Datasheet

DS2482-100: Single-Channel 1-Wire Master

21 of 22

Since a 885Ω 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. I

C Fast Speed Pullup Resistor Selection Chart

400

800

1200

1600

2000

12345

Pull-up Voltage

Minimum Rp (Ohms)

100

200

300

400

500

Load (pF)

"Minimum Rp" Max. Load at Min. Rp fast mode

PACKAGE INFORMATION

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.

PACKAGE TYPE PACKAGE TYPE DOCUMENT NO.

8 SO (150 mils) —

56-G2008-001

9 WLP W92A1+1

21-0067