LM89CIMMX - Texas Instruments High-Performance Analog

LM89

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SNIS128C –AUGUST 2002–REVISED MARCH 2013

LM89 ±0.75°C Accurate, Remote Diode and Local Digital Temperature Sensor

With Two-Wire Interface

Check for Samples: LM89

1FEATURES DESCRIPTION

The LM89 is an 11-bit digital temperature sensor with

2• Accurately Senses Die Temperature of Remote a 2-wire System Management Bus (SMBus) serial

ICs or Diode Junctions interface. The LM89 accurately measures its own

• Offset Register Allows Sensing a Variety of temperature as well as the temperature of an external

Thermal Diodes Accurately device, such as processor thermal diode or diode-

connected transistor such as the 2N3904. The

• On-Board Local Temperature Sensing temperature of any ASIC can be accurately

• 10-Bit Plus Sign Remote Diode Temperature determined using the LM89 as long as a dedicated

Data Format, 0.125°C Resolution diode (semiconductor junction) is available on the

• T_CRIT_A Output Useful for System Shutdown target die. The LM89 remote sensor accuracy of

±0.75°C is factory trimmed for the series resistance

• ALERT Output Supports SMBus 2.0 Protocol and 1.0021 typical nonideality factor of the

• SMBus 2.0 Compatible Interface, Supports IntelPentium 4 and the Mobile Pentium 4 Processor-

TIMEOUT M thermal diode. The LM89 has an Offset register to

• 8-Pin VSSOP and SOIC Packages allow measuring other diodes without requiring

continuous software management. Visit www.ti.com

APPLICATIONS to obtain the latest data for new processors.

• Processor/Computer System Thermal The LM89 and the LM89-1 have the same functions

Management but different SMBus slave addresses. This allows for

one of each to be on the bus at the same time.

(For Example, Laptop, Desktop, Workstations,

Server) Activation of the ALERT output occurs when any

• Electronic Test Equipment temperature goes outside a preprogrammed window

set by the HIGH and LOW temperature limit registers

• Office Electronics or exceeds the T_CRIT temperature limit. Activation

of the T_CRIT_A occurs when any temperature

KEY SPECIFICATIONS exceeds the T_CRIT programmed limit. The LM89 is

• Supply Voltage: 3.0 V to 3.6 V pin and register compatible with the LM86, LM90,

Analog Devices ADM1032 and Maxim MAX6657/8.

• Supply Current: 0.8 mA (typ)

• Local Temp Accuracy (includes quantization

error)

– TA= 25°C to 125°C ±3.0 °C (max)

• Remote Diode Temp Accuracy (includes

quantization error)

– TA= 30°C, TD= 80°C ±0.75 °C (max)

– TA= 30°C to 50°C, TD= 60°C to 100°C ±1.0

°C (max)

– TA= 0°C to 85°C, TD= 25°C to 125°C ±3.0 °C

(max)

1Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Control Logic

One Shot

Remote Offset

Registers

Local/Remote

Temperature

Registers

HIGH

Limit

Registers

LOW

Limit

Registers

T_CRIT Limit

& Hysteresis

Registers

Configuration

and Status

Registers

Conversion

Rate

Registers

Two-Wire Serial

Interface

Local/Remote

Diode Selector

Temperature

Sensor

Circuitry

10-Bit Plus Sign

'-6

Converter

Programable

Level

Filter

Fault

Queue

Fault

Queue

Fault

Queue

3.0V-3.6V

D+

D-

T_Crit_A

ALERT

SMBData

SMBClock

LM89

SNIS128C –AUGUST 2002–REVISED MARCH 2013

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Simplified Block Diagram

Connection Diagram

VSSOP-8 or SOIC-8

(TOP VIEW)

PIN DESCRIPTION

Label Pin No. Function Typical Connection

VDD 1 Positive Supply Voltage Input DC Voltage from 3.0 V to 3.6 V. VDD should be bypassed with a 0.1µF

capacitor in parallel with 100pF. The 100pF capacitor should be

placed as close as possible to the power supply pin. A bulk

capacitance of approximately 10µF needs to be in the near vicinity to

the LM89 VDD.

D+ 2 Diode Current Source To Diode Anode. Connected to remote discrete diode-connected

transistor junction or to the diode-connected transistor junction on a

remote IC whose die temperature is being sensed. A 2.2 nF diode

bypass capacitor is required to filter high frequency noise. Place the

2.2 nF capacitor between and as close as possible to the LM89's D+

and D−pins. Make sure the traces to the 2.2 nF capacitor are

matched.

D−3 Diode Return Current Sink To Diode Cathode.

T_CRIT_A 4 T_CRIT Alarm Output, Open-Drain, Pull-Up Resistor, Controller Interrupt or Power Supply Shutdown

Active-Low Control

GND 5 Power Supply Ground Ground

ALERT 6 Interrupt Output, Open-Drain, Pull-Up Resistor, Controller Interrupt or Alert Line

Active-Low

SMBData 7 SMBus Bi-Directional Data Line, From and to Controller, Pull-Up Resistor

Open-Drain Output

SMBCLK 8 SMBus Input From Controller, Pull-Up Resistor

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LM89

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Typical Application

Product Folder Links: LM89

SNP

V+

GND

ESD

Clamp

I/O

LM89

SNIS128C –AUGUST 2002–REVISED MARCH 2013

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These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam

during storage or handling to prevent electrostatic damage to the MOS gates.

Absolute Maximum Ratings(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 (VDD + 0.3 V)

D−Input Current ±1 mA

Input Current at All Other Pins(2) ±5 mA

Package Input Current(2) 30 mA

SMBData, ALERT, T_CRIT_A Output Sink Current 10 mA

Storage Temperature −65°C to +150°C

Soldering Information, Lead Temperature Vapor Phase (60 seconds) 215°C

SOIC or VSSOP Packages(3) Infrared (15 seconds) 220°C

ESD Susceptibility(4) Human Body Model 2000 V

Machine Model 200 V

(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.

(2) When the input voltage (VI) at any pin exceeds the power supplies (VI< GND or VI> VDD), the current at that pin should be limited to 5

mA. Parasitic components and or ESD protection circuitry are shown in Table 1 and Figure 1 for the LM89'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.

(3) Visit www.ti.com/packaging for other recommendations and methods of soldering surface mount devices.

(4) Human body model, 100pF discharged through a 1.5kΩresistor. Machine model, 200pF discharged directly into each pin.

Table 1. ESD Protection

Pin Name PIN D1 D2 D3 D4 D5 D6 D7 R1 SNP ESD

NO. CLAMP

VDD 1 x

D+ 2 x(1) x x x x x

D−3 x x x x x x

T_CRIT_A 4 x x x

ALERT 6 x x x

SMBData 7 x x x

SMBCLK 8 x

(1) An “x” indicates that the diode exists.

Figure 1. ESD Protection Input Structure

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SNIS128C –AUGUST 2002–REVISED MARCH 2013

Operating Ratings

Operating Temperature Range 0°C to +125°C

Electrical Characteristics Temperature Range TMIN≤TA≤TMAX

LM89 0°C≤TA≤+85°C

Supply Voltage Range (VDD) +3.0V to +3.6V

Temperature-to-Digital Converter Characteristics

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

TMIN≤TA≤TMAX;all other limits TA= TJ=+25°C, unless otherwise noted.

Parameter Test Conditions Typical(1) Limits(2) Unit

(Limit)

Temperature Error Using Local Diode TA= +25°C to +125°C, (3) ±1 ±3 °C (max)

Temperature Error Using Remote Diode of 0.13 TA= +30°C TD= +80°C ±0.75 °C (max)

micron Pentium 4 with typical nonideality of 1.0021 TA= +30°C to TD= +60°C to ±1 °C (max)

and series R= 3.64Ω. For other processors visit +50°C +100°C

www.ti.com to obtain the latest data. (TDis the TA= +0°C to +85°C TD= +25°C to ±3 °C (max)

Remote Diode Junction Temperature) +125°C

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 (4) 31.25 34.4 ms (max)

Setting

Quiescent Current (5) SMBus Inactive, 16Hz conversion 0.8 1.7 mA (max)

rate

Shutdown 315 µA

D−Source Voltage 0.7 V

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

110 µA (min)

Low level 13 20 µA (max)

7µA (min)

ALERT and T_CRIT_A Output Saturation Voltage IOUT = 6.0 mA 0.4 V (max)

Power-On Reset Threshold Measure on VDD input, falling edge 2.4 V (max)

1.8 V (min)

Local and Remote HIGH Default Temperature settings (6) +70 °C

Local and Remote LOW Default Temperature settings (6) 0 °C

Local T_CRIT Default Temperature Setting (6) +85 °C

Remote T_CRIT Default Temperature Setting (6) +110 °C

(1) Typical values are at TA= 25°C and represent most likely parametric norm.

(2) Limits are ensured to AOQL (Average Outgoing Quality Level).

(3) 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 LM89 and the thermal resistance. See () for the thermal resistance to be used in the self-heating

calculation.

(4) This specification is provided only to indicate how often temperature data is updated. The LM89 can be read at any time without regard

to conversion state (and will yield last conversion result).

(5) Quiescent current will not increase substantially with an SMBus.

(6) Default values set at power up.

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Logic Electrical Characteristics

DIGITAL DC CHARACTERISTICS

Unless otherwise noted, these specifications apply for VDD=+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 Test Conditions Typical(1) Limits(2) Unit

(Limit)

SMBData, SMBCLK INPUTS

VIN(1) Logical “1” Input Voltage 2.1 V (min)

VIN(0) Logical “0”Input Voltage 0.8 V (max)

VIN(HYST) SMBData and SMBCLK Digital Input 400 mV

Hysteresis

IIN(1) Logical “1” Input Current VIN = VDD 0.005 ±10 µA (max)

IIN(0) Logical “0” Input Current VIN = 0 V −0.005 ±10 µA (max)

CIN Input Capacitance 5 pF

ALL DIGITAL OUTPUTS

IOH High Level Output Current VOH = VDD 10 µA (max)

VOL SMBus Low Level Output Voltage IOL = 4mA 0.4 V (max)

IOL = 6mA 0.6

(1) Typical values are at TA= 25°C and represent most likely parametric norm.

(2) Limits are ensured to AOQL (Average Outgoing Quality Level).

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VIH

VIL

SMBCLK

VIH

SMBDAT

tBUF

tHD;STA

tLOW

tHD;DAT

tHIGH

tSU;DAT

tSU;STA tSU;STO

LM89

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SNIS128C –AUGUST 2002–REVISED MARCH 2013

SMBus DIGITAL SWITCHING CHARACTERISTICS

Unless otherwise noted, these specifications apply for VDD=+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 LM89 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 LM89. They adhere

to but are not necessarily the SMBus bus specifications.

Symbol Parameter Test Conditions Typical(1) Limits(2) Unit

(Limit)

fSMB SMBus Clock Frequency 100 kHz (max)

10 kHz (min)

tLOW SMBus Clock Low Time from VIN(0)max to VIN(0)max 4.7 µs (min)

25 ms (max)

tHIGH SMBus Clock High Time from VIN(1)min to VIN(1)min 4.0 µs (min)

tR,SMB SMBus Rise Time (3) 1 µs (max)

tF,SMB SMBus Fall Time (4) 0.3 µs (max)

tOF Output Fall Time CL= 400pF, 250 ns (max)

IO= 3mA, (4)

tTIMEOUT SMBData and SMBCLK Time Low for Reset of 25 ms (min)

Serial Interface (5) 35 ms (max)

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

tHD;DAT Data Out Stable after SMBCLK Low 300 ns (min)

900 ns (max)

tHD;STA Start Condition SMBData Low to SMBCLK Low 100 ns (min)

(Start condition hold before the first clock falling

edge)

tSU;STO Stop Condition SMBCLK High to SMBData Low 100 ns (min)

(Stop Condition Setup)

tSU;STA SMBus Repeated Start-Condition Setup Time, 0.6 µs (min)

SMBCLK High to SMBData Low

tBUF SMBus Free Time Between Stop and Start 1.3 µs (min)

Conditions

(1) Typical values are at TA= 25°C and represent most likely parametric norm.

(2) Limits are ensured to AOQL (Average Outgoing Quality Level).

(3) The output rise time is measured from (VIN(0)max + 0.15V) to (VIN(1)min −0.15V).

(4) The output fall time is measured from (VIN(1)min - 0.15V) to (VIN(1)min + 0.15V).

(5) Holding the SMBData and/or SMBCLK lines Low for a time interval greater than tTIMEOUT will reset the LM89's SMBus state machine,

therefore setting SMBData and SMBCLK pins to a high impedance state.

Figure 2. SMBus Communication

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0.01 0.1 1.0 10 100

CONVERSION RATE (Hz)

400

600

800

1000

1200

140

1600

1800

2000

SUPPLY CURRENT (PA

LM89

SNIS128C –AUGUST 2002–REVISED MARCH 2013

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FUNCTIONAL DESCRIPTION

The LM89 temperature sensor incorporates a delta VBE based temperature sensor using a Local or Remote

diode and a 10-bit plus sign ADC (Delta-Sigma Analog-to-Digital Converter). The LM89 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) user-programmable 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 LM89 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 LM89'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 nonideality error, discussed further in DIODE NONIDEALITY. The remote temperature reading

reported is adjusted by subtracting from or adding to the actual temperature reading the value placed in the

offset registers.

CONVERSION SEQUENCE

The LM89 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 LM89 to draw different

amounts of supply current as shown in Figure 3.

Figure 3. Conversion Rate Effect on Power Supply Current

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Remote High Limit

RDTS Measurement

LM89 ALERT Pin

Status Register: RTDS High

TIME

TEMPERATURE

LM89

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THE ALERT OUTPUT

The LM89'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 LM89'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 LM89.

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.

ALERT Output as a Temperature Comparator

When the LM89 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 no longer present, the ALERT is de-asserted (Figure 4). For example, if the ALERT output

was activated by the comparison of LT > LHS, when this condition is no longer true the ALERT will return HIGH.

This mode allows operation without software intervention, once all registers are configured during set-up. In order

for the ALERT to be used as a temperature comparator, bit D0 (the ALERT configure bit) in the FILTER and

ALERT CONFIGURE REGISTER (xBF) must be set high. This is not the power-on-default state.

Figure 4. ALERT Comparator Temperature Response Diagram

ALERT Output as an Interrupt

The LM89's ALERT output can be implemented as a simple interrupt signal when it is used to trigger an interrupt

service routine. In such systems it is undesirable for the interrupt flag to repeatedly trigger during or before the

interrupt service routine has been completed. Under this method of operation, during a read of the STATUS

the master has reset the ALERT mask bit, at the end of the interrupt service routine. The STATUS REGISTER

bits are cleared only upon a read command from the master (see Figure 5) and will be re-asserted at the end of

the next conversion if the triggering condition(s) persist(s). In order for the ALERT to be used as a dedicated

interrupt signal, bit D0 (the ALERT configure bit) in the FILTER and ALERT CONFIGURE REGISTER (xBF) must

be set low. This is the power-on-default state.

The following sequence describes the response of a system that uses the ALERT output pin as a interrupt flag:

1. Master Senses ALERT low

2. Master reads the LM89 STATUS REGISTER to determine what caused the ALERT

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Remote High Limit

RDTS Measurement

TIME

TEMPERATURE

LM89 ALERT pin

Status Register: RTDS High

End of Temperature

conversion

ALERT mask set in

response to reading of

status register by

master

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3. LM89 clears STATUS REGISTER, resets the ALERT HIGH and sets the ALERT mask bit (D7 in the

Configuration register).

4. Master attends to conditions that caused the ALERT to be triggered. The fan is started, setpoint limits are

adjusted, etc.

5. Master resets the ALERT mask (D7 in the Configuration register).

Figure 5. ALERT Output as an Interrupt Temperature Response Diagram

ALERT Output as an SMBus ALERT

When the ALERT output is connected to one or more ALERT outputs of other SMBus compatible devices and to

a master, an SMBus alert line is created. Under this implementation, the LM89's ALERT should be operated

using the ARA (Alert Response Address) protocol. The SMBus 2.0 ARA protocol, defined in the SMBus

specification 2.0, is a procedure designed to assist the master in resolving which part generated an interrupt and

service that interrupt while impeding system operation as little as possible.

The SMBus alert line is connected to the open-drain ports of all devices on the bus thereby AND'ing them

together. The ARA is a method by which with one command the SMBus master may identify which part is pulling

the SMBus alert line LOW and prevent it from pulling it LOW again for the same triggering condition. When an

ARA command is received by all devices on the bus, the devices pulling the SMBus alert line LOW, first, send

their address to the master and second, release the SMBus alert line after recognizing a successful transmission

of their address.

The SMBus 1.1 and 2.0 specification state that in response to an ARA (Alert Response Address) “after

acknowledging the slave address the device must disengage its SMBALERT pulldown”. Furthermore, “if the host

still sees SMBALERT low when the message transfer is complete, it knows to read the ARA again”. This SMBus

“disengaging of SMBALERT” requirement prevents locking up the SMBus alert line. Competitive parts may

address this “disengaging of SMBALERT” requirement differently than the LM89 or not at all. SMBus systems

that implement the ARA protocol as suggested for the LM89 will be fully compatible with all competitive parts.

The LM89 fulfills “disengaging of SMBALERT” by setting the ALERT mask bit (bit D7 in the Configuration

ALERT output pin. Once the ALERT mask bit is activated, the ALERT output pin will be disabled until enabled by

software. In order to enable the ALERT the master must read the STATUS REGISTER, at address 02h, during

the interrupt service routine and then reset the ALERT mask bit in the Configuration register to 0 at the end of

the interrupt service routine.

The following sequence describes the ARA response protocol.

1. Master Senses SMBus alert line low

2. Master sends a START followed by the Alert Response Address (ARA) with a Read Command.

3. Alerting Device(s) send ACK.

4. Alerting Device(s) send their Address. While transmitting their address, alerting devices sense whether their

address has been transmitted correctly. (The LM89 will reset its ALERT output and set the ALERT mask bit

once its complete address has been transmitted successfully.)

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Remote High Limit

RDTS Measurement

TIME

TEMPERATURE

ALERT mask set in

response to ARA

from master

LM89 ALERT pin

Status Register: RTDS High

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5. Master/slave NoACK

6. Master sends STOP

7. Master attends to conditions that caused the ALERT to be triggered. The STATUS REGISTER is read and

fan started, setpoint limits adjusted, etc.

8. Master resets the ALERT mask (D7 in the Configuration register).

The ARA, 000 1100, is a general call address. No device should ever be assigned this address.

Bit D0 (the ALERT configure bit) in the FILTER and ALERT CONFIGURE REGISTER (xBF) must be set low in

order for the LM89 to respond to the ARA command.

The ALERT output can be disabled by setting the ALERT mask bit, D7, of the Configuration register. The power-

on-default is to have the ALERT mask bit and the ALERT configure bit low.

Figure 6. ALERT Output as an SMBus ALERT Temperature Response Diagram

T_CRIT_A OUTPUT and T_CRIT LIMIT

T_CRIT_A is activated when any temperature reading is greater than the limit preset in the critical temperature

setpoint register (T_CRIT), as shown in Figure 7. The Status Register can be read to determine which event

caused the alarm. A bit in the Status Register is set high to indicate which temperature reading exceeded the

T_CRIT setpoint temperature and caused the alarm, see STATUS REGISTER (SR).

Local and remote temperature diodes are sampled in sequence by the A/D converter. The T_CRIT_A output and

the Status Register flags are updated after every Local and Remote temperature conversion. T_CRT_A follows

the state of the comparison, it is reset when the temperature falls below the setpoint RCS-TH. The Status

T_CRIT setpoint, as shown in Figure 7.

Figure 7. T_CRIT_A Temperature Response Diagram

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POWER-ON-DEFAULT STATES

LM89 always powers up to these known default states. The LM89 remains in these states until after the first

conversion.

1. Command Register set to 00h

2. Local Temperature set to 0°C

3. Remote Diode Temperature set to 0°C until the end of the first conversion.

4. Status Register set to 00h.

5. Configuration register set to 00h; ALERT enabled, Remote T_CRIT alarm enabled and Local T_CRIT alarm

enabled

6. 85°C Local T_CRIT temperature setpoint

7. 110°C Remote T_CRIT temperature setpoint

8. 70°C Local and Remote HIGH temperature setpoints

9. 0°C Local and Remote LOW temperature setpoints

10. Filter and Alert Configure Register set to 00h; filter disabled, ALERT output set as an SMBus ALERT

11. Conversion Rate Register set to 8h; conversion rate set to 16 conv./sec.

SMBus INTERFACE

The LM89 operates as a slave on the SMBus, so the SMBCLK line is an input and the SMBData line is bi-

directional. The LM89 never drives the SMBCLK line and it does not support clock stretching. According to

SMBus specifications, the LM89 has a 7-bit slave address. All bits A6 through A0 are internally programmed and

can not be changed by software or hardware. The LM89 and LM89-1 versions have the following SMBus slave

addresses:

Version A6 A5 A4 A3 A2 A1 A0

LM89 1 0 0 1 1 0 0

LM89-1 1 0 0 1 1 0 1

TEMPERATURE DATA FORMAT

Temperature data can only be read from the Local and Remote Temperature registers; the setpoint registers

(T_CRIT, LOW, HIGH) are read/write.

Remote temperature data is represented by an 11-bit, two's complement word with an LSB (Least Significant Bit)

equal to 0.125°C. The data format is a left justified 16-bit word available in two 8-bit registers:

Temperature Digital Output

Binary Hex

+125°C 0111 1101 0000 0000 7D00h

+25°C 0001 1001 0000 0000 1900h

+1°C 0000 0001 0000 0000 0100h

+0.125°C 0000 0000 0010 0000 0020h

0°C 0000 0000 0000 0000 0000h

−0.125°C 1111 1111 1110 0000 FFE0h

−1°C 1111 1111 0000 0000 FF00h

−25°C 1110 0111 0000 0000 E700h

−55°C 1100 1001 0000 0000 C900h

Local Temperature data is represented by an 8-bit, two's complement byte with an LSB (Least Significant Bit)

equal to 1°C:

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Temperature Digital Output

Binary Hex

+125°C 0111 1101 7Dh

+25°C 0001 1001 19h

+1°C 0000 0001 01h

0°C 0000 0000 00h

−1°C 1111 1111 FFh

−25°C 1110 0111 E7h

−55°C 1100 1001 C9h

OPEN-DRAIN OUTPUTS

The SMBData, ALERT and T_CRIT_A outputs are open-drain outputs and do not have internal pull-ups. A “high”

level will not be observed on these pins until pull-up current is provided by some external source, typically a pull-

up resistor. Choice of resistor value depends on many system factors but, in general, the pull-up resistor should

be as large as possible. This will minimize any internal temperature reading errors due to internal heating of the

LM89. The maximum resistance of the pull-up to provide a 2.1V high level, based on LM89 specification for High

Level Output Current with the supply voltage at 3.0V, is 82kΩ(5%) or 88.7kΩ(1%).

DIODE FAULT DETECTION

The LM89 is equipped with operational circuitry designed to detect fault conditions concerning the remote diode.

In the event that the D+ pin is detected as shorted to VDD or floating, the Remote Temperature High Byte (RTHB)

OPEN bit (D2) in the status register is set. As a result, if the Remote T_CRIT setpoint register (RCS) is set to a

value less than +127°C the ALERT and T_Crit output pins will be pulled low, if the Alert Mask and T_Crit Mask

are disabled. If the Remote HIGH Setpoint High Byte Register (RHSHB) is set to a value less than +127°C then

ALERT will be pulled low, if the Alert Mask is disabled. The OPEN bit itself will not trigger and ALERT.

In the event that the D+ pin is shorted to ground or D−, the Remote Temperature High Byte (RTHB) register is

loaded with −128°C (1000 0000) and the OPEN bit (D2) in the status register will not be set. Since operating the

LM89 at −128°C is beyond it's operational limits, this temperature reading represents this shorted fault condition.

If the value in the Remote Low Setpoint High Byte Register (RLSHB) is more than −128°C and the Alert Mask is

disabled, ALERT will be pulled low.

Remote diode temperature sensors that have been previously released and are competitive with the LM89 output

a code of 0°C if the external diode is short-circuited. This change is an improvement that allows a reading of 0°C

to be truly interpreted as a genuine 0°C reading and not a fault condition.

COMMUNICATING WITH THE LM89

The data registers in the LM89 are selected by the Command Register. At power-up the Command Register is

set to “00”, the location for the Read Local Temperature Register. The Command Register latches the last

location it was set to. Each data register in the LM89 falls into one of four types of user accessibility:

1. Read only

2. Write only

3. Read/Write same address

4. Read/Write different address

AWrite to the LM89 will always include the address byte and the command byte. A write to any register requires

one data byte.

Reading the LM89 can take place either of two ways:

1. If the location latched in the Command Register is correct (most of the time it is expected that the Command

read from the LM89), then the read can simply consist of an address byte, followed by retrieving the data

byte.

2. If the Command Register needs to be set, then an address byte, command byte, repeat start, and another

address byte will accomplish a read.

Product Folder Links: LM89

1 9 1 9

SMBCLK

D7 D6 D5 D4 D3 D2 D1 D0

SMBDat

aAck

LM89

Start

Master Address byte. No Ack

Master

Stop

Master

A6 A5 A4 A3 A2 A1 A0

Frame 1

Serial Bus Address Byte

Frame 2

Data Byte from the LM89

R/W

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The data byte has the most significant bit first. At the end of a read, the LM89 can accept either acknowledge or

No Acknowledge from the Master (No Acknowledge is typically used as a signal for the slave that the Master has

read its last byte). It takes the LM89 31.25ms to measure the temperature of the remote diode and internal diode.

When retrieving all 10 bits from a previous remote diode temperature measurement, the master must insure that

all 10 bits are from the same temperature conversion. This may be achieved by using one-shot mode or by

setting the conversion rate and monitoring the busy bit such that no conversion occurs in between reading the

MSB and LSB of the last temperature conversion.

SMBus Timing Diagrams

Figure 8. LM89 Timing Diagram

(a) Serial Bus Write to the internal Command Register followed by a the Data Byte

Figure 9. LM89 Timing Diagram

(b) Serial Bus Write to the Internal Command Register

Figure 10. LM89 Timing Diagram

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SERIAL INTERFACE RESET

In the event that the SMBus Master is RESET while the LM89 is transmitting on the SMBData line, the LM89

must be returned to a known state in the communication protocol. This may be done in one of two ways:

1. When SMBData is LOW, the LM89 SMBus state machine resets to the SMBus idle state if either SMBData

or SMBCLK are held low for more than 35ms (tTIMEOUT). Note that according to SMBus specification 2.0 all

devices are to timeout when either the SMBCLK or SMBData lines are held low for 25-35ms. Therefore, to

insure a timeout of all devices on the bus the SMBCLK or SMBData lines must be held low for at least 35ms.

2. When SMBData is HIGH, have the master initiate an SMBus start. The LM89 will respond properly to an

SMBus start condition at any point during the communication. After the start the LM89 will expect an SMBus

address byte.

DIGITAL FILTER

In order to suppress erroneous remote temperature readings due to noise, the LM89 incorporates a user-

configured digital filter. The filter is accessed in the FILTER and ALERT CONFIGURE REGISTER at BFh. The

filter can be set according to the following table.

D2 D1 Filter

0 0 No Filter

0 1 Level 1

1 0 Level 1

1 1 Level 2

Level 2 sets maximum filtering.

Figure 12 depicts the filter output in response to a step input and an impulse input. Figure 13 depicts the digital

filter in use in a Pentium 4 processor system. Note that the two curves, with filter and without, have been

purposely offset so that both responses can be clearly seen. Inserting the filter does not induce an offset as

shown.

Figure 11. Filter Output Response to a Step Input Figure 12. Filter Output Response to a Step Input

a) Step Response b) Impulse Response

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TEMPERATURE

nn+1 n+2 n+3 n+4 n+5

SAMPLE NUMBER

RDTS Measurement

Status Register: RTDS High

0 50 100 150 200

SAMPLE NUMBER

TEMPERATURE (oC)

LM89

with

Filter On

LM89

with

Filter Off

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A. The filter on and off curves were purposely offset to better show noise performance.

Figure 13. Digital Filter Response in a Pentium 4 processor System

FAULT QUEUE

In order to suppress erroneous ALERT or T_CRIT triggering the LM89 incorporates a Fault Queue. The Fault

Queue acts to insure a remote temperature measurement is genuinely beyond a HIGH, LOW or T_CRIT setpoint

by not triggering until three consecutive out of limit measurements have been made, see Figure 14. The fault

queue defaults off upon power-up and may be activated by setting bit D0 in the Configuration register (09h) to

“1”.

Figure 14. Fault Queue Temperature Response Diagram

ONE-SHOT REGISTER

The One-Shot register is used to initiate a single conversion and comparison cycle when the device is in standby

mode, after which the device returns to standby. This is not a data register and it is the write operation that

causes the one-shot conversion. The data written to this address is irrelevant and is not stored. A zero will

always be read from this register.

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LM89 REGISTERS

COMMAND REGISTER

Selects which registers will be read from or written to. Data for this register should be transmitted during the

Command Byte of the SMBus write communication.

P7 P6 P5 P4 P3 P2 P1 P0

Command Select

P0-P7: Command Select

Command Select Address Power-On-Default State Register Register Function

Name

Read Address Write Address <D7:D0> binary <D7:D0>

<P7:P0> hex <P7:P0> hex decimal

00h NA 0000 0000 0 LT Local Temperature

01h NA 0000 0000 0 RTHB Remote Temperature High Byte

02h NA 0000 0000 0 SR Status Register

03h 09h 0000 0000 0 C Configuration

04h 0Ah 0000 1000 8 (16 CR Conversion Rate

conv./sec)

05h 0Bh 0100 0110 70 LHS Local HIGH Setpoint

06h 0Ch 0000 0000 0 LLS Local LOW Setpoint

07h 0Dh 0100 0110 70 RHSHB Remote HIGH Setpoint High Byte

08h 0Eh 0000 0000 0 RLSHB Remote LOW Setpoint High Byte

NA 0Fh One Shot Writing to this register will initiate a

one shot conversion

10h NA 0000 0000 0 RTLB Remote Temperature Low Byte

11h 11h 0000 0000 0 RTOHB Remote Temperature Offset High

Byte

12h 12h 0000 0000 0 RTOLB Remote Temperature Offset Low

Byte

13h 13h 0000 0000 0 RHSLB Remote HIGH Setpoint Low Byte

14h 14h 0000 0000 0 RLSLB Remote LOW Setpoint Low Byte

19h 19h 0110 1110 110 RCS Remote T_CRIT Setpoint

20h 20h 0101 0101 85 LCS Local T_CRIT Setpoint

21h 21h 0000 1010 10 TH T_CRIT Hysteresis

B0h-BEh B0h-BEh Manufacturers Test Registers

BFh BFh 0000 0000 0 RDTF Remote Diode Temperature Filter

FEh NA 0000 0001 1 RMID Read Manufacturer's ID

FFh NA LM89 0011 0001 49 RDR Read Stepping or Die Revision Code

LM89-1 0011 0100 52

LOCAL and REMOTE TEMPERATURE REGISTERS (LT, RTHB, RTLB)

Table 2. LOCAL and REMOTE TEMPERATURE REGISTERS (LT, RTHB) (Read Only Address 00h, 01h):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value SIGN 64 32 16 8 4 2 1

For LT and RTHB D7–D0: Temperature Data. LSB = 1°C. Two's complement format.

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Table 3. LOCAL and REMOTE TEMPERATURE REGISTERS (RTLB) (Read Only Address 10h):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value 0.5 0.25 0.125 0 0 0 0 0

For RTLB D7–D5: Temperature Data. LSB = 0.125°C. Two's complement format.

The maximum value available from the Local Temperature register is 127; the minimum value available from the

Local Temperature register is -128. The maximum value available from the Remote Temperature register is

127.875; the minimum value available from the Remote Temperature registers is −128.875.

STATUS REGISTER (SR)

Table 4. STATUS REGISTER (SR) (Read Only Address 02h):

D7 D6 D5 D4 D3 D2 D1 D0

Busy LHIGH LLOW RHIGH RLOW OPEN RCRIT LCRIT

Power up default is with all bits “0” (zero).

D0: LCRIT: When set to “1” indicates a Local Critical Temperature alarm.

D1: RCRIT: When set to “1” indicates a Remote Diode Critical Temperature alarm.

D2: OPEN: When set to “1” indicates a Remote Diode disconnect.

D3: RLOW: When set to “1” indicates a Remote Diode LOW Temperature alarm

D4: RHIGH: When set to “1” indicates a Remote Diode HIGH Temperature alarm.

D5: LLOW: When set to “1” indicates a Local LOW Temperature alarm.

D6: LHIGH: When set to “1” indicates a Local HIGH Temperature alarm.

D7: Busy: When set to “1” ADC is busy converting.

CONFIGURATION REGISTER

Table 5. CONFIGURATION REGISTER (Read Address 03h /Write Address 09h):

D7 D6 D5 D4 D3 D2 D1 D0

ALERT mask RUN/STOP 0 Remote 0 Local 0 Fault Queue

T_CRIT_A T_CRIT_A

mask mask

Power up default is with all bits “0” (zero)

D7: ALERT mask: When set to “1” ALERT interrupts are masked.

D6: RUN/STOP: When set to “1” SHUTDOWN is enabled.

D5: is not defined and defaults to “0”.

D4: Remote T_CRIT mask: When set to “1” a diode temperature reading that exceeds T_CRIT setpoint will not

activate the T_CRIT_A pin.

D3: is not defined and defaults to “0”.

D2: Local T_CRIT mask: When set to “1” a Local temperature reading that exceeds T_CRIT setpoint will not

activate the T_CRIT_A pin.

D1: is not defined and defaults to “0”.

D0: Fault Queue: when set to “1” three consecutive remote temperature measurements outside the HIGH, LOW,

or T_CRIT setpoints will trigger an “Outside Limit” condition resulting in setting of status bits and associated

output pins..

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CONVERSION RATE REGISTER

Table 6. CONVERSION RATE REGISTER (Read

Address 04h /Write Address 0Ah)

Value Conversion Rate

00 62.5 mHz

01 125 mHz

02 250 mHz

03 500 mHz

04 1 Hz

05 2 Hz

06 4 Hz

07 8 Hz

08 16 Hz

09 32 Hz

10-255 Undefined

LOCAL and REMOTE HIGH SETPOINT REGISTERS (LHS, RHSHB, and RHSLB)

Table 7. LOCAL and REMOTE HIGH SETPOINT REGISTERS (LHS, RHSHB) (Read Address 05h, 07h /Write

Address 0Bh, 0Dh):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value SIGN 64 32 16 8 4 2 1

For LHS and RHSHB: HIGH setpoint temperature data. Power up default is LHIGH = RHIGH = 70°C. 1 LSB =

1°C. Two's complement format.

Table 8. LOCAL and REMOTE HIGH SETPOINT REGISTERS (RHSLB) (Read/Write Address 13h):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value 0.5 0.25 0.125 0 0 0 0 0

For RHSLB: Remote HIGH Setpoint Low Byte temperature data. Power up default is 0°C. 1 LSB = 0.125°C.

Two's complement format.

LOCAL and REMOTE LOW SETPOINT REGISTERS (LLS, RLSHB, and RLSLB)

Table 9. LOCAL and REMOTE LOW SETPOINT REGISTERS (LLS, RLSHB) (Read Address 06h, 08h, /Write

Address 0Ch, 0Eh):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value SIGN 64 32 16 8 4 2 1

For LLS and RLSHB: HIGH setpoint temperature data. Power up default is LHIGH = RHIGH = 0°C. 1 LSB = 1°C.

Two's complement format.

Table 10. LOCAL and REMOTE LOW SETPOINT REGISTERS (RLSLB) (Read/Write Address 14h):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value 0.5 0.25 0.125 0 0 0 0 0

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For RLSLB: Remote HIGH Setpoint Low Byte temperature data. Power up default is 0°C. 1 LSB = 0.125°C.

Two's complement format.

REMOTE TEMPERATURE OFFSET REGISTERS (RTOHB and RTOLB)

Table 11. REMOTE TEMPERATURE OFFSET REGISTERS (RTOHB)(Read/Write Address 11h):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value SIGN 64 32 16 8 4 2 1

For RTOHB: Remote Temperature Offset High Byte. Power up default is LHIGH = RHIGH = 0°C. 1 LSB = 1°C.

Two's complement format.

Table 12. REMOTE TEMPERATURE OFFSET REGISTERS (RTOLB) (Read/Write Address 12h):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value 0.5 0.25 0.125 0 0 0 0 0

For RTOLB: Remote Temperature Offset High Byte. Power up default is 0°C. 1 LSB = 0.125°C. Two's

complement format.

The offset value written to these registers will automatically be added to or subtracted from the remote

temperature measurement that will be reported in the Remote Temperature registers.

LOCAL and REMOTE T_CRIT REGISTERS (RCS and LCS)

Table 13. LOCAL and REMOTE T_CRIT REGISTERS (RCS and LCS) (Read/Write Address 20h, 19h):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value SIGN 64 32 16 8 4 2 1

D7–D0: T_CRIT setpoint temperature data. Power up default is Local T_CRIT = 85°C and Remote

T_CRIT=110°C. 1 LSB = 1°C, two's complement format.

T_CRIT HYSTERESIS REGISTER (TH)

Table 14. T_CRIT HYSTERESIS REGISTER (TH) (Read and Write Address 21h):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value 16 8 4 2 1

D7–D0: T_CRIT Hysteresis temperature. Power up default is TH = 10°C. 1 LSB = 1°C, maximum value = 31.

FILTER and ALERT CONFIGURE REGISTER

Table 15. FILTER and ALERT CONFIGURE REGISTER (Read and Write Address BFh):

BIT D7 D6 D5 D4 D3 D2 D1 D0

Value 0 0 0 0 0 Filter Level ALERT Configure

D7-D3: is not defined defaults to "0".

D2-D1: input filter setting as defined the table below:

D2 D1 Filter Level

0 0 No Filter

0 1 Level 1

1 0 Level 1

1 1 Level 2

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Level 2 sets maximum filtering.

D0: when set to "1" comparator mode is enabled.

MANUFACTURERS ID REGISTER

(Read Address FEh) The default value is 01h.

DIE REVISION CODE REGISTER

(Read Address FFh) The LM89 version has a default value of 31h or 49 decimal. The LM89-1 version has a

default value of 34h or 52 decimal. This register will increment by 1 every time there is a revision to the die by

National Semiconductor.

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Vbe = K ln (N)

k T

IF = IS e

Vbe

KVt

Vt = k T

IF = IS e - 1

Vbe

KVt

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APPLICATIONS HINTS

The LM89 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 LM89'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 surface temperature, the actual temperature of the LM89 die will be at an

intermediate temperature between the surface and air temperatures. Again, the primary thermal conduction path

is through the leads, so the circuit board temperature will contribute to the die temperature much more strongly

than will the air temperature.

To measure temperature external to the LM89's die, use a remote diode. This diode can be located on the die of

a target IC, allowing measurement of the IC's temperature, independent of the LM89's temperature. The LM89

has been optimized to measure the remote thermal diode of a 0.13 micron Pentium 4 or a Mobile Pentium 4

Processor-M processor. A discrete diode can also be used to sense the temperature of external objects or

ambient air. Remember that a discrete diode's temperature will be affected, and often dominated, by the

temperature of its leads.

Most silicon diodes do not lend themselves well to this application. It is recommended that a 2N3904 transistor

base emitter junction be used with the collector tied to the base.

An LM89 with a diode-connected 2N3904 approximates the temperature reading of the LM89 with a Pentium 4

microprocessor less 1°C.

T2N3904 = TP4 −1°C

DIODE NONIDEALITY

Diode Nonideality Factor Effect on Accuracy

When a transistor is connected as a diode, the following relationship holds for variables VBE, T and If:

where (1)

where

• q = 1.6×10−19 Coulombs (the electron charge),

• T = Absolute Temperature in Kelvin

• k = 1.38×10−23joules/K (Boltzmann's constant),

•ηis the nonideality factor of the process the diode is manufactured on,

• IS= Saturation Current and is process dependent,

• If= Forward Current through the base emitter junction

• VBE = Base Emitter Voltage drop (2)

In the active region, the -1 term is negligible and may be eliminated, yielding the following equation

(3)

In the above equation, ηand ISare dependant upon the process that was used in the fabrication of the particular

diode. By forcing two currents with a very controlled ratio (N) and measuring the resulting voltage difference, it is

possible to eliminate the ISterm. Solving for the forward voltage difference yields the relationship:

(4)

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The voltage seen by the LM89 also includes the IFRSvoltage drop of the series resistance. The nonideality

factor, η, is the only other parameter not accounted for and depends on the diode that is used for measurement.

Since ΔVBE is proportional to both ηand T, the variations in ηcannot be distinguished from variations in

temperature. Since the nonideality factor is not controlled by the temperature sensor, it will directly add to the

inaccuracy of the sensor. For the Pentium 4 and Mobile Pentium Processor-M Intel specifies a ±0.1% variation in

ηfrom part to part. As an example, assume a temperature sensor has an accuracy specification of ±1°C at room

temperature of 25 °C and the process used to manufacture the diode has a nonideality variation of ±0.1%. The

resulting accuracy of the temperature sensor at room temperature will be:

TACC = ± 1°C + (±0.1% of 298 °K) = ±1.4 °C (5)

The additional inaccuracy in the temperature measurement caused by η, can be eliminated if each temperature

sensor is calibrated with the remote diode that it will be paired with.

Processor Family η, nonideality

MIN TYP MAX

Pentium III CPUID 67h 1 1.0065 1.0125

Pentium III CPUID 68h/PGA370Socket/Celeron 1.0057 1.008 1.0125

Pentium 4, 423 pin 0.9933 1.0045 1.0368

Pentium 4, 478 pin 0.9933 1.0045 1.0368

0.13 micron, Pentium 4 1.0011 1.0021 1.0030

MMBT3904 1.003

AMD Athlon MP model 6 1.002 1.008 1.016

Compensating for Diode Nonideality

In order to compensate for the errors introduced by nonideality, the temperature sensor is calibrated for a

particular processor. National Semiconductor temperature sensors are always calibrated to the typical nonideality

of a given processor type. The LM89 is calibrated for the nonideality of a 0.13 micron, Mobile Pentium 4, 1.0021.

When a temperature sensor calibrated for a particular processor type is used with a different processor type or a

given processor type has a nonideality that strays from the typical, errors are introduced.

Temperature errors associated with nonideality may be reduced in a specific temperature range of concern

through use of the offset registers (11h and 12h).

Please visit www.ti.com requesting further information on our recommended setting of the offset register for

different processor types.

PCB LAYOUT for MINIMIZING NOISE

Figure 15. Ideal Diode Trace Layout

In a noisy environment, such as a processor mother board, layout considerations are very critical. Noise induced

on traces running between the remote temperature diode sensor and the LM89 can cause temperature

conversion errors. Keep in mind that the signal level the LM89 is trying to measure is in microvolts. The following

guidelines should be followed:

1. VDD should be bypassed with a 0.1µF capacitor in parallel with 100pF. The 100pF capacitor should be placed

as close as possible to the power supply pin. A bulk capacitance of approximately 10µF needs to be in the

near vicinity of the LM89.

2. A 2.2nF diode bypass capacitor is required to filter high frequency noise. Place the 2.2nF capacitor as close

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as possible to the LM89's D+ and D−pins. Make sure the traces to the 2.2nF capacitor are matched.

3. Ideally, the LM89 should be placed within 10cm of the Processor diode pins with the traces being as straight,

short and identical as possible. Trace resistance of 1Ωcan cause as much as 1°C of error. This error can be

compensated by using the Remote Temperature Offset Registers, since the value placed in these registers

will automatically be subtracted from or added to the remote temperature reading.

4. Diode traces should be surrounded by a GND guard ring to either side, above and below if possible. This

GND guard should not be between the D+ and D−lines. In the event that noise does couple to the diode

lines it would be ideal if it is coupled common mode. That is equally to the D+ and D−lines.

5. Avoid routing diode traces in close proximity to power supply switching or filtering inductors.

6. Avoid running diode traces close to or parallel to high speed digital and bus lines. Diode traces should be

kept at least 2cm apart from the high speed digital traces.

7. If it is necessary to cross high speed digital traces, the diode traces and the high speed digital traces should

cross at a 90 degree angle.

8. The ideal place to connect the LM89's GND pin is as close as possible to the Processors GND associated

with the sense diode.

9. Leakage current between D+ and GND should be kept to a minimum. One nano-ampere of leakage can

cause as much as 1°C of error in the diode temperature reading. Keeping the printed circuit board as clean

as possible will minimize leakage current.

Noise coupling into the digital lines greater than 400mVp-p (typical hysteresis) and undershoot less than 500mV

below GND, may prevent successful SMBus communication with the LM89. SMBus no acknowledge is the most

common symptom, causing unnecessary traffic on the bus. Although the SMBus maximum frequency of

communication is rather low (100kHz max), care still needs to be taken to ensure proper termination within a

system with multiple parts on the bus and long printed circuit board traces. An RC lowpass filter with a 3db

corner frequency of about 40MHz is included on the LM89's SMBCLK input. Additional resistance can be added

in series with the SMBData and SMBCLK lines to further help filter noise and ringing. Minimize noise coupling by

keeping digital traces out of switching power supply areas as well as ensuring that digital lines containing high

speed data communications cross at right angles to the SMBData and SMBCLK lines.

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REVISION HISTORY

Changes from Revision B (March 2013) to Revision C Page

• Changed layout of National Data Sheet to TI format .......................................................................................................... 24

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PACKAGE OPTION ADDENDUM

www.ti.com 1-Nov-2013

Addendum-Page 1

PACKAGING INFORMATION

Orderable Device Status

(1)

Package Type Package

Drawing Pins Package

Qty Eco Plan

(2)

Lead/Ball Finish

(6)

MSL Peak Temp

(3)

Op Temp (°C) Device Marking

(4/5)

Samples

LM89-1CIMM NRND VSSOP DGK 8 1000 TBD Call TI Call TI 0 to 125 T19C

LM89-1CIMM/NOPB ACTIVE VSSOP DGK 8 1000 Green (RoHS

& no Sb/Br) CU SN Level-1-260C-UNLIM 0 to 125 T19C

LM89-1CIMMX/NOPB ACTIVE VSSOP DGK 8 3500 Green (RoHS

& no Sb/Br) CU SN Level-1-260C-UNLIM 0 to 125 T19C

LM89CIMM/NOPB ACTIVE VSSOP DGK 8 1000 Green (RoHS

& no Sb/Br) CU SN Level-1-260C-UNLIM 0 to 125 T15C

LM89CIMMX/NOPB ACTIVE VSSOP DGK 8 3500 Green (RoHS

& no Sb/Br) CU SN Level-1-260C-UNLIM 0 to 125 T15C

LM89CIMX NRND SOIC D 8 2500 TBD Call TI Call TI 0 to 125 LM89

CIM

LM89CIMX/NOPB ACTIVE SOIC D 8 2500 Green (RoHS

& no Sb/Br) SN | CU SN Level-1-260C-UNLIM 0 to 125 LM89

CIM

(1) The marketing status values are defined as follows:

ACTIVE: Product device recommended for new designs.

LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.

NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.

PREVIEW: Device has been announced but is not in production. Samples may or may not be available.

OBSOLETE: TI has discontinued the production of the device.

(2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability

information and additional product content details.

TBD: The Pb-Free/Green conversion plan has not been defined.

Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that

lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.

Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between

the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.

Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight

in homogeneous material)

(3) MSL, Peak Temp. - The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.

(4) There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.

PACKAGE OPTION ADDENDUM

www.ti.com 1-Nov-2013

Addendum-Page 2

(5) Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation

of the previous line and the two combined represent the entire Device Marking for that device.

(6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish

value exceeds the maximum column width.

Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information

provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and

continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.

TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.

In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.

TAPE AND REEL INFORMATION

*All dimensions are nominal

Device Package

Type Package

Drawing Pins SPQ Reel

Diameter

(mm)

Reel

Width

W1 (mm)

(mm) B0

(mm) K0

(mm) P1

(mm) W

(mm) Pin1

Quadrant

LM89-1CIMM VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1

LM89-1CIMM/NOPB VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1

LM89-1CIMMX/NOPB VSSOP DGK 8 3500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1

LM89CIMM/NOPB VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1

LM89CIMMX/NOPB VSSOP DGK 8 3500 330.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1

LM89CIMX SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1

LM89CIMX/NOPB SOIC D 8 2500 330.0 12.4 6.5 5.4 2.0 8.0 12.0 Q1

PACKAGE MATERIALS INFORMATION

www.ti.com 23-Sep-2013

Pack Materials-Page 1

*All dimensions are nominal

Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)

LM89-1CIMM VSSOP DGK 8 1000 210.0 185.0 35.0

LM89-1CIMM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0

LM89-1CIMMX/NOPB VSSOP DGK 8 3500 367.0 367.0 35.0

LM89CIMM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0

LM89CIMMX/NOPB VSSOP DGK 8 3500 367.0 367.0 35.0

LM89CIMX SOIC D 8 2500 367.0 367.0 35.0

LM89CIMX/NOPB SOIC D 8 2500 367.0 367.0 35.0

PACKAGE MATERIALS INFORMATION

www.ti.com 23-Sep-2013

Pack Materials-Page 2

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