DS2482-100 Dallas Semiconducotr, DS2482-100 Datasheet - Page 21

• Manufacturer Part Number: DS2482-100
• Description: Single-Channel 1-Wire Master
• Manufacturer: Dallas Semiconducotr

Since a 885W pullup resistor, as would be required to meet the rise time specification at fast speed and 400pF bus
capacitance, is lower than Rpmin at 5.5V, a different approach is necessary. The "Max. Load…" line in Figure 12 is
generated by first calculating the minimum pullup resistor at any given operating voltage ("Minimum Rp" line) and
then calculating the respective bus capacitance that yields a rise time of 300ns.
Only for pullup voltages of 3V and lower can the maximum permissible bus capacitance of 400pF be maintained. A
reduced bus capacitance of 300pF is acceptable for pullup voltages of 4V and lower. For fast speed operation at
any pullup voltage, the bus capacitance must not exceed 200pF. The corresponding pullup resistor value at the
voltage is indicated by the "Minimum Rp" line.
Figure 12. I²C Fast Speed Pullup Resistor Selection Chart
PACKAGE INFORMATION
(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information, go to
www.maxim-ic.com/DallasPackInfo.)
2000
1600
1200
800
400
0
1
"Minimum Rp"
2
Pull-up Voltage
3
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Max. Load at Min. Rp fast mode
4
5
500
400
300
200
100
0