logical "0" Input Current
V
IN
= 0 V
-2
µA (max)
ALL DIGITAL INPUTS
C
IN
Input Capacitance
20
pF
ALL DIGITAL OUTPUTS
I
OH
High Level Output Current
V
OH
= V
CC
100
µA (max)
V
OL
SMBus Low Level Output
Voltage
I
OL
= 3 mA
I
OL
= 6 mA
0.4
0.6
V (max)
LM83
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