LSF0204D: LSF0204RUTR

the Speed of operation is 1 MHZ 

The pull up resistors are currently modified to 600 ohms at the o/p and 300 ohms at the input ..

bus has a cable of 30 mm length after the buffer 32 awg 

sink current capability from 1-3 mA

Hi Agxin,

Please help understand LSF will act as a switch and not a buffer and as pull-ups get stronger, VOL increases. You may further see section 5.2 of Voltage-Level Translation With the LSF Family clarifying when pull-ups are needed.

The device will work okay. However, please see TXU0304 for a more suitable buffer for SPI, thanks.

Best Regards,

Michael.

hi thanks for the response 

I have calculated the pull up based on the SINK capability in CPU i have set it to 600 ohm and reduced the frequency to 100 khz 

after changing it and the spi is working in half duplex mode uni directional 

the Clock is proper but the data is having some monotonicity ..The data is raising slowly from the cpu and able to see this at the O/P as well 

2 after LT 

3 Before LT 

TXU0304

Even with this buffer the data is raising slow at the input .

without the buffer the data is rising fast .. looks like cpu is not capable of having a better slew rate ..

are there any other buffer recommendation with even lower input capacitance