EVAL-ADM1031EB ON Semiconductor, EVAL-ADM1031EB Datasheet
EVAL-ADM1031EB
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EVAL-ADM1031EB Summary of contents
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ADM1031 Intelligent Temperature Monitor and Dual PWM Fan Controller The ADM1031 is an ACPI−compliant, three−channel digital thermometer and under/overtemperature alarm for use in personal computers and thermal management systems. Optimized for the Pentium III, the part offers a 1°C higher ...
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ADM1031 PWM PWM_OUT1 1 CONTROLLERS PWM_OUT2 3 TACH2/AIN2 4 TACH SIGNAL CONDITIONING TACH1/AIN1 2 D1+ 10 D1– 9 D2+ 12 D2– 11 BANDGAP TEMPERATURE SENSOR ABSOLUTE MAXIMUM RATINGS Parameter Positive Supply Voltage ( Voltage on Any Input or ...
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PIN ASSIGNMENT Pin No. Mnemonic 1 PWM_OUT1 Digital Output, Open−Drain. Pulse width modulated output to control fan speed. Requires pullup resistor (10 kW typical). 2 TACH1/AIN1 Digital/Analog Input. Fan tachometer input to measure FAN1 fan speed. Can be reprogrammed as ...
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ELECTRICAL CHARACTERISTICS Parameter OPEN−DRAIN SERIAL DATA BUS OUTPUT (SDA) Output Low Voltage High−Level Output Leakage Current SERIAL BUS DIGITAL INPUTS (SCL, SDA) Input High Voltage Input Low Voltage Hysteresis DIGITAL INPUT LOGIC ...
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DXP TO GND 0 DXP –5 –10 –15 –20 1 3.3 10 LEAKAGE RESISTANCE (MW) Figure 3. Temperature Error vs. PCB Track Resistance 40mV p− ...
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V = 30mV p− 20mV p−p IN –1 0 100k 1M 100M 200M 300M FREQUENCY (Hz) Figure 9. Temperature Error vs. Differential−Mode Noise Frequency 0.08 0 –0.08 –0.16 –0.24 ...
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Functional Description The ADM1031 is a temperature monitor and dual PWM fan controller for microprocessor−based systems. The device communicates with the system via a serial System Management Bus (SMBus). The serial bus controller has a hardwired address pin for device ...
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The number of data bytes that can be transmitted over the serial bus in a single read or write operation ...
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SCL SDA START BY MASTER SERIAL BUS ADDRESS BYTE Figure 16. Writing to the Address Pointer Register Only 1 SCL SDA START BY MASTER SERIAL BUS ADDRESS BYTE Figure 17. Reading Data from ...
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× BIAS D+ REMOTE SENSING D– BIAS TRANSISTOR DIODE LOW−PASS FILTER f = 65kHz C Figure 18. Signal Conditioning If a discrete transistor is used, then the collector is not grounded, and is linked ...
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Try to minimize the number of copper/solder joints, which can cause thermocouple effects. Where copper/solder joints are used, make sure that they are in both the D+ and D– path and at the same temperature. Thermocouple effects should not ...
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Bit 1 (Fan Fault) is set whenever a fan tach failure is detected. Once cleared, it reasserts on subsequent fan tach failures. Bit 2 and Bit 3 of Status Register 1 and Status Register 2 are the Remote 1 ...
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T MIN TEMPERATURE (°C) Figure 22. PWM Duty Cycle vs. Temperature Slope (T ) RANGE Figure 23 shows how, for a given T T ...
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Remote 1 temperature is measuring 70°C. The PWM duty cycle calculated by the local temperature control loop is 100% (because the temperature = T ). The PWM duty cycle MAX calculated by the Remote 1 ...
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Table 7. Programming PWM Duty Cycle Decimal Value PWM Duty Cycle (0×0A) 11 (0×0B) 12 (0×0C) 13 (0×0D) 14 (0×0E) 15 (0×0F) The temperature at which the fan runs ...
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Register 0y24 Local Temperature T <7:3> Local Temperature T . These bits set the MIN temperature at which the fan turns on when under auto fan speed control. T can be programmed in 4°C increments. MIN 00000 = 0°C 00001 ...
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READ TEMPERATURE CALCULATE NEW PWM DUTY CYCLE IS NEW NO PWM VALUE > PREVIOUS VALUE? YES INCREMENT PREVIOUS PWM VALUE BY RAMP RATE Figure 28. Filtered Mode Algorithm The filtered mode algorithm calculates a new PWM duty cycle based on ...
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Finally, Figure 32 shows how the control loop reacts to temperature with the slowest ramp rate. The ramp rate is set to 1, while all other control parameters remain the same. With the slowest ramp rate selected, it took 112 ...
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Programming the Filtered Automatic Fan Speed Control Loop 1. Program a value for T . MIN 2. Program a value for the slope MAX MIN RANGE 4. Program a value for fan ...
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Example 1: If the desired value for RPM feedback mode is 5000 RPM, the count to be programmed is: Count = (f × 60)/R × N Since the desired RPM value 5000 RPM, the value for count is: ...
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Figure 34 shows how a 3−wire fan can be driven using PWM control. 3.3 V 10kW TYPICAL TACH TACH/AIN 3.3 V ADM1031 10kΩ TYPICAL PWM_OUT Figure 34. Interfacing the ADM1031 to a 3−Wire Fan The NDT3055L n−type MOSFET was chosen ...
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CLOCK CONFIG 2 REG. BIT 2 FAN INPUT START OF FAN MONITORING MEASUREMENT CYCLE PERIOD Figure 37. Fan Speed Measurement In situations where different output drive circuits are used for fan drive, it can be desirable to invert the PWM ...
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V MAX (DO NOT CONNECT 5 TYP FAN2 2−WIRE TACH FAN NDT3055L NDT3055L (N−MOS) (NMOS) 3 SENSE 3.3 V 0.01mF THERM SIGNAL TO THROTTLE CPU CLOCK 3.3 V FAN_FAULT ...
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Table 13. Value Registers Address R/W 0x06 R Extended Temperature Resolution (see Table 18). 0x08 R/W Fan 1 Speed. This register contains the value of the Fan 1 tach measurement. 0x09 R/W Fan 2 Speed. This register contains the value ...
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Table 15. Register 0y01 Configuration 2 Power−On Default = 7FH Bit Name R/W 0 PWM 1 En R/W 1 PWM 2 En R/W 2 TACH 1 En R/W 3 TACH 2 En R/W 4 Loc Temp En R/W 5 Remote ...
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Table 18. Register 0y06 Extended Temperature Resolution Power−On Default = 00H Bit Name R/W <2:0> Remote Temp 1 R <5:3> Remote Temp 2 R <7:6> Local Temp R Table 19. Register 0y20 Fan Characteristics Register 1 Power−On Default = 5DH ...
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Table 21. Register 0y22 Fan Speed Configuration Register Power−On Default = 55H Bit Name R/W <3:0> Normal/Min Spd 1 R/W <7:4> Normal/Min Spd 2 R/W Table 22. Register 0y23 Fan Filter Register Power−On Default = 50H Bit Name R/W <7> ...
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Table 24. Register 0y25 Remote 1 Temp T Bit Name R/W <7:3> Remote 1 Temp T R/W MIN <2:0> Remote 1 Temp R/W T RANGE Table 25. Register 0y26 Remote 2 Temp T Bit Name R/W <7:3> Remote 2 Temp ...
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Table 27. Register 0y0D Local Temperature Offset Power−On Default = 00H Bit Name R/W <7> Sign R/W <3:0> Local Offset Table 28. Register 0y0E Remote 1 Temperature Offset Power−On Default = 00H Bit Name R/W <7> Sign R/W <6.4> Unused ...
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