Datasheet

LM95235

LM95235-Q1

SNIS142F –APRIL 2006–REVISED MARCH 2013

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7. If it is necessary to cross high speed digital traces, the diode traces and the high speed digital traces should

cross at a 90 degree angle.

8. The ideal place to connect the LM95235's GND pin is as close as possible to the Processors GND

associated with the sense diode.

9. Leakage current between D+ and GND and between D+ and D- should be kept to a minimum. Thirteen

nano-amperes of leakage can cause as much as 0.2°C of error in the diode temperature reading. Keeping

the printed circuit board as clean as possible will minimize leakage current.

Noise coupling into the digital lines greater than 400 mVp-p (typical hysteresis) and undershoot less than 500 mV

below GND, may prevent successful SMBus communication with the LM95235. SMBus no acknowledge is the

most common symptom, causing unnecessary traffic on the bus. Although the SMBus maximum frequency of

communication is rather low (100 kHz max), care still needs to be taken to ensure proper termination within a

system with multiple parts on the bus and long printed circuit board traces. An RC lowpass filter with a 3 dB

corner frequency of about 40 MHz is included on the LM95235's SMBCLK input. Additional resistance can be

added in series with the SMBDAT and SMBCLK lines to further help filter noise and ringing. Minimize noise

coupling by keeping digital traces out of switching power supply areas as well as ensuring that digital lines

containing high speed data communications cross at right angles to the SMBDAT and SMBCLK lines.

Product Folder Links: LM95235 LM95235-Q1