LM96163 Remote Diode Digital Temperature Sensor with Integrated Fan Control and TruTherm® BJT Transistor Beta Compensation Technology General Description The LM96163 has remote and local temperature sensors with integrated fan control that includes TruTherm BJT transistor beta compensation technology for remote diode sensing. The LM96163 accurately measures: (1) its own temperature and (2) the temperature of a diode-connected transistor, such as a 2N3904, or a thermal diode commonly found on Computer Processors, Graphics Processor Units (GPU) and other ASIC's. The LM96163 has an offset register to correct for errors caused by different non-ideality factors of other thermal diodes. For the latest information contact [email protected]. The LM96163 also features an integrated, pulse-width-modulated (PWM), open-drain fan control output. Fan speed depends on a combination of the remote temperature reading, the lookup table and register settings. The 12-step Lookup Table (LUT) enables the user to program a non-linear fan speed vs. temperature transfer function often used to quiet acoustic fan noise. In addition a fully programmable ramping function has been added to allow smooth transitions between LUT setpoints. Features ■ TruTherm BJT beta compensation technology supports ■ ■ ■ ■ ■ 45nm, 65nm and 90nm Processor remote diodes Factory trimmed for Intel® 45 nm processor thermal diodes Accurately senses diode-connected 2N3904 transistors or thermal diodes on-board large processors or ASIC's Accurately senses its own temperature Integrated PWM fan speed control output supports high resolution at 22.5kHz frequency for 4-pin fans Acoustic fan noise reduction with user-programmable 12step Lookup Table ■ LUT transition fine resolution smoothing function ■ Tachometer input for measuring fan RPM ■ Smart-Tach modes for measuring RPM of fans with pulse- width-modulated power as shown in typical application ALERT output for processor event notification TCRIT output for critical temperature system shutdown Offset register can adjust for a variety of thermal diodes 10-bit plus sign and 11-bit unsigned formats, with 1/8°C resolution Extended resolution to 1/32°C when digital filter enabled Resolves remote diode temperatures up to 255.875°C SMBus 2.0 compatible interface, with TIMEOUT and ARA LLP10 (QFN10) package ■ ■ ■ ■ ■ ■ ■ ■ Key Specifications ■ Remote Temp Accuracy (includes quantization error) LM96163 Temp +25 to +85°C +25 to +85°C -40 to +25°C Diode Temp +55 to +105°C +40 to +125°C +25 to 125°C Max Error ±0.75°C ±1.5°C ±3.0°C ■ Local Temp Accuracy (includes quantization error) LM96163 Temp 25°C to 125°C ■ Supply Voltage ■ Supply Current (0.8Hz Conversion) ±3.0°C (max) +3.0 V to +3.6 V 456 µA (typ) Applications ■ Processor Thermal Management ■ Electronic Test and Office Equipment ■ Industrial Controls Connection Diagrams Top View 30041081 LLP10 (QFN10) TruTherm® is a registered trademark of National Semiconductor Corporation. Intel® is a registered trademark of Intel Corporation. © 2008 National Semiconductor Corporation 300410 www.national.com LM96163 Remote Diode Digital Temperature Sensor with Integrated Fan Control and TruTherm BJT Transistor Beta Compensation Technology June 26, 2008 LM96163 Ordering Information Power-On Defaults Part Description Top Mark Order Number Transport Media NS Package Number On/ 45nm T63C LM96163CISD 1000 units in Tape/Reel SDA10A 110°C On/ 45nm T63C LM96163CISDX 4500 units in Tape/Reel SDA10A 123°C 123°C Off/ 3904 Not Released Preliminary LM96163CISD-1 1000 units in Tape/Reel SDA10A 123°C 123°C Off/ 3904 Not Released Preliminary LM96163CISDX-1 4500 units in Tape/Reel SDA10A HIGH Threshold T_CRIT Threshold TruTherm/ Diode LM96163C 10-pin LLP (QFN) 85°C 110°C LM96163C 10-pin LLP (QFN) 85°C LM96163C 10-pin LLP (QFN) LM96163C 10-pin LLP (QFN) Pin Descriptions Pin Name Input/Output Function and Connection Open-Drain Digital Output Open-Drain Digital Output. Connect to system shutdown. Pin activates when temperature conversion value exceeds programmed limit. Several power-on-default limit values are available. 1 TCRIT 2 VDD Power Supply Input 3 D+ Analog Input Connect to the anode (positive side) of the remote diode. A 100pF capacitor can be connected between pins 3 and 4. 4 D− Analog Input Connect to the cathode (negative side) of the remote diode. A 100pF capacitor can be connected between pins 3 and 4. 5 PWM Open-Drain Digital Output Open-Drain Digital Output. Connect to fan drive circuitry. The power-on default for this pin is low (pin 4 pulled to ground). 6 GND Ground 7 ALERT Open-Drain Digital Output 8 TACH Digital Input 9 SMBDAT Digital Input/ Open-Drain Digital Output 10 SMBCLK Digital Input www.national.com Connect to a low-noise +3.3 ± 0.3 VDC power supply, and bypass to GND with a 0.1 µF ceramic capacitor in parallel with a 100 pF ceramic capacitor. A bulk capacitance of 10 µF needs to be in the vicinity of the LM96163's VDD pin. This is the analog and digital ground return. This pin is an open-drain ALERT output. Tachometer input for measuring fan speed. Note the TACH input is disabled upon power-up and needs to be enabled for use by setting TCHEN bit 2 of Configuration Register 03h. This is the bidirectional SMBus data line. Digital Input. This is the SMBus clock input. 2 LM96163 Simplified Block Diagram 30041082 Typical Application 30041083 3 www.national.com LM96163 Junction Temperature Storage Temperature ESD Susceptibility (Note 4) Human Body Model Machine Model Charged Device Model Absolute Maximum Ratings (Notes 1, 2) Supply Voltage, VDD Voltage on SMBDAT, SMBCLK, ALERT, TCRIT, TACH, PWM Pins Voltage on Other Pins Input Current, D− Pin (Note 3) Input Current at All Other Pins (Note 3) Package Input Current (Note 3) SMBDAT, ALERT, PWM pins Output Sink Current Package Power Dissipation −0.3 V to 6.0 V −0.5 V to 6.0 V −0.3 V to (VDD + 0. 3 V) ±1 mA 125°C −65°C to +150°C 2500 V 250 V 1000 V Operating Ratings (Notes 1, 2) TMIN ≤ TA ≤ TMAX Specified Temperature Range 5 mA –40°C ≤ TA ≤ +85°C LM96163CISD Remote Diode Temperature Range 30 mA Supply Voltage Range (VDD) -40°C ≤ TD ≤ +140°C +3.0 V to +3.6 V Soldering process must comply with National Semiconductor's Reflow Temperature Profile specifications. Refer to www.national.com/packaging. (Note 6) 10 mA (Note 5) DC Electrical Characteristics TEMPERATURE-TO-DIGITAL CONVERTER CHARACTERISTICS The following specifications apply for VDD = 3.0 VDC to 3.6 VDC, and all analog source impedance RS = 50Ω unless otherwise specified in the conditions. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = +25°C; unless otherwise noted. TD is the junction temperature of the remote thermal diode. TJ is the junction temperature of the LM96163. Parameter Limits (Note 9) Units (Limits) TD = +50°C to +105°C TD = Remote Diode Junction Temperature ±0.75 °C (max) TD = +40°C to +125°C ±1.5 °C (max) ±3.0 °C (max) ±3 °C (max) ±6 °C (max) Conditions Temperature Error Using the Remote Thermal Diode of an Intel Processor on TA = +25°C to +85°C 45nm (Note 8). For other processors e-mail [email protected] to obtain T = +25°C to +85°C A the latest data. TA = -40°C to +25°C Temperature Error Using the Local Diode (Note 10) Typical (Note 7) TD = +25°C to +125°C TA = +25°C to +125°C ±1 TA = -40°C to +25°C 11 Remote Diode Resolution Local Diode Resolution 0.125 °C 8 Bits 1 °C Conversion Time, All Temperature Channels Fastest Setting 38.3 D− Source Voltage 0.4 (VD+ − VD−) = +0.65 V; High Current Diode Source Current Low Current Bits 172 41.1 ms (max) 225 µA (max) 100 µA (min) V 10.75 Diode Source Current Ratio µA 16 Operating Electrical Characteristics Symbol VPOR IS Conditions Parameter Typ (Note 7) Power-On-Reset Threshold Voltage Supply Current (Note 11) www.national.com Limits (Note 9) Units 2.8 V (max) 1.6 V (min) SMBus Inactive, 13 Hz Conversion Rate 1.1 1.6 mA (max) SMBus Inactive, 0.8 Hz Conversion Rate 456 825 µA (max) STANDBY Mode 416 700 µA (max) 4 The following specifications apply for VDD = 3.0 VDC to 3.6 VDC, and all analog source impedance RS = 50Ω unless otherwise specified in the conditions. Boldface limits apply for TA = TMIN to TMAX; all other limits TA= +25°C. Limits (Note 9) Units (Limit) Fan Count Accuracy ±7 % (max) Fan Full-Scale Count 65535 (max) Symbol Parameter Conditions Typical (Note 7) TACHOMETER ACCURACY Fan Counter Clock Frequency 90 kHz Fan Count Update Frequency 1.0 Hz FAN PWM OUTPUT Frequency Accuracy % (max) ±7 Digital Electrical Characteristics Symbol Parameter Conditions Typical (Note 7) Limits (Note 9) Units (Limit) VIH Logical High Input Voltage 2.1 V (min) VIL Logical Low Input Voltage 0.8 V (max) IIH Logical High Input Current VIN = VDD 0.005 +10 µA (max) IIL Logical Low Input Current VIN = GND −0.005 −10 µA (max) CIN Digital Input Capacitance VOL ALERT, TCRIT and PWM Output IOUT = 6 mA Saturation Voltage 0.4 V (max) COUT 5 Digital Output Capacitance pF 5 pF SMBus Logical Electrical Characteristics The following specifications apply for VDD = 3.0 VDC to 3.6 VDC, and all analog source impedance RS = 50Ω unless otherwise specified in the conditions. Boldface limits apply for TA = TMIN to TMAX; all other limits TA = +25°C. Symbol Parameter Conditions Typical (Note 7) Limits (Note 9) Units (Limit) 0.4 V (max) 10 µA (max) SMBDAT OPEN-DRAIN OUTPUT VOL Logic Low Level Output Voltage IOL = 4 mA IOH High Level Output Current VOUT = VDD COUT Digital Output Capacitance 0.03 5 pF SMBDAT, SMBCLK INPUTS VIH Logical High Input Voltage VIL Logical Low Input Voltage VHYST CIN Logic Input Hysteresis Voltage Digital Input Capacitance 5 2.1 V (min) 0.8 V (max) 320 mV 5 pF www.national.com LM96163 AC Electrical Characteristics LM96163 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 ≤ TA ≤ TMAX; all other limits TA = TJ = +25°C, unless otherwise noted. The switching characteristics of the LM96163 fully meet or exceed the published specifications of the SMBus version 2.0. The following parameters are the timing relationships between SMBCLK and SMBDAT signals related to the LM96163. They adhere to but are not necessarily the same as the SMBus bus specifications. Symbol Parameter Conditions Limits (Note 9) Units (Limit) 10 100 kHz (min) kHz (max) fSMB SMBus Clock Frequency tLOW SMBus Clock Low Time From VIN(0) max to VIN(0) max 4.7 µs (min) tHIGH SMBus Clock High Time From VIN(1) min to VIN(1) min 4.0 50 µs (min) µs (max) tR SMBus Rise Time (Note 12) 1 µs (max) tF SMBus Fall Time (Note 13) 0.3 µs (max) tOF Output Fall Time CL = 400 pF, IO = 3 mA 250 ns (max) tTIMEOUT SMBDAT and SMBCLK Time Low for Reset of Serial Interface See (Note 14) 25 35 ms (min) ms (max) tSU:DAT Data In Setup Time to SMBCLK High 250 ns (min) tHD:DAT Data Out Hold Time after SMBCLK Low 300 1075 ns (min) ns (max) tHD:STA Hold Time after (Repeated) Start Condition. After this period the first clock is generated. 4.0 µs (min) tSU:STO Stop Condition SMBCLK High to SMBDAT Low (Stop Condition Setup) 100 ns (min) tSU:STA SMBus Repeated Start-Condition Setup Time, SMBCLK High to SMBDAT Low 4.7 µs (min) tBUF SMBus Free Time between Stop and Start Conditions 4.7 µs (min) 30041004 SMBus Timing Diagram for SMBCLK and SMBDAT Signals Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is functional, but do not guarantee performance limits. For guaranteed specifications and test conditions, see the Electrical Characteristics. The guaranteed specifications apply only for the test conditions listed. Some performance characteristics may degrade when the device is not operated under the listed test conditions. Note 2: All voltages are measured with respect to GND, unless otherwise noted. Note 3: When the input voltage (VIN) at any pin exceeds the power supplies (VIN < GND or VIN > V+), the current at that pin should be limited to 5 mA. Parasitic components and/or ESD protection circuitry are shown below for the LM96163's pins. Care should be taken not to forward bias the parasitic diode, D2, present on pins D+ and D−. Doing so by more than 50 mV may corrupt temperature measurements. www.national.com 6 Label Circuit 1 TCRIT A 2 VDD B 3 D+ B 4 D- B 5 PWM A 6 GND B 7 ALERT A 8 TACH A 9 SMBDAT A 10 SMBCLK A LM96163 Pin # Pin ESD Protection Structure Circuits CIRCUIT A CIRCUIT B Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pin. Charged Device Model (CDM) simulates a pin slowly acquiring charge (such as from a device sliding down the feeder in an automated assembler) then rapidly being discharged. Note 5: Thermal resistance junction to ambient when attached to a 2 layer 4"x3" printed circuit board with copper thickness of 2oz. as described in JEDEC specification EIA/JESD51-3 is 137°C/W. Thermal resistance junction to ambient when attached to a 4 layer 4"x3" printed circuit board with copper thickness 2oz./ 1oz./1oz/2oz. and 4 thermal vias as described in JEDEC specification EIA/JESD51-7 is 40.3°C/W. Note 6: Reflow temperature profiles are different for packages containing lead (Pb) than for those that do not. Note 7: “Typicals” are at TA = 25°C and represent most likely parametric norm. They are to be used as general reference values not for critical design calculations. Note 8: The accuracy of the LM96163 is guaranteed when using a typical thermal diode of an Intel processor on a 45 nm process, as selected in the Remote Diode Model Select register. See typical performance curve for performance with Intel processor on 65 nm or 90 nm process. Note 9: Limits are guaranteed to National's AOQL (Average Outgoing Quality Level). Note 10: 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 LM96163 and the thermal resistance. See (Note 5) for the thermal resistance to be used in the self-heating calculation. Note 11: The supply current will not increase substantially with an SMBus transaction. Note 12: The output rise time is measured from (VIL max - 0.15 V) to (VIH min + 0.15 V). Note 13: The output fall time is measured from (VIH min + 0.15 V) to (VIL max - 0.15 V). Note 14: Holding the SMBDAT and/or SMBCLK lines Low for a time interval greater than tTIMEOUT will reset the LM96163’s SMBus state machine, therefore setting SMBDAT and SMBCLK pins to a high impedance state. 7 www.national.com LM96163 Typical Performance Characteristics Intel Processor on 45nm, 65nm, or 90 nm Process Thermal Diode Performance Comparison Remote Temperature Reading Sensitivity to Thermal Diode Filter Capacitance, TruTherm Enabled 30041050 30041051 Remote Temperature Reading Sensitivity to Thermal Diode Filter Capacitance, TruTherm Disabled Thermal Diode Capacitor or PCB Leakage Current Effect on Remote Diode Temperature Reading 30041053 30041022 Conversion Rate Effect on Average Power Supply Current 30041006 www.national.com 8 The LM96163 Remote Diode Temperature Sensor with Integrated Fan Control incorporates a ΔVBE-based temperature sensor utilizing a Local or Remote diode and a 10-bit plus sign ΔΣ ADC (Delta-Sigma Analog-to-Digital Converter). The LM96163 includes TruTherm BJT beta compensation technology that allows precision temperature sensing of remote diodes found in sub-micron processes. The pulse-width modulated (PWM) open-drain output, with a pull-up resistor, is driven by a 12-point temperature to duty cycle look-up table (LUT) and can directly drive a PWM input of a 4-pin fan in order to modulate it's speed enabling optimum system acoustic performance. The LM96163 LUT fan control algorithm also includes a smoothing function that allows the PWM duty cycle to gradually change over a programmed time interval when switching from one level to the next in the LUT. When running at a frequency of 22.5kHz the PWM output resolution is 0.39%. The LM96163 includes a TACH input that can measure the speed of a fan using the pulses from a 3 or 4 pin fan’s tachometer output. The LM96163 includes a smart-tach measurement mode to accommodate the corrupted tachometer pulses when using switching transistor power drive to modulate the fan speed. The LM96163 has an ALERT open-drain output that will be pulled low when the measured temperature exceeds certain programmed limits when enabled. Details are contained in the sections below. The LM96163's two-wire interface is compatible with the SMBus Specification 2.0 . For more information the reader is directed to www.smbus.org. In the LM96163 digital comparators are used to compare the measured Local Temperature (LT) to the Local High Setpoint user-programmable temperature limit register. The measured Remote Temperature (RT) is digitally compared to the Remote High Setpoint (RHS), the Remote Low Setpoint (RLS), and the Remote T_CRIT Setpoint (RCS) user-programmable temperature limits. An ALERT output will occur when the measured temperature is: (1) higher than either the High Setpoint or the T_CRIT Setpoint, or (2) lower than the Low Setpoint. The ALERT Mask register allows the user to prevent the generation of these ALERT outputs. A TCRIT output will occur when the measured temperature is higher than the T_CRIT Setpoint. The TCRIT function and the look-up table temperature hysteresis can be set separately. The hysteresis value associated with the TCRIT output is set in the Remote T_CRIT Hysteresis Register. The value associated with the look-up table function is set in the Lookup Table Hysteresis Register. The LM96163 may be placed in a low power Standby mode by setting the Standby bit found in the Configuration Register. In the Standby mode continuous conversions are stopped. In Standby mode the user may choose to allow the PWM output signal to continue, or not, by programming the PWM Disable in Standby bit in the Configuration Register. 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. A digital filter may be invoked for remote temperature readings that increases the resolution from 11bits to 13-bits. The temperature readings are also available in an unsigned format allowing resolution above 127°C. Two Remote Temperature Offset (RTO) Registers: High Byte and Low Byte (RTOHB and RTOLB) may be used to correct the temperature readings by adding or subtracting a fixed value based on a different non-ideality factor and series resistance 1.2 ALERT and TCRIT OUTPUTS In this section we will address the ALERT and TCRIT activelow open-drain output functions. When the ALERT Mask bit in the Configuration register is written as zero the ALERT interrupts are enabled. The LM96163's ALERT pin is versatile and can produce three different methods of use to best serve the system designer: (1) as a temperature comparator (2) as a temperature-based interrupt flag, and (3) 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 LM96163. The remote temperature (RT) reading is associated with a T_CRIT Setpoint Register, and both local and remote temperature (LT and RT) readings are associated with a HIGH setpoint register (LHS and RHS). The RT is also associated with a LOW setpoint register (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 ALERT Status Register is set. If the ALERT mask bit is low, any bit set in the ALERT Status Register, with the exception of Busy or RDFA, will cause the ALERT output to be pulled low. Any temperature conversion that is out of the limits defined in the temperature setpoint registers will trigger an ALERT. Additionally, the ALERT Mask Bit must be cleared to trigger an ALERT in all modes. The format of the Remote High limit and T_CRIT limit comparison is programmable. The USF bit found in the Enhanced Configuration register controls whether comparisons use a signed or unsigned format. The temperature format used for Remote High and T_CRIT limit comparisons is +255.875 °C to -256 °C. The three different ALERT modes and TCRIT function will be discussed in the following sections. 1.2.1 ALERT Output as a Temperature Comparator When the LM96163 is used in a system in which does not require temperature-based interrupts, the ALERT output could be used as a temperature comparator. In this mode, once the condition that triggered the ALERT to go low is no longer present, the ALERT is negated (Figure 1). 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, the Comparator Mode bit in the Remote Diode Temperature Filter and Comparator Mode Register must be asserted. This is not the power-on default state. 9 www.national.com LM96163 of the thermal diode if different from the thermal diode found in the Intel processors on 45 nm process. See section 3.4 DIODE NON-IDEALITY. 1.0 Functional Description LM96163 30041008 30041007 FIGURE 1. ALERT Output as Temperature Comparator Response Diagram FIGURE 2. ALERT Output as an Interrupt Temperature Response Diagram 1.2.2 ALERT Output as an Interrupt The LM96163'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 desirable for the interrupt flag to repeatedly trigger during or before the interrupt service routine has been completed. Under this method of operation, during the read of the ALERT Status Register the LM96163 will set the ALERT Mask bit in the Configuration Register if any bit in the ALERT Status Register is set, with the exception of Busy and RDFA. This prevents further ALERT triggering until the master has reset the ALERT Mask bit, at the end of the interrupt service routine. The ALERT Status Register bits are cleared only upon a read command from the master (see Figure 2 ) 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, the Comparator Mode bit in the Remote Diode Temperature Filter and Comparator Mode Register 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 an interrupt flag: 1. Master senses ALERT low. 2. Master reads the LM96163 ALERT Status Register to determine what caused the ALERT. 3. LM96163 clears ALERT Status Register, resets the ALERT HIGH and sets the ALERT Mask bit 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 bit in the Configuration Register. 1.2.3 ALERT Output as an SMBus ALERT An SMBus alert line is created when the ALERT output is connected to: (1) one or more ALERT outputs of other SMBus compatible devices, and (2) to a master. Under this implementation, the LM96163'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 determining which part generated an interrupt and to service that interrupt. The SMBus alert line is connected to the open-drain ports of all devices on the bus, thereby AND'ing them together. The ARA method allows the SMBus master, with one command, to identify which part is pulling the SMBus alert line LOW. It also prevents the part from pulling the line 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: (1) send their address to the master and (2) release the SMBus alert line after acknowledgement of their address. The SMBus Specifications 1.1 and 2.0 state that in response to and ARA (Alert Response Address) “after acknowledging the slave address the device must disengage its ALERT pulldown”. Furthermore, “if the host still sees ALERT low when the message transfer is complete, it knows to read the ARA again.” This SMBus “disengaging ALERT requirement prevents locking up the SMBus alert line. Competitive parts may address the “disengaging of ALERT” differently than the LM96163 or not at all. SMBus systems that implement the ARA protocol as suggested for the LM96163 will be fully compatible with all competitive parts. The LM96163 fulfills “disengaging of ALERT” by setting the ALERT Mask Bit in the Configuration Register after sending out its address in response to an ARA and releasing the 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 ALERT Status Register, 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. www.national.com 10 Alerting Device(s) send their address. While transmitting their address, alerting devices sense whether their address has been transmitted correctly. (The LM96163 will reset its ALERT output and set the ALERT Mask bit once its complete address has been transmitted successfully.) 5. Master/slave NoACK 6. Master sends STOP 7. Master attends to conditions that caused the ALERT to be triggered. The ALERT Status Register is read and fan started, setpoints adjusted, etc. 8. Master resets the ALERT Mask bit in the Configuration Register. The ARA, 000 1100, is a general call address. No device should ever be assigned to this address. The ALERT Configuration bit in the Remote Diode Temperature Filter and Comparator Mode Register must be set low in order for the LM96163 to respond to the ARA command. The ALERT output can be disabled by setting the ALERT Mask bit in the Configuration Register. The power-on default is to have the ALERT Mask bit and the ALERT Configuration bit low. 1.3 SMBus INTERFACE Since the LM96163 operates as a slave on the SMBus the SMBCLK line is an input and the SMBDAT line is bidirectional. The LM96163 never drives the SMBCLK line and it does not support clock stretching. According to SMBus specifications, the LM96163 has a 7-bit slave address. All bits, A6 through A0, are internally programmed and cannot be changed by software or hardware. The complete slave address is: A6 A5 A4 A3 A2 A1 A0 1 0 0 1 1 0 0 1.4 POWER-ON RESET (POR) DEFAULT STATES For information on the POR default states see Section 2.2 LM96163 Register Map in Functional Order. 1.5 TEMPERATURE DATA FORMAT Temperature data can only be read from the Local and Remote Temperature value registers. The data format for all temperature values is left justified 16-bit word available in two 8-bit registers. Unused bits will always report "0". All temperature data is clamped and will not roll over when a temperature exceeds full-scale value. Remote temperature and remote high setpoint temperature data can be represented by an 11-bit, two's complement word or unsigned binary word with an LSb (Least Significant Bit) equal to 0.125°C. 11-bit, 2's complement (10-bit plus sign) Temperature 30041009 FIGURE 3. ALERT Output as an SMBus ALERT Temperature Response Diagram 1.2.4 TCRIT Function The TCRIT output will be activated whenever the RCRIT bit in the ALERT Status register is set. This occurs whenever the remote temperature exceeds the value set by the Remote T_CRIT Setpoint register. There is a hysteresis associated with the T_CRIT Setpoint that is set by the value in the Remote T_CRIT Hysteresis register. The RCRIT bit will be reset when the remote temperature equals or is less than the value defined by Remote T_CRIT Setpoint minus T_CRIT Hysteresis. The resolution of the comparison is 1 °C. For example if T_CRIT = 110 °C and THYST = 5 °C the TCRIT output will activate when the temperature reading is 111 °C and deactivate when the temperature reading is 105 °C. When the LM96163 powers up the T_CRIT limit is locked to the default value. It may be changed after the T_CRIT Limit Override bit (TCRITOV) bit, found in the Configuration Register, is set. The format of the Remote T_CRIT setpoint register is controlled by the USF bit found in the Enhanced configuration register. The temperature reading format used for the T_CRIT comparisons is +255 °C to -256°C. Digital Data 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 11-bit, unsigned binary Temperature Digital Data Binary Hex +255.875°C 1111 1111 1110 0000 FFE0h +255°C 1111 1111 0000 0000 FF00h +201°C 1100 1001 0000 0000 C900h +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 When the digital filter is enabled on the remote channel, temperature data is represented by a 13-bit unsigned binary or 12-bit plus sign (two's complement) word with an LSb equal to 0.03125°C. 11 www.national.com LM96163 4. LM96163 1.6 OPEN-DRAIN OUTPUTS The SMBDAT, ALERT, TCRIT and PWM outputs are opendrain 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 an internal source, typically through a pull-up resistor. Choice of resistor value depends on several factors but, in general, the value should be as high as possible consistent with reliable operation. This will lower the power dissipation of the LM96163 and avoid temperature errors caused by selfheating of the device. The maximum value of the pull-up resistor to provide the 2.1 V high level is 88.7 kΩ. 13-bit, 2's complement (12-bit plus sign) Temperature Digital Data Binary Hex +125°C 0111 1101 0000 0000 7D00h +25°C 0001 1001 0000 0000 1900h +1°C 0000 0001 0000 0000 0100h +0.03125°C 0000 0000 0000 1000 0008h 0°C 0000 0000 0000 0000 0000h −0.03125°C 1111 1111 1111 1000 FFF8h −1°C 1111 1111 0000 0000 FF00h −25°C 1110 0111 0000 0000 E700h −55°C 1100 1001 0000 0000 C900h 1.7 DIODE FAULT DETECTION The LM96163 is equipped with operational circuitry designed to detect remote diode fault conditions: • D+ shorted to VDD • D+ open or floating • D+ shorted to GND. In the event that the D+ pin is grounded the Remote Temperature reading is forced to –128.000 °C if signed format is read and 0 °C if unsigned format is read. When the D+ pin is detected as shorted to VDD or floating, the Remote Temperature reading is forced to +127.000 °C if signed format is read and +255.000 °C is unsigned format is read. In addition, the ALERT Status register bit RDFA is set. Setting of the RDFA bit will not cause ALERT or TCRIT to activate. Under fault conditions remote diode setpoint comparisons will use these forced temperature values therefore other bits in the ALERT Status Register may be set thus activating the ALERT or TCRIT outputs unless these bits are masked. The function of the ALERT and TCRIT is fully described in Section 1.2 ALERT and TCRIT OUTPUTS. 13-bit, unsigned binary Temperature Digital Data Binary Hex +255.875°C 1111 1111 1110 0000 FFE0h +255°C 1111 1111 0000 0000 FF00h +201°C 1100 1001 0000 0000 C900h +125°C 0111 1101 0000 0000 7D00h +25°C 0001 1001 0000 0000 1900h +1°C 0000 0001 0000 0000 0100h +0.03125°C 0000 0000 0000 1000 0008h 0°C 0000 0000 0000 0000 0000h Local Temperature and Remote T_CRIT setpoint data is represented by an 8-bit, two's complement, word with an LSb equal to 1°C. 1.8 COMMUNICATING WITH THE LM96163 Each data register in the LM96163 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 A Write to the LM96163 is comprised of an address byte and a command byte. A write to any register requires one data byte. Reading the LM96163 Registers can take place after the requisite register setup sequence takes place. See Section 2.1.1 LM96163 Required Initial Fan Control Register Sequence. The data byte has the Most Significant Bit (MSB) first. At the end of a read, the LM96163 can accept either Acknowledge or No-Acknowledge from the Master. Note that the No-Acknowledge is typically used as a signal for the slave indicating that the Master has read its last byte. 8-bit, 2's complement (7-bit plus sign) Temperature Digital Data 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 Remote T_CRIT setpoint data can also be represented by an 8-bit, unsigned, word with an LSb equal to 1°C. 8-bit, unsigned binary Temperature Digital Data Binary Hex +255°C 1111 1111 FFh +150°C 1001 0110 96h +125°C 0111 1101 7Dh +25°C 0001 1001 19h +1°C 0000 0001 01h 0°C 0000 0000 00h www.national.com 12 RDTF[1:0] Filter Setting 0 0 No Filter 0 1 Filter (equivalent to Level 2 filter of the LM86/LM89) 1 0 Reserved 1 1 Enhanced Filter (Filter with transient noise clipping) 30041011 a) Seventeen and fifty degree step response 30041052 b) Impulse response with input transients less than 4°C 30041024 c) Impulse response with input transients great than 4°C FIGURE 4. Filter Impulse and Step Response Curves 13 www.national.com LM96163 Figure 4 describes the filter output in response to a step input and an impulse input. 1.9 DIGITAL FILTER In order to suppress erroneous remote temperature readings due to noise as well as increase the resolution of the temperature, the LM96163 incorporates a digital filter for remote temperature readings. The filter is accessed in the Remote Diode Temperature Filter and Comparator Mode Register. The filter can be set according to the following table. LM96163 1.11 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 data returns to standby. This is not a data register. A write operation 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. 1.12 SERIAL INTERFACE RESET In the event that the SMBus Master is reset while the LM96163 is transmitting on the SMBDAT line, the LM96163 must be returned to a known state in the communication protocol. This may be done in one of two ways: 1. When SMBDAT is Low, the LM96163 SMBus state machine resets to the SMBus idle state if either SMBDAT or SMBCLK are held Low for more than 35 ms (tTIMEOUT). Devices are to timeout when either the SMBCLK or SMBDAT lines are held Low for 25 ms – 35 ms. Therefore, to insure a timeout of devices on the bus, either the SMBCLK or the SMBDAT line must be held Low for at least 35 ms. 2. With both SMBDAT and SMBCLK High, the master can initiate an SMBus start condition with a High to Low transition on the SMBDAT line. The LM96163 will respond properly to an SMBus start condition at any point during the communication. After the start the LM96163 will expect an SMBus Address address byte. 30041012 FIGURE 5. Digital Filter Response in a typical Intel processor on a 65 nm or 90 nm process. The filter curves were purposely offset for clarity. Figure 5 shows the filter in use in a typical Intel processor on a 65/90 nm process system. Note that the two curves have been purposely offset for clarity. Inserting the filter does not induce an offset as shown. 1.10 FAULT QUEUE The LM96163 incorporates a Fault Queue to suppress erroneous ALERT triggering . The Fault Queue prevents false triggering by requiring three consecutive out-of-limit HIGH or LOW temperature readings. See Figure 6. The Fault Queue defaults to OFF upon power-up and may be activated by setting the RDTS Fault Queue bit in the Configuration Register to a 1. 30041013 FIGURE 6. Fault Queue Temperature Response Diagram www.national.com 14 The following pages include: Section 2.1, a Register Map in Hexadecimal Order, which shows a summary of all registers and their bit assignments, Section 2.2, a Register Map in Functional Order, and Section 2.3, a detailed explanation of each register. Do not address the unused or manufacturer’s test registers. 2.1 LM96163 REGISTER MAP IN HEXADECIMAL ORDER The following is a Register Map grouped in hexadecimal address order. Some address locations have been left blank to maintain compatibility with LM86, LM63 and LM64. Addresses in parenthesis are mirrors of “Same As” address for backwards compatibility with some older software. Reading or writing either address will access the same 8-bit register. Register 0x[HEX] R/ W POR Val 00 R – 01 R Register Name DATA BITS D7 D6 D5 D4 D3 D2 D1 D0 Local Temperature (Signed MSB) LT7 SIGN LT6 64 LT5 32 LT4 16 LT3 8 LT2 4 LT1 2 LT0 1 – Rmt Temp MSB RT12 SIGN RT11 64 RT10 32 RT9 16 RT8 8 RT7 4 RT6 2 RT5 1 02 R – ALERT Status BUSY LHIGH 0 RHIGH RLOW RDFA RCRIT TACH 03 R/ W 00 Configuration ALTMSK STBY PWMDIS 0 0 TCHEN TCRITO V FLTQUE 04 R/ W 08 Conversion Rate 0 0 0 0 CONV3 CONV2 CONV1 CONV0 05 R/ W 46 Local High Setpoint LHS7 SIGN LHS6 64 LHS5 32 LHS4 16 LHS3 8 LHS2 4 LHS1 2 LHS0 1 07 R/ W 55 Rmt High Setpoint MSB RHS10 SIGN /128 RHS9 64 RHS8 32 RHS7 16 RHS6 8 RHS5 4 RHS4 2 RHS3 1 08 R/ W 00 Rmt Low Setpoint MSB RLS10 SIGN RLS9 64 RLS8 32 RLS7 16 RLS6 8 RLS5 4 RLS4 2 RLS3 1 (09) R/ W 00 Same as 03 ALTMSK STBY PWMDIS 0 0 TCHEN TCRITO V FLTQUE (0A) R/ W 08 Same as 04 0 0 0 0 CONV3 CONV2 CONV1 CONV0 (0B) R/ W 46 Same as 05 LHS7 SIGN LHS6 64 LHS5 32 LHS4 16 LHS3 8 LHS2 4 LHS1 2 LHS0 1 06 [Reserved] Not Used 0C R 00 [Reserved] (0D) R/ W 55 Same as 07 RHS10 SIGN /128 RHS9 64 RHS8 32 RHS7 16 RHS6 8 RHS5 4 RHS4 2 RHS3 1 (0E) R/ W 00 Same as 08 RLS10 SIGN RLS9 64 RLS8 32 RLS7 16 RLS6 8 RLS5 4 RLS4 2 RLS3 1 0F W – One Shot 10 R – Rmt Temp LSB (Dig Filter On or Reg 45h STFBE bit set) Not Used Write Only. Write command triggers one temperature conversion cycle. RT4 ½ RT3 ¼ RT2 ⅛ Rmt Temp LSB (Dig Filter Off) RT1 1/16 RT0 1/32 0 0 0 0 0 11 R/ W 00 Rmt Temp Offset MSB RTO10 SIGN RTO9 64 RTO8 32 RTO7 16 RTO7 8 RTO5 4 RTO4 2 RTO3 1 12 R/ W 00 Rmt Temp Offset LSB RTO2 ½ RTO1 ¼ RTO0 ⅛ 0 0 0 0 0 13 R/ W 00 Rmt High Setpoint LSB RHS2 ½ RHS1 ¼ RHS0 ⅛ 0 0 0 0 0 15 www.national.com LM96163 2.0 LM96163 Registers LM96163 Register 0x[HEX] R/ W POR Val 14 R/ W 00 Rmt Low Setpoint LSB 15 R 00 [Reserved] 16 R/ W A4 ALERT Mask Register Name 17-18 R 00 [Reserved] 19 R/ W 6E Rmt T_CRIT Setpoint 1A–20 R 00 [Reserved] 21 R/ W 0A Rmt T_CRIT Hysteresis DATA BITS D7 D6 D5 D4 D3 D2 D1 D0 RLS2 ½ RLS1 ¼ RLS0 ⅛ 0 0 0 0 0 1 RTAM TCHAM RCS2 4 RCS1 2 RCS0 1 RTH2 4 RTH1 2 RTH0 1 Not Used 1 LHAM 1 RHAM RCS7 SIGN /128 RCS6 64 RCS5 32 RCS4 16 RLAM Not Used RCS3 8 Not Used RTH7 0 RTH6 64 RTH5 32 RTH4 16 RTH3 8 22–2F R 00 [Reserved] 30 R/ W 02 Remote Diode TruTherm Enable 0 0 0 0 0 0 RDTE 0 31 R – Rmt Temp U-S MSB RTU12 128 RTU11 64 RTU10 32 RTU9 16 RTU8 8 RTU7 4 RTU6 2 RTU5 1 32 R – Rmt Temp U-S LSB Dig Filter On RTU4 ½ RTU3 ¼ RTU2 ⅛ RTU1 1/16 RTU0 1/32 0 0 0 0 0 0 0 0 RRS0 PSRR Not Used Rmt Temp U-S LSB Dig Filter Off 33 R - POR Status 34–44 R 00 [Reserved] 45 R/ W 00 Enhanced Config 0 STFBE LRES PHR USF RRS1 46 R – Tach Count LSB TAC5 TAC4 TAC3 TAC2 TAC1 TAC0 47 R – Tach Count MSB TAC13 TAC12 TAC11 TAC10 TAC9 TAC8 48 R/ W FF Tach Limit LSB TACL5 TACL4 TACL3 TACL2 TACL1 TACL0 49 R/ W FF Tach Limit MSB TACL13 TACL12 TACL11 TACL10 TACL9 TACL8 TACL7 TACL6 4A R/ W 20 PWM and RPM Config 0 0 PWPGM PWOP PWCKSL 0 TACH1 TACH0 4B R/ W 3F Fan Spin-Up Config 0 0 SPINUP SPNDTY SPNDTY SPNTIM SPNTIM1 SPNTIM0 1 0 2 4C R/ W 00 PWM Value 4D R/ W 17 PWM Frequency 0 0 0 PWMF4 PWMF3 PWMF2 PWMF1 PWMF0 4E R/ W 00 Lookup Table Temp Offset 0 0 TO5 32 TO4 16 TO3 8 TO2 4 TO1 2 TO0 1 4F R/ W 04 Lookup Table Hysteresis 0 0 0 Lookup Table Lookup Table of up to 12 PWM (3F) and Temp Pairs in 8-bit Registers (7F) 50–67 R/ 3F, 7F W 68–BE R 00 [Reserved] BF R/ W 00 Rmt Diode Temp Filter NR 0 0 0 0 Not Used TEDGE1 TEDGE0 TAC7 TAC6 Not Used Not Used 0 - HPWVAL HPWVAL PWVAL5 PWVAL4 PWVAL3 PWVAL2 PWVAL1 PWVAL0 7 6 LOOKH4 LOOKH3 LOOKH2 LOOKH1 LOOKH0 16 8 4 2 1 Not Used 0 0 0 0 0 RDTF1 RDTF0 ALT/CMP C0–FD R 00 [Reserved] FE R 01 Manufacturer’s ID 0 0 0 0 0 0 0 1 FF R 49 Step/Die Rev. ID 0 1 0 0 1 0 0 1 www.national.com Not Used 16 The following is a Register Map grouped in Functional Order. Some address locations have been left blank to maintain compatibility with LM86. Addresses in parenthesis are mirrors of named address. Reading or writing either address will access the same 8-bit register. The Fan Control and Configuration Registers are listed first, as there is a required order to setup these registers first and then setup the others. The detailed explanations of each register will follow the order shown below. POR = Power-On-Reset. Register [HEX] Register Name Read/Write POR Default [HEX] FAN CONTROL REGISTERS 45 Enhanced Configuration R/W 00 4A PWM and RPM Configuration R/W 20 4B Fan Spin-Up Configuration R/W 3F 4D PWM Frequency R/W 17 Read Only (R/W if Override Bit is Set) 00 00 4C PWM Value 4E Lookup Table Temperature Offset R/W 4F Lookup Table Hysteresis Temperature R/W 04 Lookup Table R/W See Table R/W 00 50–67 CONFIGURATION REGISTER 03 (09) Configuration TACHOMETER COUNT AND LIMIT REGISTERS 46 Tach Count LSB Read Only N/A 47 Tach Count MSB Read Only N/A 48 Tach Limit LSB R/W FF 49 Tach Limit MSB R/W FF LOCAL TEMPERATURE AND LOCAL SETPOINT REGISTERS 00 Local Temperature Read Only N/A 05 (0B) Local High Setpoint R/W 46 (70°) REMOTE DIODE TEMPERATURE AND SETPOINT REGISTERS 01 Remote Temperature Signed MSB Read Only N/A 10 Remote Temperature Signed LSB Read Only N/A 31 Remote Temperature Unsigned MSB Read Only N/A 32 Remote Temperature Unsigned LSB Read Only N/A 11 Remote Temperature Offset MSB R/W 00 12 Remote Temperature Offset LSB R/W 00 07 (0D) Remote High Setpoint MSB R/W 55 (85°C) 13 Remote High Setpoint LSB R/W 00 08 (0E) Remote Low Setpoint MSB R/W 00 (0°C) 14 Remote Low Setpoint LSB R/W 00 19 Remote T_CRIT Setpoint R/W 6E (110°C) 21 Remote T_CRIT Hyst R/W 0A (10°C) 30 Remote Diode TruTherm Enable R/W 02 BF Remote Diode Temperature Filter and Comparator Mode R/W 00 R/W 08 Write Only N/A CONVERSION AND ONE-SHOT REGISTERS 04 (0A) 0F Conversion Rate One-Shot STATUS AND MASK REGISTERS 02 ALERT Status Read Only N/A 16 ALERT Mask R/W A4 33 Power On Reset Status Read Only N/A Read Only 01 ID AND TEST REGISTERS FE Manufacturer ID 17 www.national.com LM96163 2.2 LM96163 REGISTER MAP IN FUNCTIONAL ORDER LM96163 Register [HEX] FF Register Name Stepping/Die Rev. ID Read/Write POR Default [HEX] Read Only 49 [RESERVED] REGISTERS—NOT USED 06 Not Used N/A N/A 0C Not Used N/A N/A 15 Not Used N/A N/A 17-18 Not Used N/A N/A 1A–20 Not Used N/A N/A 22–29 Not Used N/A N/A 34–44 Not Used N/A N/A 68–BE Not Used N/A N/A C0–FD Not Used N/A N/A 2.3 LM96163 REQUIRED INITIAL FAN CONTROL REGISTER SEQUENCE Important! The BIOS or firmware must follow the sequence below to configure the following Fan Registers for the LM96163 before using any of the Fan or Tachometer or PWM registers: Step [Register]HEX and Setup Instructions 1 After power up check to make sure that the Not Ready bit is cleared in the POR Status register [33] bit 7. 2 Enable or disable Remote Diode TruTherm mode, [30] bit 1. 3 [4A] Write bits 0 and 1; 3 and 4. This includes tach settings if used, PWM internal clock select (1.4 kHz or 360 kHz) and PWM Output Polarity. 4 [4B] Write bits 0 through 5 to program the spin-up settings. 5 [4D] Write bits 0 through 4 to set the frequency settings. This works with the PWM internal clock select. If 22.5 kHz is selected then enhanced fan control functions such as Lookup Table transition smoothing with extended PWM duty cycle resolution is available and should be setup [45]. 6 Choose, then write, only one of the following: A. [4F–67] the Lookup Table and [4E] the Lookup Table Offset, [45] Lookup Table Temperature Resolution can also be modified or B. [4C] the PWM value bits 0 through 5 or bits 0 through 7 if extended duty cycle resolution is selected. 7 If Step 4A, Lookup Table, was chosen and written then write [4A] bit 5 PWPGM = 0. PWPGM should be set to 1 to enable writing to the fan control registers listed in this table. All other registers can be written at any time after the above sequence. www.national.com 18 The following is a Register Map grouped in functional and sequence order. New register addresses have been added to maintain compatibility with the LM63 and LM64 register sets. Addresses in parenthesis are mirrors of named address for backwards compatibility with some older software. Reading or writing either address will access the same 8-bit register. Fan Control Registers Address Read/ POR Bits Hex Write Value Name Description 45HEX ENHANCED CONFIGURATION R R/W R/W R/W R/W 7 6 5 4 3 0 0 0 0 0 [Reserved] STFBE R/W 2:1 0 00 0 Signed Temperature Filter Bits Enable 0: external signed temperature LSbs [4:3] will always read "0" (backwards compatible with the LM63) 1: when the digital filter is enabled the external signed temperature LSbs [4:3] (1/16 and 1/32 resolution) are enabled LRES Lookup Table Resolution Extension 0: LUT temperature resolution 7-bits (LSb = 1°C, backwards compatible with the LM63) 1: enable 8-bit LUT temperature resolution (LSb extended to 0.5°C) PHR 22.5kHz PWM High Resolution Control (only effective when PWM frequency set to 22.5kHz) 0: PWM resolution 6.25% (backwards compatible with the LM63) 1: enable high resolution (0.39%) USF Unsigned High and T_CRIT Setpoint Format 0: enable signed format for High and T_CRIT setpoints (11-bit is -128.000°C to 127.875°C or 8-bit is -128°C to 127°C) 1: enable unsigned format for High and T_CRIT setpoints (11-bit is 0°C to 255.875°C or 8-bit is 0°C to 255°C) RRS1:RRS0 PWM Smoothing Ramp Rate Setting (these bits can modified only when PWM Programming is enabled, 0x4A[5]=1) 00: 0.023 s per step (5.45 seconds for 0 to 100% duty cycle transition with 0.39% resolution) 01: 0.046 s per step (10.9 seconds for 0 to 100% duty cycle transition with 0.39% resolution) 10: 0.91 s per step (21.6 seconds for 0 to 100% duty cycle transition with 0.39% resolution) 11: 0.182 s per step (43.7 seconds for 0 to 100% duty cycle transition with 0.39% resolution) Note: PWM smoothing is disabled for PWM spinup and for duty cycle setting override caused by a TCRIT event, thus it is only enabled during LUT transitions. PWM smoothing is only effective when PWM frequency is set to 22.5kHz. PSRR PWM Smoothing Ramp Rate Control (this bit can modified only when the PWM Programming is enabled, 0x4A[5]=1) 0: PWM smoothing disabled (LM63 backwards compatible) 1: enable ramp rate control (as controlled by 0x45[2:1]) Note: PWM smoothing is disabled for PWM spinup and for duty cycle setting override caused by a TCRIT event, thus it is only enabled during LUT transitions. PWM smoothing is only effective when PWM frequency is set to 22.5kHz 45 R/W This bit is unused and always read as 0. 19 www.national.com LM96163 2.4 LM96163 DETAILED REGISTER DESCRIPTIONS IN FUNCTIONAL ORDER LM96163 Address Read/ POR Bits Hex Write Value Name Description 4AHEX FAN PWM AND TACHOMETER CONFIGURATION REGISTER R 4A 7:6 00 [Reserved] 5 1 PWPGM 4 0 PWOP 3 0 PWCLSL 2 0 [Reserved] R/W 1:0 www.national.com 00 TACH1:TACH0 These bits are unused and always read as 0. PWM Programming enable 0: the PWM Value (register 0x4C), the PWM Smoothing (0x45[2:0]) and the Lookup Table (Registers 0x50–0x67) are read-only. The PWM value (0 to 100%) is determined by the current remote diode temperature and the Lookup Table, and can be read from the PWM value register. 1: the PWM value (register 0x4C), the PWM Smoothing (0x45[2:0]) and the Lookup Table (Registers 0x50–0x67) are read/write enabled. Writing the PWM Value register will set the PWM output. This is also the state during which the Lookup Table can be written. PWM Output Polarity 0: the PWM output pin will be 0V for fan OFF and open for fan ON. 1: the PWM output pin will be open for fan OFF and 0V for fan ON. PWM Master Clock Select 0: the master PWM clock is 360 kHz 1: the master PWM clock is 1.4 kHz. Always write 0 to this bit. Tachometer Mode 00: Traditional tach input monitor, false readings when under minimum detectable RPM. (Smart-TACH mode disabled) 01: Traditional tach input monitor, FFFFh reading when under minimum detectable RPM. Smart-TACH mode enabled, PWM duty cycle not affected. Use with direct PWM drive of fan power. TACH readings can cause an error event if TACH setpoint register is set to less than FFFFh even though fan may be spinning properly. 10: Most accurate readings, FFFFh reading when under minimum detectable RPM. Smart-TACH mode enabled, PWM duty cycle modified. Use with direct PWM drive of fan power. This mode extends the TACH monitoring low RPM sensitivity. 11: Least effort on programmed PWM of fan, FFFF reading when under minimum detectable RPM. Smart-TACH mode enabled. Use with direct PWM drive of fan power. This mode extends the TACH monitoring low RPM sensitivity the most. Note: If the PWM Master Clock is 360 kHz, mode 00 is used regardless of the setting of these two bits. 20 Name LM96163 Address Read/ POR Bits Hex Write Value Description 4BHEX FAN SPIN-UP CONFIGURATION REGISTER R 7:6 5 4B R/W 4:3 2:0 0 1 [Reserved] SPINUP These bits are unused and always read as 0 Fast Tachometer Spin-up If 0, the fan spin-up uses the duty cycle and spin-up time, bits 0–4. If 1, the LM96163 sets the PWM output to 100% until the spin-up times out (per bits 0–2) or the minimum desired RPM has been reached (per the Tachometer Setpoint setting) using the tachometer input, whichever happens first. This bit overrides the PWM Spin-Up Duty Cycle register (bits 4:3)—PWM output is always 100%. Register x03, bit 2 = 1 for Tachometer mode. If PWM Spin-Up Time (bits 2:0) = 000, the Spin-Up cycle is bypassed, regardless of the state of this bit. 11 PWM Spin-Up Duty Cycle 00: Spin-Up cycle bypassed (no Spin-Up), unless Fast Tachometer Terminated SPNDTY1:SPNDT Spin-Up (bit 5) is set. Y0 01: 50% 10: 75%–81% Depends on PWM Frequency. See Applications Notes. 11: 100% 111 PWM Spin-Up Time Interval 000: Spin-Up cycle bypassed (No Spin-Up) 001: 0.05 seconds 010: 0.1 s SPNTIM2:SPNTIM 011: 0.2 s 0 100: 0.4 s 101: 0.8 s 110: 1.6 s 111: 3.2 s 4CHEX PWM VALUE REGISTER 4C Read (Write only if reg 4A bit 5 = 1.) 7:6 00 5:0 0x00 HPWVAL7:HPWV PWM High Resolution and Low Resolution Values AL6 If PWM Program (register 4A, bit 5) = 0 this register is read only, this register reflects the LM96163’s current PWM value from the Lookup Table. If PWM Program (register 4A, bit 5) = 1, this register is read/write and the desired PWM value is written directly to this register, instead of from the Lookup Table, PWVAL5:PWVAL0 for direct fan speed control. This register will read 0 during the Spin-Up cycle. See Application Notes section at the end of this datasheet for more information regarding the PWM Value and Duty Cycle in %. 4DHEX FAN PWM FREQUENCY REGISTER R 4D R/W 7:5 4:0 000 0x17 [Reserved] PWMF4:PWMF0 These bits are unused and always read as 0 PWM Output Frequency The PWM Frequency = PWM_Clock / 2n, where PWM Master Clock = 360 kHz or 1.4 kHz (per the PWM Master Clock Select bit in Register 4A), and n = value of the register. Note: n = 0 is mapped to n = 1. See the Application Note at the end of this datasheet. 4EHEX LOOKUP TABLE TEMPERATURE OFFSET R 4E R/W 7:6 5:0 00 0x00 [Reserved] TO5:TO0 These bits are unused and always read as 0. The temperature offset applied to the temperature values of the lookup table. This offset allows the lookup table temperature settings to be extended above 127°C. The value, which is always positive, has an unsigned format with 1°C resolution. The maximum offset that can be programmed is +63°C. 4FHEX LOOKUP TABLE HYSTERESIS 4F R 7:5 000 R/W 4:0 0x04 [Reserved] These bits are unused and always read as 0 Lookup Table Hysteresis LOOKH4:LOOKH0 The amount of hysteresis applied to the Lookup Table. (1 LSb = 1°C, max value 31°C, default value 10°C). 21 www.national.com LM96163 Address Read/ POR Bits Hex Write Value Name Description 50HEX to 67HEX LOOKUP TABLE (7/8 Bits for Temperature and 6/8 Bits for PWM for each Temperature/PWM Pair) 50 7 0 E1T7 6:0 0x7F E1T6:E1T0 Read. (Write only if reg 4A bit 5 = 1) 7:6 00 E1D7:E1D6 Lookup Table PWM Duty Cycle Extended Entry 1 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x50. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E1D5:E1D0 Lookup Table PWM Duty Cycle Entry 1 The PWM value corresponding to the temperature limit in register 0x50 for the low resolution PWM mode. 7 0 E2T7 6:0 0x7F E2T6:E2T0 51 52 Read. (Write only if reg 4A bit 5 = 1) Lookup Table Temperature Entry 2 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x53. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 7:6 00 E2D7:E2D6 Lookup Table PWM Duty Cycle Extended Entry 2 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x52. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E2D5:E2D0 Lookup Table PWM Duty Cycle Entry 2 The PWM value corresponding to the temperature limit in register 0x52 for the low resolution PWM mode. 53 www.national.com Lookup Table Temperature Entry 1 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x51. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 22 54 Name Description Lookup Table Temperature Entry 3 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x55. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 7 0 E3T7 6:0 0x7F E3T6:E3T0 Read. (Write only if reg 4A bit 5 = 1) 7:6 00 E3D7:E3D6 Lookup Table PWM Duty Cycle Extended Entry 3 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x54. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E3D5:E3D0 Lookup Table PWM Duty Cycle Entry 3 The PWM value corresponding to the temperature limit in register 0x54 for the low resolution PWM mode. 7 0 E4T7 6:0 0x7F E4T6:E4T0 55 56 Read. (Write only if reg 4A bit 5 = 1) Lookup Table Temperature Entry 4 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x57. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 7:6 00 E4D7:E4D6 Lookup Table PWM Duty Cycle Extended Entry 4 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x56. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E4D5:E4D0 Lookup Table PWM Duty Cycle Entry 4 The PWM value corresponding to the temperature limit in register 0x56 for the low resolution PWM mode. 57 23 www.national.com LM96163 Address Read/ POR Bits Hex Write Value LM96163 Address Read/ POR Bits Hex Write Value 58 Name Description Lookup Table Temperature Entry 5 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x59. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 7 0 E5T7 6:0 0x7F E5T6:E5T0 Read. (Write only if reg 4A bit 5 = 1) 7:6 00 E5D7:E5D6 Lookup Table PWM Duty Cycle Extended Entry 5 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x58. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E5D5:E5D0 Lookup Table PWM Duty Cycle Entry 5 The PWM value corresponding to the temperature limit in register 0x58 for the low resolution PWM mode. 7 0 E6T7 6:0 0x7F E6T6:E6T0 59 5A Read. (Write only if reg 4A bit 5 = 1) 7:6 00 E6D7:E6D6 Lookup Table PWM Duty Cycle Extended Entry 6 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x5A. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E6D5:E6D0 Lookup Table PWM Duty Cycle Entry 6 The PWM value corresponding to the temperature limit in register 0x5A for the low resolution PWM mode. 5B www.national.com Lookup Table Temperature Entry 6 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x5B. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 24 5C Name Description Lookup Table Temperature Entry 7 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x5D. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 7 0 E7T7 6:0 0x7F E7T6:E7T0 Read. (Write only if reg 4A bit 5 = 1) 7:6 00 E7D7:E7D6 Lookup Table PWM Duty Cycle Extended Entry 7 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x5C. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E7D5:E7D0 Lookup Table PWM Duty Cycle Entry 7 The PWM value corresponding to the temperature limit in register 0x5C for the low resolution PWM mode. 7 0 E8T7 6:0 0x7F E8T6:E8T0 5D 5E Read. (Write only if reg 4A bit 5 = 1) Lookup Table Temperature Entry 8 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x5F. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 7:6 00 E8D7:E8D6 Lookup Table PWM Duty Cycle Extended Entry 8 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x5E. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E8D5:E8D0 Lookup Table PWM Duty Cycle Entry 8 The PWM value corresponding to the temperature limit in register 0x5E for the low resolution PWM mode. 5F 25 www.national.com LM96163 Address Read/ POR Bits Hex Write Value LM96163 Address Read/ POR Bits Hex Write Value 60 Name Description Lookup Table Temperature Entry 9 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x61. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 7 0 E9T7 6:0 0x7F E9T6:E9T0 Read. (Write only if reg 4A bit 5 = 1) 7:6 00 E9D7:E9D6 Lookup Table PWM Duty Cycle Extended Entry 9 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x60. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E9D5:E9D0 Lookup Table PWM Duty Cycle Entry 9 The PWM value corresponding to the temperature limit in register 0x60 for the low resolution PWM mode. 7 0 E10T7 6:0 0x7F E10T6:E10T0 61 62 Read. (Write only if reg 4A bit 5 = 1) 7:6 00 E10D7:E10D6 Lookup Table PWM Duty Cycle Extended Entry 10 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x62. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E10D5:E10D0 Lookup Table PWM Duty Cycle Entry 10 The PWM value corresponding to the temperature limit in register 0x62 for the low resolution PWM mode. 63 www.national.com Lookup Table Temperature Entry 10 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x63. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 26 64 Name Description Lookup Table Temperature Entry 11 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x65. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 7 0 E11T7 6:0 0x7F E11T6:E11T0 Read. (Write only if reg 4A bit 5 = 1) 7:6 00 E11D7:E11D6 Lookup Table PWM Duty Cycle Extended Entry 11 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x64. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E11D5:E11D0 Lookup Table PWM Duty Cycle Entry 11 The PWM value corresponding to the temperature limit in register 0x64 for the low resolution PWM mode. 7 0 E12T7 6:0 0x7F E12T6:E12T0 65 66 Read. (Write only if reg 4A bit 5 = 1) Lookup Table Temperature Entry 12 Bit 7 is unused and always set to 0 in the low resolution temperature LUT mode. In the high resolution temperature LUT mode bit 7 in conjunction with bits 6:0 of this register are used to determine the limit temperature that the remote diode temperature is compared to. In high resolution the range is 0°C to 127.5°C. In low resolution mode the range is 0°C to 127°C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 0x67. Only 9bits of the temperature reading are used in high resolution and 8-bits in low resolution. Only positive temperature values can be programed in this register and in all cases the sign bit is assumed to be zero. Temperatures greater than 127 °C or 127.5 °C can be programmed through the use of the Lookup Table Temperature Offset Register (4Eh). 7:6 00 E12D7:E12D6 Lookup Table PWM Duty Cycle Extended Entry 12 These bits are unused and always set to 0 in the low resolution duty cycle LUT mode. In the high resolution duty cycle LUT mode these bits in association with bits 5:0 of this register are used for the PWM value associated with the temperature limit in register 0x66. These bits can only be activated when PWM frequency of 22.5kHz is chosen. 5:0 0x3F E12D5:E12D0 Lookup Table PWM Duty Cycle Entry 12 The PWM value corresponding to the temperature limit in register 0x66 for the low resolution PWM mode. 67 27 www.national.com LM96163 Address Read/ POR Bits Hex Write Value LM96163 Configuration Register Address Read/ POR Bits Hex Write Value Name Description 03 (09)HEX CONFIGURATION REGISTER 7 R/W 03 (09) R 6 0 0 ALTMSK ALERT Mask 0: ALERT interrupts are enabled. 1: ALERT interrupts are masked, and the ALERT pin is always in a high impedance (open) state. STBY Standby 0: the LM96163 is in operational mode, converting, comparing, and updating the PWM output continuously. 1: the LM96163 enters a low power standby mode. In standby, continuous conversions are stopped, but a conversion/comparison cycle may be initiated by writing any value to register 0x0F the One-shot Register. Operation of the PWM output in standby depends on the setting of bit 5 in this register. PWM Disable in Standby 0: the LM96163’s PWM output continues to output the current fan control signal while in STANDBY. 1: the PWM output is disabled (as defined by the PWM polarity bit) while in STANDBY. 5 0 PWMDIS 4:3 00 [Reserved] 2 0 TCHEN 1 0 TCRITOV T_CRIT Limit Override 0: locks the T_CRIT limit for the remote diode, POR setting is nominally 110°C 1: unlocks the T_CRIT limit and allows it to be reprogrammed multiple times FLTQUE RDTS Fault Queue 0: an ALERT will be generated if any Remote Diode conversion result is above the Remote High Set Point or below the Remote Low Setpoint. 1: an ALERT will be generated only if three consecutive Remote Diode conversions are above the Remote High Set Point or below the Remote Low Setpoint. R/W 0 0 This bit is unused and always read as 0. TACH Enable 0: disables the TACH input 1: enables the TACH input Tachometer Count and Limit Registers Address Hex Read/ POR Bits Write Value Name Description 47HEX TACHOMETER COUNT (MSB) and 46HEX TACHOMETER COUNT (LSB) REGISTERS (16 bits: Read LSB first to lock MSB and ensure MSB and LSB are from the same reading) 47 R 7:0 N/A TAC13:TAC6 R 7:2 N/A TAC5:TAC0 Tachometer Count (MSB and LSB) These registers contain the current 16-bit Tachometer Count, representing the period of time between tach pulses. Note that the 16-bit tachometer MSB and LSB register addresses are in reverse order from the 16 bit temperature readings. Tachometer Edge Programming Bits 46 Edges Used 00: R 1:0 00 TEDGE1:TEDGE0 Tach_Count_Multiple Reserved - do not use 01: 2 4 10: 3 2 11: 5 1 Note: If PWM_Clock_Select = 360 kHz, then Tach_Count_Multiple = 1 regardless of the setting of these bits. www.national.com 28 Read/ POR Bits Write Value Name LM96163 Address Hex Description 49HEX TACHOMETER LIMIT (MSB) and 48HEX TACHOMETER LIMIT (LSB) REGISTERS 49 48 R/W 7:0 R/W 7:2 R/W 1:0 0xFF 0xFF TACL13:TACL6 TACHL5:TACL0 [Reserved] Tachometer Limit (MSB and LSB) These registers contain the current 14-bit Tachometer Count, representing the period of time between tach pulses. Fan RPM = (f * 5,400,000) / (Tachometer Count), where f = 1 for 2 pulses/rev fan; f = 2 for 1 pulse/rev fan; and f = 2/3 for 3 pulses/rev fan. See the Applications Notes section for more tachometer information. Note that the 16-bit tachometer MSB and LSB register addresses are in reverse order from the 16 bit temperature readings. These bits are not used and write 0 or 1. Local Temperature and Local High Setpoint Registers Address Read/ Bits Hex Write POR Value Name Description 00HEX LOCAL TEMPERATURE REGISTER (8-bits) 00 R 7:0 N/A LT7:LT0 Local Temperature Reading (8-bit) 8-bit integer representing the temperature of the LM96163 die. LT7 is the SIGN bit LT6 has a bit weight of 64°C LT5 has a bit weight of 32°C LT4 has a bit weight of 16°C LT3 has a bit weight of 8°C LT2 has a bit weight of 4°C LT1 has a bit weight of 2°C LT0 has a bit weight of 1°C 05 (0B)HEX LOCAL HIGH SETPOINT REGISTER (8-bits) 05 R/W 7:0 0x46 (70°) LHS7:LHS0 Local HIGH Setpoint High Setpoint for the internal diode. LHS7 is the SIGN bit LHS6 has a bit weight of 64°C LHS5 has a bit weight of 32°C LHS4 has a bit weight of 16°C LHS3 has a bit weight of 8°C LHS2 has a bit weight of 4°C LHS1 has a bit weight of 2°C LHS0 has a bit weight of 1°C Remote Diode Temperature, Offset and Setpoint Registers Address Hex Read/ POR Bits Write Value Name Description 01HEX AND 10HEX SIGNED REMOTE DIODE TEMPERATURE REGISTERS 01 R 7:0 N/A RT12:RT5 Most Significant Byte of the Signed Remote Diode Temperature Reading The most significant 8-bits of the 2’s complement value, representing the temperature of the remote diode connected to the LM96163. Bit 7 is the sign bit, bit 6 has a weight of 64°C, and bit 0 has a weight of 1°C. This byte to be read before the LSB. 29 www.national.com LM96163 Address Hex Read/ POR Bits Write Value 10 R Name Description Least Significant Byte of the Signed Remote Diode Temperature Reading This is the LSB of the 2’s complement value, representing the temperature of the remote diode connected to the LM96163. RT4 has a weight 0.5°C, RT3 has a weight of 0.25°C, and RT2 has a weight of 0.125°C. If the digital filter is turned off RT1:RT0 have a value of 00 unless extended resolution (Reg 45h STFBE bit set) is enabled. If extended resolution is chosen, for readings greater than 127.875 RT1:RT0=11 and for other cases RT1:RT0=00. When the digital filter is turned on and extended resolution enabled: RT1 has a weight of 0.0625 and RT0 has a weight of 0.03125°C 7:3 N/A RT4:RT0 2:0 00 [Reserved] These bits are unused and always read as 0. 31HEX AND 32HEX UNSIGNED REMOTE DIODE TEMPERATURE REGISTERS 31 R 32 R 7:0 N/A RTU12:RTU5 Most Significant Byte of the Unsigned Format Remote Diode Temperature Reading The most significant 8-bits of the unsigned format value, representing the temperature of the remote diode connected to the LM96163. Bit 7 has a weight of 128°C, bit 6 has a weight of 64°C, and bit 0 has a weight of 1°C. This byte to be read before the LSB. Least Significant Byte of the Unsigned Format Remote Diode Temperature Reading This is the LSB of the unsigned value, representing the temperature of the remote diode connected to the LM96163. Bit 4 has a weight 0.5°C, bit 3 has a weight of 0.25°C, and bit 2 has a weight of 0.125°C. if the digital filter is turned off RUT1:RUT0 have a value of 00. When the digital filter is turned on: bit 1 has a weight of 0.0625 and bit 0 has a weight of 0.03125°C 7:3 N/A RUT4:RUT0 2:0 00 [Reserved] These bits are unused and always read as 0. 11HEX AND 12HEX REMOTE TEMPERATURE OFFSET REGISTERS 11 12 R/W 7:0 0x00 RTO10:RTO3 R/W 7:5 000 RTO2:RTO1 R 4:0 000 [Reserved] Remote Temperature Offset (MSB and LSB) These registers contain the value added to or subtracted from the remote diode’s reading to compensate for the different non-ideality factors of different processors, diodes, etc. The 2’s complement value, in these registers is added to the output of the LM96163’s ADC to form the temperature reading contained in registers 01 and 10. These registers have the same format as the MSB and LSB Remote Diode Temperature Reading registers with the digital filter off. These bits are not used and always read as 0. 07 (0D)HEX AND 13HEX REMOTE HIGH SETPOINT REGISTERS 07 (0D) 13 R/W 7:0 0x55 (85°C) RHS10:RHS3 R/W 7:5 000 RHS2:RHS0 R 4:0 0x00 [Reserved] Remote HIGH Setpoint (MSB and LSB) High setpoint temperature for remote diode. Same format as Unsigned Remote Temperature Reading (registers 31 and 32) or Signed Remote Temperature Reading (registers 01 and 10) with the digital filter off. Is it programmable by the USF bit found in the Enhanced configuration Register. These bits are not used and always read as 0. 08 (0E)HEX AND 14HEX REMOTE LOW SETPOINT REGISTERS 08 (0E) 14 00 (0°C) RTS10:RTS3 7:5 000 RTS2:RTS0 Remote LOW Setpoint (MSB and LSB) Low setpoint temperature for remote diode. Same format as Signed Remote Temperature Reading (registers 01 and 10) with the digital filter off. 4:0 0x00 [Reserved] These bits are not used and always read as 0. R/W 7:0 R/W R www.national.com 30 Read/ POR Bits Write Value Name LM96163 Address Hex Description 19HEX REMOTE DIODE T_CRIT SETPOINT REGISTER 19 R/W 7:0 0x6E (110° C) RCS7:RCS0 Remote Diode T_CRIT Setpoint Limit This 8-bit integer stores the T_CRIT limit and is nominally 110°C. The value of this register can be locked by setting T_CRIT Limit Override (bit 1) in the Configuration register to a 0, then programming a new T_CRIT value into this register. The format of this register is programmable. When the USF bit in the Enhanced Configuration register is cleared: LCS7 is the SIGN bit LCS6 has a bit weight of 64°C LCS5 has a bit weight of 32°C LCS4 has a bit weight of 16°C LCS3 has a bit weight of 8°C LCS2 has a bit weight of 4°C LCS1 has a bit weight of 2°C LCS0 has a bit weight of 1°C 21HEX T_CRIT HYSTERESIS REGISTER 7 21 R/W RTH7 0x0A 6:0 (10°C) RTH6:RTH0 This bit is unused. OK to write 1 or 0. Remote Diode T_CRIT Hysteresis T_CRIT stays activated until the remote diode temperature goes below [(T_CRIT Limit)—(T_CRIT Hysteresis)]. RTH6 has a bit weight of 64°C RTH5 has a bit weight of 32°C RTH4 has a bit weight of 16°C RTH3 has a bit weight of 8°C RTH2 has a bit weight of 4°C RTH1 has a bit weight of 2°C RTH0 has a bit weight of 1°C 30HEX REMOTE DIODE TruTherm ENABLE REGISTER R 30 7:2 0x00 [Reserved] R/W 1 1 RDTE R 0 0 [Reserved] These bits are unused and always read as 0. Remote Diode TruTherm Enable 0: TruTherm beta compensation technology is turned off. Use this mode when using an MMBT3904 as a thermal diode. 1: TruTherm beta compensation technology is turned on. Use this mode when sensing a thermal diode in an Intel processor on 45 nm or 65 nm process. This bit is unused and always read as 0. BFHEX REMOTE DIODE TEMPERATURE FILTER AND COMPARATOR MODE R/W 7:6 00 [Reserved] These bits are unused and always write 0. R 5:3 000 [Reserved] These bits are unused and always read as 0. 2:1 00 RDTF1:RDTF0 Remote Diode Temperature Filter Control 00: Filter Disabled 01: Filter Level 2 (minimal filtering, same as 10; Like LM63, LM63 Level 1 not supported) 10: Filter Level 2 (minimal filtering, same as 01; like LM63, LM63 Level 1 not supported) 11: Filter Enhanced Level 2 (maximum filtering) ALT/CMP Comparator Mode 0: the ALERT pin functions normally. 1: the ALERT pin behaves as a comparator, asserting itself when an ALERT condition exists, de-asserting itself when the ALERT condition goes away. BF R/W 0 0 31 www.national.com LM96163 ALERT Status and Mask Registers Address Hex Read/ POR Bits Write Value Name Description 02HEX ALERT STATUS REGISTER (8-bits) (All Alarms are latched until read, then cleared if alarm condition was removed at the time of the read.) 7 Busy 0: the ADC is not converting. 1: the ADC is performing a conversion. This bit does not affect ALERT status. Local High Alarm 0: the internal temperature of the LM96163 is at or below the Local High Setpoint. 1: the internal temperature of the LM96163 is above the Local High Setpoint, and an ALERT is triggered. 0 LHIGH 5 0 [Reserved] 3 0 0 1 0 0 0 0 This bit is unused and always read as 0. RHIGH Remote High Alarm 0: the temperature of the Remote Diode is at or below the Remote High Setpoint. 1: the temperature of the Remote Diode is above the Remote High Setpoint, and an ALERT is triggered. RLOW Remote Low Alarm 0: the temperature of the Remote Diode is at or above the Remote Low Setpoint. 1: the temperature of the Remote Diode is below the Remote Low Setpoint, and an ALERT is triggered. RDFA Remote Diode Fault Alarm 0: the Remote Diode appears to be correctly connected. 1: the Remote Diode may be disconnected or shorted to ground. This Alarm does not trigger an ALERT or a TCRIT. RCRIT Remote T_CRIT Alarm When this bit is a 0, the temperature of the Remote Diode is at or below the T_CRIT Limit. When this bit is a 1, the temperature of the Remote Diode is above the T_CRIT Limit, ALERT and TCRIT are triggered. TACH Tach Alarm When this bit is a 0, the Tachometer count is lower than or equal to the Tachometer Limit (the RPM of the fan is greater than or equal to the minimum desired RPM). When this bit is a 1, the Tachometer count is higher than the Tachometer Limit (the RPM of the fan is less than the minimum desired RPM), and an ALERT is triggered. R 2 www.national.com BUSY 6 4 0x02 0 32 Read/ POR Bits Write Value Name LM96163 Address Hex Description 16HEX ALERT MASK REGISTER (8-bits) R 7 1 [Reserved] R/W 6 0 LHAM R 5 1 [Reserved] 4 0 RHAM Remote High Alarm Mask 0: Remote High Alarm event will generate an ALERT. 1: a Remote High Alarm event will not generate an ALERT. 3 0 RLAM Remote Low Alarm Mask 0: a Remote Low Alarm event will generate an ALERT. 1: a Remote Low Alarm event will not generate an ALERT. 2 1 [Reserved] 1 0 RTAM 0 0 TCHAM R/W 16 R R/W This bit is unused and always read as 1. Local High Alarm Mask 0: a Local High Alarm event will generate an ALERT. 1: a Local High Alarm will not generate an ALERT This bit is unused and always read as 1. This bit is unused and always read as 1. Remote T_CRIT Alarm Mask 0: a Remote T_CRIT event will generate an ALERT. 1: a Remote T_CRIT event will not generate an ALERT. TACH Alarm Mask When this bit is a 0, a Tach Alarm event will generate an ALERT. When this bit is a 1, a Tach Alarm event will not generate an ALERT. 33HEX POWER ON RESET STATUS REGISTER 33 R 7 NR — 6:0 [Reserved] Power On Reset Status 0: Power On Reset cycle over part ready 1: Power On Reset cycle in progress part not ready These bits are unused and will always report 0. Conversion Rate and One-Shot Registers Address Hex Read/ POR Bits Write Value Name Description 04 (0A)HEX CONVERSION RATE REGISTER (8-bits) R 04 (0A) R/W 7:4 3:0 [Reserved] 0x08 CONV3:CONV0 These bits are unused and will always be set to 0. Conversion Rate Sets the conversion rate of the LM96163. 0000 = 0.05 Hz 0001 = 0.1 Hz 0010 = 0.204 Hz 0011 = 0.406 Hz 0100 = 0.813 Hz 0101 = 1.625 Hz 0110 = 3.25 Hz 0111 = 6.5 Hz 1000 = 13 Hz 1001 = 26 Hz All other values = 26 Hz 0FHEX ONE-SHOT REGISTER (8-bits) 0F Write Only 7:0 N/A One Shot Trigger With the LM96163 in the STANDBY mode a single write to this register will initiate one complete temperature conversion cycle. Any value may be written. 33 www.national.com LM96163 ID Registers Address Hex Read/ POR Bits Write Value Name Description FEHEX MANUFACTURER’S ID REGISTER (8-bits) FE R 7:0 0x01 Manufacturer’s ID 0x01 = National Semiconductor FFHEX STEPPING / DIE REVISION ID REGISTER (8-bits) FF R 7:0 Stepping/Die Revision ID 0x49 Version of LM96163 3.0 Application Notes 3.1 FAN CONTROL DUTY CYCLE VS. REGISTER SETTINGS AND FREQUENCY The following table is true only when the 22.5 kHz PWM frequency high resolution duty cycle is not selected. PWM Freq 4D [4:0] PWM Freq at 1.4 kHz Internal Clock, Hz Actual Duty Cycle, % When 75% is Selected 180.0 703.1 50.0 2 90.00 351.6 75.0 3 60.00 234.4 83.3 6 4 45.00 175.8 75.0 8 5 36.00 140.6 80.0 12 9 6 30.00 117.2 75.0 14 11 7 25.71 100.4 78.6 6.25 16 12 8 22.50 87.9 75.0 77.8 Step Resolution, % PWM Value 4C [5:0] for 100% PWM Value 4C [5:0] for about 75% 50 2 1 1 2 25 4 3 3 16.7 6 5 4 12.5 8 5 10.0 10 6 8.33 7 7.14 8 0 1 PWM Value 4C [5:0] for 50% PWM Freq at 360 kHz Internal Clock, kHz Address 0 is mapped to Address 1 9 5.56 18 14 9 20.00 78.1 10 5.00 20 15 10 18.00 70.3 75.0 11 4.54 22 17 11 16.36 63.9 77.27 12 4.16 24 18 12 15.00 58.6 75.00 13 3.85 26 20 13 13.85 54.1 76.92 14 3.57 28 21 14 12.86 50.2 75.00 15 3.33 30 23 15 12.00 46.9 76.67 16 3.13 32 24 16 11.25 43.9 75.00 17 2.94 34 26 17 10.59 41.4 76.47 18 2.78 36 27 18 10.00 39.1 75.00 19 2.63 38 29 19 9.47 37.0 76.32 20 2.50 40 30 20 9.00 35.2 75.00 21 2.38 42 32 21 8.57 33.5 76.19 22 2.27 44 33 22 8.18 32.0 75.00 23 2.17 46 35 23 7.82 30.6 76.09 24 2.08 48 36 24 7.50 29.3 75.00 25 2.00 50 38 25 7.20 28.1 76.00 26 1.92 52 39 26 6.92 27.0 75.00 27 1.85 54 41 27 6.67 26.0 75.93 28 1.79 56 42 28 6.42 25.1 75.00 29 1.72 58 44 29 6.21 24.2 75.86 30 1.67 60 45 30 6.00 23.4 75.00 31 1.61 62 47 31 5.81 22.7 75.81 www.national.com 34 PWM Freq 4D [4:0] Step Resolution, % PWM Value 4C [7:0] for 100% (Hex) PWM Value 4C [7:0] for about 75% (Hex) PWM Value 4C [7:0] for 50% (Hex) PWM Freq at 360 kHz Internal Clock, kHz PWM Freq at 1.4 kHz Internal Clock, Hz Actual Duty Cycle, % When Approximately 75% is Selected 8 0.392 FF BF 80 22.50 Not Available 74.902 3.1.1 Computing Duty Cycles for a Given Frequency Select a PWM Frequency from the first column corresponding to the desired actual frequency in columns 6 or 7. Note the PWM Value for 100% Duty Cycle. Find the Duty Cycle by taking the PWM Value of Register 4C and computing: Example: For a PWM Frequency of 24, a PWM Value at 100% = 48 and PWM Value actual = 28, then the Duty Cycle is (28/48) × 100% = 58.3%. 3.2 LUT FAN CONTROL The LM96163 fan control uses a temperature to duty cycle look-up table (LUT) that has 12 indexes. High resolution duty cycle (0.392%) is available when the PWM frequency is set to 22.5 kHz. In addition ramp rate control is available to acoustically smooth the duty cycle transition between LUT steps. Shown in Figure 7(a) is an example of the 12-point LUT temperature to PWM transfer function that can be realized without smoothing enabled. The table is comprised of twelve DutyCycle and Temperature set-point pairs. Notice that the transitions between one index of the LUT to the next happen instantaneously. If the PWM levels are set far enough apart this can be acoustically very disturbing. The typical acoustical threshold of change in duty cycle is 2%. Figure 7(b) has an overlaid curve (solid line) showing what occurs at the transitions when smoothing is enabled. The dashed lines shown in Figure 7(b) are there to point out that multiple slopes can be realized easily. At the transitions the duty cycle increments in LSb (0.39% for the case shown) steps. In the example shown in Figure 7(b) the first pair is set for a duty-cycle of 31.25% and a temperature of 0°C. For temperatures less than 0°C the duty cycle is set to 0. When the temperature is greater than 0 °C but is less than 91 °C the duty cycle will remain at 31.25%. The next pair is set at 37.5% and 91°C. Once the temperature exceeds 91°C the duty cycle on the PWM output will gradually transition from 31.25% to 37.5% in 0.39% steps at the programmed time interval. The LUT comparison temperature resolution is programmable to either 1 °C or 0.5 °C. For the curves of Figure 7 the comparison resolution is set to 0.5 °C that is why the actual duty cycle transitions happen 0.5 °C higher than the actual LUT entry. The duty cycle transition time interval is programmable and is shown in the table titled PWM Smoothing Time Intervals. Care should be taken so that the LUT PWM and Temperature values are setup in ascending weight. 30041034 30041035 (a) Without smoothing (b) With smoothing FIGURE 7. Fan Control Transfer Function Example 35 www.national.com LM96163 The following table is true only when the 22.5 kHz PWM frequency with high resolution duty cycle is selected by setting bit 4 (PHR) of the Enhanced Configuration register (0x45), clearing bit 3 (PWCKSL) of the PWM and RPM Configuration register (0x4A) and setting PWM Frequency (0x4D) register to 0x08. LM96163 Also included is programmable hysteresis that is not described by the curves of Figure 7. The hysteresis takes effect as temperature is decreasing and moves all the temperature set-points down by the programmed amount. For the example shown here if the hysteresis is set to 1°C and if the temperature is decreasing from 96.5°C the duty cycle will remain at 68.75% and will not transition to 62.5% until the temperature drops below 95.5°C. If at any time the TCRIT output were to activate the PWM duty cycle will be instantaneously forced to 100% thus forcing the fans to full on. where f = 1 for 2 pulses/rev fan tachometer output; f = 2 for 1 pulse/rev fan tachometer output, and f = 2 / 3 for 3 pulses/rev fan tachometer output For our example PWM Smoothing Time Intervals Time Interval (seconds) 0-100% DC Time w/ 6.25% resolution (seconds) w/ 0.39% resolution Seconds 0.182 2.913 43.7 0.091 1.456 21.6 0.046 0.728 10.9 0.023 0.364 5.45 3.4 DIODE NON-IDEALITY The LM96163 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 LM96163'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 LM96163 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. The LM96163 incorporates remote diode temperature sensing technology allowing the measurement of remote temperatures. This diode can be located on the die of a target IC, allowing measurement of the IC's temperature, independent of the LM96163's die temperature. 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 an MMBT3904 transistor base emitter junction be used with the collector tied to the base. The LM96163’s TruTherm BJT beta compensation technology allows accurate sensing of integrated thermal diodes, such as those found on most processors. With TruTherm technology turned off, the LM96163 can measure a diode-connected transistor such as the MMBT3904 or the thermal diode found in an AMD processor. The LM96163 has been optimized to measure the remote thermal diode integrated in a typical Intel processor on 45nm, 65 nm or 90 nm process or an MMBT3904 transistor. Using the Remote Diode TruTherm Enable register the remote input can be optimized for a typical Intel processor on 45nm, 65 nm or 90 nm process or an MMBT3904. The PWM Smoothing Time Intervals table describes the programmable time interval preventing abrupt changes in the PWM output duty cycle and thus preventing abrupt acoustical noise changes as well. The threshold of acoustically detecting fan noise transition is at about a 2% duty cycle change. The table describes the time intervals that can be programmed and the total amount of time it will take for the PWM output to change from 0% to 100% for each time interval. For example if the time interval for each step is set to 0.091 seconds the time it will take to make a 0 to 100% duty cycle change will be 21.6 seconds when the duty cycle resolution is set to 0.39% or 1.46 seconds when the resolution is 6.25%. One setting will apply to all LUT transitions. 3.3 COMPUTING RPM OF THE FAN FROM THE TACH COUNT The Tach Count Registers 46HEX and 47HEX count the number of periods of the 90 kHz tachometer clock in the LM96163 for the tachometer input from the fan assuming a 2 pulse per revolution fan tachometer, such as the fans supplied with the Intel boxed processors. The RPM of the fan can be computed from the Tach Count Registers 46HEX and 47HEX. This can best be shown through an example. Example: Given: the fan used has a tachometer output with 2 per revolution. Let: Register 46 (LSB) is BFHEX = Decimal (11 x 16) + 15 = 191 and Register 47 (MSB) is 7HEX = Decimal (7 x 256) = 1792. The total Tach Count, in decimal, is 191 + 1792 = 1983. The RPM is computed using the formula www.national.com 36 (3) (1) Solving Equation 3 for temperature yields: where: (4) Equation 4 holds true when a diode connected transistor such as the MMBT3904 is used. When this “diode” equation is applied to an integrated diode such as a processor transistor with its collector tied to GND as shown in Figure 8 it will yield a wide non-ideality spread. This wide non-ideality spread is not due to true process variation but due to the fact that Equation 4 is an approximation. TruTherm BJT beta compensation technology uses the transistor equation, Equation 5, which is a more accurate representation of the topology of the thermal diode found in an FPGA or processor. • • • • q = 1.6×10−19 Coulombs (the electron charge), T = Absolute Temperature in Kelvin k = 1.38×10−23 joules/K (Boltzmann's constant), η is the non-ideality 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 In the active region, the -1 term is negligible and may be eliminated, yielding the following equation (2) (5) In Equation 2, η and IS are dependant upon the process that was used in the fabrication of the particular diode. By forcing two currents with a very controlled ratio(IF2 / IF1) and measuring the resulting voltage difference, it is possible to eliminate TruTherm should only be enabled when measuring the temperature of a transistor integrated as shown in the processor of Figure 8, because Equation 5 only applies to this topology. 30041043 FIGURE 8. Thermal Diode Current Paths 37 www.national.com LM96163 the IS term. Solving for the forward voltage difference yields the relationship: 3.4.1 Diode Non-Ideality Factor Effect on Accuracy When a transistor is connected as a diode, the following relationship holds for variables VBE, T and IF: LM96163 celled out by subtracting it from the output readings of the LM96163 using the Remote Temperature Offset register. 3.4.2 Calculating Total System Accuracy The voltage seen by the LM96163 also includes the IFRS voltage drop of the series resistance. The non-ideality 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 η and T, the variations in η cannot 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 for Intel processor on 65nm process, Intel specifies a +4.06%/ −0.897% variation in η from part to part when the processor diode is measured by a circuit that assumes diode equation, Equation 4, as true. As an example, assume a temperature sensor has an accuracy specification of ±1.0°C at a temperature of 80°C (353 Kelvin) and the processor diode has a nonideality variation of +4.06%/−0.89%. The resulting system accuracy of the processor temperature being sensed will be: Processor Family Transistor Equation ηT, non-ideality min typ max Intel Processor on 45 nm process 0.997 1.001 1.008 4.5 Intel Processor on 65 nm process 0.997 1.001 1.005 4.52 Series R,Ω 3.5 PCB LAYOUT FOR MINIMIZING NOISE TACC = + 1.0°C + (+4.06% of 353 K) = +15.3 °C and TACC = - 1.0°C + (−0.89% of 353 K) = −4.1 °C TruTherm technology uses the transistor equation, Equation 4, resulting in a non-ideality spread that truly reflects the process variation which is very small. The transistor equation non-ideality spread is ±0.39% for the 65nm thermal diode. The resulting accuracy when using TruTherm technology improves to: 30041021 FIGURE 9. Ideal Diode Trace Layout TACC = ±0.75°C + (±0.39% of 353 K) = ± 2.16 °C 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 LM96163 can cause temperature conversion errors. Keep in mind that the signal level the LM96163 is trying to measure is in microvolts. The following guidelines should be followed: 1. Use a low-noise +3.3VDC power supply, and bypass to GND with a 0.1 µF ceramic capacitor in parallel with a 100 pF ceramic capacitor. The 100 pF capacitor should be placed as close as possible to the power supply pin. A bulk capacitance of 10 µF needs to be in the vicinity of the LM96163's VDD pin. 2. A 100 pF diode bypass capacitor is recommended to filter high frequency noise but may not be necessary. Place the recommended 100 pF diode capacitor as close as possible to the LM96163's D+ and D− pins. Make sure the traces to the 100 pF capacitor are matched. The LM96163 can handle capacitance up to 3 nF placed between the D+ and D- pins, See Typical Performance Characteristic curves titled Remote Temperature Reading Sensitivity to Thermal Diode Filter Capacitance. 3. Ideally, the LM96163 should be placed within 10 cm of the Processor diode pins with the traces being as straight, short and identical as possible. Trace resistance of 1 Ω can cause as much as 0.62°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. Intel does not specify the diode model ideality and series resistance of the thermal diodes on 45nm so a similar comparison cannot be calculated, but lab experiments have shown similar improvement. For the 45nm processor the ideality spread as specified by Intel is -0.399% to +0.699%. The resulting spread in accuracy when using TruTherm technology with the thermal diode on Intel processors with 45nm process is: TACC = -0.75°C + (-0.39% of 353 K) = -2.16 °C to TACC = +0.75°C + (+0.799% of 353 K) = +4.32 °C The next error term to be discussed is that due to the series resistance of the thermal diode and printed circuit board traces. The thermal diode series resistance is specified on most processor data sheets. For Intel processors in 45 nm process, this is specified at 4.5Ω typical with a minimum of 3Ω and a maximum of 7Ω. The LM96163 accommodates the typical series resistance of Intel Processor on 45 nm process. The error that is not accounted for is the spread of the processor's series resistance. The equation used to calculate the temperature error due to series resistance (TER) for the LM96163 is simply: (6) Solving Equation 6 for RPCB equal to -1.5Ω to 2.5Ω results in the additional error due to the spread in this series resistance of -0.93°C to +1.55°C. The spread in error cannot be canceled out, as it would require measuring each individual thermal diode device. This is quite difficult and impractical in a large volume production environment. Equation 6 can also be used to calculate the additional error caused by series resistance on the printed circuit board. Since the variation of the PCB series resistance is minimal, the bulk of the error term is always positive and can simply be canwww.national.com 38 GND, may prevent successful SMBus communication with the LM96163. SMBus no acknowledge is the most common symptom, causing unnecessary traffic on the bus. Although the SMBus maximum frequency of communication is rather low (100 kHz 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 3 dB corner frequency of about 40 MHz is included on the LM96163's SMBCLK input. Additional resistance can be added in series with the SMBDAT 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 SMBDAT and SMBCLK lines. 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 2 cm 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 LM96163's GND pin is as close as possible to the Processor's GND associated with the sense diode. 9. Leakage current between D+ and GND should be kept to a minimum. Thirteen nano-amperes of leakage can cause as much as 0.2°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 400 mVp-p (typical hysteresis) and undershoot less than 500 mV below 39 www.national.com LM96163 5. LM96163 Physical Dimensions inches (millimeters) unless otherwise noted 10-Lead Lead Less Package (LLP or QFN) JEDEC Registration Number MO-229-WEED-5 Order Number LM96163CISD or LM96163CISDX NS Package Number SDA10A www.national.com 40 LM96163 Notes 41 www.national.com LM96163 Remote Diode Digital Temperature Sensor with Integrated Fan Control and TruTherm BJT Transistor Beta Compensation Technology Notes For more National Semiconductor product information and proven design tools, visit the following Web sites at: Products Design Support Amplifiers www.national.com/amplifiers WEBENCH www.national.com/webench Audio www.national.com/audio Analog University www.national.com/AU Clock Conditioners www.national.com/timing App Notes www.national.com/appnotes Data Converters www.national.com/adc Distributors www.national.com/contacts Displays www.national.com/displays Green Compliance www.national.com/quality/green Ethernet www.national.com/ethernet Packaging www.national.com/packaging Interface www.national.com/interface Quality and Reliability www.national.com/quality LVDS www.national.com/lvds Reference Designs www.national.com/refdesigns Power Management www.national.com/power Feedback www.national.com/feedback Switching Regulators www.national.com/switchers LDOs www.national.com/ldo LED Lighting www.national.com/led PowerWise www.national.com/powerwise Serial Digital Interface (SDI) www.national.com/sdi Temperature Sensors www.national.com/tempsensors Wireless (PLL/VCO) www.national.com/wireless THE CONTENTS OF THIS DOCUMENT ARE PROVIDED IN CONNECTION WITH NATIONAL SEMICONDUCTOR CORPORATION (“NATIONAL”) PRODUCTS. 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