ADT7473ARQZ-1R7 ON Semiconductor, ADT7473ARQZ-1R7 Datasheet - Page 45

• Manufacturer Part Number: ADT7473ARQZ-1R7
• Description: IC THERM MON FAN CTLR 16-QSOP
• Manufacturer: ON Semiconductor
• Series: dBCool®r

Specifications of ADT7473ARQZ-1R7

• Function: Fan Control, Temp Monitor
• Topology: ADC, Comparator, Fan Speed Counter, Multiplexer, Register Bank
• Sensor Type: External & Internal
• Sensing Temperature: -40°C ~ 125°C, External Sensor
• Output Type: SMBus™
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Surface Mount
• Package / Case: 16-QSOP
• Full Temp Accuracy: +/- 0.5 C
• Digital Output - Bus Interface: Serial (3-Wire, 4-Wire)
• Maximum Operating Temperature: + 125 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Programming Operating Point Registers
temperature channel. These 8−bit registers allow the
operating point temperatures to be programmed with 1°C
resolution.
Step 10: High and Low Limits for Temperature
Channels
value starts to be increased, if temperature falls below this
value. This has the net effect of reducing the fan speed,
allowing the system to get hotter. An interrupt can be
generated when the temperature drops below the low limit.
value starts to be reduced, if temperature increases above
this value. This has the net effect of increasing fan speed to
cool down the system. An interrupt can be generated when
the temperature rises above the high limit.
Programming High and Low Limits
associated with each temperature channel. These 8−bit
registers allow the high and low limit temperatures to be
programmed with 1°C resolution.
Temperature Limit Registers
Register 0x4E, Remote 1 Temperature Low Limit = 0x01
Register 0x4F, Remote 1 Temperature High Limit = 0x7F
Register 0x50, Local Temperature Low Limit = 0x01
There are three operating point registers, one for each
The low limit defines the temperature at which the T
The high limit defines the temperature at which the T
There are six limit registers; a high limit and low limit are
Figure 67. Operating Point Value Dynamically Adjusts Automatic Fan Control Settings
http://onsemi.com
MIN
MIN
45
Operating Point Registers
Register 0x33, Remote 1 Operating Point = 0xA4
(100°C default)
Register 0x34, Local Operating Point = 0xA4
(100°C default)
Register 0x35, Remote 2 Operating Point = 0xA4
(100°C default).
Register 0x51, Local Temperature High Limit = 0x7F
Register 0x52, Remote 2 Temperature Low Limit = 0x01
Register 0x53, Remote 2 Temperature High Limit = 0x7F
How Dynamic T
in these steps. A number of conditions govern the situations
in which T
The basic premise is as follows:
However, the loop operation is not as simple as described
1. Set the target temperature for the temperature
2. As the temperature in that zone (Remote 1
3. As the temperature drops below the operating
zone, which could be, for example, the Remote 1
thermal diode. This value is programmed to the
Remote 1 operating temperature register.
temperature) rises toward and exceeds the
operating point temperature, T
the fan speed increases.
point temperature, T
speed is reduced.
MIN
can increase or decrease.
MIN
Control Works
MIN
is increased, and the fan
MIN
is reduced, and