Document
LM96000 Hardware Monitor with Integrated Fan Control
November 2004
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. 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. n n n n n n n n Noise filtering of temperature reading for fan control 1.0˚C digital temperature sensor resolution 3 PWM fan speed control outputs Provides high and low PWM frequency ranges 4 fan tachometer inputs Monitors 5 VID control lines 24-pin TSSOP package XOR-tree test mode
Key Specifications
Voltage Measurement Accuracy Resolution Temperature Sensor Accuracy Temperature Range — LM96000 Operational — Remote Temp Accuracy n Power Supply Voltage n Power Supply Current n n n n
± 2% FS (max)
8-bits, 1˚C
± 3˚C (max)
0˚C to +85˚C 0˚C to +125˚C +3.0V to +3.6V 0.53 mA
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
Applications
n Desktop PC n Microprocessor based equipment (e.g. Base-stations, Routers, ATMs, Point of Sales)
Block Diagram
20084601
© 2004 National Semiconductor Corporation
DS200846
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LM96000
Connection Diagram
24 Pin TSSOP
20084602
NS Package MTC24E Top View LM96000CIMT (61 units per rail), or LM96000CIMTX (2500 units per tape and reel)
Pin Descriptions
Symbol SMBus SMBDAT SMBCLK VID0 Processor VID Lines VID1 VID2 VID3 VID4 3.3V Power Pin 1 2 5 6 7 8 19 4 Type Digital I/O (Open-Drain) Digital Input Digital Input Digital Input Digital Input Digital Input Digital Input POWER Name and Function/Connection System Management Bus Data. Open-drain output. 5V tolerant, SMBus 2.0 compliant. System Management Bus Clock. Tied to Open-drain output. 5V tolerant, SMBus 2.0 compliant. Voltage identification signal from the processor. This value is read in the VID0–VID4 Status Register. Voltage identification signal from the processor. This value is read in the VID0–VID4 Status Register. Voltage identification signal from the processor. This value is read in the VID0–VID4 Status Register. Voltage identification signal from the processor. This value is read in the VID0–VID4 Status Register. Voltage identification signal from the processor. This value is read in the VID0–VID4 Status Register. +3.3V pin. Can be powered by +3.3V Standby power if monitoring in low power states is required. This pin also serves as the analog input to monitor the 3.3V supply. This pin should be bypassed with a 0.1µf capacitor in parallel with 100pf. A bulk capacitance of approximately 10µf needs to be in the near vicinity of the LM96000. Ground for all analog and digital circuitry. Analog input for +5V monitoring. Analog input for +12V monitoring. Analog input for +2.5V monitoring. Analog input for VCCP (processor voltage) monitoring.
GND Voltage Inputs 5V 12V 2.5V VCCP_IN
3 20 21 22 23
GROUND Analog Input Analog Input Analog Input Analog Input
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2
LM96000
Pin Descriptions
Symbol Remote1+
(Continued) Pin 18 Type Name and Function/Connection
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. Remote Thermal Negative input (current sink) from the first remote thermal diode. Diode Negative Serves as the negative input into the A/D. Connected to Input THERMDC pin of Pentium processor or the emmiter of a diode connected MMBT3904 NPN transistor. 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 Output THERMDA pin of Pentium processor or the base of a diode connected MMBT3904 NPN transistor. Remote Thermal Negative input (current sink) from the first remote thermal diode. Diode Negative Serves as the negative input into the A/D. Connected to Input THERMDC pin of Pentium processor or the emmiter of a diode connected MMBT3904 NPN transistor. Digital Input Digital Input Digital Input Digital Input Input for monitoring tachometer output of fan 1. Input for monitoring tachometer output of fan 2. Input for monitoring tachometer output of fan 3. Input .