SCPS277B November 2022 – November 2023 TCAL6408
PRODUCTION DATA
The pull-up resistors, RP, for the SCL and SDA lines need to be selected appropriately and take into consideration the total capacitance of all responders on the I2C bus. The minimum pull-up resistance is a function of VCCI, VOL,(max), and IOL:
The maximum pull-up resistance is a function of the maximum rise time, tr (120 ns for fast-mode-plus operation, fSCL = 1 MHz) and bus capacitance, Cb:
The maximum bus capacitance for an I2C bus must not exceed 400 pF for standard-mode or fast-mode operation, or 550pF for fast-mode-plus. The bus capacitance can be approximated by adding the capacitance of the TCAL6408, Ci for SCL or Cio for SDA, the capacitance of wires/connections/traces, and the capacitance of additional responders on the bus.