ne1618 NXP Semiconductors, ne1618 Datasheet - Page 13

• Manufacturer Part Number: ne1618
• Description: Temperature Monitor For Microprocessor Systems
• Manufacturer: NXP Semiconductors

Philips Semiconductors
PC BOARD LAYOUT CONSIDERATION
Because the NE1618 is used to measure a very small voltage from
the remote sensor, care must be taken to minimize noise induced at
the sensor inputs, especially in the computer motherboard noisy
environment. These precautions should be considered:
– Place the NE1618 as close as possible to the remote sensor. It
– Route the D+ and D– lines in parallel and close together with
– Leakage currents due to PC board contamination must be
– Use wide tracks to reduce inductance and noise pickup that may
2002 Jan 04
can be from 4 to 8 inches, as long as the worst noise sources
such as clock generator, data and address buses, CRTs are
avoided.
ground guards enclosed.
considered. Error can be introduced by the leakage current as
shown on the characteristics curve (Temperature Error vs. PC
Board Resistance).
be introduced by narrow ones. The width of 10 mil and space of
10 mil are recommended.
Temperature monitor for microprocessor systems
13
– Place a bypass capacitor of 0.1 F close to the V
– A shielded twisted pair is recommended for a long distance
input filter capacitor of 2200 pF close to the D+ and D– pins.
remote sensor. Connect the shield of the cable at the device side
to the NE1618 GND pin and leave the shield at the remote end
unconnected to avoid ground loop. Also notice that the series
resistance of the cable may introduce measurement error;
1
can introduce about 0.5 C.
GND
GND
D+
D–
NE1618
DD
pin and an
Product data
SL01218