ADT7460ARQ-REEL ON Semiconductor, ADT7460ARQ-REEL Datasheet
ADT7460ARQ-REEL
Specifications of ADT7460ARQ-REEL
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ADT7460ARQ-REEL Summary of contents
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FEATURES Controls and monitors fan speeds 1 on-chip and 2 remote temperature sensors Dynamic T control mode optimizes system acoustics MIN intelligently Automatic fan speed control mode controls system cooling based on measured temperature Enhanced acoustic mode ...
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ADT7460 TABLE OF CONTENTS Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 5 Thermal Characteristics .............................................................. 5 ESD Caution.................................................................................. 5 Pin Configuration and Function Descriptions............................. 6 Typical Performance Characteristics ............................................. 7 Product Description......................................................................... 9 Measurement Inputs .................................................................... 9 Sequential Measurement ............................................................. 9 Recommended ...
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SPECIFICATIONS unless otherwise noted. A MIN MAX CC MIN MAX Table Parameter POWER SUPPLY Supply Voltage Supply Current TEMPERATURE-TO-DIGITAL CONVERTER Local ...
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ADT7460 Parameter DIGITAL INPUT LOGIC LEVELS (TACH INPUTS) Input High Voltage Input Low Voltage Hysteresis DIGITAL INPUT LOGIC LEVELS (THERM) Input High Voltage Input Low Voltage DIGITAL INPUT CURRENT ...
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ABSOLUTE MAXIMUM RATINGS Table 2. Parameter Positive Supply Voltage ( Voltage on Any Other Input or Output Pin Input Current at Any Pin Package Input Current Maximum Junction Temperature (T max) J Storage Temperature Range Lead Temperature, Soldering ...
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ADT7460 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS PWM3/ADDRESS ENABLE Table Func tion Descript ions Pin No. Mnemonic Description 1 SCL Digital Input (Open Drain). SMBus serial clock input. Requires SMBus pull-up. 2 GND Ground Pin for the ADT7 ...
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TYPICAL PERFORMANCE CHARACTERISTICS 15 10 DXP TO GND 5 0 –5 DXP TO V (3.3V) CC –10 –15 –20 1 3.3 10.0 LEAKAGE RESISTANCE (M Ω ) Figure 4. Remote Temperature Error vs. Leakage Resistance 3 REMOTE TEMPERATURE ERROR (°C) ...
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ADT7460 1.90 1.85 1.80 1.75 1.70 1.65 1.60 1.55 1.50 1.45 1.40 2.6 3.0 3.4 3.8 4.2 2.5 SUPPLY VOLTAGE (V) Figure 10. Supply Current vs. Supply Voltage 16 20mV 10mV –2 ...
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PRODUCT DESCRIPTION The ADT7460 is a thermal monitor and multiple fan controller for any system requiring monitoring and cooling. The device communicates with the system via a serial System Management Bus (SMBus). The serial bus controller has an optional address ...
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ADT7460 ADT7460 AD DRES S SELECTION Pin 8 is the dual -functio n PWM 3/ ADDRESS ENABLE pin. If Pin 8 is pulled low on p ower-up, the ADT7460 reads the state of Pin 9 (T ACH4/ADDRE SS SELECT/ THERM ...
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THEORY OF OPERATION SERIAL BUS INTERFACE Control of the ADT7460 is carried out using the serial System Management Bus (SMBus). The ADT7460 is connected to this bus as a slave device, under the control of a master controller. The ADT7460 ...
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ADT7460 2. Data is sent over the serial bus in sequences of nine clock pulses, eight bits of data followed by an Acknowledge bit from the slave device. Transitions on the data line must occ during the low period of ...
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When reading data from a register, there are two possibilities: • If the ADT7460’s address pointer register value is unknown or not the desired value first necessary to set it to the correct value before data can be ...
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ADT7460 For the ADT 7460, the send byte protocol is used to write to the address pointer register for a subsequent single-byte read from the same address. This is illustrated in Figure 21 SLAVE REGISTER S ...
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SMBus Timeout The ADT7460 includes an SMBus timeout feature. If there is no SMBus activity for 25 ms, the ADT7460 assumes that the bus is locked and releases the bus. This prevents the device from locking or holding the SMBus ...
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ADT7460 Table 9. 10-Bit A/D Output Code vs. V Input Voltage (3 <0.0065 <0.0042 0.0065–0.0130 0.0042–0.0085 0.0130–0.0195 0.0085–0.0128 0.0195–0.0260 0.0128–0.0171 0.0260–0.0325 0.0171–0.0214 0.0325–0.0390 0.0214–0.0257 0.0390–0.0455 0.0257–0.0300 0.0455–0.0521 0.0300–0.0343 0.0521–0.0586 0.0343–0.0386 • • • ...
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ADDITIONAL ADC FUNCTIONS FOR VOLTAGE MEASUREMENTS A number of other functions are available on the ADT7460 to offer the systems designer increased flexibility. Turn-Off Averaging For each voltage measurement read from a value register, 16 readings have actually been made ...
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ADT7460 If a discrete transistor is used, the collector is not grounded, and it should be linked to the base PNP transistor is used, the base is connected to the D− input and the emitter to the D+ ...
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Nulling Out Temperature Errors As CPUs run faster, it becomes more difficult to avoid high frequency clocks when routing the D+, D− traces around a system board. Even when recommended layout guidelines are followed, there may still be temperature errors ...
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ADT7460 LIMITS, STATUS REGISTERS, AND INTERRUPTS Limit Val ues Associ ated with ea ch measuremen t channel on the ADT7460 are hig h and low li mits. These can fo rm the basis of status monitoring: a status bit can ...
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Figure 31. Temperature = High Limit: No INT Figure 32. Temperature > High Limit: INT Occurs Analog Monitoring Cycle Time The analog monitoring cycle begins when written to the start bit (Bit 0) of Configuration Register 1 ...
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ADT7460 T able 23. Status Register 1 (Reg. 0x41) Bit Mnemonic Descriptio n 7 OOL 1 denotes a bit in Status Register 2 is set and Status Register 2 should be read. 6 R2T 1 indicates that the Remote 2 ...
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HIGH LIMIT TEMPERATURE “STICKY” STATUS BIT TEMP BACK IN LIMIT (STATUS BIT STAYS SET) SMBALERT INTERRUPT MASK BIT SET Figure 36. How Masking the Interrupt Source Affects SMBALERT Output Masking Interrupt Sources Interrupt Mask Registers 1 and 2 are located ...
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ADT7460 THERM TIMER The ADT7460 has an internal timer to measure THERM assertion time. For example, the THERM input may be connected to the PROCHOT output of a Pentium 4 CPU and m easure system performance. The THERM connected to ...
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THERM LIMIT 364.16ms (REG. 0x7A) 182.08ms 91.04ms 45.52ms 22.76ms Figure 39. Functional Diag 2.914s 1.457s 728.32ms 364.16ms 182.08ms 91.04ms 45.52ms 22.76ms ...
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ADT7460 Configuring the Desired THERM Behavior 1. Configure the THERM input. Setting Bit 1 ( THERM ENABLE) of Configuration Register 3 (Reg. 0x78) enables the THERM monitoring function. 2. Select the desired fan behavior for THERM events. Setting Bit 2 ...
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FAN DRIVE USING PWM CONTROL The ADT7460 uses pulse width modulation (PWM) to control fan speed. This relies on varying the duty cycle (or on/off ratio square wave applied to the fan to vary the fan speed. The ...
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ADT7460 Figure 43. Interfacing Two Fans in Parallel to the PWM Figure 44. Interfacing Two Fans in Par Table 29. SYNC : Enhance Acoustics Register 1 (Reg. 0x62) Bit Mnemonic Description <4> SYNC 1 synchronizes TACH2, TACH3, and TACH4 to ...
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CH1 100mV CH2 5.00mV M 4.00ms CH3 50.0mV CH4 50.0mV T –1.00000ms Figure 46. Fan Speed Sensing Waveform at TACH/AIN Pin Laying Out 2-Wire and 3-Wire Fans Figure 47 shows how to lay out a comm for 2-wire and 3-wire ...
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ADT7460 12V <1kΩ R1* TACH TACH R2* OUTPUT *SEE TEXT Figure 51. Fan with Stro ng TACH Pull-Up to > V Attenuated with R1/R2 Fan Speed Measure ment Th e fan count er does n ot count the fan TACH ...
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Calculating Fan Spe ed Assuming a fan with a two pulses/revolution (and two pulses/ revolution being measured), fan speed is calculated by Fan Speed (RPM) = 90,000 × 60/Fan TACH Reading where: Fan TACH Reading = 16-Bit Fan Tachometer Reading ...
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ADT7460 Table 36. PWM1–PWM3 Con figuration (Reg. 0x5C–0x5E) Bit Mnemonic Description <2:0> SPIN These bits control the start-up timeout for PWM1. 000 = no start-up timeout 001 = 100 ms 010 = 250 ms (default) 011 = 400 ms 100 ...
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Table 40. PWM Duty Cycle Registers Register Description 0x30 PWM1 duty cycle 0x31 PWM2 duty cycle 0x32 PWM3 duty cycle By readin PWMx current duty cycle gisters, users c keep track current duty c ...
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ADT7460 ADT7460 REGISTER SUMMARY Tabl 7460 Registers T Addre ss R/W Description 0x20 R 2.5 V Reading 0x22 R V Reading CC 0x25 R Remote 1 Temperature 0x26 R Local Temperature 0x27 R Remote 2 Temperature ...
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Address R/W Description 0x67 R/W Remote 1 Tem p T MIN 0x68 R/W Local Temp T MIN 0x69 R/W Remote 2 Tem p T MIN 0x6A R/W Remote 1 THERM Limit 0x6B R/W Local THERM Limit 0x6C R/W Remote 2 ...
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ADT7460 Table 44. Fan Tachometer Reading Registers (Power-On Default = 0x00) Reg ist er Addr ess R/W 0x28 Read-Only 0x29 Read-Only 0x2A Read-Only 0x2B Read-Only 0x2C Read-Only 0x2D Read-Only 0x2E Read-Only 0x2F Read-Only The Fan Tachometer Reading re gisters count ...
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Table 47. Register 0x36—Dynamic T MIN Bit Desc ription <0> ad/Write 3-Bit Remote 2 Cycle Value. The other two bits of the code reside in Dynamic T (Reg. 0x37). These ...
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ADT7460 Table 48. Register 0x37—Dynamic T MIN Bit Nam Descr <2:0> Read/W ite r 3-Bit Remote 1 Cycle Value. These three bits define the delay time between making subse adjustments in the control loop for ...
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Table 49. Register 0x40—Configuration Register 1 (Power-On Default = 0x00) Bit Name R/W Description <0> STRT Read/Write L ogic 1 enables monitorin L ogic 0 disables monitoring and PWM control based on the default power-up limit settings. Note that the ...
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ADT7460 Table 51. Register 0x42—Interrupt Status Register 2 (Power-On Defaul Bit Name R/ W Description <0> RES Read-Only Reserved for future use. <1> OVT Read-Only A 1 indicates that one of the THERM overte o f the status re <2> ...
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Table 54. Fan Tachometer Limit Registers (Power-On Default = 0xFF) Register Address R/W 0x54 Read/Write 0x55 Read/Write 0x56 Read/Write 0x57 Read/Write 0x58 Read/Write 0x59 Read/Write 0x5A Read/Write 0x5B Read/Write Exceeding any TACH limit registe in Inter rup ...
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ADT7460 Table 57. TEMP T /PWM Frequency Registers (Power-On Default 0xC4) RANGE Reg iste r Addre s s 0x5F 0x60 0x61 These re isters b g ecom es read-o nly fect. Table 58. TEM ...
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Table 59. Register 0x62—Enhance Acoustics Register 1 (Power-On Default = 0x00) Bit Name escription <2:0> ACOU R ead/Write T hese bits select the ramp rate applied to the PWM1 output. Instead of PWM1 jumping instantaneously to i ...
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ADT7460 Table 60. Register 0x63— Enhance Acoustics Register 2 (Power-On Default = 0x00) Bit Name R/W Description <2:0> ACOU3 Read/Write Th ese bits sele its newly calcu en hances the a Time Slot Increase 000 001 010 011 100 101 ...
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Table 63. T Registers MIN Register Address R/W 0x67 Read 0x68 Read/Write 0x69 Read/Write These are the T registers for each temperature channel. When the temperature measured exceeds T MIN minimum speed and increase with temperature according to T These ...
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ADT7460 Table 67. Remote 1 Temperature Offset Register (Power-On Default = 0x00) Reg ter Add R/W 0x70 Read/W e rit <7:0> Read/Writ e This register becomes read-only when the Configuration Register 1 lock bit is set to ...
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Table 70. Register 0x73—Configuration Register 2 (Power-On Default = 0x00) Bit escription 0 AIN 1 Re ad/Write Speed of 3-wire fa re configured to measure the speed of 2-wire fans using ...
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ADT7460 Table 72. Register 0x75—Interrupt Mask Register 2 (Power-On Default = 0x00 Bit Name R/W Description 0 RES Read/Write Reserved for future use. 1 OVT Read-Only A 1 masks SMBALERT for overtemperature THERM conditions. 2 FAN1 Read/Write A 1 masks ...
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Table 76. Register 0x79— THERM Status Register (Power-On Default = 0x00) Bit Name R /W Descrip <7:1> TMR Read-On ly Times how long THERM exceeds 45.52 ms. <0> ASRT/TMR0 Read-Only Is set high on the assertion of the THERM input. ...
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ADT7460 Table 79. Register 0x7D—Configur ation Register 4 (Power-On Default = 0x00) Bit Name R/W Des cription <0> AL2.5V Read/Write AL2. Pin 14 (2.5V/SMBALERT) is configured as an SMBALERT interrupt output to indicate out-of-limit error conditions. AL2.5V = ...
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... OUTLINE DIMENSIONS 0.010 0.004 COPLANARITY ORDERING GUIDE Model Temperature Range ADT7460ARQ −40°C to +120°C ADT7460ARQ-REEL −40°C to +120°C ADT7460ARQ-REEL7 −40°C to +120°C 1 ADT7460ARQZ −40°C to +120°C 1 ADT7460ARQZ-REEL −40°C to +120°C 1 ADT7460ARQZ-REEL7 −40°C to +120°C EVAL-ADT7460EB Pb-free part ...
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ADT7460 NOTES © 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. C03228–0–3/05(C) Rev Page ...