f75387 Feature Integration Technology Inc., f75387 Datasheet - Page 10

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

External Resistor
Address
Power On PWM Duty Cycle/DAC Linear Voltage Output
Power On DACOUT/PWMOUT Mode
There are four voltage inputs in the F75387 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 as follows.
6.3.
The F75387 provides one serial access interface, Serial Bus, to read/write internal registers. The address of Serial
Bus is configurable by using power-on trapping. The pin 3 (PWM1/DAC1/ADDR_TRAP) is a multi-function pin.
During power-on, this pin serves as input detection of logic high or logic low. Two Serial Bus address 0x5A
(0101_1010) and
indicates the configuration:
(a)
Serial bus write to internal address register followed by the data byte
Access Interface and Power On Configuration
Voltage Inputs
Typical BJT
Connection
0x5C (0101_1100) can be selected by changing external pull-up resistors. Following table
VIN(Higher than
VIN (Lower than 2.048V)
3Vcc
2N3906
VIN
=
R
V
+
R
12
10K, 1%
10K, 25 C
THM
V
×
Figure 6-1
60% x 3VCC
DACOUT
R
(directly connect to the chip)
(directly connect to the chip)
R1
0x5A
1
NC
8
R
+
2
Typical Thermister
Connection
R
2
V
VIN1(Max2.048V)
+12v
R2
where
Pin 14 or 15
100% x 3VCC
will be 1.907V, which is within the tolerance.
VREF
DACOUT
200K
0x5C
V
Pin 13
+12V
is the analog input voltage, for example.
60% Duty Cycle
150K
150K
8-bit ADC
8 mV LSB
PWMOUT
0x5C
10K
with
VIN3.3
100% Duty Cycle
PWMOUT
0x5A
2.2K
July, 2007
F75387
0.27P