LM64 Remote Diode Temperature Sensor with Control GPIO's LM64 rem
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LM64 Remote Diode Temperature Sensor with Control GPIO's
LM64 Remote Diode Temperature Sensor with Control GPIO's
LM64 remote diode temperature sensor with control. LM64 accurately measures temperature that remote diode. LM64 remote temperature accuracy factory trimmed MMBT3904 diodeconnected transistor with 16°C offset high temperatures. TACTUAL DIODE JUNCTION TLM64 16°C LM64 features PWM, open-drain, control output, GPIO (General Purpose Input/Output) (General Purpose Default) pins. 8-step Lookup Table allows non-linear speed temperature transfer function often used quiet acoustic noise.
Specifications
Remote Diode Temperature Accuracy (includes quantization error) Ambient Temp 30°C 50°C 85°C Diode Temp 120°C 140°C 25°C 140°C Error
1.0°C (max) 3.0°C (max)
Local Temp Accuracy (includes quantization error) Ambient Temp 25°C 125°C Power Supply Requirements Error
3.0°C (max)
Features
Accurately senses remote local diode temperatures Integrated speed control output Programmable 8-step Lookup Table quieting fans ALERT T_Crit open-drain outputs Tachometer input measuring plus sign remote diode temperature data format, with 0.125°C resolution SMBus compatible interface, supports TIMEOUT General Purpose Input/Output pins General Purpose Default input pins 24-pin package
Supply Voltage Supply Current
(typ)
Applications
Computer Processor Thermal Management Graphics Processor Thermal Management Voltage Regulator Modules Electronic Instrumentation Power Supplies Projectors
Connection Diagram
20065501
2003 National Semiconductor Corporation
DS200655
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LM64
Descriptions
Name GPIO1 GPIO2 GPIO3 Input/Output Digital Input/ Open-Drain Output Digital Input/ Open-Drain Output Digital Input/ Open-Drain Output Open-Drain Digital Output Function Connection General Purpose Open-Drain Digital Output Digital Input. Typical pull-up resistor VDD. General Purpose Open-Drain Digital Output Digital Input. Typical pull-up resistor VDD. General Purpose Open-Drain Digital Output Digital Input. Typical pull-up resistor VDD. Open-Drain Digital Output. Connect drive circuitry. power-on default this (pin pulled ground). Connect low-noise +3.3 power supply, bypass with ceramic capacitor parallel with ceramic capacitor. bulk capacitance needs vicinity LM64's pin. Connect anode (positive side) remote diode. ceramic capacitor must connected between pins Connect cathode (negative side) remote diode. ceramic capacitor must connected between pins Open-Drain Digital Output. Typical pull-up resistor VDD. Connection. Connection. Connection. SMBus Address Select pin. High, SMBus address 0x4E Low, SMBus address 0x18. Typical pull-up resistor VDD. This analog digital ground return. This open-drain ALERT Output. Typical pull-up resistor VDD. This digital tachometer input. Typical pull-up resistor VDD. This bi-directional SMBus data line. Typical pull-up resistor VDD. This SMBus clock input. Typical pull-up resistor VDD. General Purpose Open-Drain Digital Output Digital Input. Typical pull-up resistor VDD. General Purpose Open-Drain Digital Output Digital Input. Typical pull-up resistor VDD. General Purpose Default Input Pin. Typical pull-up resistor VDD. Always connect logical High level. General Purpose Default Input Pin. Typical pull-up resistor VDD. Always connect logical High level. General Purpose Default Input Pin. Typical pull-up resistor VDD. Always connect logical High level. General Purpose Default Input Pin. Typical pull-up resistor VDD. Always connect logical High level. General Purpose Default Input Pin. Typical pull-up resistor VDD. Always connect logical High level.
Power Supply Input
DT_Crit ALERT TACH SMBDAT SMBCLK GPIO5 GPIO4 GPD1 GPD2 GPD3 GPD4 GPD5
Analog Input Analog Input Open-Drain Digital Output Digital Input Ground Open-Drain Digital Output Digital Input Digital Input/ Open-Drain Output Digital Input Digital Input/ Open-Drain Output Digital Input/ Open-Drain Output Digital Input Digital Input Digital Input Digital Input Digital Input
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LM64
Simplified Block Diagram
20065502
Ordering Information
Part Description LM64 24-pin LM64 24-pin LM64 Evaluation Board With Software Manual Order Number LM64CILQ-F LM64CILQX-F LM64EVAL Mark 64CILQF 64CILQF Transport Media 1000 Units Tape Reel 4500 Units Tape Reel Packaged
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LM64
Typical Application
20065503
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LM64
Absolute Maximum Ratings
Supply Voltage, Voltage SMBDAT, SMBCLK, ALERT, T_Crit, Pins Voltage Other Pins Input Current, Input Current Other Pins (Note Package Input Current (Note Package Power Dissipation SMBDAT, ALERT, T_Crit, pins Output Sink Current Storage Temperature
(Notes
Susceptibility (Note Human Body Model 2000 Machine Model Soldering Information National Semiconductor Application Note AN-1187, "Leadless Leadframe Package" information Assembly using Packages. This available
-0.3 -0.5 -0.3 (VDD
(Note -65°C +150°C
Operating Ratings (Notes
LM64 Operating Temperature Range Remote Diode Temperature Range Electrical Characteristics Supply Voltage Range (VDD) +85°C 25°C +140°C TMIN TMAX +3.0 +3.6
Electrical Characteristics
TEMPERATURE-TO-DIGITAL CONVERTER CHARACTERISTICS following specifications apply VDC, analog source impedance unless otherwise specified conditions. Boldface limits apply TMIN TMAX; other limits +25°C. Parameter Temperature Error using diode-connected MMBT3904 transistor. Remote Diode Junction Temperature. TLM64 16°C Temperature Error Using Local Diode Remote Diode Resolution Local Diode Resolution Conversion Time Temperatures Source Voltage (VD+ VD-) +0.65 High Current Current Fastest Setting Conditions +30°C +50°C +0°C +85°C +120°C +140°C +25°C +140°C Typical (Note Limits (Note Units (Limits) (max) (max) (max) Bits Bits 34.4 (max) (max) (min) (max) (min)
0.125 31.25
+25°C +125°C (Note
Diode Source Current
Operating Electrical Characteristics
Parameter ALERT, T_Crit Output Saturation Voltage Power-On-Reset Threshold Voltage Supply Current (Note SMBus Inactive, Conversion Rate STANDBY Mode Conditions ALERT, T_Crit IOUT IOUT 0.55 (max) (max) (min) (max) (Note Limits (Note Units
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LM64
Electrical Characteristics
following specifications apply VDC, analog source impedance unless otherwise specified conditions. Boldface limits apply TMIN TMAX; other limits +25°C. Symbol Parameter Conditions Typical (Note Limits (Note Units (Limit) (max) (max)
TACHOMETER ACCURACY Control Accuracy Full-Scale Count Counter Clock Frequency Count Update Frequency OUTPUT Frequency Accuracy
65535
(max)
Digital Electrical Characteristics
Symbol Parameter Logical High Input Voltage Logical Input Voltage Logical High Input Current Logical Input Current Digital Input Capacitance 0.005 -0.005 Conditions Typical (Note Limits (Note Units (Limit) (min) (max) (max) (max)
SMBus Logical Electrical Characteristics
following specifications apply VDC, analog source impedance unless otherwise specified conditions. Boldface limits apply TMIN TMAX; other limits +25°C. Symbol Parameter Conditions Typical (Note Limits (Note 0.03 Units (Limit) (max) (max) (min) (max)
SMBDAT OPEN-DRAIN OUTPUT VHYST Logic Level Output Voltage High Level Output Current Logical High Input Voltage Logical Input Voltage Logic Input Hysteresis Voltage VOUT
SMBDAT, SMBCLK INPUTS
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LM64
SMBus Digital Switching Characteristics
Unless otherwise noted, these specifications apply +3.0 +3.6 VDC, (load capacitance) output lines Boldface limits apply TMIN TMAX; other limits +25°C, unless otherwise noted. switching characteristics LM64 fully meet exceed published specifications SMBus version 2.0. following parameters timing relationships between SMBCLK SMBDAT signals related LM64. They adhere necessarily same SMBus specifications. Symbol fSMB tLOW tHIGH tTIMEOUT tSU:DAT tHD:DAT tHD:STA tSU:STO tSU:STA tBUF Parameter SMBus Clock Frequency SMBus Clock Time SMBus Clock High Time SMBus Rise Time SMBus Fall Time Output Fall Time SMBData SMBCLK Time Reset Serial Interface (Note Data Setup Time SMBCLK High Data Hold Time after SMBCLK Hold Time after (Repeated) Start Condition. After this period first clock generated. Stop Condition SMBCLK High SMBDAT (Stop Condition Setup) SMBus Repeated Start-Condition Setup Time, SMBCLK High SMBDAT SMBus Free Time between Stop Start Conditions From VIN(0) From VIN(1) (Note (Note VIN(0) VIN(1) Conditions Limits (Note
Units (Limit) (min) (max) (min) (min) (max) (max) (max) (max) (min) (max) (min) (min) (max) (min) (min) (min) (min)
20065504
FIGURE SMBus Timing Diagram SMBCLK SMBDAT Signals
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LM64
Notes
Note Absolute Maximum Ratings indicate limits beyond which damage device occur. Operating Ratings indicate conditions which device functional, guarantee performance limits. guaranteed specifications test conditions, Electrical Characteristics. guaranteed specifications apply only test conditions listed. Some performance characteristics degrade when device operated under listed test conditions. Note voltages measured with respect GND, unless otherwise noted. Note When input voltage (VIN) exceeds power supplies (VIN V+), current that should limited Parasitic components and/or protection circuitry shown table below, LM64's pins, when exists. Care should taken forward bias parasitic diode, present pins Doing more than corrupt temperature measurements.
Name GPIO1 GPIO2 GPIO3 T_Crit ALERT TACH SMBDAT SMBCLK GPIO5 GPIO4 GPD1 GPD2 GPD3 GPD4 GPD5
CLAMP
20065505
FIGURE Protection Input Structure
Note Human body model, discharged through resistor. Machine model, discharged directly into each pin. Figure above Protection Input Structure. Note National Semiconductor Application Note AN-1187 Thermal Resistance Junction-to-Ambient Temperature. Note National Semiconductor Application Note AN-1187 recommendations assembly using packages. Note "Typicals" 25°C represent most likely parametric norm. They used general reference values critical design calculations. Note Limits guaranteed National's AOQL (Average Outgoing Quality Level). Note supply current will increase substantially with SMBus transaction. Note Local temperature accuracy does include effects self-heating. rise temperature self-heating product internal power dissipation LM64 thermal resistance. (Note thermal resistance used self-heating calculation. Note output rise time measured from (VIL 0.15 (VIH 0.15 Note output fall time measured from (VIH 0.15 (VIL 0.15 Note Holding SMBData and/or SMBCLK lines time interval greater than tTIMEOUT will reset LM64's SMBus state machine, therefore setting SMBDAT SMBCLK pins high impedance state.
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LM64
Functional Description
LM64 Remote Diode Temperature Sensor with Integrated Control incorporates VBE-based temperature sensor using Local Remote diode 10-bit plus sign (Delta-Sigma Analog-to-Digital Converter). pulse-width modulated (PWM) open-drain output, with pull-up resistor, drive switching transistor modulate fan. LM64 measure speed pulses from fan's open-collector tachometer output, pulled resistor VDD. ALERT open-drain output will pulled under certain conditions descibed sections below. T_Crit open-drain output will pulled when T_Crit setpoint temperature limit exceeded. This behaves typical comparator function without latching. LM64's two-wire interface compatible with SMBus Specification more information reader directed www.smbus.org. LM64, digital comparators used compare measured Local Temperature (LT) Local High Setpoint user-programmable temperature limit register. measured Remote Temperature (RT) digitally compared Remote High Setpoint (RHS), Remote Setpoint (RLS), Remote T_CRIT Setpoint (RCS) userprogrammable temperature limits. ALERT output will occur when measured temperature higher than either High Setpoint T_CRIT Setpoint, lower than Setpoint. ALERT Mask register allows user prevent generation these ALERT outputs. temperature hysteresis value placed Hysteresis Register (TH). LM64 placed power Standby mode setting Standby found Configuration Register. Standby mode continuous conversions stopped. Standby mode user choose allow output signal continue, not, programming Disable Standby Configuration Register. Local Temperature reading setpoint data registers 8-bits wide. format 11-bit remote temperature data 16-bit left justified word. 8-bit registers, high bytes, provided each setpoint well temperature reading. Remote Temperature Offset (RTO) Registers: High Byte Byte (RTOHB RTOLB) used correct temperature readings adding subtracting fixed value based different non-ideality factor thermal diode different from graphics processor thermal diode. Section Thermal Diode Non-Ideality. CONVERSION SEQUENCE LM64 takes approximately 31.25 convert Local Temperature (LT), Remote Temperature (RT), update registers. Conversion Rate modified using Conversion Rate Register. When conversion rate modified delay inserted between conversions, actual conversion time remains 31.25 Different Conversion Rates will cause LM64 draw different amounts supply current shown Figure
20065506
FIGURE Supply Current Conversion Rate ALERT OUTPUT When ALERT Mask Configuration register written zero ALERT interrupts enabled. LM64's ALERT versatile produce three different methods best serve system designer: temperature comparator temperature-based interrupt flag, part SMBus ALERT System. three methods further described below. ALERT interrupt methods different only user interacts with LM64. remote temperature (RT) reading associated with T_CRIT Setpoint Register, both local remote temperature readings associated with HIGH setpoint register (LHS RHS). also associated with setpoint register (RLS). every temperature reading digital comparison determines whether that reading above HIGH T_CRIT setpoint below setpoint. corresponding ALERT Status Register set. ALERT mask low, ALERT Status Register, with exception Busy Open, will cause ALERT output pulled low. temperature conversion that limits defined temperature setpoint registers will trigger ALERT. Additionally, ALERT Mask must cleared trigger ALERT modes. three different ALERT modes will discussed following sections. 1.2.1 ALERT Output Temperature Comparator When LM64 used system which does require temperature-based interrupts, ALERT output could used temperature comparator. this mode, once condition that triggered ALERT longer present, ALERT negated (Figure example, ALERT output activated comparison LHS, when this condition longer true, ALERT will return HIGH. This mode allows operation without software intervention, once registers configured during set-up. order ALERT used temperature comparator, Comparator Mode Remote Diode Temperature Filter Comparator Mode Register must asserted. This power-on default state.
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LM64
Functional Description
(Continued)
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FIGURE ALERT Output Interrupt Temperature Response Diagram 1.2.3 ALERT Output SMBus ALERT SMBus alert line created when ALERT output connected more ALERT outputs other SMBus compatible devices, master. Under this implementation, LM64's ALERT should operated using (Alert Response Address) protocol. SMBus protocol, defined SMBus specification 2.0, procedure designed assist master determining which part generated interrupt service that interrupt. SMBus alert line connected open-drain ports devices bus, thereby AND'ing them together. method allows SMBus master, with command, identify which part pulling SMBus alert line LOW. also prevents part from pulling line again same triggering condition. When command received devices bus, devices pulling SMBus alert line LOW: send their address master release SMBus alert line after acknowledgement their address. SMBus Specifications state that response (Alert Response Address) "after acknowledging slave address device must disengage ALERT pulldown". Furthermore, host still sees ALERT when message transfer complete, knows read again." This SMBus "disengaging ALERT requirement prevents locking SMBus alert line. Competitive parts address "disengaging ALERT" differently than LM64 all. SMBus systems that implement protocol suggested LM64 will fully compatible with competitive parts. LM64 fulfills "disengaging ALERT" setting ALERT Mask Configuration Register after sending address response releasing ALERT output pin. Once ALERT Mask activated, ALERT output will disabled until enabled software. order enable ALERT master must read ALERT Status Register, during interrupt service routine then reset ALERT Mask Configuration Register interrupt service routine. following sequence describes response protocol. Master senses SMBus alert line
FIGURE ALERT Output Temperature Comparator Response Diagram 1.2.2 ALERT Output Interrupt LM64's ALERT output implemented simple interrupt signal when used trigger interrupt service routine. such systems desirable interrupt flag repeatedly trigger during before interrupt service routine been completed. Under this method operation, during read ALERT Status Register LM64 will ALERT Mask Configuration Register ALERT Status Register set, with exception Busy Open. This prevents further ALERT triggering until master reset ALERT Mask bit, interrupt service routine. ALERT Status Register bits cleared only upon read command from master (see Figure will re-asserted next conversion triggering condition(s) persist(s). order ALERT used dedicated interrupt signal, Comparator Mode Remote Diode Temperature Filter Comparator Mode Register must low. This power-on default state. following sequence describes response system that uses ALERT output interrupt flag: Master senses ALERT low. Master reads LM64 ALERT Status Register determine what caused ALERT. LM64 clears ALERT Status Register, resets ALERT HIGH sets ALERT Mask Configuration Register. Master attends conditions that caused ALERT triggered. started, setpoint limits adjusted, etc. Master resets ALERT Mask Configuration Register.
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LM64
Functional Description
(Continued)
SMBus INTERFACE Since LM64 operates slave SMBus, SMBCLK line input SMBDAT line bidirectional. LM64 never drives SMBCLK line does support clock stretching. LM64 hardware-selectable 7-bit slave addresses. user input logical High Address select pre-programmed SMBus slave addresses. options follows: SMBus Address 0x[Hex] SMBus Slave Address Bits
Master sends START followed Alert Response Address (ARA) with Read Command. Alerting Device(s) send ACK. Alerting Device(s) send their address. While transmitting their address, alerting devices sense whether their address been transmitted correctly. (The LM64 will reset ALERT output ALERT Mask once complete address been transmitted successfully.) Master/slave NoACK Master sends STOP Master attends conditions that caused ALERT triggered. ALERT Status Register read started, setpoints adjusted, etc.
Master resets ALERT Mask Configuration Register. ARA, 1100, general call address. device should ever assigned this address. ALERT Configuration Remote Diode Temperature Filter Comparator Mode Register must order LM64 respond command. ALERT output disabled setting ALERT Mask Configuration Register. power-on default have ALERT Mask ALERT Configuration low.
POWER-ON RESET (POR) DEFAULT STATES information default states Section LM64 Register Functional Order.
20065509
FIGURE ALERT Output SMBus ALERT Temperature Response Diagram
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LM64
Functional Description
TEMPERATURE DATA FORMAT
(Continued)
Temperature data only read from Local Remote Temperature registers. High, T_CRIT setpoint registers Read/Write.
Remote temperature data represented 11-bit, two's complement word with Least Significant (LSB) equal 0.125°C. data format left justified 16-bit word available 8-bit registers. Some examples temperature conversions shown below.
Actual LM64 Remote Temperature Conversion Actual Remote Diode Temperature,°C
Output 11-bit two's complement word. 0.125
LM64 Remote Diode Temperature Register, +104 +109 +110 +114 +119 +124
Binary Results LM64 Remote Temperature Register 0110 1000 0000 0000 0110 1101 0000 0000 0110 1110 0000 0000 0111 0010 0010 0000 0111 0111 0000 0000 0111 1100 0000 0000
Remote Temperature Register 6800h 6D00h 6E00h 7200h 7700h 7C00h
Actual Remote T_Crit Setpoint Example Actual Remote Diode T_Crit Setpoint,°C Remote T_CRIT High Setpoint, +110 Binary Remote T_CRIT High Setpoint Value 0110 1110 Remote T_CRIT High Setpoint Value
Local Temperature data represented 8-bit, two's complement byte with equal 1°C: Temperature +125°C +25°C +1°C -1°C -25°C -55°C Digital Output Binary 0111 1101 0001 1001 0000 0001 0000 0000 1111 1111 1110 0111 1100 1001
OPEN-DRAIN OUTPUTS, INPUTS, PULL-UP RESISTORS SMBDAT, ALERT, T_Crit, GPIO open-drain outputs GPD, TACH, inputs pulled-up pull-up resistors VDDas suggested table below. Name SMBCLK SMBDAT ALERT T_Crit GPIOx GPDx TACH Number 1-3;18,19 20-24 Suggested Pull-up Resistor Range (Note Typical (Note
DIODE FAULT DETECTION LM64 detect fault conditions caused remote diode. detected shorted VDD, open: Remote Temperature High Byte (RTHB) register loaded with 127°C, Remote Temperature Byte (RTLB) register loaded with OPEN (D2) status register set. Therefore, Remote T_CRIT setpoint register (RCS): value less than +127°C ALERT Mask disabled, then ALERT output will pulled low. Remote High Setpoint High Byte (RHSHB) value less than +127°C ALERT Mask disabled, then ALERT T_Crit outputs will pulled low. OPEN itself will trigger ALERT. shorted either ground then Remote Temperature High Byte (RTHB) register loaded with -128°C (1000 0000) OPEN ALERT Status Register will set. temperature reading -128°C indicates that shorted either ground value Remote Setpoint High Byte (RLSHB) Register more than -128°C ALERT Mask Disabled, ALERT will pulled low. COMMUNICATING WITH LM64 Each data register LM64 falls into four types user accessibility: Read Only Write Only Read/Write same address Read/Write different address Write LM64 comprised address byte command byte. write register requires data byte. Reading LM64 Registers take place after requisite register setup sequence takes place. Section 2.1.1 LM64 Required Initial Control Register Sequence.
Note Depends drive circuitry connected this pin. absence control circuitry pull-up resistor VDD.
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LM64
Functional Description
(Continued)
data byte Most Significant (MSB) first. read, LM64 accept either Acknowledge No-Acknowledge from Master. Note that NoAcknowledge typically used signal slave indicating that Master read last byte. DIGITAL FILTER LM64 incorporates user-configured digital filter suppress erroneous Remote Temperature readings noise. filter accessed Remote Diode Temperature Filter Comparator Mode Register. filter according following table. Level maximum filtering.
20065511
Digital Filter Selection Table Filter Filter Level Level Level
FIGURE Impulse Response Digital Filter
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20065510
FIGURE Step Response Digital Filter
FIGURE Digital Filter Response Intel Pentium processor System. Filter curves were purposely offset better show noise performance.
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LM64
Functional Description
1.10 FAULT QUEUE
(Continued)
LM64 incorporates Fault Queue suppress erroneous ALERT triggering Fault Queue prevents false triggering requiring three consecutive out-of-limit HIGH, LOW, T_CRIT temperature readings. Figure Fault Queue defaults upon power-up activated setting RDTS Fault Queue Configuration Register
1.11 ONE-SHOT REGISTER One-Shot Register used initiate single conversion comparison cycle when device standby mode, after which data returns standby. This data register. write operation causes one-shot conversion. data written this address irrelevant stored. zero will always read from this register. 1.12 SERIAL INTERFACE RESET event that SMBus Master reset while LM64 transmitting SMBDAT line, LM64 must returned known state communication protocol. This done ways: When SMBDAT Low, LM64 SMBus state machine resets SMBus idle state either SMBData SMBCLK held more than (tTIMEOUT). devices timeout when either SMBCLK SMBDAT lines held Therefore, insure timeout devices bus, either SMBCLK SMBData line must held least With both SMBDAT SMBCLK High, master initiate SMBus start condition with High transition SMBDAT line. LM64 will respond properly SMBus start condition point during communication. After start LM64 will expect SMBus Address address byte.
20065513
FIGURE Fault Queue Temperature Response Diagram
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LM64
LM64 Registers
following pages include: Section 2.1, Register Hexadecimal Order, which shows summary registers their assignments, Section 2.2, Register Functional Order, Section 2.3, detailed explanation each register. address unused manufacturer's test registers. LM64 REGISTER HEXADECIMAL ORDER following Register grouped hexadecimal address order. Some address locations have been left blank maintain compatibility with LM86. Addresses parenthesis mirrors "Same address backwards compatibility with some older software. Reading writing either address will access same 8-bit register. Register 0x[HEX] (09) (0A) (0B) (0D) (0E) 1C-1F 22-2F 30-3F 40-45 Register Name Local Temperature Temp ALERT Status Configuration Conversion Rate Local High Setpoint [Reserved] Setpoint Same Same Same [Reserved] Same Same Shot Temp Temp Offset Temp Offset High Setpoint Setpoint [Reserved] ALERT Mask [Reserved] [Reserved] TCRIT Setpoint General Purpose Input General Purpose Output [Reserved] [Reserved] TCRIT Hysteresis [Reserved] [Reserved] [Reserved] Tach Count Tach Count Tach Limit Tach Limit Spin-Up Config Value TCLB5 TCHB13 TLLB7 TLHB15 TCLB4 TCHB12 TLLB6 TLHB14 TCLB3 TCHB11 TLLB5 TLHB13 PWPGM SPINUP PWVAL5 RTH7 RTH6 RTH5 RCS7 RCS6 RCS5 ALTMSK6 RTLB7 RTOLB7 RHSLB7 RLSLB7 Write Only. Write command triggers temperature conversion cycle. RTLB6 RTOLB6 RHSLB6 RLSLB6 RTLB5 RTOLB5 RHSLB5 RLSLB5 Used ALTMSK4 ALTMSK3 Used Used RCS4 GPI5 GPO5 RCS3 GPI4 GPO4 RCS2 GPI3 GPO3 RCS1 GPI2 GPO2 RCS0 GPI1 GPO1 ALTMSK1 ALTMSK0 RTOHB9 RTOHB8 RTOHB15 RTOHB14 RTOHB13 RTOHB12 RTOHB11 RTOHB10 Used DATA BITS RTHB BUSY ALTMSK LHS7 RTHB14 LHIGH STBY LHS6 RTHB13 PWMDIS LHS5 RTHB12 RHIGH LHS4 RTHB11 RLOW CONV3 LHS3 Used RHSHB9 RLSHB9 RHSHB8 RLSHB8 RLSHB15 RLSHB14 RLSHB13 RLSHB12 RLHBS11 RLSHB10 RTHB10 RDFA ALT/TCH CONV2 LHS2 RTHB9 RCRIT TCRITOV CONV1 LHS1 RTHB8 TACH FLTQUE CONV0 LHS0
High Setpoint RHSHB15 RHSHB14 RHHBS13 RHSHB12 RHSHB11 RHSHB10
Used Used RTH4 RTH3 RTH2 RTH1 RTH0 Used Used Used TCLB2 TCHB10 TLLB4 TLHB12 PWOUT PWVAL4 TCLB1 TCHB9 TLLB3 TLHB11 PWCKSL PWVAL3 TCLB0 TCHB8 TLLB2 TLHB10 PWVAL2 TEDGE1 TCHB7 Used TLHB9 TACH1 PWVAL1 TEDGE0 TCHB6 Used TLHB8 TACH0 PWVAL0
SPNDTY1 SPNDTY0 SPNUPT2 SPNUPT1 SPNUPT0
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LM64
LM64 Registers
Register 0x[HEX] 50-5F 60-BE C0-FD Register Name Frequency [Reserved] Lookup Table Hystersis Lookup Table [Reserved] Diode Temp Filter [Reserved] Manufacturer's Stepping/Die Rev.
(Continued) DATA BITS PWMF4 LOOKH4 PWMF3 LOOKH3 PWMF2 LOOKH2 PWMF1 LOOKH1 PWMF0 LOOKH0
Used Lookup Table Temp Pairs 8-bit Registers Used Used RDTF1 RDTF0 ALTCOMP
LM64 REGISTER FUNCTIONAL ORDER following Register grouped Functional Order. Some address locations have been left blank maintain compatibility with LM86. Addresses parenthesis mirrors named address. Reading writing either address will access same 8-bit register. Control Configuration Registers listed first, there required order setup these registers first then setup others. detailed explanations each register will follow order shown below. Power-On-Reset. Register [HEX] CONTROL REGISTERS 50-5F (09) (0B) (0D) (0E) Spin-Up Configuration Frequency Value Lookup Table Lookup Table Hysteresis Configuration Tach Count Tach Count Tach Limit Tach Limit Local Temperature Local High Setpoint Remote Temperature Remote Temperature Remote Temperature Offset Remote Temperature Offset Remote High Setpoint Remote High Setpoint Remote Setpoint Remote Setpoint Remote TCRIT Setpoint Remote TCRIT Remote Diode Temperature Filter Read Only (R/W Override Set) Read Only Read Only Read Only Read Only Read Only Table (70°) (70°C) (0°C) (85°C) (10°C) Register Name Read/Write Default [HEX]
CONFIGURATION REGISTER TACHOMETER COUNT LIMIT REGISTERS
LOCAL TEMPERATURE LOCAL SETPOINT REGISTERS
REMOTE DIODE TEMPERATURE SETPOINT REGISTERS
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LM64
LM64 Registers
Register [HEX] (0A) 1C-1F 22-2F 30-3F 40-45 60-BE C0-FD Conversion Rate One-Shot ALERT Status ALERT Mask Manufacturer's Stepping/Die Rev. General Purpose Input
(Continued) Register Name Read/Write Default [HEX] (Note (Note
CONVERSION ONE-SHOT REGISTERS Write Only Read Only Read Only Read Only Read Only
ALERT STATUS MASK REGISTERS
REGISTERS
GENERAL PURPOSE REGISTERS General Purpose Output Used Used Used Used Used Used Used Used Used Used Used Used Used
[RESERVED] REGISTERS USED
Note Register 0x1A Power-On-Reset five LSB's logic states present GPIOx pins. Note Register 0x1B Power-On-Reset five LSB's logic states present GPDx pins.
LM64 INITIAL REGISTER SEQUENCE REGISTER DESCRIPTIONS FUNCTIONAL ORDER following Register grouped functional sequence order. Some address locations have been left blank maintain compatibility with LM86. Addresses parenthesis mirrors named address backwards compatibility with some older software. Reading writing either address will access same 8-bit register. 2.3.1 LM64 Required Initial Control Register Sequence Important! BIOS must follow sequence below configure following Registers LM64 before using Tachometer registers: Step [Register]HEX Setup Instructions [4A] Write bits This includes tach settings used, internal clock select (1.4 kHz) Output Polarity. [4B] Write bits through program spin-up settings. [4D] Write bits through frequency settings. This works with internal clock select. Choose, then write, only following: [4F-5F] Lookup Table, [4C] value bits through Step Lookup Table, chosen written then write [4A]
other registers written time after above sequence.
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LM64
LM64 Registers
(Continued)
LM64 REGISTER DESCRIPTIONS FUNCTIONAL ORDER
Control Registers
Address Read/ Write Bits Value Name Description
4AHEX REGISTER These bits unused always Value (register Lookup Table (50-5F) read-only. value 100%) determined current remote diode temperature Lookup Table, read from value register. value (register Lookup Table (Register 50-5F) read/write enabled. Writing Value register will output. This also state during which Lookup Table written. output will open output will open master clock master clock kHz. Always write this bit. Traditional tach input monitor, false readings when under minimum detectable RPM. Traditional tach input monitor, FFFF reading when under minimum detectable RPM. Most accurate readings, FFFF reading when under minimum detectable RPM. Least effort programmed fan, FFFF reading when under minimum detectable RPM. Note: Clock kHz, mode used regardless setting these bits. These bits unused always spin-up uses duty cycle spin-up time, bits 0-4. LM64 sets output 100% until spin-up times (per bits 0-2) minimum desired been reached (per Tachometer Setpoint setting) using tachometer input, whichever happens first. This overrides Spin-Up Duty Cycle register (bits 4:3) output always 100%. Spin-Up Time (bits 2:0) 000, Spin-Up cycle bypassed, regardless state this bit. Spin-Up cycle bypassed Spin-Up), unless Fast Tachometer Terminated Spin-Up (bit set. 75%-81% Depends Frequency. Applications Notes. 100% 000: 001: 010: 011: 100: 101: 110: 111: Spin-Up cycle bypassed Spin-Up) 0.05 seconds
Program
Output Polarity Clock Select [Reserved]
Tachometer Mode
4BHEX SPIN-UP CONFIGURATION REGISTER
Fast Tachometer Spin-Up
Spin-Up Duty Cycle
Spin-Up Time
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LM64
LM64 Registers
Address Read/ Write Value
(Continued) (Continued) Name Description
Control Registers
Bits
4DHEX FREQUENCY REGISTER These bits unused always Frequency Frequency PWM_Clock where PWM_Clock (per Clock Select Register 4A), value register. Note: mapped Application Note this datasheet. These bits unused always Program (register this register read only reflects LM64's current value from Lookup Table. Program (register this register read/write desired value written directly this register, instead from Lookup Table, direct speed control. This register will read during Spin-Up cycle. Application Notes section this datasheet more information regarding Value Duty Cycle
10111
4CHEX VALUE REGISTER Read (Write only
000000
Value
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LM64
LM64 Registers
Address Read/ Write Value 0x7F 0x3F 0x7F 0x3F 0x7F 0x3F 0x7F 0x3F 0x7F 0x3F 0x7F 0x3F 0x7F 0x3F 0x7F 0x3F
(Continued) (Continued) Name Description
Control Registers
Bits
50HEX 5FHEX LOOKUP TABLE Bits Temperature Bits each Temperature/PWM Pair) Read. (Write only Lookup Table Temperature Entry Lookup Table Entry Lookup Table Temperature Entry Lookup Table Entry Lookup Table Temperature Entry Lookup Table Entry Lookup Table Temperature Entry Lookup Table Entry Lookup Table Temperature Entry Lookup Table Entry Lookup Table Temperature Entry Lookup Table Entry Lookup Table Temperature Entry Lookup Table Entry Lookup Table Temperature Entry Lookup Table Entry Lookup Table Hysteresis This unused always remote diode temperature exceeds this value, output will value Register These bits unused always value corresponding temperature limit register This unused always remote diode temperature exceeds this value, output will value Register These bits unused always value corresponding temperature limit register This unused always remote diode temperature exceeds this value, output will value Register These bits unused always value corresponding temperature limit register This unused always remote diode temperature exceeds this value, output will value Register These bits unused always value corresponding temperature limit register This unused always remote diode temperature exceeds this value, output will value Register These bits unused always value corresponding temperature limit register This unused always remote diode temperature exceeds this value, output will value Register These bits unused always value corresponding temperature limit register This unused always remote diode temperature exceeds this value, output will value Register These bits unused always value corresponding temperature limit register This unused always remote diode temperature exceeds this value, output will value Register These bits unused always value corresponding temperature limit register These bits unused always amount hysteresis applied Lookup Table. 1°C).
4FHEX LOOKUP TABLE HYSTERESIS 00100
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LM64
LM64 Registers
ADDRESS Read/ Write Value
(Continued)
Configuration Register
Bits Name Description
(09)HEX CONFIGURATION REGISTER ALERT Mask When this ALERT interrupts enabled. When this ALERT interrupts masked, ALERT always high impedance (open) state. When this LM64 operational mode, converting, comparing, updating output continuously. When this LM64 enters power standby mode. STANDBY, continuous conversions stopped, conversion/comparison cycle initiated writing value register 0x0F. Operation output STANDBY depends setting this register. When this LM64's output continues output current control signal while STANDBY. When this output disabled defined polarity bit) while STANDBY. These bits unused always ALERT will generated Remote Diode conversion result above Remote High Point below Remote Setpoint. ALERT will generated only three consecutive Remote Diode conversions above Remote High Point below Remote Setpoint.
STANDBY
(09)
Disable STANDBY
0000
RDTS Fault Queue
Tachometer Count Limit Registers
ADDRESS Read/ Write Bits Value Name Description
47HEX TACHOMETER COUNT (MSB) 46HEX TACHOMETER COUNT (LSB) REGISTERS bits: Read first lock ensure from same reading) Read Only Read Only Tachometer Count (MSB) Tachometer Count (LSB) These registers contain current 16-bit Tachometer Count, representing period time between tach pulses. Note that 16-bit tachometer reversed from 16-bit temperature readings. Bits Read Only Tachometer Edge Count Edges Used Tach_Count_Multiple Reserved
Note: PWM_Clock_Select kHz, then Tach_Count_Multiple regardless setting these bits. 49HEX TACHOMETER LIMIT (MSB) 48HEX TACHOMETER LIMIT (LSB) REGISTERS 0xFF Tachometer Limit MSB) Tachometer Limit (LSB) [Reserved] These registers contain current 16-bit Tachometer Count, representing period time between tach pulses. 5,400,000) (Tachometer Count), where pulses/rev fan; pulse/rev fan; pulses/rev fan. Applications Notes section more tachometer information. Note that 16-bit tachometer reversed from temperature readings. Used.
0xFF
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LM64
LM64 Registers
ADDRESS Read/ Bits Write Value Read Only
(Continued)
Local Temperature Local High Setpoint Registers
Name Description
00HEX LOCAL TEMPERATURE REGISTER (8-bits) Local Temperature Reading (8-bit) 8-bit temperature LM64.
(0B)HEX LOCAL HIGH SETPOINT REGISTER (8-bits) 0x46 (70°) Local HIGH Setpoint High Setpoint internal diode.
Remote Diode Temperature, Offset Setpoint Registers
ADDRESS Read/ Write Read Only Bits Value Name Remote Diode Temperature Reading (MSB) Description This LM64 remote diode temperature value, complement. sign bit, weight 64°C, weight 1°C. Read this byte first. actual remote diode temperature 16°C higher than values registers 0x01 0x10. This LM64 remote diode temperature value, complement. weight 0.5°C, weight 0.25°C, weight 0.125°C. actual remote diode temperature 16°C higher than values registers 0x01 0x10. Always Remote Temperature OFFSET (MSB) Remote Temperature OFFSET (LSB) Remote HIGH Setpoint (MSB) Remote HIGH Setpoint (LSB) Remote Setpoint (MSB) Remote Setpoint (LSB) Remote Diode T_CRIT Limit Remote Diode T_CRIT Hysteresis These registers contain offset value added subtracted from, remote diode's reading compensate different non-ideality factors different processors, diodes, etc. complement value, these registers added output LM64's form temperature reading contained registers Always High setpoint temperature remote diode. Same format Remote Temperature Reading (registers 10). Always setpoint temperature remote diode. Same format Remote Temperature Reading (registers 10). Always This 8-bit integer storing T_CRIT limit initially 85°C (101°C actual remote T_Crit limit). This value changed time after power-up. 8-bit integer storing T_CRIT hysteresis. T_CRIT stays activated until remote diode temperature goes below [(T_CRIT Limit) (T_CRIT Hysteresis)]. These bits unused should always Remote Diode Temperature Filter Filter Filter Filter Filter Disabled Level (minimal filtering, same Level (minimal filtering, same Level (maximum filtering)
Read Only
Remote Diode Temperature Reading (LSB)
(0D) (0E)
0x46 (70°C) (0°C) 0x55 (85°C) 0x0A (10°C) 00000
Comparator Mode
ALERT functions Interrupt mode. ALERT behaves comparator, asserting itself when ALERT condition exists, de-asserting itself when ALERT condition goes away.
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LM64
LM64 Registers
ADDRESS Read/ Write Value
(Continued)
ALERT Status Mask Registers
Bits Name Description
02HEX ALERT STATUS REGISTER (8-bits) (All Alarms latched until read, then cleared alarm condition removed time read.) Busy When this converting. When this performing conversion. This does affect ALERT status. When this internal temperature LM64 below Local High Setpoint. When this internal temperature LM64 above Local High Setpoint, ALERT triggered. This unused always read Remote High Alarm When this temperature Remote Diode below Remote High Setpoint. When this temperature Remote Diode above Remote High Setpoint, ALERT triggered. When this temperature Remote Diode above Remote Setpoint. When this temperature Remote Diode below Remote Setpoint, ALERT triggered. When this Remote Diode appears correctly connected. When this Remote Diode disconnected shorted. This Alarm does trigger ALERT. When this temperature Remote Diode below T_CRIT Limit. When this temperature Remote Diode above T_CRIT Limit, ALERT triggered. When this Tachometer count lower than equal Tachometer Limit (the greater than equal minimum desired RPM). When this Tachometer count higher than Tachometer Limit (the less than minimum desired RPM), ALERT triggered. This unused always read Local High Alarm Mask When this Local High Alarm event will generate ALERT. When this Local High Alarm will generate ALERT This unused always read Remote High Alarm Mask Remote Alarm Mask When this Remote High Alarm event will generate ALERT. When this Remote High Alarm event will generate ALERT. When this Remote Alarm event will generate ALERT. When this Remote Alarm event will generate ALERT. This unused always read Remote T_CRIT Alarm Mask Tach Alarm Mask When this Remote T_CRIT event will generate ALERT. When this Remote T_CRIT event will generate ALERT. When this Tach Alarm event will generate ALERT. When this Tach Alarm event will generate ALERT.
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Local High Alarm
0x02
Read Only
Remote Alarm
Remote Diode Fault Alarm
Remote T_CRIT Alarm
Tach Alarm
16HEX ALERT MASK REGISTER (8-bits)
LM64
LM64 Registers
ADDRESS Read/ Write Value
(Continued)
Conversion Rate One-Shot Registers
Bits Name Description
(0A)HEX CONVERSION RATE REGISTER (8-bits) Sets conversion rate LM64. 00000000 0.0625 00000001 0.125 00000010 0.25 00000011 00000100 00000101 00000110 00000111 00001000 00001001 other values With LM64 STANDBY mode single write this register will initiate complete temperature conversion cycle.
(0A)
0x08
Conversion Rate
(0A)HEX ONE-SHOT REGISTER (8-bits) Write Only Shot Trigger
Registers
ADDRESS Read/ Write Read Only Read Only Bits Value Name Description
FFHEX STEPPING REVISION REGISTER (8-bits) 0x51 Stepping/Die Revision Version LM64
FEHEX MANUFACTURER'S REGISTER (8-bits) 0x01 Manufacturer's 0x01 National Semiconductor
General Purpose Registers
ADDRESS Read/ Write Bits Value (Note General Purpose Input Name Description
1AHEX GENERAL PURPOSE INPUT REGISTER (8-bits) Read Only These bits unused always These bits reflect logic states GPIOx pins.
1BHEX GENERAL PURPOSE OUTPUT REGISTER (8-bits) (Note General Purpose Output These bits unused always These bits reflect register bits [4:0] except Power-On-Default when they logic states General Pupose Default (GPD) input pins.
Note Register 0x1A Power-On-Reset five LSB's logic states present GPIOx pins. Note Register 0x1B Power-On-Reset five LSB's logic states present GPDx pins.
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LM64
Application Notes
CONTROL DUTY CYCLE REGISTER SETTINGS FREQUENCY Freq [4:0] 16.7 12.5 10.0 8.33 7.14 6.25 5.56 5.00 4.54 4.16 3.85 3.57 3.33 3.13 2.94 2.78 2.63 2.50 2.38 2.27 2.17 2.08 2.00 1.92 1.85 1.79 1.72 1.67 1.61 Value [5:0] 100% Value [5:0] about Value [5:0] Freq Internal Clock, 180.0 90.00 60.00 45.00 36.00 30.00 25.71 22.50 20.00 18.00 16.36 15.00 13.85 12.86 12.00 11.25 10.59 10.00 9.47 9.00 8.57 8.18 7.82 7.50 7.20 6.92 6.67 6.42 6.21 6.00 5.81 Freq Internal Clock, 703.1 351.6 234.4 175.8 140.6 117.2 100.4 87.9 78.1 70.3 63.9 58.6 54.1 50.2 46.9 43.9 41.4 39.1 37.0 35.2 33.5 32.0 30.6 29.3 28.1 27.0 26.0 25.1 24.2 23.4 22.7
Step Resolution,
Actual Duty Cycle, When Selected
Address mapped Address 50.0 75.0 83.3 75.0 80.0 75.0 78.6 75.0 77.8 75.0 77.27 75.00 76.92 75.00 76.67 75.00 76.47 75.00 76.32 75.00 76.19 75.00 76.09 75.00 76.00 75.00 75.93 75.00 75.86 75.00 75.81
3.1.1 Computing Duty Cycles Given Frequency Select Frequency from first column corresponding desired actual frequency columns Note Value 100% Duty Cycle. Find Duty Cycle taking Value Register computing:
Example: Frequency Value 100% Value actual then Duty Cycle (28/48) 100% 58.3%.
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LM64
Application Notes
(Continued)
LOOKUP TABLE NON-LINEAR VALUES TEMPERATURE Lookup Table, Registers through used create non-linear Temperature curve that could used reduce acoustic noise from processor linear step transfer functions. example given below: EXAMPLE: particular system found that best acoustic noise performance found occur when Temperature transfer function curve parabolic shape. From 25°C 105°C from 100%. Since there steps Lookup Table will break Temperature range into separate temperatures. 80°C over 8-steps 10°C step. This takes care x-axis. Value, first select Frequency. this example will make Frequency (Register 100% Duty Cycle then, value minimum (0.2) then arrange PWM, Temperature pairs parabolic fashion form 0.005 -25)2 Temperature Value Calculated 10.0 12.5 16.0 20.5 26.0 32.5 40.0 Closest Value
IC's temperature, independent LM64's temperature. LM64 been optimized with MMBT3904 diode-connected transistor. discrete diode also used sense temperature external objects ambient air. Remember that discrete diode's temperature will affected, often dominated temperature leads. Most silicon diodes lend themselves well this application. recommended that diode-connected MMBT3904 transistor used. base transistor connected collector becomes anode. emitter cathode. 3.3.1 Diode Non_Ideality When transistor connected diode following relationship holds Vbe,
where
then program Lookup Table with temperature Closest Values required curve required example. NON-IDEALITY FACTOR TEMPERATURE ACCURACY LM64 applied remote diode sensing same other integrated-circuit temperature sensors. soldered printed-circuit board, because path best thermal conductivity between pins, temperature will effectively that printedcircuit board lands traces soldered pins. This presumes that ambient temperature nearly same surface temperature printed-circuit board. temperature much higher lower than surface temperature, actual temperature LM64 will intermediate temperature between surface temperatures. Again, primary thermal conduction path through leads, circuit board surface temperature will contribute temperature much more than temperature. measure temperature external remote diode. This diode located target such processor chip, allowing measurement
1.38x10-23 joules/K (Boltzmann's constant) non-ideality factor manufacturing process used make thermal diode Saturation Current process dependent Forward Current through base emitter junction Base Emitter Voltage Drop active region, term negligible eliminated, yielding following equation
1.6x10-19 Coulombs (the electron charge) Absolute Temperature Kelvin
above equation, dependent upon process that used fabrication particular diode. forcing currents with very controlled ratio measuring resulting voltage difference, possible eliminate term. Solving forward voltage difference yields relationship:
non-ideality factor, only other parameter accounted depends diode that used measurement. Since proportional both variations cannot distinguished from variations temperature. Since temperature sensor does control non-ideality factor, will directly inaccuracy sensor.
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LM64
Application Notes
(Continued)
example, processor manufacturer specifies 0.1% variation from part part. example, assume that temperature sensor accuracy specification room temperature 25°C. resulting accuracy will TACC 0.1% 298°K) 1.3°C additional inaccuracy temperature measurement caused eliminated each temperature sensor calibrated with remote diode that will paired with. Refer processor datasheet non-ideality factor. 3.3.2 Compensating Diode Non-Ideality order compensate errors introduced nonideality, temperature sensor calibrated particular processor. National Semiconductor temperature sensors always calibrated typical non-ideality particular processor type. LM64 calibrated MMBT3904 diode-connected transistor. When temperature sensor, calibrated specific type processor used with different processor type given processor type non-ideality that strays form typical value, errors introduced. Temperature errors associated with non-ideality introduced specific temperature range concern through Temperature Offset Registers 11HEX 12HEX. user encouraged send e-mail hardware.monitor.team@nsc.com further request information recommended setting offset register different processor types. COMPUTING FROM TACH COUNT Tach Count Registers 46HEX 47HEX count number periods tachometer clock LM64 tachometer input from assuming pulse
revolution tachometer, such fans supplied with Pentium boxed processors. computed from Tach Count Registers 46HEX 47HEX. This best shown through example. Example: Given: used tachometer output with revolution. Let: Register (LSB) BFHEX Decimal Register (MSB) 7HEX Decimal 256) 1792. total Tach Count, decimal, 1792 1983. computed using formula
where pulses/rev tachometer output; pulse/rev tachometer output, pulses/rev tachometer output example
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LM64
Application Notes
(Continued)
LAYOUT MINIMIZING NOISE
guard should between lines. event that noise does couple diode lines would ideal coupled common mode. That equally lines. Avoid routing diode traces close proximity power supply switching filtering inductors. Avoid running diode traces close parallel high speed digital lines. Diode traces should kept least apart from high speed digital traces. necessary cross high speed digital traces, diode traces high speed digital traces should cross degree angle. ideal place connect LM64's close possible Processor's associated with sense diode. Leakage current between should kept minimum. nano-ampere leakage cause much error diode temperature reading. Keeping printed circuit board clean possible will minimize leakage current. Noise coupling into digital lines greater than mVp-p (typical hysteresis) undershoot less than below GND, prevent successful SMBus communication with LM64. SMBus acknowledge most common symptom, causing unnecessary traffic bus. Although SMBus maximum frequency communication rather (100 max), care still needs taken ensure proper termination within system with multiple parts long printed circuit board traces. lowpass filter with corner frequency about included LM64's SMBCLK input. Additional resistance added series with SMBData SMBCLK lines further help filter noise ringing. Minimize noise coupling keeping digital traces switching power supply areas well ensuring that digital lines containing high speed data communications cross right angles SMBData SMBCLK lines.
20065521
FIGURE Ideal Diode Trace Layout noisy environment, such processor mother board, layout considerations very critical. Noise induced traces running between remote temperature diode sensor LM64 cause temperature conversion errors. Keep mind that signal level LM64 trying measure microvolts. following guidelines should followed: Place power supply bypass capacitor close possible recommended capacitor close possible LM64's pins. Make sure traces capacitor matched. Ideally, LM64 should placed within Processor diode pins with traces being straight, short identical possible. Trace resistance cause much error. This error compensated using Remote Temperature Offset Registers, since value placed these registers will automatically subtracted from added remote temperature reading. Diode traces should surrounded guard ring either side, above below possible. This
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LM64 Remote Diode Temperature Sensor with Control GPIO's
Physical Dimensions
inches (millimeters) unless otherwise noted
24-Lead Leadless Leadframe (LLP) Package Number LQA24A
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critical component component life support device system whose failure perform reasonably expected cause failure life support device system, affect safety effectiveness.
National does assume responsibility circuitry described, circuit patent licenses implied National reserves right time without notice change said circuitry specifications.
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