LM63 NSC | Alldatasheet
Document overview
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Technical content
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 (with quantization error) Ambient Temp Diode Temp IPWML Max Version Max Error 30 to 50˚C 60 to 100˚C 5 mA LM63C ±1.0˚C 30 to 50˚C 60 to 100˚C 5 mA LM63D ±3.0˚C 0 to 85˚C 25 to 125˚C 8 mA All ±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. May 2003 LM63±1˚C/±3˚C Accurate Remote Diode Digital Temperature Sensor with Integrated Fan Control © 2003 National Semiconductor Corporation DS200570 www.national.com
Pin Name Input/Output Function and Connection 1V DD 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 V DD 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
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 This is the analog and digital ground return.
6 ALERT/TACH Digital I/O
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.
7 SMBDAT Digital Input/
Open-Drain Output This is the bi-directional SMBus data line. 8 SMBCLK Digital Input Digital Input. This is the SMBus clock input. Simplified Block Diagram 20057002 LM63 www.national.com 2
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 LM63 www.national.com3
Absolute Maximum Ratings(Notes 1, 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 −0.3 V to (V DD +0 .3V ) Input Current, D− Pin ±1m A Input Current at All Other Pins (Note 3) 5 mA Package Input Current (Note 3) 30 mA Package Power Dissipation (Note 5) SMBDAT, ALERT, PWM pins Output Sink Current 10 mA Storage Temperature −65˚C to +150˚C ESD Susceptibility(Note 4) Human Body Model 2000 V Machine Model 200 V Soldering Information, Lead Temperature Vapor Phase (60 seconds) 215˚C Infrared (15 seconds) 220˚C Operating Ratings(Notes 1, 2) Specified Temperature Range TMIN ≤ TA ≤ TMAX LM63CIM, LM63DIM 0˚C ≤ TA ≤ +85˚C Remote Diode Temperature Range 0˚C ≤ TA ≤ +125˚C Supply Voltage Range (V DD) +3.0 V to +3.6 V TEMPERATURE-TO-DIGITAL CONVERTER CHARACTERISTICSThe following specifications apply for V DD = 3.0 VDC to 3.6 VDC, and all analog source impedance R S =5 0Ω unless otherwise specified in the conditions. Boldface limits apply for TA =T MIN to TMAX; all other limits T A = +25˚C. Parameter Conditions Version Typical (Note 7) Limits (Note 8) Units (Limits) 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 hardware.monitor.team @nsc.com to obtain the latest data. TA = +30 to +50˚C IPWML ≤ 5m A TD = +60 to +100˚C TD = Remote Diode Junction Temperature LM63C ±1 ˚C (max) LM63D ±3 ˚C (max) TA = +0 to +85˚C IPWML ≤ 8m A TD = +25 to +125˚C All ±3 ˚C (max) Temperature Error Using the Local Diode TA = +25 to +125˚C (Note 10) All ±1 ±3 ˚C (max) Remote Diode Resolution All 11 Bits 0.125 ˚C Local Diode Resolution All 8 Bits 1˚ C Conversion Time, All Temperatures Fastest Setting All 31.25 34.4 ms (max) D− Source Voltage All 0.7 V Diode Source Current (VD+ −V D−) = +0.65 V; High Current All 160 315 µA (max) 110 µA (min) Low Current All 13 20 µA (max) 7 µA (min) Operating Electrical Characteristics Parameter Conditions Typ (Note 7) Limits (Note 8) Units ALERT and PWM Output Saturation Voltage ALERT PWM IOUT 4m A 5m A 0.4 V (max)IOUT 6 mA 0.55 Power-On-Reset Threshold Voltage 2.4 V (max)
1.8 V (min)
Supply Current (Note 9) SMBus Inactive, 16 Hz Conversion Rate 1.1 2.0 mA (max) STANDBY Mode 300 µA LM63 www.national.com 4
The following specifications apply for V DD = 3.0 VDC to 3.6 VDC, and all analog source impedance R S =5 0Ω unless other- wise specified in the conditions. Boldface limits apply for TA =T MIN to TMAX; all other limits T A= +25˚C. Symbol Parameter Conditions Typical (Note 7) Limits (Note 8) Units (Limit) TACHOMETER ACCURACY Fan Control Accuracy ±10 % (max) Fan Full-Scale Count 65535 (max) Fan Counter Clock Frequency 90 kHz Fan Count Update Frequency 1.0 Hz FAN PWM OUTPUT Frequency Accuracy ±10 % (max) Digital Electrical Characteristics Symbol Parameter Conditions Typical (Note 7) Limits (Note 8) 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 V IN =V DD 0.005 +10 µA (max) IIL Logical Low Input Current V IN = GND −0.005 −10 µA (max) CIN Digital Input Capacitance 20 pF SMBus Logical Electrical Characteristics The following specifications apply for V DD = 3.0 VDC to 3.6 VDC, and all analog source impedance R S =5 0Ω unless other- wise specified in the conditions. Boldface limits apply for TA =T MIN to TMAX; all other limits T A = +25˚C. Symbol Parameter Conditions Typical (Note 7) Limits (Note 8) Units (Limit) SMBDAT OPEN-DRAIN OUTPUT VOL Logic Low Level Output Voltage I OL =4m A 0.4 V (max) IOH High Level Output Current V OUT =V DD 0.03 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 mV LM63 www.national.com5
SMBus Digital Switching Characteristics Unless otherwise noted, these specifications apply for V DD = +3.0 VDC to +3.6 VDC, C L (load capacitance) on output lines = 80 pF. Boldface limits apply for TA =T J;T MIN ≤ TA ≤ TMAX; all other limits T A =T J = +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 Conditions Limits (Note 8) Units (Limit) f SMB SMBus Clock Frequency 10 100 kHz (min) kHz (max) tLOW SMBus Clock Low Time From V IN(0) max to VIN(0) max 4.7 µs (min) tHIGH SMBus Clock High Time From V IN(1) min to VIN(1) min 4.0 µs (min) µs (max) tR SMBus Rise Time (Note 11) 1 µs (max) tF SMBus Fall Time (Note 12) 0.3 µs (max) tOF Output Fall Time C L = 400 pF, I O =3m A 250 ns (max) tTIMEOUT SMBData and SMBCLK Time Low for Reset of Serial Interface See (Note 13) 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) 20057004 SMBus Timing Diagram for SMBCLK and SMBDAT Signals LM63 www.national.com 6
Note 2: All voltages are measured with respect to GND, unless otherwise noted. 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. 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. 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 (V IL max - 0.15 V) to (V IH min + 0.15 V). Note 12: The output fall time is measured from (V IH min + 0.15 V) to (V IL min - 0.15 V). SMBDAT and SMBCLK pins to a high impedance state.
1.0 Functional Description
are contained in the sections below. to prevent the generation of these ALERT outputs. FIGURE 1. ESD Protection Input Structure
1.0 Functional Description (Continued)
Disable in Standby bit in the Configuration Register.
1.1 CONVERSION SEQUENCE
1.2 THE ALERT/TACH PIN AS ALERT OUTPUT
address the ALERT active-low open-drain output function. written as zero the ALERT interrupts are enabled. interrupt flag, and (3) as part of an SMBus ALERT System. user interacts with the LM63. trigger an ALERT in all modes.
1.2.1 ALERT Output as a Temperature Comparator
must be asserted. This is not the power-on default state.
1.2.2 ALERT Output as an Interrupt
FIGURE 2. Supply Current vs Conversion Rate FIGURE 3. ALERT Output as Temperature Comparator
- Master reads the LM63 ALERT Status Register to deter-
- LM63 clears ALERT Status Register, resets the ALERT
- Master attends to conditions that caused the ALERT to
- Master resets the ALERT Mask bit in the Configuration
1.2.3 ALERT Output as an SMBus ALERT
Register to 0 at the end of the interrupt service routine.
- Master senses SMBus alert line low
- Master sends a START followed by the Alert Response
Address (ARA) with a Read Command.
- Alerting Device(s) send ACK.
- Alerting Device(s) send their address. While transmitting
- Master attends to conditions that caused the ALERT to
started, setpoints adjusted, etc.
- Master resets the ALERT Mask bit in the Configuration
should ever be assigned to this address. order for the LM63 to respond to the ARA command. FIGURE 4. ALERT Output as an Interrupt Temperature
1.3 SMBus INTERFACE
changed by software or hardware.
1.4 POWER-ON RESET (POR) DEFAULT STATES
LM63 Register Map in Functional Order.
1.5 TEMPERATURE DATA FORMAT
setpoint registers are Read/Write.
1.6 OPEN-DRAIN OUTPUTS
resistor to provide the 2.1 V high level is 88.7 k Ω.
1.7 DIODE FAULT DETECTION
ALERT Mask is disabled, then the ALERT will be pulled low. The OPEN bit by itself will not trigger an ALERT. abled, ALERT will be pulled low.
1.8 COMMUNICATING WITH THE LM63
- Read/Write different address
LM63 Required Initial Fan Control Register Sequence. FIGURE 5. ALERT Output as an SMBus ALERT
indicating that the Master has read its last byte.
1.9 DIGITAL FILTER
set according to the following table. Level 2 is maximum filtering. FIGURE 6. Step Response of the Digital Filter FIGURE 7. Impulse Response of the Digital Filter FIGURE 8. Digital Filter Response in an Intel Pentium 4 purposely offset to better show noise performance.
1.10 FAULT QUEUE
1.11 ONE-SHOT REGISTER
register. A write operation causes the one-shot conversion. stored. A zero will always be read from this register.
1.12 SERIAL INTERFACE RESET
returned to a known state in the communication protocol.
- When SMBDAT is Low, the LM63 SMBus state machine
- With both SMBDAT and SMBCLK High, the master can
an SMBus Address address byte. FIGURE 9. Fault Queue Temperature Response
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. Register 0x[HEX] Register Name DATA BITS D7 D6 D5 D4 D3 D2 D1 D0
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
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] Not Used (0D) Same as 07 (0E) Same as 08 0F One Shot Write Only. Write command triggers one temperature conversion cycle.
10 Rmt Temp LSB RTLB7 RTLB6 RTLB5 0 0 0 0 0
11 Rmt Temp Offset MSB RTOHB15 RTOHB14 RTOHB13 RTOHB12 RTOHB11 RTOHB10 RTOHB9 RTOHB8
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
15 [Reserved] Not Used
16 ALERT Mask 1 ALTMSK6 1 ALTMSK4 ALTMSK3 1 ALTMSK1 ALTMSK0
17 [Reserved] Not Used 18 [Reserved] Not Used
19 Rmt TCRIT Setpoint RCS7 RCS6 RCS5 RCS4 RCS3 RCS2 RCS1 RCS0
1A–1F [Reserved] Not Used 20 [Reserved] Not Used
21 Rmt TCRIT Hysteresis RTH7 RTH6 RTH5 RTH4 RTH3 RTH2 RTH1 RTH0
22–2F [Reserved] Not Used 30–3F [Reserved] Not Used 40–45 [Reserved] Not Used
46 Tach Count LSB TCLB5 TCLB4 TCLB3 TCLB2 TCLB1 TCLB0 TEDGE1 TEDGE0
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 LM63 www.national.com13
2.0 LM63 Registers (Continued)
0x[HEX] Register Name DATA BITS D7 D6 D5 D4 D3 D2 D1 D0 4F Lookup Table Hystersis 0 0 0 LOOKH4 LOOKH3 LOOKH2 LOOKH1 LOOKH0 50–5F Lookup Table Lookup Table of up to 8 PWM and Temp Pairs in 8-bit Registers 60–BE [Reserved] Not Used BF Rmt Diode Temp Filter 0 0 0 0 0 RDTF1 RDTF0 ALTCOMP C0–FD [Reserved] Not Used FE Manufacturer’s ID 0 0 0 0 0001 FF Stepping/Die Rev. ID 0 1 0 0 0001
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 50–5F Lookup Table R/W See Table 4F Lookup Table Hysteresis R/W 04 CONFIGURATION REGISTER 03 (09) Configuration R/W 00 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
12 Remote Temperature Offset LSB R/W 00
07 (0D) Remote High Setpoint MSB R/W 46 (70˚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 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) Conversion Rate R/W 08 0F One-Shot Write Only N/A LM63 www.national.com 14
[HEX] 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
FF Stepping/Die Rev. ID Read Only 41 [RESERVED] REGISTERS — NOT USED
06 Not Used N/A N/A
15 Not Used N/A N/A
17 Not Used N/A N/A
18 Not Used N/A 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 oneof 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. LM63 www.national.com15
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 4A R/W 7:6 00 PWM Program These bits are unused and always set to 0. 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. PWM Output Polarity 0: the PWM output pin will b e 0 V for fan OFF and open for fan ON. 1: the PWM output pin will be open for fan OFF an d 0 V for fan ON.
30 PWM Clock
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. 1:0 00 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. LM63 www.national.com 16
Fan Control Registers(Continued) Address Hex Read/ Write Bits POR Value Name Description 4BHEX FAN PWM AND TACHOMETER CONFIGURATION REGISTER 4B R/W 7:6 0 Fast Tachometer Spin-Up These bits are unused and always set to 0 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. 4:3 11 PWM Spin-Up Duty Cycle 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% 2:0 111 PWM Spin-Up Time 000: Spin-Up cycle bypassed (No Spin-Up) 001: 0.05 seconds 010: 0.1 s 011: 0.2 s 100: 0.4 s 101: 0.8 s 110: 1.6 s 111: 3.2 s HEX FAN PWM FREQUENCY REGISTER 4D R/W 7:5 000 PWM Frequency These bits are unused and always set to 0 4:0 10111 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. HEX PWM VALUE REGISTER Read (Write only if reg 4A bit 5 = 1.) 7:6 00 PWM Value These bits are unused and always set to 0 5:0 000000 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 %. LM63 www.national.com17
Fan Control Registers(Continued) Address Hex Read/ Write Bits POR Value Name Description 50HEX to 5FHEX LOOKUP TABLE (7 Bits for Temperature and 6 Bits for PWM for each Temperature/PWM Pair) Read. (Write only if reg 4A bit 5 = 1.)
70 Lookup Table
This bit is unused and always set to 0. 6:0 0x7F If the remote diode temperature exceeds this value, the PWM output will be the value in Register 51. 51 7:6 00 Lookup Table PWM Entry 1 These bits are unused and always set to 0. 5:0 0x3F The PWM value corresponding to the temperature limit in register 50. This bit is unused and always set to 0. 6:0 0x7F If the remote diode temperature exceeds this value, the PWM output will be the value in Register 53. 53 7:6 00 Lookup Table PWM Entry 2 These bits are unused and always set to 0. 5:0 0x3F The PWM value corresponding to the temperature limit in register 52. This bit is unused and always set to 0. 6:0 0x7F If the remote diode temperature exceeds this value, the PWM output will be the value in Register 55. 55 7:6 00 Lookup Table PWM Entry 3 These bits are unused and always set to 0. 5:0 0x3F The PWM value corresponding to the temperature limit in register 54. This bit is unused and always set to 0. 6:0 0x7F If the remote diode temperature exceeds this value, the PWM output will be the value in Register 57. 57 7:6 00 Lookup Table PWM Entry 4 These bits are unused and always set to 0. 5:0 0x3F The PWM value corresponding to the temperature limit in register 56. This bit is unused and always set to 0. 6:0 0x7F If the remote diode temperature exceeds this value, the PWM output will be the value in Register 59. 59 7:6 00 Lookup Table PWM Entry 5 These bits are unused and always set to 0. 5:0 0x3F The PWM value corresponding to the temperature limit in register 58. This bit is unused and always set to 0. 6:0 0x7F If the remote diode temperature exceeds this value, the PWM output will be the value in Register 5B. 5B 7:6 00 Lookup Table PWM Entry 6 These bits are unused and always set to 0. 5:0 0x3F The PWM value corresponding to the temperature limit in register 5A. This bit is unused and always set to 0. 6:0 0x7F If the remote diode temperature exceeds this value, the PWM output will be the value in Register 5D. 5D 7:6 00 Lookup Table PWM Entry 7 These bits are unused and always set to 0. 5:0 0x3F The PWM value corresponding to the temperature limit in register 5C. This bit is unused and always set to 0. 6:0 0x7F If the remote diode temperature exceeds this value, the PWM output will be the value in Register 5F. 5F 7:6 00 Lookup Table PWM Entry 8 These bits are unused and always set to 0. 5:0 0x3F The PWM value corresponding to the temperature limit in register 5E. 4FHEX LOOKUP TABLE HYSTERESIS 4F R/W 7:5 000 Lookup Table Hysteresis These bits are unused and always set to 0 4:0 00100 The amount of hysteresis applied to the Lookup Table. (1 LSB = 1˚C). LM63 www.national.com 18
03 (09)HEX CONFIGURATION REGISTER 03 (09) R/W
70 ALERT
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. 6 0 STANDBY 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.
50 PWM Disable
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.
20 ALERT/Tach
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.
10 T_CRIT Limit
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.
00 RDTS Fault
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. LM63 www.national.com19
Tachometer Count And Limit Registers ADDRESS Hex Read/ 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) 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. Read Only 7:2 N/A Tachometer Count (LSB) Read Only 1:0 00 Tachometer Edge Count Bits Edges Used Tach_Count_Multiple 00: 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. HEX TACHOMETER LIMIT (MSB) and 48HEX TACHOMETER LIMIT (LSB) REGISTERS
49 R/W 7:0 0xFF Tachometer
Limit MSB) 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.48 R/W 7:2 0xFF Tachometer Limit (LSB) R/W 1:0 [Reserved] 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 R/W 7:0 0x46
(70˚) Local HIGH Setpoint High Setpoint for the internal diode. LM63 www.national.com 20
Remote Diode Temperature, Offset And Setpoint Registers ADDRESS Hex Read/ Write Bits POR Value Name Description
01 Read
Only 7:0 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.
10 Read
7:5 N/A Remote Diode Temperature Reading (MSB) 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. 4:0 00 Always 00.
11 R/W 7:5 00
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 10.12 R/W 7:5 00 Remote Temperature OFFSET (LSB)4:0 00 Always 00. 07 (0D) R/W 7:0 0x46 (70˚C) Remote HIGH Setpoint (MSB) High setpoint temperature for remote diode. Same format as Remote Temperature Reading(registers 01 and 10).
13 R/W 7:5 00 Remote HIGH
Setpoint (LSB)4:0 00 Always 00. 08 (0E) R/W 7:0 00 (0˚C) Remote LOW Setpoint (MSB) Low setpoint temperature for remote diode. Same format as Remote Temperature Reading(registers 01 and 10).
14 R/W 7:5 00 Remote LOW
Setpoint (LSB)4:0 00 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)]. BF R/W 7:3 00000 These bits are unused and should always set to 0. 2:1 00 Remote Diode Temperature Filter 00: Filter Disabled 01: Filter Level 1 (minimal filtering, same as 10) 10: Filter Level 1 (minimal filtering, same as 01) 11: Filter Level 2 (maximum filtering)
00 Comparator
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. LM63 www.national.com21
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.) 0x02 Read Only 7 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.
60 Local
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 This bit is unused and always read as 0.
40 Remote
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.
30 Remote
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.
20 Remote Diode
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.
10 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.. 0 0 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. LM63 www.national.com 22
ALERT Status And Mask Registers(Continued) ADDRESS Hex Read/ Write Bits POR Value Name Description 16HEX ALERT MASK REGISTER (8-bits)
16 R/W
7 1 This bit is unused and always read as 1.
60 Local High
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 5 1 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. Remote Low Alarm Mask 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. 2 1 This bit is unused and always read as 1. 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.
00 Tach
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. 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 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 POR Value Name Description FFHEX STEPPING / DIE REVISION ID REGISTER (8-bits) FF Read Only 7:0 0x41 Stepping/Die FEHEX MANUFACTURER’S ID REGISTER (8-bits) FE Read Only 7:0 0x01 Manufacturer’s ID 0x01 = National Semiconductor LM63 www.national.com23
3.0 Application Notes
3.1 FAN CONTROL DUTY CYCLE VS. REGISTER SETTINGS AND FREQUENCY PWM Freq [4:0] Step Resolution, PWM Value 4D [5:0] for 100% PWM Value 4C [5:0] for about 75% 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
0 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 correspond- ing 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 LM63 www.national.com 24
3.0 Application Notes (Continued)
3.2 USE OF THE LOOKUP TABLE FOR NON-LINEAR
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. 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 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
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 printed- circuit 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. 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 approxi- mates the temperature reading of the LM63 with the Pentium 4 processor by 1˚C. T 2N3904 =T PENTIUM 4 − 1˚C
3.3.1 Diode Non_Ideality
When a transistor is connected to a diode the following relationship holds for V be, T, and IF: 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 In the above equation, η and I s 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 I s term. Solving for the forward voltage difference yields the relationship: The voltage seen by the LM63 also includes the I FxRS voltage drop across the internal series resistance of the LM63 www.national.com25
Pentium 4 processor’s thermal diode. The non-ideality factor, η, is the only other parameter not accounted for and de- pends on the diode that is used for measurement. Since be 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 non- ideality 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: 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 non- ideality, 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 proces- sors. 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 in- troduced in a specific temperature range of concern through the use of the Temperature Offset Registers 11 HEX and 12HEX. The user is encouraged to send an e-mail to hardware.monitor.team@nsc.com to further request infor- mation on our recommended setting of the offset register for different processor types.
3.4 COMPUTING RPM OF THE FAN FROM THE TACH
The Tach Count Registers 46 HEX and 47HEX count the num- ber of periods of the 90 kHz tachometer clock in the LM63 for the tachometer input from the fan assumin g 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 46 HEX 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 BF HEX = Decimal (11 x 16) + 15 = 191 and Register 47 (MSB) is 7 HEX = Decimal (7 x 256) = 1792. The total Tach Count, in decimal, is 191 + 1792 = 1983. The RPM is computed using the formula 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 LM63 www.national.com 26
3.5 PCB LAYOUT FOR MINIMIZING NOISE
sor and the LM63 can cause temperature conversion errors.
- Place a 0.1 µF power supply bypass capacitor as close
- Ideally, the LM63 should be placed within 10 cm of the
- Diode traces should be surrounded by a GND guard ring
- Avoid routing diode traces in close proximity to power
supply switching or filtering inductors.
- Avoid running diode traces close to or parallel to high
at least 2 cm apart from the high speed digital traces.
- If it is necessary to cross high speed digital traces, the
- The ideal place to connect the LM63’s GND pin is as
- Leakage current between D+ and GND should be kept
sible will minimize leakage current. FIGURE 10. Ideal Diode Trace Layout
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 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. 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 Americas Customer Support Center Email: new.feedback@nsc.com Tel: 1-800-272-9959 National Semiconductor Europe Customer Support Center Fax: +49 (0) 180-530 85 86 Email: europe.support@nsc.com Deutsch Tel: +49 (0) 69 9508 6208 English Tel: +44 (0) 870 24 0 2171 Français Tel: +33 (0) 1 41 91 8790 National Semiconductor Asia Pacific Customer Support Center Email: ap.support@nsc.com National Semiconductor Japan Customer Support Center Fax: 81-3-5639-7507 Email: jpn.feedback@nsc.com Tel: 81-3-5639-7560 www.national.com LM63 ±1˚C/±3˚C Accurate Remote Diode Digital Temperature Sensor with Integrated Fan Control National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the righ t at any time without notice to change said circuitry and specifications.