ADT7460ARQ-REEL ON Semiconductor, ADT7460ARQ-REEL Datasheet - Page 36

• Manufacturer Part Number: ADT7460ARQ-REEL
• Description: IC SENSOR TEMP FAN-CTRL 16QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7460ARQ-REEL

• Rohs Status: RoHS non-compliant
• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 120°C, External Sensor
• Output Type: SMBus™
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 5.5 V
• Operating Temperature: -40°C ~ 120°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP

ADT7460
Table 44. Fan Tachometer Reading Registers (Power-On Default = 0x00)
Reg
0x28
0x29
0x2A
0x2B
0x2C
0x2D
0x2E
0x2F
The Fan Tachometer Reading re
numb r of co
The number of TACH pulses use
speed to be accurately measured
Both the low and high bytes are
TACH measur
A count of 0xFFFF indicates tha
1.
2.
3.
4.
5.
Table 45. C
Register Address
0x30
0x31
0x32
These registers reflect the PWM duty cycle driving each fan at any given time. When in automatic fan speed control mode, the ADT7460
reports the PWM duty cycles back through these registers. The PWM duty cycle values vary according to temperature in automatic fan
speed control mode. During fan startup, these registers report back 0x00. In software mode, the PWM duty cycle outputs can be set to any
duty cycle value by writing to these registers.
Table 46. Operating Point Registers (Power-On Default = 0x64)
Register Address
0x33
0x34
0x35
These registers become read-only when the Configuration Register 1 lock bit is set to 1. Any subsequent attempts to write to these
registers will fail.
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.
ist
Stalled or Blocked (object j
F iled
Not Populated (The ADT7
minimum high and low byt
Alternate Function, for exa
2-
e
a
er Addr
Wir
e Instea
(interna
urrent
nsecu
ess
eme
nt is read in
d of 3-Wire Fan
tive fan TAC pulses (default = 2).
PWM Duty ycle Registers (Power-On Default = 0xFF)
l circuitry d
R/W
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
Read-Only
R/W
Read/Write
Read/Write
Read/Write
R/W
Read/Write
Read/
Read/Write
to
e
C
H
gisters count the numbe
t a fan is
. Since a valid fan tachometer reading requires that two bytes are read, the low byte MUST be read first.
then frozen until read. At power-on, these registers contain 0x0000 until such time as the first valid fan
460 expects to see a fan connected to each TACH. If a fan is not connected to that TACH, its TACH
e should
amming the fan)
stroyed)
mple, TACH4 reconfigured as THERM pin
Write
d to count can be changed using the fan pulses per revolution register (Reg. 0x7B). This allows the f
these registers. This prevents false interrupts from occurring while the fans are spinning up.
be set to 0xFFFF.)
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
Description
PWM1 Current Duty Cycle (0% to 100% Duty Cycle = 0x00 to 0xFF)
PWM2 Current Duty Cycle (0%
PWM3 Current Duty Cycle (0% to 100% Duty Cycle = 0x00 to 0xFF)
Description
Remote 1 Operating Point Register (Default = 100°C)
Local Temp Operating Point Register (Default = 100°C)
Remote 2 Operating Point Register (Default = 100°C)
r of 11.11 µs periods (based on an internal 90 kHz clock) that occur between a
Rev. C | Page 36 of 52
to 100% Duty Cycle = 0x00 to 0xFF)
MIN
control feature is enabled.
an