f75387 Feature Integration Technology Inc., f75387 Datasheet - Page 19

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

7. PCB Layout Guide
PCB can be electrically noisy environments, and the F75387 is measuring very small voltage from the remote sensor,
so care must be taken to minimize noise which is occurred at the sensor inputs. The following guideline should be
taken to reduce the measurement error of the temperature sensors:
1. Place the F75387 as close as practical to the remote sensing diode. In noisy environments, such as a computer
2. Route the D+ and Pin9 GND(D-) tracks close together, in parallel, with grounded guard tracks on each side.
6.14. VOLT_FAULT# (Voltage Fault Signal)
When voltage leaps from the security range setting by BIOS, the warning signal VOLT_FAULT# will be activated.
Shown in figure 6-6
main-board, the distance can be 4 to 8 inches. (typ). This length can be increased if the worst noise sources are
avoided. Noise sources generally include clock generators, switching power plane, CRTs, memory buses and
PCI/ISA bus etc.
Provide a ground plane under the tracks if possible. Do not route D+ & Pin9 GND(D-) lines next to the deflection
coil of the CRT. And also don’t route the trace across fast digital signals which can easily induce bigger error.
MINIMUM
VOLT_FAULT#
10MILS
10MILS
Low limit
High limit
Figure 6-6
17
Pin9 GND(D-)
GND
GND
D+
10MILS
10MILS
July, 2007
F75387
0.27P