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LM96000

Hardware Monitor with Integrated Fan Control

General Description

The LM96000, hardware monitor, has a two wire digital

interface compatible with SMBus 2.0. Using an 8-bit Σ∆

ADC, the LM96000 measures:

– the temperature of two remote diode connected transis-

tors as well as its own die

– the VCCP, 2.5V, 3.3VSBY, 5.0V, and 12V supplies (in-

ternal scaling resistors).

To set fan speed, the LM96000 has three PWM outputs that

are each controlled by one of three temperature zones. High

and low PWM frequency ranges are supported. The

LM96000 includes a digital filter that can be invoked to

smooth temperature readings for better control of fan speed.

The LM96000 has four tachometer inputs to measure fan

speed. Limit and status registers for all measured values are

included.

Features

n 2-wire, SMBus 2.0 compliant, serial digital interface

n 8-bit Σ∆ ADC

n Monitors VCCP, 2.5V, 3.3 VSBY, 5.0V, and 12V

motherboard/processor supplies

n Monitors 2 remote thermal diodes

n Programmable autonomous fan control based on

temperature readings

n Noise filtering of temperature reading for fan control

n 1.0˚C digital temperature sensor resolution

n 3 PWM fan speed control outputs

n Provides high and low PWM frequency ranges

n 4 fan tachometer inputs

n Monitors 5 VID control lines

n 24-pin TSSOP package

n XOR-tree test mode

Key Specifications

n Voltage Measurement Accuracy

2% FS (max)

n Resolution 8-bits, 1˚C

n Temperature Sensor Accuracy

3˚C (max)

n Temperature Range

— LM96000 Operational 0˚C to +85˚C

— Remote Temp Accuracy 0˚C to +125˚C

n Power Supply Voltage +3.0V to +3.6V

n Power Supply Current 0.53 mA

Applications

n Desktop PC

n Microprocessor based equipment

(e.g. Base-stations, Routers, ATMs, Point of Sales)

Block Diagram

20084601

November 2004

LM96000 Hardware Monitor with Integrated Fan Control

Summary of content (28 pages)

PAGE 1
LM96000 Hardware Monitor with Integrated Fan Control General Description The LM96000, hardware monitor, has a two wire digital interface compatible with SMBus 2.0. Using an 8-bit Σ∆ ADC, the LM96000 measures: – the temperature of two remote diode connected transistors as well as its own die – the VCCP, 2.5V, 3.3VSBY, 5.0V, and 12V supplies (internal scaling resistors). To set fan speed, the LM96000 has three PWM outputs that are each controlled by one of three temperature zones.
PAGE 2
4 Pin TSSOP 20084602 NS Package MTC24E Top View LM96000CIMT (61 units per rail), or LM96000CIMTX (2500 units per tape and reel) Symbol Pin Type SMBDAT 1 Digital I/O (Open-Drain) System Management Bus Data. Open-drain output. 5V tolerant, SMBus 2.0 compliant. SMBCLK 2 Digital Input System Management Bus Clock. Tied to Open-drain output. 5V tolerant, SMBus 2.0 compliant. VID0 5 Digital Input Voltage identification signal from the processor.
PAGE 3
Remote Fan Tachometer Inputs Fan Control (Continued) Symbol Pin Remote1+ 18 Remote Thermal Positive input (current source) from the first remote thermal diode. Diode Positive Serves as the positive input into the A/D. Connected to Input THERMDA pin of Pentium processor or the base of a diode connected MMBT3904 NPN transistor. Type Name and Function/Connection Remote1− 17 Remote Thermal Negative input (current sink) from the first remote thermal diode.
PAGE 4
LM96000 Absolute Maximum Ratings (Notes 1, 2) Storage Temperature If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. Soldering process must comply with National’s reflow temperature profile specifications. Refer to www.national.com/packaging/. (Note 6) −65˚C to +150˚C Supply Voltage, V+ −0.5V to 6.0V Voltage on Any Digital Input or Output Pin −0.5V to 6.
PAGE 5
(Continued) The following specifications apply for V+ = 3.0V to 3.6V, and all analog input source impedance RS = 50Ω unless otherwise specified in conditions. Boldface limits apply for TA = TJ over TMIN =0˚C to TMAX=85˚C; all other limits TA =TJ= 25˚C. TA is the ambient temperature of the LM96000; TJ is the junction temperature of the LM96000; TD is the thermal diode junction temperature.
PAGE 6
LM96000 AC Electrical Characteristics (Continued) The following specifications apply for V+ = 3.0V to 3.6V unless otherwise specified in conditions. Boldface limits apply for TA = TJ over TMIN =0˚C to TMAX=85˚C; all other limits TA =TJ= 25˚C. Symbol Parameter fBUF Conditions Typical (Note 7) Limits (Note 8) Units (Limits) SMBus Free Time Between Stop And Start Condition 4.7 µs (min) tHD_STA Hold Time After (Repeated) Start Condition (after this period, the first clock is generated) 4.
PAGE 7
Pin Name Circuit 1 SMBDAT A 2 SMBCLK 3 GND 4 3.3V 5 VID0 6 VID1 7 VID2 8 VID3 9 TACH3 10 PWM2 11 TACH1 12 TACH2 13 PWM3/AddEnable 14 TACH4/AddSel 15 REMOTE2− C 16 REMOTE2+ D 17 REMOTE1− C 18 REMOTE1+ D 19 VID4 A 20 5V E 21 12V 22 2.5V 23 VCCP_IN 24 PWM1/xTEXTOUT LM96000 Pin # All Input Circuits B Circuit A A Circuit B Circuit C Circuit D A Circuit E Note 4: Human body model, 100pF discharged through a 1.5kΩ resistor.
PAGE 8
LM96000 Note 14: Holding the SMBDAT and/or SMBCLK lines Low for a time interval greater than tTIMEOUT will reset the LM96000’s SMBus state machine, therefore setting the SMBDAT pin to a high impedance state. Functional Description 1.0 SMBUS The LM96000 is compatible with devices that are compliant to the SMBus 2.0 specification. More information on this bus can be found at: http://www.smbus.org/. Compatibility of SMBus2.0 to other buses is discussed in the SMBus 2.0 specification. 1.
PAGE 9
1. LM96000 Functional Description (Continued) Set limits and parameters (not necessarily in this order): – [5F-61h] Set PWM frequencies and auto fan control range. – [62-63h] Set spike smoothing and min/off. – [5C-5Eh] Set the fan spin-up delays. – [5C-5Eh] Match each fan with a corresponding thermal zone. – [67-69h] Set the fan temperature limits. – [6A-6Ch] Set the temperature absolute limits. – [64-66h] Set the PWM minimum duty cycle. 2. 3. – [6D-6Eh] Set the temperature Hysteresis values.
PAGE 10
LM96000 Functional Description (Continued) Register Read/ Register Address Write Name Bit 7 Bit 6 (MSB) Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 (LSB) Default Lock? Value 49h R/W 3.
PAGE 11
(Continued) Register Read/ Register Address Write Name Bit 7 Bit 6 (MSB) Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 (LSB) RES Default Lock? Value 6Fh R/W XOR Test Tree Enable RES RES RES RES RES RES XEN 00h 74h R/W Tach Monitor Mode RES RES T3/4-1 T3/4-0 T2-1 T2-0 T1-1 T1-0 00h 75h R/W Fan Spin-up Mode RES RES RES PWM3 SU PWM2 SU PWM1 SU 7h RES RES U U Note: Reserved bits will always return 0 when read. 4.
PAGE 12
LM96000 Functional Description (Continued) TABLE 1. Temperature vs Register Reading (Continued) Temperature Reading (Dec) Reading (Hex) . . . . . . . . . 0˚C 0 00h . . . . . . . . . 127˚C 127 7Fh (SENSOR ERROR) 80h 4.
PAGE 13
LM96000 Functional Description (Continued) Current Duty Value (Decimal) Value (Hex) 0.3922% 1 01h . . . . . . . . . 25.098% 64 40h . . . . . . . . . 50.196% 128 80h . . . . . . . . . 100% 255 FFh 4.5 Register 3Eh: Company ID Register Address Read/ Write Register Name Bit 7 (MSB) Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 (LSB) Default Value 3Eh R Company ID 7 6 5 4 3 2 1 0 01h The company ID register contains the company identification number.
PAGE 14
LM96000 Functional Description (Continued) Bit Name R/W Default Description 0 START R/W 0 When software writes a 1 to this bit, the LM96000 fan monitoring and PWM output control functions will use the values set in the fan control limit and parameter registers (address 5Ch through 6Eh). Before this bit is set, the LM96000 will not update the used register values, the default values will remain in effect.
PAGE 15
LM96000 Functional Description (Continued) Bit Name R/W Default Description 4 Zone 1 Limit Exceeded R 0 The LM96000 automatically sets this bit to 1 when the temperature input measured by the Remote1− and Remote1+ inputs is less than or equal to the limit set in the Processor (Zone1) Low Temp register or more than the limit set in the Processor (Zone1) High Temp register. This bit will be set when a diode fault is detected.
PAGE 16
LM96000 Functional Description (Continued) Bit Name R/W Default Description 7 Remote Diode 2 Fault R 0 The LM96000 automatically sets this bit to 1 when there is either a short or open circuit fault on the Remote2+ or Remote2− thermal diode input pins. A diode fault will also set bit 6, Diode 2 Zone Limit bit, of Interrupt Status Register 1. 4.
PAGE 17
(Continued) Register Address Read/ Write Register Name Bit 7 (MSB) Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 (LSB) Default Value 50h R/W Processor (Zone2) Low Temp 7 6 5 4 3 2 1 0 81h 51h R/W Processor (Zone2) High Temp 7 6 5 4 3 2 1 0 7Fh 52h R/W Processor (Zone3) Low Temp 7 6 5 4 3 2 1 0 81h 53h R/W Processor (Zone3) High Temp 7 6 5 4 3 2 1 0 7Fh If an external temperature input or the internal temperature sensor either exceeds the value set in
PAGE 18
LM96000 Functional Description (Continued) to ensure that the limit is high enough not to cause sporadic alerts. The fan tachometer will not cause a bit to be set in Interrupt Status Register 2 if the current value in Current PWM Duty registers is 00h or if the fan 1 disabled via the Fan Configuration Register. Interrupts will never be generated for a fan if its minimum is set to FF FFh.
PAGE 19
LM96000 Functional Description (Continued) TABLE 5. Fan Spin-Up Register SPIN[2:0] Spin Up Time 000 0 sec 001 100 ms 010 250 ms 011 400 ms 100 700 ms 101 1000 ms 110 2000 ms 111 4000 ms 4.
PAGE 20
LM96000 Functional Description (Continued) Above (Zone 1 Fan Temp Limit) + (Zone 1 Range), the duty cycle will be 100%. PWM frequency bits [3:0] The PWM frequency bits [3:0] determine the PWM frequency for the fan.The LM96000 has high and low frequency ranges for the PWM outputs, that are controlled by the HLFRQ bit. PWM Frequency Selection (Default = 0011 = 30.04 Hz). TABLE 6. Register Setting vs PWM Frequency HLFRQ Freq [2:0] PWM Frequency 0 000 10.01 Hz 0 001 15.02 Hz 0 010 23.
PAGE 21
(Continued) Register Read/ Register Address Write Name Bit 7 Bit 6 (MSB) 63h ZN2E R/W Zone2, Zone3 Spike Smoothing Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0 Default Lock? (LSB) Value ZN2-2 ZN2-1 ZN2-0 ZN3E ZN3-2 ZN3-1 ZN3-0 00h U The Off/Min Bits [7:5] specify whether the duty cycle will be 0% or Minimum Fan Duty when the measured temperature falls below the Temperature LIMIT register setting (see table below). OFF1 applies to fan 1, OFF2 applies to fan 2, and OFF3 applies to fan 3.
PAGE 22
LM96000 Functional Description (Continued) 4.
PAGE 23
(Continued) 27.7KHz PWM Frequency PWM Duty Cycle Level (%) Value in Decimal 25.7KHz PWM Frequency PWM Duty Cycle Level (%) Value in Decimal Value in Hex 0 0 0 7.14 1 - 17 01 - 11 14.29 18 - 36 12 - 24 21.43 37 - 54 25 - 36 28.57 55 - 72 37 - 48 35.71 73 - 90 49 - 5A 42.86 91 - 109 5B - 6D 50.00 110 - 127 6E - 7F 57.14 128 - 145 80 - 91 64.29 146 - 164 92 - A4 71.43 165 - 182 98 - 117 62 - 75 53.85 118 - 137 76 - 89 61.54 138 - 157 8A - 9D 69.
PAGE 24
LM96000 Functional Description (Continued) TABLE 10. Temperature Limit vs Register Setting (Continued) Temperature Reading (Decimal) Reading (Hex) 0˚C 0 00h . . . . . . . . . 50˚C 50 32h . . . . . . . . . 127˚C 127 7Fh 4.
PAGE 25
(Continued) – The fan will remain on, at Fan PWM Minimum, until the temperature goes a certain amount below Fan Temp Limit. – The Hysteresis registers control this amount. See below table for details. These registers become Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further attempts to write to thses registers shall have no effect.
PAGE 26
LM96000 Functional Description (Continued) • Mode 2: This mode is optimized for accurate RPM readings and activates circuitry that extends the lower side of the RPM reading as shown in the following table. • Mode 3: This mode minimizes the effect on the RPM setting and activates circuitry that extends the lower side of the RPM reading as shown in the following table. PWM Frequency Mode 0 and 1 Minimum RPM 10.01 841 Mode 2 and 3 Minimum RPM 210 15.02 1262 315 23.14 1944 420 30.
PAGE 27
LM96000 Applications Information 20084609 Typical Applications Schematic 27 www.national.
PAGE 28
LM96000 Hardware Monitor with Integrated Fan Control Physical Dimensions inches (millimeters) unless otherwise noted 24-Lead Molded TSSOP Package, Order Number LM96000CIMT or LM96000CIMTX NS Package Number MTC24E JEDEC Registration MO-153, Variation AD 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.