Datasheet ADT7461 (ON Semiconductor) - 3

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ADT7461 Table 3. PIN ASSIGNMENT Pin No. Mnemonic Description
1 VDD Positive Supply, 3.0 V to 5.5 V. 2 D+ Positive Connection to Remote Temperature Sensor. 3 D− Negative Connection to Remote Temperature Sensor. 4 THERM Open-Drain output that can be used to turn a fan on/off or throttle a CPU clock in the event of an overtemperature condition. Requires pullup to VDD. 5 GND Supply Ground Connection. 6 ALERT/THERM2 Open-Drain Logic Output Used as Interrupt or SMBus Alert. This may also be configured as a second THERM output. Requires pullup resistor. 7 SDATA Logic Input/Output, SMBus Serial Data. Open-Drain output. Requires pullup resistor. 8 SCLK Logic Input, SMBus Serial Clock. Requires pullup resistor.
Table 4. SMBus TIMING SPECIFICATIONS
(Note 1)
Parameter Limit at TMIN and TMAX Unit Description
fSCLK 400 kHz max − tLOW 1.3 ms min Clock low period, between 10% points. tHIGH 0.6 ms min Clock high period, between 90% points. tR 300 ns max Clock/data rise time. tF 300 ns max Clock/data fall time. tSU; STA 600 ns min Start condition setup time. tHD; STA (Note 2) 600 ns min Start condition hold time. tSU; DAT (Note 3) 100 ns min Data setup time. tHD; DAT 300 ns min Data hold time. tSU; STO (Note 4) 600 ns min Stop condition setup time. tBUF 1.3 ms min Bus free time between stop and start conditions. 1. Guaranteed by design, but not production tested. 2. Time from 10% of SDATA to 90% of SCLK. 3. Time for 10% or 90% of SDATA to 10% of SCLK. 4. Time for 90% of SCLK to 10% of SDATA.
tF tLOW t tHD; STA R SCLK tHD; STA tHIGH tSU; STA t t t SU; STO HD; DAT SU; DAT SDATA tBUF STOP START START STOP Figure 2. Serial Bus Timing http://onsemi.com 3