LM63 ± 1˚C/ ± 3˚C Accurate Remote Diode Digital Temperature Sensor with Integrated Fan Control General Description The LM63 is a remote diode temperature sensor with integrated fan control. The LM63 accurately measures: (1) its own temperature and (2) the temperature of a diodeconnected transistor, such as a 2N3904, or a thermal diode commonly found on Computer Processors, Graphics Processor Units (GPU) and other ASIC’s. The LM63 remote temperature sensor’s accuracy is factory trimmed for the series resistance and 1.0021 non-ideality of the Intel ® 0.13 µm Pentium ® 4 and Mobile Pentium 4 Processor-M thermal diode. The LM63 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 LM63 also features an integrated, pulse-widthmodulated (PWM), open-drain fan control output. Fan speed is a combination of the remote temperature reading, the lookup table and the register settings. The 8-step Lookup Table enables the user to program a non-linear fan speed vs. temperature transfer function often used to quiet acoustic fan noise. Features n Accurately senses diode-connected 2N3904 transistors or thermal diodes on-board large processors or ASIC’s n Accurately senses its own temperature n Factory trimmed for Intel Pentium 4 and Mobile Pentium 4 Processor-M thermal diodes n Integrated PWM fan speed control output n Acoustic fan noise reduction with User-programmable 8-step Lookup Table n Multi-function, user-selectable pin for either ALERT output, or Tachometer input, functions n Tachometer input for measuring fan RPM n Offset register can adjust for a variety of thermal diodes n 10 bit plus sign remote diode temperature data format, with 0.125˚C resolution n SMBus 2.0 compatible interface, supports TIMEOUT n LM86-compatible pinout n LM86-compatible register set n 8-pin SOIC package Key Specifications j Remote Diode Temp Accuracy error) Ambient Temp Diode Temp IPWML Max (with quantization Max Error Version 30 to 50˚C 60 to 100˚C 5 mA LM63C 30 to 50˚C 60 to 100˚C 5 mA LM63D 0 to 85˚C 25 to 125˚C 8 mA All ± 1.0˚C ± 3.0˚C ± 3.0˚C j Local Temp Accuracy (includes quantization error) Ambient Temp Max Error 25˚C to 125˚C ± 3.0˚C j Supply Voltage 3.0 V to 3.6 V j Supply Current 1.3 mA (typ) Applications n Computer Processor Thermal Management (Laptop, Desktop, Workstations, Servers) n Graphics Processor Thermal Management n Electronic Test Equipment n Projectors n Office Equipment n Industrial Controls Connection Diagram 20057001 Intel ® and Pentium ® are registered trademarks of Intel Corporation. © 2003 National Semiconductor Corporation DS200570 www.national.com LM63 ± 1˚C/ ± 3˚C Accurate Remote Diode Digital Temperature Sensor with Integrated Fan Control May 2003 LM63 Pin Descriptions Pin Name Input/Output Function and Connection 1 VDD Power Supply Input 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 LM63’s VDD pin. 2 D+ Analog Input Connect to the anode (positive side) of the remote diode. A 2.2 nF ceramic capacitor must be connected between pins 2 and 3. 3 D− Analog Input Connect to the cathode (negative side) of the remote diode. A 2.2 nF ceramic capacitor must be connected between pins 2 and 3. 4 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). 5 GND Ground 6 ALERT/TACH Digital I/O 7 SMBDAT Digital Input/ Open-Drain Output 8 SMBCLK Digital Input This is the analog and digital ground return. Depending on how the LM63 is programmed, this pin is either an open-drain ALERT output or a tachometer input for measuring fan speed. The power-on default for this pin is the ALERT function. This is the bi-directional SMBus data line. Digital Input. This is the SMBus clock input. Simplified Block Diagram 20057002 www.national.com 2 LM63 Typical Application 20057003 Ordering Information Part Description Top Mark Order Number Transport Media LM63C ( ± 1˚C) 8-pin SOIC LM63CIMA LM63CIMAX 2500 Units in Tape and Reel LM63C ( ± 1˚C) 8-pin SOIC LM63CIMA LM63CIMA 95 Units in Rail LM63D ( ± 3˚C) 8-pin SOIC LM63DIMA LM63DIMAX 2500 Units in Tape and Reel LM63D ( ± 3˚C) 8-pin SOIC LM63DIMA LM63DIMA 95 Units in Rail LM63 Evaluation Board With Software and User’s Guide N/A LM63EVAL Packaged 3 www.national.com LM63 Absolute Maximum Ratings ESD Susceptibility (Note 4) (Notes 1, Human Body Model 2) Supply Voltage, VDD −0.3 V to 6.0 V Voltage on SMBDAT, SMBCLK, ALERT/Tach, PWM Pins −0.5 V to 6.0 V Voltage on Other Pins SOIC-8 Package (Note 6) ± 1 mA Input Current at All Other Pins (Note 3) 5 mA Package Input Current (Note 3) Vapor Phase (60 seconds) 215˚C Infrared (15 seconds) 220˚C Operating Ratings (Notes 1, 2) 30 mA Package Power Dissipation (Note 5) 10 mA Storage Temperature TMIN ≤ TA ≤ TMAX Specified Temperature Range SMBDAT, ALERT, PWM pins Output Sink Current 200 V Soldering Information, Lead Temperature −0.3 V to (VDD + 0. 3 V) Input Current, D− Pin 2000 V Machine Model −65˚C to +150˚C LM63CIM, LM63DIM 0˚C ≤ TA ≤ +85˚C Remote Diode Temperature Range 0˚C ≤ TA ≤ +125˚C Supply Voltage Range (VDD) +3.0 V to +3.6 V 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 = TMIN to TMAX; all other limits TA = +25˚C. Parameter Temperature Error Using the Remote Thermal Diode of an Intel Pentium 4 or Mobile Pentium 4 Processor-M with typical non-ideality of 1.0021.For other processors e-mail [email protected] to obtain the latest data. Temperature Error Using the Local Diode Conditions TA = +30 to +50˚C IPWML ≤ 5 mA TD = +60 to +100˚C TD = Remote Diode Junction Temperature TA = +0 to +85˚C IPWML ≤ 8 mA TD = +25 to +125˚C TA = +25 to +125˚C (Note 10) Typical (Note 7) Units (Limits) LM63C ±1 ˚C (max) LM63D ±3 ˚C (max) All ±3 ˚C (max) ±3 ˚C (max) ±1 All Remote Diode Resolution 11 All Local Diode Resolution Conversion Time, All Temperatures Limits (Note 8) Version ˚C 8 Bits All Fastest Setting D− Source Voltage (VD+ − VD−) = +0.65 V; High Current 1 All 31.25 All 0.7 All 160 Diode Source Current Low Current Bits 0.125 All ˚C 34.4 ms (max) V 315 µA (max) 110 µA (min) 20 µA (max) 7 µA (min) 13 Operating Electrical Characteristics Parameter Typ (Note 7) Conditions ALERT and PWM Output Saturation Voltage ALERT IOUT 4 mA IOUT 6 mA www.national.com 5 mA 0.4 0.55 SMBus Inactive, 16 Hz Conversion Rate 1.1 STANDBY Mode 300 4 Units PWM Power-On-Reset Threshold Voltage Supply Current (Note 9) Limits (Note 8) V (max) 2.4 V (max) 1.8 V (min) 2.0 mA (max) µA LM63 AC 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. Limits (Note 8) Units (Limit) Fan Control Accuracy ± 10 % (max) Fan Full-Scale Count 65535 (max) Symbol Parameter Typical (Note 7) Conditions TACHOMETER ACCURACY Fan Counter Clock Frequency 90 kHz Fan Count Update Frequency 1.0 Hz FAN PWM OUTPUT ± 10 Frequency Accuracy % (max) Digital Electrical Characteristics Symbol Parameter Typical (Note 7) Conditions Limits (Note 8) Units (Limit) 2.1 V (min) VIH Logical High Input Voltage 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 20 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 8) Units (Limit) SMBDAT OPEN-DRAIN OUTPUT VOL Logic Low Level Output Voltage IOL = 4 mA IOH High Level Output Current VOUT = VDD 0.03 0.4 V (max) 10 µA (max) SMBDAT, SMBCLK INPUTS VIH Logical High Input Voltage 2.1 V (min) VIL Logical Low Input Voltage 0.8 V (max) VHYST Logic Input Hysteresis Voltage 320 5 mV www.national.com LM63 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 LM63 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 LM63. They adhere to but are not necessarily the same as the SMBus bus specifications. Symbol Parameter fSMB SMBus Clock Frequency Conditions to VIN(0) Limits (Note 8) Units (Limit) 10 100 kHz (min) kHz (max) tLOW SMBus Clock Low Time From VIN(0) max tHIGH SMBus Clock High Time From VIN(1) min tR SMBus Rise Time (Note 11) tF SMBus Fall Time (Note 12) 0.3 µs (max) tOF Output Fall Time CL = 400 pF, IO = 3 mA 250 ns (max) tTIMEOUT SMBData and SMBCLK Time Low for Reset of Serial Interface See (Note 13) 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 300 930 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) to VIN(1) max min 4.7 µs (min) 4.0 50 µs (min) µs (max) 1 µs (max) 20057004 SMBus Timing Diagram for SMBCLK and SMBDAT Signals www.national.com 6 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 LM63’s pins. The nominal breakdown voltage of D3 is 6.5 V. Care should be taken not to forward bias the parasitic diode, D1, present on pins D+ and D−. Doing so by more than 50 mV may corrupt temperature measurements. An "X" means it exists in the circuit. Pin Name PIN # D1 D2 D3 D4 D5 D6 R1 X X X X X SNP VDD 1 D+ 2 X X D− 3 X X PWM 4 X X X X ALERT/Tach 6 X X X X SMBDAT 7 X X X X SMBCLK 8 X X ESD CLAMP X X X X X 20057005 FIGURE 1. ESD Protection Input Structure Note 4: Human body model, 100 pF discharged through a 1.5 kΩ resistor. Machine model, 200 pF discharged directly into each pin. See Figure 1 above for the ESD Protection Input Structure. Note 5: Thermal resistance junction-to-ambient when attached to a printed circuit board with 2 oz. foil is 168˚C/W. Note 6: See the URL “http://www.national.com/packaging/” for other recommendations and methods of soldering surface mount devices. 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: Limits are guaranteed to National’s AOQL (Average Outgoing Quality Level). Note 9: The supply current will not increase substantially with an SMBus transaction. 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 LM63 and the thermal resistance. See (Note 5) for the thermal resistance to be used in the self-heating calculation. Note 11: The output rise time is measured from (VIL max - 0.15 V) to (VIH min + 0.15 V). Note 12: The output fall time is measured from (VIH min + 0.15 V) to (VIL min - 0.15 V). Note 13: Holding the SMBData and/or SMBCLK lines Low for a time interval greater than tTIMEOUT will reset the LM63’s SMBus state machine, therefore setting SMBDAT and SMBCLK pins to a high impedance state. In the LM63 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) userprogrammable 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. The temperature hysteresis is set by the value placed in the Hysteresis Register (TH). The LM63 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 1.0 Functional Description The LM63 Remote Diode Temperature Sensor with Integrated Fan Control incorporates a ∆VBE-based temperature sensor using a Local or Remote diode and a 10-bit plus sign ∆Σ ADC (Delta-Sigma Analog-to-Digital Converter). The pulse-width modulated (PWM) open-drain output, with a pull-up resistor, can drive a switching transistor to modulate the fan. When the ALERT/Tach is programmed to the Tach mode the LM63 can measure the fan speed on the pulses from the fan’s tachometer output. When the ALERT/Tach pin is programmed to the ALERT mode the ALERT open-drain output will be pulled low when the measured temperature exceeds certain programmed limits when enabled. Details are contained in the sections below. The LM63’s two-wire interface is compatible with the SMBus Specification 2.0 . For more information the reader is directed to www.smbus.org. 7 www.national.com LM63 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. LM63 1.0 Functional Description 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 Open, 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. (Continued) 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. 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 of the thermal diode if different from the 0.13 micron Intel Pentium 4 or Mobile Pentium 4 Processor-M processor’s thermal diode. See Section 4.1 Thermal Diode Non-Ideality. The three different ALERT modes will be discussed in the following sections. 1.1 CONVERSION SEQUENCE 1.2.1 ALERT Output as a Temperature Comparator When the LM63 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 3). 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. The LM63 takes approximately 31.25 ms to convert the Local Temperature (LT), Remote Temperature (RT), and to update all of its registers. The Conversion Rate may be modified using the Conversion Rate Register. When the conversion rate is modified a delay is inserted between conversions, the actual conversion time remains at 31.25 ms. Different Conversion Rates will cause the LM63 to draw different amounts of supply current as shown in Figure 2. 20057006 20057007 FIGURE 2. Supply Current vs Conversion Rate FIGURE 3. ALERT Output as Temperature Comparator Response Diagram 1.2 THE ALERT/TACH PIN AS ALERT OUTPUT The ALERT/Tach pin is a multi-use pin. In this section we will address the ALERT active-low open-drain output function. When the ALERT/Tach Select bit is written as a zero in the Configuration Register the ALERT output is selected. Also, when the ALERT Mask bit in the Configuration register is written as zero the ALERT interrupts are enabled. The LM63’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 LM63. www.national.com 1.2.2 ALERT Output as an Interrupt The LM63’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 LM63 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 Open. 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 8 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 LM63 or not at all. SMBus systems that implement the ARA protocol as suggested for the LM63 will be fully compatible with all competitive parts. The LM63 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. (Continued) cleared only upon a read command from the master (see Figure 4 ) 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. 2. Master senses ALERT low. Master reads the LM63 ALERT Status Register to determine what caused the ALERT. 3. LM63 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. Master senses SMBus alert line low Master sends a START followed by the Alert Response Address (ARA) with a Read Command. 3. Alerting Device(s) send ACK. 4. 5. 6. 7. 8. 20057008 Alerting Device(s) send their address. While transmitting their address, alerting devices sense whether their address has been transmitted correctly. (The LM63 will reset its ALERT output and set the ALERT Mask bit once its complete address has been transmitted successfully.) Master/slave NoACK Master sends STOP Master attends to conditions that caused the ALERT to be triggered. The ALERT Status Register is read and fan started, setpoints adjusted, etc. 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 LM63 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. FIGURE 4. ALERT Output as an Interrupt Temperature Response Diagram 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 LM63’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. 9 www.national.com LM63 1.0 Functional Description LM63 1.0 Functional Description Local Temperature data is represented by an 8-bit, two’s complement byte with an LSB equal to 1˚C: (Continued) Temperature Digital Output Binary Hex +125˚C 0111 1101 7D +25˚C 0001 1001 19 +1˚C 0000 0001 01 0˚C 0000 0000 00 −1˚C 1111 1111 FF −25˚C 1110 0111 E7 −55˚C 1100 1001 C9 1.6 OPEN-DRAIN OUTPUTS The SMBDAT, ALERT, and PWM outputs are open-drain outputs and do not have internal pull-ups. A “High” level will not be observed on these pins until pull-up current is provided by 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 LM63 and avoid temperature errors caused by self-heating of the device. The maximum value of the pull-up resistor to provide the 2.1 V high level is 88.7 kΩ. 20057009 FIGURE 5. ALERT Output as an SMBus ALERT Temperature Response Diagram 1.3 SMBus INTERFACE Since the LM63 operates as a slave on the SMBus the SMBCLK line is an input and the SMBDAT line is bidirectional. The LM63 never drives the SMBCLK line and it does not support clock stretching. According to SMBus specifications, the LM63 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 1.7 DIODE FAULT DETECTION The LM63 can detect fault conditions caused by the remote diode. If the D+ pin is detected to be shorted to VDD, or open: (1) the Remote Temperature High Byte (RTHB) register is loaded with 127˚C, (2) the Remote Temperature Low Byte (RTLB) register is loaded with 0, and (3) the OPEN bit (D2) in the status register is set. Therefore, if the Remote T_CRIT setpoint register (RCS): (1) is set to a value less than +127˚C and (2) the ALERT Mask is disabled, then the ALERT output pin will be pulled low. If the Remote High Setpoint High Byte (RHSHB) is set to a value less than +127˚C and (2) the ALERT Mask is disabled, then the ALERT will be pulled low. The OPEN bit by itself will not trigger an ALERT. If the D+ pin is shorted to either ground or D−, then the Remote Temperature High Byte (RTHB) register is loaded with −128˚C (1000 0000) and the OPEN bit in the ALERT Status Register will not be set. A temperature reading of −128˚C indicates that D+ is shorted to either ground or D-. If the value in the Remote Low Setpoint High Byte (RLSHB) Register is more than −128˚C and the ALERT Mask is Disabled, ALERT will be pulled low. 1.4 POWER-ON RESET (POR) DEFAULT STATES For information on the POR default states see Section 2.2 LM63 Register Map in Functional Order. 1.5 TEMPERATURE DATA FORMAT Temperature data can only be read from the Local and Remote Temperature registers. The High, Low and T_CRIT setpoint registers are Read/Write. Remote temperature data is represented by an 11-bit, two’s complement word with a Least Significant Bit (LSB) equal to 0.125˚C. The data format is a left justified 16-bit word available in two 8-bit registers: Temperature Digital Output Binary Hex +125˚C 0111 1101 0000 0000 7D00 +25˚C 0001 1001 0000 0000 1900 +1˚C 0000 0001 0000 0000 0100 +0.125˚C 0000 0000 0010 0000 0020 0˚C 0000 0000 0000 0000 0000 −0.125˚C 1111 1111 1110 0000 FFE0 −1˚C 1111 1111 0000 0000 FF00 −25˚C 1110 0111 0000 0000 E700 −55˚C 1100 1001 0000 0000 C900 www.national.com 1.8 COMMUNICATING WITH THE LM63 Each data register in the LM63 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 LM63 is comprised of an address byte and a command byte. A write to any register requires one data byte. Reading the LM63 Registers can take place after the requisite register setup sequence takes place. See Section 2.1.1 LM63 Required Initial Fan Control Register Sequence. The data byte has the Most Significant Bit (MSB) first. At the end of a read, the LM63 can accept either Acknowledge or 10 LM63 1.0 Functional Description (Continued) No-Acknowledge from the Master. Note that the NoAcknowledge is typically used as a signal for the slave indicating that the Master has read its last byte. 1.9 DIGITAL FILTER The LM63 incorporates a user-configured digital filter to suppress erroneous Remote Temperature readings due to noise. The filter is accessed in the Remote Diode Temperature Filter and Comparator Mode Register. The filter can be set according to the following table. Level 2 is maximum filtering. Digital Filter Selection Table 20057011 D2 D1 Filter 0 0 No Filter 0 1 Level 1 1 0 Level 1 1 1 Level 2 FIGURE 7. Impulse Response of the Digital Filter 20057012 20057010 FIGURE 8. Digital Filter Response in an Intel Pentium 4 processor System. The Filter on and off curves were purposely offset to better show noise performance. FIGURE 6. Step Response of the Digital Filter 11 www.national.com LM63 1.0 Functional Description (Continued) 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. 1.10 FAULT QUEUE The LM63 incorporates a Fault Queue to suppress erroneous ALERT triggering . The Fault Queue prevents false triggering by requiring three consecutive out-of-limit HIGH, LOW, or T_CRIT temperature readings. See Figure 9. 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. 1.12 SERIAL INTERFACE RESET In the event that the SMBus Master is reset while the LM63 is transmitting on the SMBDAT line, the LM63 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 LM63 SMBus state machine resets to the SMBus idle state if either SMBData or SMBCLK are held Low for more than 35 ms (tTIMEOUT). All 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 all devices on the bus, either the SMBCLK or the SMBData 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 LM63 will respond properly to an SMBus start condition at any point during the communication. After the start the LM63 will expect an SMBus Address address byte. 20057013 FIGURE 9. Fault Queue Temperature Response Diagram www.national.com 12 LM63 2.0 LM63 Registers 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 LM63 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. 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. DATA BITS Register 0x[HEX] Register Name 00 Local Temperature LT7 LT6 LT5 LT4 LT3 LT2 LT1 LT0 01 Rmt Temp MSB RTHB ± RTHB14 RTHB13 RTHB12 RTHB11 RTHB10 RTHB9 RTHB8 02 ALERT Status BUSY LHIGH 0 RHIGH RLOW RDFA RCRIT TACH 03 Configuration ALTMSK STBY PWMDIS 0 0 ALT/TCH TCRITOV FLTQUE D7 D6 D5 D4 D3 D2 D1 D0 04 Conversion Rate 0 0 0 0 CONV3 CONV2 CONV1 CONV0 05 Local High Setpoint LHS7 LHS6 LHS5 LHS4 LHS3 LHS2 LHS1 LHS0 06 [Reserved] Not Used 07 Rmt High Setpoint MSB RHSHB15 RHSHB14 RHHBS13 RHSHB12 RHSHB11 RHSHB10 RHSHB9 RHSHB8 08 Rmt Low Setpoint MSB RLSHB15 RLSHB14 RLSHB13 RLSHB12 RLHBS11 RLSHB10 RLSHB9 RLSHB8 (09) Same as 03 (0A) Same as 04 (0B) Same as 05 0C [Reserved] (0D) Same as 07 (0E) Same as 08 0F One Shot 10 Rmt Temp LSB Not Used Write Only. Write command triggers one temperature conversion cycle. RTLB7 RTLB6 RTLB5 0 0 0 0 RTOHB9 RTOHB8 11 Rmt Temp Offset MSB 12 Rmt Temp Offset LSB RTOLB7 RTOLB6 RTOLB5 0 0 0 0 0 13 Rmt High Setpoint LSB RHSLB7 RHSLB6 RHSLB5 0 0 0 0 0 14 Rmt Low Setpoint LSB RLSLB7 RLSLB6 RLSLB5 0 0 0 0 0 1 ALTMSK6 1 15 [Reserved] 16 ALERT Mask 17 [Reserved] RTOHB15 RTOHB14 RTOHB13 RTOHB12 RTOHB11 RTOHB10 0 Not Used ALTMSK4 ALTMSK3 1 ALTMSK1 ALTMSK0 Not Used 18 [Reserved] 19 Rmt TCRIT Setpoint Not Used 1A–1F [Reserved] Not Used 20 [Reserved] Not Used RCS7 RTH7 RCS6 RTH6 RCS5 RTH5 RCS4 RTH4 RCS3 21 Rmt TCRIT Hysteresis 22–2F [Reserved] Not Used RTH3 30–3F [Reserved] Not Used RCS2 RCS1 RCS0 RTH2 RTH1 RTH0 TEDGE0 40–45 [Reserved] 46 Tach Count LSB TCLB5 TCLB4 TCLB3 TCLB2 Not Used TCLB1 TCLB0 TEDGE1 47 Tach Count MSB TCHB13 TCHB12 TCHB11 TCHB10 TCHB9 TCHB8 TCHB7 TCHB6 48 Tach Limit LSB TLLB7 TLLB6 TLLB5 TLLB4 TLLB3 TLLB2 Not Used Not Used 49 Tach Limit MSB TLHB15 TLHB14 TLHB13 TLHB12 TLHB11 TLHB10 TLHB9 TLHB8 4A PWM and RPM 0 0 PWPGM PWOUT ± PWCKSL 0 TACH1 TACH0 4B Fan Spin-Up Config 0 0 SPINUP SPNDTY1 SPNDTY0 SPNUPT2 SPNUPT1 SPNUPT0 4C PWM Value 0 0 PWVAL5 PWVAL4 PWVAL3 PWVAL2 PWVAL1 PWVAL0 4D PWM Frequency 0 0 0 PWMF4 PWMF3 PWMF2 PWMF1 PWMF0 4E [Reserved] Not Used 13 www.national.com LM63 2.0 LM63 Registers Register 0x[HEX] Register Name 4F Lookup Table Hystersis 50–5F Lookup Table 60–BE [Reserved] BF Rmt Diode Temp Filter C0–FD [Reserved] (Continued) DATA BITS D7 D6 D5 D4 D3 D2 D1 D0 0 0 0 LOOKH4 LOOKH3 LOOKH2 LOOKH1 LOOKH0 Lookup Table of up to 8 PWM and Temp Pairs in 8-bit Registers Not Used 0 0 0 0 0 RDTF1 RDTF0 ALTCOMP Not Used FE Manufacturer’s ID 0 0 0 0 0 0 0 1 FF Stepping/Die Rev. ID 0 1 0 0 0 0 0 1 2.2 LM63 REGISTER MAP IN FUNCTIONAL ORDER 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 4A PWM and RPM R/W 20 4B Fan Spin-Up Configuration R/W 3F 4D PWM Frequency R/W 17 4C PWM Value Read Only (R/W if Override Bit is Set) 00 Lookup Table R/W See Table Lookup Table Hysteresis R/W 04 R/W 00 50–5F 4F 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 MSB Read Only N/A 10 Remote Temperature LSB Read Only N/A 11 Remote Temperature Offset MSB R/W 00 Remote Temperature Offset LSB R/W 00 Remote High Setpoint MSB R/W 46 (70˚C) 12 07 (0D) 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 TCRIT Setpoint R/W 55 (85˚C) 21 Remote TCRIT Hys R/W 0A (10˚C) BF Remote Diode Temperature Filter R/W 00 CONVERSION AND ONE-SHOT REGISTERS 04 (0A) 0F Conversion Rate One-Shot www.national.com 14 R/W 08 Write Only N/A Register [HEX] LM63 2.0 LM63 Registers (Continued) Register Name Read/Write POR Default [HEX] ALERT STATUS AND MASK REGISTERS 02 ALERT Status Read Only N/A 16 ALERT Mask R/W A4 Read Only 41 ID AND TEST REGISTERS FF Stepping/Die Rev. ID [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 Not Used N/A N/A N/A 18 Not Used N/A 1A–1F Not Used N/A N/A 20 Not Used N/A N/A 22–2F Not Used N/A N/A 30–3F Not Used N/A N/A 40–45 Not Used N/A N/A 4E Not Used N/A N/A 60–BE Not Used N/A N/A C0–FD Not Used N/A N/A 2.3 LM63 INITIAL REGISTER SEQUENCE AND REGISTER DESCRIPTIONS IN FUNCTIONAL ORDER The following is a Register Map grouped in functional and sequence order. Some address locations have been left blank to maintain compatibility with LM86. 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. 2.3.1 LM63 Required Initial Fan Control Register Sequence Important! The BIOS must follow the sequence below to configure the following Fan Registers for the LM63 before using any of the Fan or Tachometer or PWM registers: Step [Register]HEX and Setup Instructions 1 [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. 2 [4B] Write bits 0 through 5 to program the spin-up settings. 3 [4D] Write bits 0 through 4 to set the frequency settings. This works with the PWM internal clock select. 4 Choose, then write, only one of the following: A. [4F–5F] the Lookup Table, or B. [4C] the PWM value bits 0 through 5. 5 If Step 4A, Lookup Table, was chosen and written then write [4A] bit 5 = 0. All other registers can be written at any time after the above sequence. 15 www.national.com LM63 2.0 LM63 Registers (Continued) LM63 Register Descriptions In Functional Order Fan Control Registers Address Hex Read/ Write Bits POR Value Name Description 4AHEX FAN PWM AND TACHOMETER CONFIGURATION REGISTER 7:6 4A R/W 00 These bits are unused and always set to 0. 5 1 0: the PWM Value (register 4C) and the Lookup Table (50–5F) 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 4C) and the Lookup Table (Register 50–5F) 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. 4 0 PWM Output Polarity 3 0 PWM Clock Select if 0, the master PWM clock is 360 kHz if 1, the master PWM clock is 1.4 kHz. 2 0 [Reserved] Always write 0 to this bit. Tachometer Mode 00: Traditional tach input monitor, false readings when under minimum detectable RPM. 01: Traditional tach input monitor, FFFF reading when under minimum detectable RPM. 10: Most accurate readings, FFFF reading when under minimum detectable RPM. 11: Least effort on programmed PWM of fan, FFFF reading when under minimum detectable RPM. Note: If the PWM Clock is 360 kHz, mode 00 is used regardless of the setting of these two bits. 1:0 www.national.com 00 PWM Program 0: the PWM output pin will be 0 V for fan OFF and open for fan ON. 1: the PWM output pin will be open for fan OFF and 0 V for fan ON. 16 (Continued) Fan Control Registers Address Hex Read/ Write Bits LM63 2.0 LM63 Registers POR Value (Continued) Name Description 4BHEX FAN PWM AND TACHOMETER CONFIGURATION REGISTER 7:6 5 4B 0 These bits are unused and always set to 0 1 If 0, the fan spin-up uses the duty cycle and spin-up time, bits 0–4. If 1, the LM63 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. R/W 4:3 2:0 11 111 Fast Tachometer Spin-Up PWM Spin-Up Duty Cycle PWM Spin-Up Time 00: Spin-Up cycle bypassed (no Spin-Up), unless Fast Tachometer Terminated Spin-Up (bit 5) is set. 01: 50% 10: 75%–81% Depends on PWM Frequency. See Applications Notes. 11: 100% 000: 001: 010: 011: 100: 101: 110: 111: Spin-Up cycle bypassed (No Spin-Up) 0.05 seconds 0.1 s 0.2 s 0.4 s 0.8 s 1.6 s 3.2 s 4DHEX FAN PWM FREQUENCY REGISTER 7:5 4D R/W 4:0 000 10111 These bits are unused and always set to 0 PWM Frequency The PWM Frequency = PWM_Clock / 2n, where PWM_Clock = 360 kHz or 1.4 kHz (per the PWM 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. 4CHEX PWM VALUE REGISTER 7:6 4C Read (Write only if reg 4A bit 5 = 1.) 5:0 00 000000 These bits are unused and always set to 0 PWM Value If PWM Program (register 4A, bit 5) = 0 this register is read only and reflects the LM63’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, 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 %. 17 www.national.com LM63 2.0 LM63 Registers (Continued) Fan Control Registers Address Hex Read/ Write Bits (Continued) POR Value Name Description 50HEX to 5FHEX LOOKUP TABLE (7 Bits for Temperature and 6 Bits for PWM for each Temperature/PWM Pair) 50 51 52 53 54 55 56 57 58 Read. (Write only if reg 4A bit 5 = 1.) 59 5A 5B 5C 5D 5E 5F 7 0 6:0 0x7F 7:6 00 5:0 0x3F 7 0 6:0 0x7F 7:6 00 5:0 0x3F 7 0 6:0 0x7F 7:6 00 5:0 0x3F 7 0 6:0 0x7F 7:6 00 5:0 0x3F 7 0 6:0 0x7F 7:6 00 5:0 0x3F 7 0 6:0 0x7F 7:6 00 5:0 0x3F 7 0 6:0 0x7F 7:6 00 5:0 0x3F 7 0 6:0 0x7F 7:6 00 5:0 0x3F Lookup Table Temperature Entry 1 This bit is unused and always set to 0. Lookup Table PWM Entry 1 These bits are unused and always set to 0. Lookup Table Temperature Entry 2 This bit is unused and always set to 0. Lookup Table PWM Entry 2 These bits are unused and always set to 0. Lookup Table Temperature Entry 3 This bit is unused and always set to 0. Lookup Table PWM Entry 3 These bits are unused and always set to 0. Lookup Table Temperature Entry 4 This bit is unused and always set to 0. Lookup Table PWM Entry 4 These bits are unused and always set to 0. Lookup Table Temperature Entry 5 This bit is unused and always set to 0. Lookup Table PWM Entry 5 Lookup Table Temperature Entry 6 Lookup Table PWM Entry 6 If the remote diode temperature exceeds this value, the PWM output will be the value in Register 51. The PWM value corresponding to the temperature limit in register 50. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 53. The PWM value corresponding to the temperature limit in register 52. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 55. The PWM value corresponding to the temperature limit in register 54. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 57. The PWM value corresponding to the temperature limit in register 56. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 59. These bits are unused and always set to 0. The PWM value corresponding to the temperature limit in register 58. This bit is unused and always set to 0. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 5B. These bits are unused and always set to 0. The PWM value corresponding to the temperature limit in register 5A. Lookup Table Temperature Entry 7 This bit is unused and always set to 0. Lookup Table PWM Entry 7 These bits are unused and always set to 0. Lookup Table Temperature Entry 8 This bit is unused and always set to 0. Lookup Table PWM Entry 8 These bits are unused and always set to 0. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 5D. The PWM value corresponding to the temperature limit in register 5C. If the remote diode temperature exceeds this value, the PWM output will be the value in Register 5F. The PWM value corresponding to the temperature limit in register 5E. 4FHEX LOOKUP TABLE HYSTERESIS 4F www.national.com 7:5 000 4:0 00100 R/W Lookup Table Hysteresis These bits are unused and always set to 0 The amount of hysteresis applied to the Lookup Table. (1 LSB = 1˚C). 18 LM63 2.0 LM63 Registers (Continued) Configuration Register ADDRESS Hex Read/ Write Bits POR Value Name Description 03 (09)HEX CONFIGURATION REGISTER 7 6 03 (09) 0 ALERT Mask When this bit is a 0, ALERT interrupts are enabled. When this bit is set to a 1, ALERT interrupts are masked, and the ALERT pin is always in a high impedance (open) state. When this bit is a 0, the LM63 is in operational mode, converting, comparing, and updating the PWM output continuously. When this bit is a 1, the LM63 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. Operation of the PWM output in STANDBY depends on the setting of bit 5 in this register. 0 STANDBY 5 0 PWM Disable in STANDBY When this bit is a 0, the LM63’s PWM output continues to output the current fan control signal while in STANDBY. When this bit is a 1, the PWM output is disabled (as defined by the PWM polarity bit) while in STANDBY. 4:3 00 These bits are unused and always set to 0. 0 ALERT/Tach Select When this bit is a 0, the ALERT/Tach pin is an open drain ALERT output. When this bit is a 1, the ALERT/Tach pin is a high impedance Tachometer input. Note that if this bit is set, the function of the ALERT/Tach pin must be Tach input, so an external ALERT condition will not occur. T_CRIT Limit Override The T_CRIT limit for the remote diode is nominally 85˚C. This value can be changed once after power-up by first setting this bit to a 1, then programming a new T_CRIT value into the Remote Diode T_CRIT Limit (register 0x19). The T_CRIT value can not be changed again except by cycling power to the LM63. 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 2 1 0 0 0 19 www.national.com LM63 2.0 LM63 Registers (Continued) Tachometer Count And Limit Registers ADDRESS Read/ Hex Write Bits POR 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 Read Only 7:0 N/A Tachometer Count (MSB) Read Only 7:2 N/A Tachometer Count (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 are reversed from the 16-bit temperature readings. Bits Edges Used 00: 46 Read Only 1:0 00 Tachometer Edge Count 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. 49HEX TACHOMETER LIMIT (MSB) and 48HEX TACHOMETER LIMIT (LSB) REGISTERS 49 48 R/W 7:0 0xFF Tachometer Limit MSB) R/W 7:2 0xFF Tachometer Limit (LSB) R/W 1:0 [Reserved] These registers contain the current 16-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 are reversed from the 16 bit temperature readings. Not Used. Local Temperature And Local High Setpoint Registers ADDRESS Hex Read/ Write Bits POR Value Name Description 00HEX LOCAL TEMPERATURE REGISTER (8-bits) 00 Read Only 7:0 N/A Local Temperature Reading (8-bit) 8-bit integer representing the temperature of the LM63 die. 05 (0B)HEX LOCAL HIGH SETPOINT REGISTER (8-bits) 05 www.national.com R/W 7:0 0x46 (70˚) Local HIGH Setpoint High Setpoint for the internal diode. 20 LM63 2.0 LM63 Registers (Continued) Remote Diode Temperature, Offset And Setpoint Registers ADDRESS Hex Read/ Write 01 Read Only 10 Read Only 11 R/W 12 R/W 07 (0D) R/W 13 R/W 08 (0E) R/W 14 R/W Bits 7:0 POR Value Name Description N/A Remote Diode Temperature Reading (MSB) This is the MSB of the 2’s complement value, representing the temperature of the remote diode connected to the LM63. Bit 7 is the sign bit, bit 6 has a weight of 0x40 (64˚), and bit 0 has a weight of 1˚C. This byte to be read first. Remote Diode Temperature Reading (MSB) 7:5 N/A 4:0 00 7:5 00 7:5 00 4:0 00 Remote Temperature OFFSET (LSB) 7:0 0x46 (70˚C) Remote HIGH Setpoint (MSB) 7:5 00 4:0 00 Remote HIGH Setpoint (LSB) 7:0 00 (0˚C) Remote LOW Setpoint (MSB) 7:5 00 4:0 00 Remote LOW Setpoint (LSB) This is the LSB of the 2’s complement value, representing the temperature of the remote diode connected to the LM63. Bit 7 has a weight 0.5˚C, bit 6 has a weight of 0.25˚C, and bit 5 has a weight of 0.125˚C. Always 00. Remote Temperature OFFSET (MSB) 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 LM63’s ADC to form the temperature reading contained in registers 01 and 10. Always 00. High setpoint temperature for remote diode. Same format as Remote Temperature Reading (registers 01 and 10). Always 00. Low setpoint temperature for remote diode. Same format as Remote Temperature Reading (registers 01 and 10). Always 00. 19 R/W 7:0 0x55 (85˚C) Remote Diode T_CRIT Limit This 8-bit integer storing the T_CRIT limit is nominally 85˚C. This value can be changed once after power-up by setting T_CRIT Limit Override (bit 1) in the Configuration register to a 1, then programming a new T_CRIT value into this register. The T_CRIT Limit can not be changed again except by cycling power to the LM63. 21 R/W 7:0 0x0A (10˚C) Remote Diode T_CRIT Hysteresis 8-bit integer storing T_CRIT hysteresis. T_CRIT stays activated until the remote diode temperature goes below [(T_CRIT Limit) — (T_CRIT Hysteresis)]. 7:3 00000 2:1 BF 00 Remote Diode Temperature Filter 0 Comparator Mode R/W 0 These bits are unused and should always set to 0. 00: 01: 10: 11: Filter Filter Filter Filter Disabled Level 1 (minimal filtering, same as 10) Level 1 (minimal filtering, same as 01) Level 2 (maximum filtering) 0: the ALERT/Tach pin functions normally. 1: the ALERTTach pin behaves as a comparator, asserting itself when an ALERT condition exists, de-asserting itself when the ALERT condition goes away. 21 www.national.com LM63 2.0 LM63 Registers (Continued) ALERT Status And Mask Registers ADDRESS Hex Read/ Write Bits POR 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.) 0 Busy When this bit is a 0, the ADC is not converting. When this bit is set to a 1, the ADC is performing a conversion. This bit does not affect ALERT status. 6 0 Local High Alarm When this bit is a 0, the internal temperature of the LM63 is at or below the Local High Setpoint. When this bit is a 1, the internal temperature of the LM63 is above the Local High Setpoint, and an ALERT is triggered. 5 0 7 4 3 0x02 This bit is unused and always read as 0. 0 Remote High Alarm When this bit is a 0, the temperature of the Remote Diode is at or below the Remote High Setpoint. When this bit is a 1, the temperature of the Remote Diode is above the Remote High Setpoint, and an ALERT is triggered. 0 Remote Low Alarm When this bit is a 0, the temperature of the Remote Diode is at or above the Remote Low Setpoint. When this bit is a 1, the temperature of the Remote Diode is below the Remote Low Setpoint, and an ALERT is triggered. 0 Remote Diode Fault Alarm When this bit is a 0, the Remote Diode appears to be correctly connected. When this bit is a 1, the Remote Diode may be disconnected or shorted. This Alarm does not trigger an ALERT. 0 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, and an ALERT is triggered.. 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. Note that if this bit is set, the function of the ALERT/Tach pin must be Tach input, so an external ALERT condition will not be generated. The user may read the status register periodically to find out if and ALERT condition has occurred. Read Only 2 1 0 www.national.com 0 22 LM63 2.0 LM63 Registers (Continued) ALERT Status And Mask Registers ADDRESS Hex Read/ Write Bits POR Value (Continued) Name Description 16HEX ALERT MASK REGISTER (8-bits) 7 16 R/W 1 This bit is unused and always read as 1. Local High Alarm Mask When this bit is a 0, a Local High Alarm event will generate an ALERT. When this bit is a 1, a Local High Alarm will not generate an ALERT 6 0 5 1 4 0 Remote High Alarm Mask 3 0 Remote Low Alarm Mask 2 1 1 0 Remote T_CRIT Alarm Mask When this bit is a 0, a Remote T_CRIT event will generate an ALERT. When this bit is a 1, a Remote T_CRIT event will not generate an ALERT. 0 0 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. This bit is unused and always read as 1. When this bit is a 0, Remote High Alarm event will generate an ALERT. When this bit is a 1, a Remote High Alarm event will not generate an ALERT. When this bit is a 0, a Remote Low Alarm event will generate an ALERT. When this bit is a 1, a Remote Low Alarm event will not generate an ALERT. This bit is unused and always read as 1. Conversion Rate And One-Shot Registers ADDRESS Hex Read/ Write Bits POR Value Name Description 04 (0A)HEX CONVERSION RATE REGISTER (8-bits) 04 (0A) R/W 7:0 0x08 Conversion Rate Sets the conversion rate of the LM63. 00000000 = 0.0625 Hz 00000001 = 0.125 Hz 00000010 = 0.25 Hz 00000011 = 0.5 Hz 00000100 = 1 Hz 00000101 = 2 Hz 00000110 = 4 Hz 00000111 = 8 Hz 00001000 = 16 Hz 00001001 = 32 Hz All other values = 32 Hz 04 (0A)HEX ONE-SHOT REGISTER (8-bits) 0F Write Only 7:0 N/A One Shot Trigger POR Value Name With the LM63 in the STANDBY mode a single write to this register will initiate one complete temperature conversion cycle. ID Registers ADDRESS Hex Read/ Write Bits Description FFHEX STEPPING / DIE REVISION ID REGISTER (8-bits) FF Read Only 7:0 0x41 Stepping/Die Revision ID Version of LM63 FEHEX MANUFACTURER’S ID REGISTER (8-bits) FE Read Only 7:0 0x01 Manufacturer’s ID 0x01 = National Semiconductor 23 www.national.com LM63 3.0 Application Notes 3.1 FAN CONTROL DUTY CYCLE VS. REGISTER SETTINGS AND FREQUENCY PWM Freq 4D [4:0] Step Resolution, % PWM Value 4D [5:0] for 100% PWM Value 4C [5:0] for about 75% 0 PWM Value 4C [5:0] for 50% PWM Freq at 360 kHz Internal Clock, kHz PWM Freq at 1.4 kHz Internal Clock, Hz Actual Duty Cycle, % When 75% is Selected Address 0 is mapped to Address 1 1 50 2 1 1 180.0 703.1 50.0 2 25 4 3 2 90.00 351.6 75.0 3 16.7 6 5 3 60.00 234.4 83.3 4 12.5 8 6 4 45.00 175.8 75.0 5 10.0 10 8 5 36.00 140.6 80.0 6 8.33 12 9 6 30.00 117.2 75.0 7 7.14 14 11 7 25.71 100.4 78.6 8 6.25 16 12 8 22.50 87.9 75.0 9 5.56 18 14 9 20.00 78.1 77.8 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 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: www.national.com 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) x 100% = 58.3%. 24 The LM63 has been optimized for use with the thermal diode on the die of an Intel Pentium 4 or a Mobile Pentium 4 Processor-M processor. A discrete diode can also be used to sense the temperature of external objects or ambient air. Remember that a discrete diode’s temperature will be affected, and often dominated by, the temperature of its leads. Most silicon diodes do not lend themselves well to this application. It is recommended that a diode-connected 2N3904 transistor be used. The base of the transistor is connected to the collector and becomes the anode. The emitter is the cathode. A LM63 with a diode-connected 2N3904 transistor approximates the temperature reading of the LM63 with the Pentium 4 processor by 1˚C. T2N3904 = TPENTIUM 4 − 1˚C (Continued) 3.2 USE OF THE LOOKUP TABLE FOR NON-LINEAR PWM VALUES VS TEMPERATURE The Lookup Table, Registers 50 through 5F, can be used to create a non-linear PWM vs Temperature curve that could be used to reduce the acoustic noise from processor fan due to linear or step transfer functions. An example is given below: EXAMPLE: In a particular system it was found that the best acoustic fan noise performance was found to occur when the PWM vs Temperature transfer function curve was parabolic in shape. From 25˚C to 105˚C the fan is to go from 20% to 100%. Since there are 8 steps to the Lookup Table we will break up the Temperature range into 8 separate temperatures. For the 80˚C over 8-steps = 10˚C per step. This takes care of the x-axis. For the PWM Value, we first select the PWM Frequency. In this example we will make the PWM Frequency (Register 4C) 20. 3.3.1 Diode Non_Ideality When a transistor is connected to a diode the following relationship holds for Vbe, T, and IF: For 100% Duty Cycle then, the PWM value is 40. For 20% the minimum is 40 x (0.2) = 8. We can then arrange the PWM, Temperature pairs in a parabolic fashion in the form of y = 0.005 • (x −25)2 + 8 Temperature PWM Value Calculated Closest PWM Value 25 8.0 8 35 8.5 9 45 10.0 10 55 12.5 13 65 16.0 16 75 20.5 21 85 26.0 26 95 32.5 33 105 40.0 40 where • • • • q = 1.6x10−19 Coulombs (the electron charge) T = Absolute Temperature in Kelvin k = 1.38x10−23 joules/K (Boltzmann’s constant) η is the non-ideality factor of the manufacturing process used to make the thermal diode • 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 We can then program the Lookup Table with the temperature and Closest PWM Values required for the curve required in our example. 3.3 NON-IDEALITY FACTOR AND TEMPERATURE ACCURACY The LM63 can be applied to remote diode sensing in the same way as other integrated-circuit temperature sensors. 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 printedcircuit board lands and traces soldered to its pins. This presumes that the ambient air temperature is nearly 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 LM63 die will be an intermediate temperature between the surface and air temperatures. Again, the primary thermal conduction path is through the leads, so the circuit board surface temperature will contribute to the die temperature much more than the air temperature. To measure the temperature external to the die use a remote diode. This diode can be located on the die of the target IC, such as a CPU processor chip, allowing measurement of the IC’s temperature, independent of the LM63’s temperature. In the above equation, η and Is are dependent upon the process that was used in the fabrication of the particular diode. By forcing two currents with a very controlled ratio (N) and measuring the resulting voltage difference, it is possible to eliminate the Is term. Solving for the forward voltage difference yields the relationship: The voltage seen by the LM63 also includes the IFxRS voltage drop across the internal series resistance of the 25 www.national.com LM63 3.0 Application Notes LM63 3.0 Application Notes 3.4 COMPUTING RPM OF THE FAN FROM THE TACH COUNT (Continued) Pentium 4 processor’s thermal diode. The non-ideality factor, η, is the only other parameter not accounted for and depends on the diode that is used for measurement. Since ∆Vbe is proportional to both η and T, the variations in η cannot be distinguished from variations in temperature. Since the temperature sensor does not control the nonideality factor, it will directly add to the inaccuracy of the sensor. For the Intel Pentium 4 and Mobile Pentium 4 Processor-M processors Intel specifies a ± 0.1% variation in η from part to part. As an example, assume that a temperature sensor has an accuracy specification of ± 1%˚C at room temperature of 25˚C and process used to manufacture the diode has a non-ideality variation of ± 0.1%. The resulting accuracy will be: TACC = ± 1˚C + ( ± 0.1% of 298˚K) = ± 1.3˚C The Tach Count Registers 46HEX and 47HEX count the number of periods of the 90 kHz tachometer clock in the LM63 for the tachometer input from the fan assuming a 2 pulse per revolution fan tachometer, such as the fans supplied with the Pentium 4 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 The additional inaccuracy in the temperature measurement caused by η, can be eliminated if each temperature sensor is calibrated with the remote diode that it will be paired with.Refer to the processor datasheet for the non-ideality factor. 3.3.2 Compensating for Diode Non-Ideality In order to compensate for the errors introduced by nonideality, the temperature sensor is calibrated for a particular processor. National Semiconductor temperature sensors are always calibrated to the typical non-ideality of a particular processor type. The LM63 is calibrated for the non-ideality of the 0.13 micron Intel Pentium 4 and Mobile Pentium 4 Processor-M processors. 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 When a temperature sensor, calibrated for a specific type of processor is used with a different processor type or a given processor type has a non-ideality that strays form the typical value, errors are introduced. Temperature errors associated with non-ideality may be introduced in a specific temperature range of concern through the use of the Temperature Offset Registers 11HEX and 12HEX. The user is encouraged to send an e-mail to [email protected] to further request information on our recommended setting of the offset register for different processor types. www.national.com 26 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. (Continued) 3.5 PCB LAYOUT FOR MINIMIZING NOISE 4. Avoid routing diode traces in close proximity to power supply switching or filtering inductors. 5. 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. 6. 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. 7. The ideal place to connect the LM63’s GND pin is as close as possible to the Processor’s GND associated with the sense diode. 8. Leakage current between D+ and GND should be kept to a minimum. One nano-ampere of leakage can cause as much as 1˚C of error in the diode temperature reading. Keeping the printed circuit board as clean as possible will minimize leakage current. 20057021 FIGURE 10. Ideal Diode Trace Layout In a noisy environment, such as a processor mother board, layout considerations are very critical. Noise induced on traces running between the remote temperature diode sensor and the LM63 can cause temperature conversion errors. Keep in mind that the signal level the LM63 is trying to measure is in microvolts. The following guidelines should be followed: 1. Place a 0.1 µF power supply bypass capacitor as close as possible to the VDD pin and the recommended 2.2 nF capacitor as close as possible to the LM63’s D+ and D− pins. Make sure the traces to the 2.2 nF capacitor are matched. 2. Ideally, the LM63 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 1˚C of error. This error can be compensated by using the Remote Temperature Offset Registers, since the value placed in these registers will automatically be subtracted from or added to the remote temperature reading. 3. Diode traces should be surrounded by a GND guard ring to either side, above and below if possible. This GND Noise coupling into the digital lines greater than 400 mVp-p (typical hysteresis) and undershoot less than 500 mV below GND, may prevent successful SMBus communication with the LM63. 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 LM63’s SMBCLK input. Additional resistance can be added in series with the SMBData and SMBCLK lines to further help filter noise and ringing. Minimize noise coupling by keeping digital traces out of switching power supply areas as well as ensuring that digital lines containing high speed data communications cross at right angles to the SMBData and SMBCLK lines. 27 www.national.com LM63 3.0 Application Notes LM63 ± 1˚C/ ± 3˚C Accurate Remote Diode Digital Temperature Sensor with Integrated Fan Control Physical Dimensions inches (millimeters) unless otherwise noted 8-Lead (0.154-Inch Wide) Molded Narrow Small-Outline Package (SOIC) JEDEC Registration Number MS-012 Order Number LM63CIM NS Package Number M008A LIFE SUPPORT POLICY NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant into the body, or (b) support or sustain life, and whose failure to perform when properly used in accordance with instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the user. National Semiconductor Americas Customer Support Center Email: [email protected] Tel: 1-800-272-9959 www.national.com National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: [email protected] Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 2. A critical component is any component of a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or system, or to affect its safety or effectiveness. National Semiconductor Asia Pacific Customer Support Center Email: [email protected] National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: [email protected] Tel: 81-3-5639-7560 National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right at any time without notice to change said circuitry and specifications.