ADT7470 Analog Devices, Inc., ADT7470 Datasheet
ADT7470
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ADT7470 Summary of contents
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... Temperature Sensor Hub and Fan Controller GENERAL DESCRIPTION The ADT7470 controller is a multichannel temperature sensor and PWM fan controller and fan speed monitor for noise- sensitive systems requiring active system cooling designed to interface directly fans using a service processor ...
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... TABLE OF CONTENTS Specifications..................................................................................... 3 Absolute Maximum Ratings............................................................ 5 Thermal Characteristics .............................................................. 5 ESD Caution.................................................................................. 5 Pin Configuration and Function Descriptions............................. 6 Functional Description .................................................................... 7 General Description..................................................................... 7 Fan Speed Measurement.............................................................. 7 Internal Registers of the ADT7470 ............................................ 7 2 SMBus/I C Communications Interface..................................... 7 Address Selection ......................................................................... 7 Write Operations ........................................................................ 10 Read Operations ......................................................................... 11 SMBus Timeout .......................................................................... 11 General-Purpose I/O Pins (Open Drain) ............................... 11 Temperature Measurement Using TMP05/TMP06 ...
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... Rev Page ADT7470 Test Conditions/Comments Fan count = 0xBFFF Fan count = 0x3FFF Fan count = 0x0438 Fan count = 0x021C I = –8.0 mA +3.3 V OUT OUT –4.0 mA +3.3 V OUT OUT ...
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... ADT7470 Parameter SCL, SDA Fall Time Data Setup Time, t SU;DAT Detect Clock Low Timeout, t TIMEOUT 1 V should never be floated in the presence of SCL/SDA activity. Charge injection can be sufficient to induce approximately 0 All voltages are measured with respect to GND, unless otherwise specified. ...
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... V to +6.5 V section of this specification is not implied. Exposure to absolute –0 0 maximum rating conditions for extended periods may affect 150°C device reliability. –65°C to +150°C 215°C 200°C 3000 V Rev Page ADT7470 ...
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... Digital I/O (Open Drain). Pulse-width modulated output to control the speed of Fan 1. Requires 10 kΩ typical pull-up. Can be configured as GPIO by setting Bit 0x7F<3> SDA Digital I/O (Open Drain). SMBus bidirectional serial data. Requires SMBus pull-up. SCL 1 16 SDA GND 15 PWM1 2 ADT7470 V 14 SMBALERT 3 CC TOP VIEW TACH3 FULL_SPEED/TMP_START 4 (Not to Scale) 13 PWM2 ...
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... This interface is fully compatible with SMBus 2.0 electrical specifications and meets 400 pF bus capacitance requirements. The device also supports fast I (400 kHz max). The ADT7470 is connected to the bus as a slave device under the control of a master controller or service processor. ...
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... The facility to make hardwired changes to the SMBus slave address allows the user to avoid conflicts with other devices sharing the same serial bus, for example, if more than one ADT7470 is used in a system. The serial bus protocol operates as follows: 1. ...
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... In the ADT7470, write operations contain either one or two bytes, and read operations contain one byte and perform the following functions. To write data to one of the device data registers or read data from it, the address pointer register must be set so that the correct data register is addressed. Then data can be written into that register or read from it ...
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... The slave asserts ACK on SDA. 6. The master asserts a stop condition on SDA, and the transaction ends. For the ADT7470, the send byte protocol is used to write a register address to RAM for a subsequent single byte read from the same address. This is shown in Figure 10 SLAVE ...
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... The master receives a data byte. 5. The master asserts NO ACK on SDA. 6. The master asserts a stop condition on SDA and the transaction ends. In the ADT7470, the receive byte protocol is used to read a single byte of data from a register whose address was previously set by a send byte or write byte operation ...
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... Using Reg7Ch and Reg7Dh, the user can set up which TMP05 0x00 controls which fan. An individual TMP05, or the hottest TMP05 in the daisy chain, can control each fan. This allows the ADT7470 to create and control up to four independent thermal zones system with n TMP05s possible to have TMP05s controlling each fan ...
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... IS GENERATED BY TMP05 2. 2 STOP EACH START/STOP PULSE IS TYPICALLY 25µs. TMP05s MUST BE IN DAISY-CHAIN MODE. SEE THE TMP05 DATA SHEET FOR MORE INFORMATION. Figure 14. Typical Timing Diagram of ADT7470 with Two TMP05s Connected in Daisy-Chain Mode 1. Set Register 40<7> This starts the temperature measurements. 2. Wait 200 ms for each TMP05/TMP06 in the loop. ...
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... The fan tach measurements are 16-bit results. The fan tach limits are also 16 bits, consisting of two bytes: a high byte and low byte. On the ADT7470 it is possible to set both high and low speed fan limits for overspeed and underspeed or stall con- ditions. Be aware that, because the fan tach period is actually being measured, exceeding the limit by 1 indicates a slow or stalled fan ...
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... OUT-OF-LIMIT COMPARISONS Once all limits are programmed, the ADT7470 can be enabled to begin monitoring. The ADT7470 measures all parameters in round-robin format and sets the appropriate status bit for out- of-limit conditions. Figure 15. Temperature > Low Limit—No INT Figure 16. Temperature = Low Limit— INT Occurs Comparisons are done differently depending on whether the measured value is compared to a high limit or a low limit ...
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... ADT7470 MONITORING CYCLE TIME The monitoring cycle begins when written to the start bit (Bit 0) of Configuration Register 1 (Register 0x40). Each fan tach input is monitored in turn, and, as each measurement is completed, the result is automatically stored in the appropri- ate value register. Multiple temperature channels can also be monitored by clocking in temperatures using the TMP_IN pin ...
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... R8T A 1 indicates that TMP05 Temperature 8 high or low limit has been exceeded. SMBALERT INTERRUPT BEHAVIOR The ADT7470 can be polled for status SMBALERT interrupt can be generated for out-of-limit conditions. Note how the SMBALERT output and status bits behave when writing interrupt handler software. ...
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... ADT7470 MASKING INTERRUPT SOURCES Interrupt Mask Register 1 and Interrupt Mask Register 2 are located at Address 0x72 and Address 0x73. These allow indi- vidual interrupt sources to be masked out to prevent unwanted SMBALERT interrupts. Masking an interrupt source prevents only the SMBALERT output from being asserted; the appropriate status bit is still set as usual ...
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... V fan (or greater voltage (or less) logic device. In all cases, the tach signal from the fan must be kept below 5 V maximum to prevent damage to the ADT7470. The three resistors in Figure 23 ensure that the tach voltage is kept within safe levels for typical desktop and notebook systems ...
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... TACH INPUTS Pin 6, Pin 7, Pin 4, and Pin 9 are open-drain tach inputs intended for fan speed measurement. Signal conditioning in the ADT7470 accommodates the slow rise and fall times typical of fan tachometer outputs. The maxi- mum input signal range even where V than 5 V ...
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... TACH Figure 30. Fan Speed Measurement Fan Speed Measurement Registers The fan tachometer readings are 16-bit values consisting of a 2-byte read from the ADT7470. Table 14. Fan Speed Measurement Registers Register Address Description 0x2A Tach 1 Low Byte 0x2B Tach 1 High Byte ...
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... The ADT7470 has a unique fan spin-up function. Fans are PWMMAX on if there is no interaction with the ADT7470. It incorporates a 2 second bus alive/dead detection feature bus activity is seen and the ADT7470 is not specifically written to within 2 seconds, the PWM outputs autodrive PWMMAX. This is useful where a system lock-up occurs before software has a chance to configure the basic system devices ...
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... This is most suitable for use with 4-wire fans also possible to use low frequency PWM drive, such as 1.4 kHz. MANUAL FAN SPEED CONTROL The ADT7470 allows the duty cycle of any PWM output to be manually adjusted. This can be useful if users want to change fan speed in software or want to adjust PWM duty cycle output for test purposes ...
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... ADT7470 REGISTERS Table 21. ADT7470 Register Map Address R/W Description 0x20 R Temperature 1 Reading 0x21 R Temperature 2 Reading 0x22 R Temperature 3 Reading 0x23 R Temperature 4 Reading 0x24 R Temperature 5 Reading 0x25 R Temperature 6 Reading 0x26 R Temperature 7 Reading 0x27 R Temperature 8 Reading 0x28 R Temperature 9 Reading 0x29 R Temperature 10 Reading 0x2A R Tach 1 Low Byte ...
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... Rev Page ADT7470 Bit 2 Bit 1 Bit 0 Default R10T R9T R8T 0xXX Fan 2 Fan 1 Fan 1 0x55 0x81 0x7F 0x81 0x7F 0x81 ...
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... ADT7470 Address R/W Description 0x60 R/W Tach 1 Max Low Byte 0x61 R/W Tach 1 Max High Byte 0x62 R/W Tach 2 Max Low Byte 0x63 R/W Tach 2 Max High Byte 0x64 R/W Tach 3 Max Low Byte 0x65 R/W Tach 3 Max High Byte 0x66 R/W Tach 4 Max Low Byte 0x67 R/W Tach 4 Max High ...
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... Failed (internal circuitry destroyed). • Not populated. The ADT7470 expects to see a fan connected to each tach fan is not connected to that tach, its tach minimum high and low byte should be set to 0xFFFF. Table 23. Register 0x2A to Register 0x31. Fan Tach Reading Registers (Power-On Default = 0x00) ...
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... Read/Write 0x3A Read/Write 0x3B Read/Write The device ID register contains the ADT7470 device ID value as a means of identifying the part over the bus. Table 27. Register 0x3D. Device ID Register (Power-On Default = 0x70) Register Address Read/Write 0x3D Read/Write The company ID register contains the “0x41, ” the manufacturer ID number representative of Analog Devices’ product. ...
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... This bit is not set when the PWM 3 output is off indicates that Fan 4 has gone above max speed, dropped below min speed, or has stalled. This bit is not set when the PWM 4 output is off. Rev Page ADT7470 ) and that the fans are MIN ...
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... ADT7470 Table 33. Register 0x43. Fan Pulses Per Revolution Register (Power-On Default = 0x55) Bit Name Read/Write Description <1:0> Fan 1 Read/Write Sets the number of pulses to be counted when measuring Fan 1 speed. Can be used to determine fan’s pulses per revolution number for unknown fan type. ...
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... PWM2 (automatic fan control mode). This bit assigns fan behavior for PWM1 output manual fan control mode (PWM duty cycle controlled in software fastest speed calculated by all temperatures control PWM1 (automatic fan control mode). Rev Page ADT7470 Power-On Default 0xFF 0xFF 0xFF ...
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... N/A <3> N/A <4> INV4 Read/Write <5> INV3 Read/Write <6> BHVR4 Read/Write <7> BHVR3 Read/Write Registers 0x6A to 0x6D become read-only when the ADT7470 is in automatic fan control mode. Table 38. Register 0x6A to Register 0x6D. PWM Register Address Read/Write 0x6A Read/Write 0x6B Read/Write 0x6C Read/Write 0x6D Read/Write ...
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... A 1 masks the Temperature 9 value from generating an interrupt on the SMBALERT output. The R9T bit is set as normal in the status register for out-of-limit conditions masks the Temperature 8 value from generating an interrupt on the SMBALERT output. The R8T bit is set as normal in the status register for out-of-limit conditions. Rev Page ADT7470 ...
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... ADT7470 Table 42. Register 0x74. Configuration Register 2 (Power-On Default = 0x00) Bit Name Read/Write <7> SHDN Read/Write <6:4> FREQ Read/Write <3> T4_dis Read/Write <2> T3_dis Read/Write <1> T2_dis Read/Write <0> T1_dis Read/Write Table 43. Register 0x75. Enhance Acoustics 1 (Power-On Default = 0x00) Bit Name Read/Write <7> EN1 Read/Write <6:4> ACOU1 Read/Write <3> EN2 Read/Write < ...
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... This register indicates the maximum of all TMP05 temperatures. Description This register contains Bits 9:2 of the optional TMP05 gain coefficient. Description These bits contain Bits 1:0 of the optional TMP05 gain coefficient. These bits contain Bits 8:3 of the optional TMP05 offset coefficient. See also Register 0x7B in the next table. Rev Page ADT7470 ...
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... ADT7470 Table 48. Register 0x7B. TMP05 COEF Option 3 (Power-On Default = 0x00) Bit Name Read/Write <7:5> TMP05_OFFS Read/Write <2:0> AFC_Spin_Up Read/Write Table 49. Register 0x7C. TMP05 Zone Select 1 (Power-On Default = 0x00) Bit Name Read/Write <7:4> zone_fan1<3:0> Read/Write <3:0> zone_fan2<3:0> Read/Write Description These bits contain Bits 2:0 of the optional TMP05 offset coefficient. ...
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... Description These bits determine whether the default TMP05 (coef_sel<x> coefficients or the optional coefficients (0x79 to 0x7B) are used (coef_sel<x> = 1). Reserved. This bit should be set to 0. PWM1 becomes a GPIO. PWM2 becomes a GPIO. PWM3 becomes a GPIO. PWM4 becomes a GPIO. Rev Page ADT7470 ...
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... ADT7470 Table 53. Register 0x80. GPIO CONFIG (Power-On Default = 0x00) Bit Name Read/Write <7> GPIO1_d Read/Write <6> GPIO1_p Read/Write <5> GPIO2_d Read/Write <4> GPIO2_p Read/Write <3> GPIO3_d Read/Write <2> GPIO3_p Read/Write <1> GPIO4_d Read/Write <0> GPIO4_p Read/Write Table 54. Register 0x81. GPIO Status (Power-On Default = 0x00) Bit Name Read/Write <7:4> GPIO_s Read/Write < ...
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... ADT7470ARQ −40°C to +125°C ADT7470ARQ-REEL −40°C to +125°C ADT7470ARQ-REEL7 −40°C to +125°C ADT7470ARQZ 1 −40°C to +125°C 1 ADT7470ARQZ-REEL −40°C to +125°C 1 ADT7470ARQZ-REEL7 −40°C to +125°C EVAL-ADT7470EB Pb-free part. 0.193 BSC 16 9 0.154 BSC 0.236 1 BSC ...
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... ADT7470 NOTES Purchase of licensed components of Analog Devices or one of its sublicensed Associated Companies conveys a license for the purchaser under the Philips I 2 Rights to use these components system, provided that the system conforms to the I © 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners ...