TMP468: I2C Pullup Resistors

joe lindula

Part Number: TMP468

Hello, I'm using the TMP468 Temperature Monitor and I need some guidance on the value of the pullup resistors for the I2C pins. I have connected V+ to 1.8V. I see in the datasheet page 30 they show a RSCL and RSDA but there is no equation for the resistance value. I see on page 6 under section 6.5 the SDA output-low sink current is 20mA, would I take 1.8V divided by 20mA to find the min resistor value?

Thank you,

Joe

over 4 years ago

0 David Vaseliou over 4 years ago

TI__Expert 6820 points

Hi Joe,

Please see below app not on calculating the pull-up resistor range for your system.

http://www.ti.com/lit/an/slva689/slva689.pdf

Thanks,
David

0 joe lindula over 4 years ago in reply to David Vaseliou

Mastermind 6850 points

HI David,

Thanks for responding to my message. Quick question for you, is the value of Cb in the TMP468 datasheet or should I use the information in Figure 3 of the slva698.pdf?

Thanks,

Joe

0 David Vaseliou over 4 years ago in reply to joe lindula

TI__Expert 6820 points

Hi Joe,

Cb is the capacitance of the entire bus including the TMP468 input capacitance, other devices'capacitance on the bus, board parasitic capacitance, etc. A very common resistor value is ~10kohm.

Thanks,

Sensors

Sensors forum

TMP468: I2C Pullup Resistors