EVAL-ADT7467EBZ ON Semiconductor, EVAL-ADT7467EBZ Datasheet - Page 62

• Manufacturer Part Number: EVAL-ADT7467EBZ
• Description: BOARD EVALUATION FOR ADT7467
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of EVAL-ADT7467EBZ

• Sensor Type: Temperature
• Sensing Range: -40°C ~ 120°C
• Interface: SMBus (2-Wire/I²C)
• Sensitivity: ±1.5°C
• Voltage - Supply: 3 V ~ 5.5 V
• Embedded: No
• Utilized Ic / Part: ADT7467
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADT7467
Table 20. Fan Tachometer Reading Registers (Power-On Default = 0x00)
Register Address
0x28
0x29
0x2A
0x2B
0x2C
0x2D
0x2E
0x2F
1
Table 21. Current PWM Duty Cycle Registers (Power-On Default = 0x00)
Register Address
0x30
0x31
0x32
1
Table 22. Operating Point Registers (Power-On Default = 0xA4)
Register Address
0x33
0x34
0x35
1
2
3
These registers count the number of 11.11 μs periods (based on an internal 90 kHz clock) that occur between a number of consecutive fan TACH pulses (default = 2).
The number of TACH pulses used to count can be changed using the TACH pulses per revolution register (0x7B). This allows the fan speed to be accurately measured.
Because a valid fan tachometer reading requires that two bytes are read, the low byte must be read first. Both the low and high bytes are then frozen until read. At
power-on, these registers contain 0x0000 until the first valid fan TACH measurement is read into these registers. This prevents false interrupts from occurring while the
fans are spinning up.
A count of 0xFFFF indicates that a fan is one of the following:
•
•
•
•
•
These registers reflect the PWM duty cycle driving each fan at any given time. When in automatic fan speed control mode, the ADT7467 reports the PWM duty cycles
through these registers. The PWM duty cycle values vary according to the temperature in automatic fan speed control mode. During fan startup, these registers report
0x00. In software mode, the PWM duty cycle outputs can be set to any duty cycle value by writing to these registers.
These registers set the target operating point for each temperature channel when the dynamic T
The fans being controlled are adjusted to maintain temperature about an operating point.
These registers become read-only registers when the Configuration Register 1 LOCK bit is set to 1. Any subsequent attempts to write to these registers fail.
Stalled or blocked (object jamming the fan).
Failed (internal circuitry destroyed).
Not populated. (The ADT7467 expects to see a fan connected to each TACH. If a fan is not connected to a TACH, the minimum high and low bytes of that TACH
should be set to 0xFFFF.)
Alternate function (for example, TACH4 reconfigured as THERM pin).
2-wire instead of 3-wire fan.
R/W
Read/write
Read/write
Read/write
R/W
Read/write
Read/write
Read/write
Description
PWM1 current duty cycle (0% to 100% duty cycle = 0x00 to 0xFF).
PWM2 current duty cycle (0% to 100% duty cycle = 0x00 to 0xFF).
PWM3 current duty cycle (0% to 100% duty cycle = 0x00 to 0xFF).
Description
Remote 1 operating point register (default = 100°C).
Local temperature operating point register (default = 100°C).
Remote 2 operating point register (default = 100°C).
Rev. 3 | Page 62 of 77 | www.onsemi.com
R/W
Read only
Read only
Read only
Read only
Read only
Read only
Read only
Read only
1, 2, 3
1
1
MIN
control feature is enabled.
Description
TACH1 low byte.
TACH1 high byte.
TACH2 low byte.
TACH2 high byte.
TACH3 low byte.
TACH3 high byte.
TACH4 low byte.
TACH4 high byte.