NSC LM86CIMM Datasheet

LM86

±

0.75˚C 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
for the 1.008 typical non-ideality factor of the mobile Pen-

™

tium
register to allow measuring other diodes without
requiring continuous software management. Contact
hardware.monitor.team
new processors.

Activation of the ALERT output occurs when any tempera­ture 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.

III thermal diode. The LM86 has an Offset

@

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±

0.75˚C is factory trimmed

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

=25˚C to 125˚C

A

j

Remote Diode Temp Accuracy (includes quantization

error)

=30˚C, TD=80˚C

T

A

T

=30˚C to 50˚C, TD=60˚C to 100˚C

A

T

=0˚C to 85˚C, TD=25˚C to 125˚C

A

Applications

n Computer System Thermal Management

(e.g. Laptop, Desktop, Workstations, Server)

n Electronic Test Equipment
n Office Electronics

April 2003

±

3.0˚C (max)

±

0.75˚C (max)

±

1.0˚C (max)

±

3.0˚C (max)

Interface

LM86

±

0.75˚C Accurate, Remote Diode and Local Digital Temperature Sensor with Two-Wire

Simplified Block Diagram

10130301

Pentium™is a trademark of Intel Corporation.

© 2003 National Semiconductor Corporation DS101303 www.national.com

Connection Diagram

LM86

MSOP-8 or SOIC-8

TOP VIEW

10130302

Ordering Information

Package

Marking

LM86CIMM T10C MUA08A

LM86CIMMX T10C MUA08A

LM86CIM LM86CIM M08A

LM86CIMX LM86CIM M08A

NS Package

Number

(MSOP-8)

(MSOP-8)

(SOIC-8)

(SOIC-8)

Pin Descriptions

Label Pin

V

DD

D+ 2

D− 3 Diode Return Current Sink To Diode Cathode.

T_CRIT_A

GND 5 Power Supply Ground Ground

ALERT

SMBData 7

SMBCLK 8 SMBus Input From Controller, Pull-Up Resistor

#

1

4

6

Positive Supply Voltage
Input

Diode Current Source To Diode Anode. Connected to remote discrete

T_CRIT Alarm Output,
Open-Drain, Active-Low

Interrupt Output,
Open-Drain, Active-Low

SMBus Bi-Directional Data
Line, Open-Drain Output

Function Typical Connection

DC Voltage from 3.0 V to 3.6 V

diode conected transistor junction or to the diode
connected transistor junction on a remote IC whose
die temperature is being sensed.

Pull-Up Resistor, Controller Interrupt or Power
Supply Shutdown Control

Pull-Up Resistor, Controller Interrupt or Alert Line

From and to Controller, Pull-Up Resistor

Transport

Media

1000 Units on
Tape and Reel

3500 Units on
Tape and Reel

95 Units in Rail

2500 Units on
Tape and Reel

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Typical Application

LM86

10130303

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Absolute Maximum Ratings (Note 1)

LM86

Supply Voltage −0.3 V to 6.0 V

Voltage at SMBData, SMBCLK,
ALERT, T_CRIT_A

Voltage at Other Pins −0.3 V to

D− Input Current

Input Current at All Other Pins (Note

2)

Package Input Current (Note 2) 30 mA

SMBData, ALERT, T_CRIT_A Output
Sink Current 10 mA

Storage Temperature −65˚C to

−0.5V to 6.0V

+ 0.3 V)

(V

DD

±

1mA

±

5mA

+150˚C

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)

Operating Temperature Range 0˚C to +125˚C

Electrical Characteristics
Temperature Range T

LM86 0˚C≤TA≤+85˚C

Supply Voltage Range (V

) +3.0V to +3.6V

DD

MIN≤TA≤TMAX

Soldering Information, Lead Temperature

SOIC-8 or MSOP-8 Packages (Note

3)

Temperature-to-Digital Converter Characteristics

Unless otherwise noted, these specifications apply for VDD=+3.0Vdc to 3.6Vdc. Boldface limits apply for TA=TJ=
T

MIN≤TA≤TMAX

Temperature Accuracy Using Local Diode T

Temperature Accuracy Using Remote Diode of
mobile Pentium III with typical non-ideality of

1.008. For other processors email
hardware.monitor.team
latest data. (T
Temperature)

Remote Diode Measurement Resolution 11 Bits

Local Diode Measurement Resolution 8 Bits

Conversion Time of All Temperatures at the
Fastest Setting

Quiescent Current (Note 9) SMBus Inactive, 16Hz conversion

D− Source Voltage 0.7 V

Diode Source Current (D+ − D−)= + 0.65V; high level 160 315 µA (max)

ALERT and T_CRIT_A Output Saturation
Voltage

Power-On Reset Threshold Measure on VDDinput, falling

Local and Remote HIGH Default Temperature
settings

Local and Remote LOW Default Temperature
settings

; all other limits TA=TJ=+25˚C, unless otherwise noted.

Parameter Conditions Typical Limits Units

(Note 6) (Note 7) (Limit)

@

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is the Remote Diode Junction

D

= +25˚C to +125˚C, (Note 8)

A

T

= +30˚C TD= +80˚C

A

T

= +30˚C to

A

+50˚C

= +0˚C to

T

A

+85˚C

TD= +60˚C
to +100˚C

TD= +25˚C
to +125˚C

±

1

±

3 ˚C (max)

±

0.75

±

1

±

3 ˚C (max)

0.125 ˚C

1˚C

(Note 10) 31.25 34.4 ms (max)

0.8 1.7 mA (max)

rate

Shutdown 315 µA

110 µA (min)

Low level 13 20 µA (max)

7 µA (min)

I

= 6.0 mA 0.4

OUT

2.4

edge

1.8

(Note 11) +70 ˚C

(Note 11) 0 ˚C

˚C (max)

˚C (max)

V (max)

V (max)

V (min)

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Temperature-to-Digital Converter Characteristics (Continued)

Unless otherwise noted, these specifications apply for VDD=+3.0Vdc to 3.6Vdc. Boldface limits apply for TA=TJ=
T

MIN≤TA≤TMAX

; all other limits TA=TJ=+25˚C, unless otherwise noted.

Parameter Conditions Typical Limits Units

(Note 6) (Note 7) (Limit)

Local and Remote T_CRIT Default

(Note 11) +85 ˚C

Temperature Setting

Logic Electrical Characteristics

DIGITAL DC CHARACTERISTICS Unless otherwise noted, these specifications apply for VDD=+3.0 to 3.6 Vdc. Boldface lim­its apply for T

A=TJ=TMIN

to T

Symbol Parameter Conditions Typical Limits Units

SMBData, SMBCLK INPUTS

V

V

IN(1)

IN(0)

V

IN(HYST)

Logical “1” Input Voltage 2.1 V (min)

Logical “0”Input Voltage 0.8 V (max)

SMBData and SMBCLK Digital
Input Hysteresis

I

I

C

IN(1)

IN(0)

IN

Logical “1” Input Current VIN=V

Logical “0” Input Current VIN= 0 V −0.005

Input Capacitance 5 pF

ALL DIGITAL OUTPUTS

I

OH

V

OL

High Level Output Current VOH=V

SMBus Low Level Output Voltage IOL= 4mA

SMBus DIGITAL SWITCHING CHARACTERISTICS Unless otherwise noted, these specifications apply for VDD=+3.0 Vdc to
+3.6 Vdc, C
T

A=TJ

(load capacitance) on output lines = 80 pF. Boldface limits apply for TA=TJ=T

L

= +25˚C, unless otherwise noted. The switching characteristics of the LM86 fully meet or exceed the published specifi­cations of the SMBus version 2.0. The following parameters are the timing relationships between SMBCLK and SMBData sig­nals related to the LM86. They adhere to but are not necessarily the SMBus bus specifications.

Symbol Parameter Conditions Typical Limits Units

f

SMB

t

LOW

t

HIGH

t

R,SMB

t

F,SMB

t

OF

t

TIMEOUT

SMBus Clock Frequency 100

SMBus Clock Low Time from V

SMBus Clock High Time from V

SMBus Rise Time (Note 12) 1 µs (max)

SMBus Fall Time (Note 13) 0.3 µs (max)

Output Fall Time CL= 400pF,

SMBData and SMBCLK Time Low for
Reset of Serial Interface (Note 14)

t

SU;DAT

t

HD;DAT

t

HD;STA

Data In Setup Time to SMBCLK High 250 ns (min)

Data Out Stable after SMBCLK Low 300

Start Condition SMBData Low to SMBCLK
Low (Start condition hold before the first
clock falling edge)

t

SU;STO

Stop Condition SMBCLK High to SMBData
Low (Stop Condition Setup)

t

SU;STA

SMBus Repeated Start-Condition Setup
Time, SMBCLK High to SMBData Low

; all other limits TA=TJ=+25˚C, unless otherwise noted.

MAX

(Note 6) (Note 7) (Limit)

400 mV

0.005

min 4.0 µs (min)

IN(1)

I

OL

= 6mA

V

IN(0)

I

O

DD

DD

max to

IN(0)

max

min to V

IN(1)

= 3mA, (Note 13)

±

10 µA (max)

±

10 µA (max)

10 µA (max)

0.4

V (max)

0.6

MIN

to T

; all other limits

MAX

(Note 6) (Note 7) (Limit)

kHz (max)

10

4.7
25

kHz (min)

µs (min)

ms (max)

250 ns (max)

25
35

ms (min)

ms (max)

ns (min)

900

ns (max)

100 ns (min)

100 ns (min)

0.6 µs (min)

LM86

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SMBus DIGITAL SWITCHING CHARACTERISTICS Unless otherwise noted, these specifications apply for VDD=+3.0 Vdc to

LM86

+3.6 Vdc, C
T

A=TJ

(load capacitance) on output lines = 80 pF. Boldface limits apply for TA=TJ=T

L

MIN

to T

; all other limits

MAX

= +25˚C, unless otherwise noted. The switching characteristics of the LM86 fully meet or exceed the published specifi­cations of the SMBus version 2.0. The following parameters are the timing relationships between SMBCLK and SMBData sig­nals 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)

t

BUF

SMBus Free Time Between Stop and Start

1.3 µs (min)

Conditions

SMBus Communication

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifications do not apply when operating

the device beyond its rated operating conditions.

Note 2: When the input voltage (V

Parasitic components and or ESD protection circuitry are shown in the figure below for the LM86’s pins. The nominal breakdown voltage of D3 is 6.5 V. Care should
be taken not to forward bias the parasitic diode, D1, present on pins: D+, D−. Doing so by more than 50 mV may corrupt a temperature measurements.

) at any pin exceeds the power supplies (V

I

<

I

GND or V

>

VDD), the current at that pin should be limited to 5 mA.

I

10130340

Pin Name PIN

V

(V+) 1 x x

DD

#

D1 D2 D3 D4 D5 D6 R1 SNP ESD CLAMP

D+ 2 xx xxx x

D− 3 xx xxx x

T_CRIT_A

ALERT

4xxx

6xxx

SMBData 7 x x x

SMBCLK 8 x

Note: An “x” indicates that the diode exists.

10130313

FIGURE 1. ESD Protection Input Structure

Note 3: See the URL ”http://www.national.com/packaging/“ for other recommendations and methods of soldering surface mount devices.

Note 4: Human body model, 100pF discharged through a 1.5kΩ resistor. Machine model, 200pF discharged directly into each pin.

Note 5: Thermal resistance junction-to-ambient when attached to a printed circuit board with 2 oz. foil:

– SOIC-8 = 168˚C/W

– MSOP-8 = 210˚C/W

Note 6: Typicals are at T

Note 7: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level).

= 25˚C and represent most likely parametric norm.

A

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Note 8: Local temperature accuracy does not include the effects of self-heating. The rise in temperature due to self-heating is the product of the internal power
dissipation of the LM86 and the thermal resistance. See (Note 5) for the thermal resistance to be used in the self-heating calculation.

Note 9: Quiescent current will not increase substantially with an SMBus.

Note 10: This specification is provided only to indicate how often temperature data is updated. The LM86 can be read at any time without regard to conversion state

(and will yield last conversion result).

Note 11: Default values set at power up.

Note 12: The output rise time is measured from (V

Note 13: The output fall time is measured from (V

Note 14: Holding the SMBData and/or SMBCLK lines Low for a time interval greater than t

SMBData and SMBCLK pins to a high impedance state.

max + 0.15V) to (V

IN(0)

min - 0.15V) to (V

IN(1)

min − 0.15V).

IN(1)

min + 0.15V).

IN(1)

will reset the LM86’s SMBus state machine, therefore setting

TIMEOUT

1.0 Functional Description

The LM86 temperature sensor incorporates a delta V
based temperature sensor using a Local or Remote diode
and a 10-bit plus sign ADC (Delta-Sigma Analog-to-Digital
Converter). The LM86 is compatible with the serial SMBus
version 2.0 two-wire interface. Digital comparators compare
the measured Local Temperature (LT) to the Local High
(LHS), Local Low (LLS) and Local T_CRIT (LCS) user­programmable temperature limit registers. The measured
Remote Temperature (RT) is digitally compared to the Re­mote High (RHS), Remote Low (RLS) and Remote T_CRIT
(RCS) user-programmable temperature limit registers. Acti­vation of the ALERT output indicates that a comparison is
greater than the limit preset in a T_CRIT or HIGH limit
register or less than the limit preset in a LOW limit register.
The T_CRIT_A output responds as a true comparator with
built in hysteresis. The hysteresis is set by the value placed
in the Hysteresis register (TH). Activation of T_CRIT_A oc­curs when the temperature is above the T_CRIT setpoint.
T_CRIT_A remains activated until the temperature goes be­low the setpoint calculated by T_CRIT − TH. The hysteresis
register impacts both the remote temperature and local tem­perature readings.

The LM86 may be placed in a low power consumption
(Shutdown) mode by setting the RUN/STOP bit found in the
Configuration register. In the Shutdown mode, the LM86’s
SMBus interface remains while all circuitry not required is
turned off.

The Local temperature reading and setpoint data registers
are 8-bits wide. The format of the 11-bit remote temperature
data is a 16-bit left justified word. Two 8-bit registers, high
and low bytes, are provided for each setpoint as well as the
temperature reading. Two offset registers (RTOLB and
RTOHB) can be used to compensate for non_ideality error,
discussed further in Section 4.1 DIODE NON-IDEALITY.
The remote temperature reading reported is adjusted by
subtracting from or adding to the actual temperature reading
the value placed in the offset registers.

1.1 CONVERSION SEQUENCE

The LM86 takes approximately 31.25 ms to convert the
Local Temperature (LT), Remote Temperature (RT), and to
update all of its registers. Only during the conversion pro­cess the busy bit (D7) in the Status register (02h) is high.
These conversions are addressed in a round robin se­quence. The conversion rate may be modified by the Con­version Rate Register (04h). When the conversion rate is
modified a delay is inserted between conversions, the actual
conversion time remains at 31.25ms. Different conversion
rates will cause the LM86 to draw different amounts of
supply current as shown in Figure 2.

BE

10130339

FIGURE 2. Conversion Rate Effect on Power Supply

Current

1.2 THE ALERT OUTPUT

The LM86’s ALERT pin is an active-low open-drain output
that is triggered by a temperature conversion that is outside
the limits defined by the temperature setpoint registers. Re­set of the ALERT output is dependent upon the selected
method of use. The LM86’s ALERT pin is versatile and will
accommodate three different methods of use to best serve
the system designer: as a temperature comparator, as a
temperature based interrupt flag, and as part of an SMBus
ALERT system. The three methods of use are further de­scribed below. The ALERT and interrupt methods are differ­ent only in how the user interacts with the LM86.

Each temperature reading (LT and RT) is associated with a
T_CRIT setpoint register (LCS, RCS), a HIGH setpoint reg­ister (LHS and RHS) and a LOW setpoint register (LLS and
RLS). At the end of every temperature reading, a digital
comparison determines whether that reading is above its
HIGH or T_CRIT setpoint or below its LOW setpoint. If so,
the corresponding bit in the STATUS REGISTER is set. If the
ALERT mask bit is not high, any bit set in the STATUS
REGISTER, with the exception of Busy (D7) and OPEN
(D2), will cause the ALERT output to be pulled low. Any
temperature conversion that is out of the limits defined by the
temperature setpoint registers will trigger an ALERT. Addi­tionally, the ALERT mask bit in the Configuration register
must be cleared to trigger an ALERT in all modes.

1.2.1 ALERT Output as a Temperature Comparator

When the LM86 is implemented in a system in which it is not
serviced by an interrupt routine, the ALERT output could be
used as a temperature comparator. Under this method of
use, once the condition that triggered the ALERT to go low is

LM86

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