f75387 Feature Integration Technology Inc., f75387 Datasheet - Page 20

• Manufacturer Part Number: f75387
• Description: ?1o C Accuracy H/w Monitor Ic With Automatic Fan Speed Control
• Manufacturer: Feature Integration Technology Inc.

8. Register Description
Power on default <7:0> = 0000_0101 b
3. Use wide tracks to minimize inductance and reduce noise pickup. 10 mil track minimum width and spacing is
4. Try to minimize the number of copper/solder joints, which can cause thermocouple effects. Where copper/solder
5. Place a 0.1µF bypass capacitor close to the V
6. If the distance to the remote sensor is more than 8 inches, the use of twisted pair cable is recommended. It will
7. Because the measurement technique uses switched current sources, excessive cable and/or filter capacitance
8.1.
Bit
7
6
5
4
3
2
recommended.
joints are used, make sure that they are in both the D+ and Pin9 GND(D-) path and at the same temperature.
Thermocouple effects should not be a major problem as 1
copper-solder thermocouple exhibits 3µV/ ℃ , and takes about 200µV of the voltage error at D+ & Pin9 GND(D-)
to cause a 1 ℃ measurement error. Adding a few thermocouples causes a negligible error.
filter capacitors across D+, Pin9 GND(D-) close to the F75387.
work up to around 6 to 12 feet.
will affect the measurement accuracy. When using long cables, the filter capacitor may be reduced or removed.
Cable resistance can also induce errors. 1 Ω series resistance introduces about 0.5
Configuration Register  Index 00h
POWR_DOWN
CLK24M_SEL
LOW_POWR
Reserved
EN_SMI
Name
INIT
Attribute
R/W
R/W
R/W
R/W
R/W
RO
Set this bit to 1, then each monitor cycle become 0.2 Sec
Set one restores power on default value to all registers except the Serial
Bus Address register. This bit clears itself since the power on default is
zero.
Read back will be 0
When external clock is used, set this bit to 1 indicates the external clock is
24MHz.
Set the bit to 1 will power down internal circuit..
0: disable SMI function.
1: enable SMI function. (default)
DD
pin. In very noisy environments, place an external 2200pF input
18
℃
corresponds to about 200µV. It means that a
Description
℃
error.
July, 2007
F75387
0.27P