f75375 Feature Integration Technology Inc., f75375 Datasheet - Page 10

• Manufacturer Part Number: f75375
• Description: Fintek Hardware Monitor Ic Datasheet
• Manufacturer: Feature Integration Technology Inc.

6 Functional Description
6.1
graphic cards. The chip can monitor up to 4 analog voltage inputs, 2 fan tachometer inputs and 2 remote
temperature sensors. The remote temperature sensor can be performed by thermistor, transistor and thermal
diode. The F75375S can provide automatic fan speed control so that the system can operate at the minimum
acoustic noise. Also the users can set up the upper and lower limits (alarm thresholds) of all monitored
parameters and this chip can also issue warning messages for system protection when there is something
wrong with monitored items.
2V (ex:1.5V) can directly connected to these analog inputs. The voltage higher than 2V should be reduced by a factor with
external resistors so as to obtain the input range. Only 3VCC is an exception for it is main power of the F75375S. Therefore
3VCC can directly connect to this chip and need no external resistors. There are two functions in this pin with 3.3V. The first
function is to supply internal analog power of the F75375S and the second function is that this voltage with 3.3V is connected to
internal serial resistors to monitor the +3.3V voltage. The internal serial resistors are two 50K ohm, so that the internal reduced
voltage is half +3.3V.
There are four voltage inputs in the F75375S and the voltage divided formula is shown as follows:
If we choose R1=27K, R2=5.1K, the exact input voltage for
As for application circuit, it can be refer to the figure shown as follows.
13
Pin No.
8
7
Analog Input
F75375S is a system hardware monitoring and automatic fan speed controlling IC specific designed for
For the 8-bit ADC has the 7.8125mv LSB, the maximum input voltage of the analog pin is 2V. Therefore the voltage under
Serial Bus Control Pin
Fintek
VREF
Pin Name
SDATA
SCLK
AOUT
Type
IN
IN
ts
t s
/OD
VIN
12
=
Reference Voltage.
Description
Serial Bus data.
Serial Bus clock.
V
+
12
V
×
R
1
R
V
4
+
2
+12v will be 1.907V, which is within the tolerance.
R
2
Feature Integration Technology Inc.
where
V
+12V
F75375S/F75375SG
is the analog input voltage, for example.
July 2007
V0.26P