ADT7460ARQZ ON Semiconductor, ADT7460ARQZ Datasheet - Page 42

• Manufacturer Part Number: ADT7460ARQZ
• Description: IC REMOTE THRML/FAN CTRLR 16QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7460ARQZ

• 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
• Full Temp Accuracy: +/- 3 C
• Digital Output - Bus Interface: Serial (3-Wire)
• Maximum Operating Temperature: + 120 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

1. This register becomes read−only when the Configuration Register 1 lock bit is set to 1. Further attempts to write to this register have no effect.
1. This register becomes read−only when the Configuration Register 1 lock bit is set to 1. Further attempts to write to this register have no effect.
Table 66. Remote 2 Temperature Offset Register (Power−On Default = 0x00)
Table 67. Register 0x73 — Configuration Register 2 (Power−On Default = 0x00)
Table 68. Register 0x74 — Interrupt Mask Register 1 (Power−On Default <7:0> = 0x00)
Bit No.
Bit No.
Register Address
0
1
2
3
4
5
6
7
0
1
2
3
4
5
6
7
<7:0>
0x72
Mnemonic
Mnemonic
CONV
SHDN
ATTN
AIN1
AIN2
AIN3
AIN4
AVG
2.5V
RES
RES
OOL
R1T
R2T
V
LT
CC
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
Bits <7:5> Reg. 0x55
Remote 2 Temperature Offset
Allows a twos complement offset value to be automatically added to or subtracted from the
Remote 2 temperature reading. This is to compensate for any inherent system offsets such as
PCB trace resistance. LSB value = 0.25°C.
AIN1 = 0, Speed of 3−wire fans measured using the TACH output from the fan. AIN1 = 1, Pin 6
is reconfigured to measure the speed of 2−wire fans using an external sensing resistor and
coupling capacitor. AIN voltage threshold is set via Configuration Register 4 (Reg. 0x7D).
AIN2 = 0, Speed of 3−wire fans measured using the TACH output from the fan. AIN2 = 1, Pin 7
is reconfigured to measure the speed of 2−wire fans using an external sensing resistor and
coupling capacitor. AIN voltage threshold is set via Configuration Register 4 (Reg. 0x7D).
AIN3 = 0, Speed of 3−wire fans measured using the TACH output from the fan. AIN3 = 1, Pin 4
is reconfigured to measure the speed of 2−wire fans using an external sensing resistor and
coupling capacitor. AIN voltage threshold is set via Configuration Register 4 (Reg. 0x7D).
AIN4 = 0, Speed of 3−wire fans measured using the TACH output from the fan. AIN4 = 1, Pin 9
is reconfigured to measure the speed of 2−wire fans using an external sensing resistor and
coupling capacitor. AIN voltage threshold is set via Configuration Register 4 (Reg. 0x7D).
AVG = 1, Averaging on the temperature and voltage measurements is turned off. This allows
measurements on each channel to be made much faster.
ATTN = 1, the ADT7460 removes the attenuators from the 2.5 V input. The input can be used
for other functions such as connecting up external sensors.
CONV = 1, the ADT7460 is put into a single−channel ADC conversion mode. In this mode, the
ADT7460 can be made to read continuously from one input only, for example, Remote 1
temperature. It is also possible to start ADC conversions using an external clock on Pin 6 by
setting Bit 2 of Test Register 2 (Reg. 0x7F). This mode could be useful if, for example, users
wanted to characterize/profile CPU temperature quickly. The appropriate ADC channel is
selected by writing to Bits <7:5> of TACH1 min high byte register (Reg. 0x55).
000
010
101
110
111
SHDN = 1, ADT7460 goes into shutdown mode. All PWM outputs assert low (or high
depending, on state of INV bit) to switch off all fans. The PWM current duty cycle registers read
0x00 to indicate that the fans are not being driven.
A 1 masks SMBALERT for out−of−limit conditions on the 2.5 V channel.
Reserved for future use.
A 1 masks SMBALERT for out−of−limit conditions on the V
Reserved for future use.
A 1 masks SMBALERT for out−of−limit conditions on the Remote 1 temperature channel.
A 1 masks SMBALERT for out−of−limit conditions on the Local temperature channel.
A 1 masks SMBALERT for out−of−limit conditions on the Remote 2 temperature channel.
A 1 masks SMBALERT for any out−of−limit condition in Status Register 2.
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ADT7460
42
Channel Selected
2.5V
V
Remote 1 Temp
Local Temp
Remote 2 Temp
CC
(3.3V)
Description
Description
Description
(Note 1)
(Note 1)
CC
channel.