PC87591L datasheet(189/437 Pages) NSC

No. de pieza	PC87591L

Descripción Electrónicos	LPC Mobile Embedded Controllers

PDF	437 Pages

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Fabricante Electrónico	NSC [National Semiconductor (TI)]

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Embedded Controller Modules (Continued)

Revision 1.07

189

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Twisted Pair and Shielded Cables

For remote sensor distances longer than 8 inches or in particularly noisy environments, a twisted pair cable is recommended.

Its practical length is 6 feet to 12 feet (typical) before noise becomes a problem, as tested in a noisy electronics laboratory.

For longer distances, the best solution is a shielded twisted pair such as that used for audio microphones. Connect the twist-

ed pair to DP and DN and the shield to AGND close to the PC87591x, and leave the remote end of the shield unterminated.

For very long cable runs, the cable parasitic capacitance adds a delay to the Temperature Channel. You should add the

cable capacitance to the value of the CD (see “Calculating the Temperature Channel Delay” on page 188) and correct the

delay setting accordingly.

Cable resistance also affects remote sensor accuracy. A 1

Ω series resistance introduces about +1.0˚C to +0.5˚C error.

AGND

10 mil

Minimum

10 mil

AGND

Figure 65. DP and DN, PCB Traces

PC87591L Datasheet(PDF) 189 Page - National Semiconductor (TI)