LSF0108: pull up resistor

Tommy Tzeng

Genius 5780 points

Part Number: LSF0108
Other Parts Discussed in Thread: LSF0102, SN74AUC244, SN74AUC1G126, TXS0108E, TXS0102

Hi Sir,

If Vref_B < Vref_A+0.8V, can be no need to add an pull up resistor? as below schematic.

also, any suggestion for improve when the schematic of LSF0102 is the same? thanks.

over 3 years ago

0 Clemens Ladisch over 3 years ago

Guru 317000 points

Section 9.2.3 tells you that pull-up resistors on the A side are needed. For unidirectional downconversion, a buffer with overvoltage-tolerant inputs like the SN74AUC244/SN74AUC1G126 would be simpler and more robust.

0 Tommy Tzeng over 3 years ago in reply to Clemens Ladisch

Genius 5780 points

Hi Ladisch,

thnaks for you reply, if the LSF series Vref_A and Vref_B are both push-pulll, can be bi-directional? right.

0 Clemens Ladisch over 3 years ago in reply to Tommy Tzeng

Guru 317000 points

Yes, LSF is bidirectional.

Are your signals bidirectional, or do they have a fixed direction?

0 Tommy Tzeng over 3 years ago in reply to Clemens Ladisch

Genius 5780 points

Hi Ladisch,

signal bidirectional, thanks for your help.

but because the customer is high-speed application,so it may not be possible to use external pull up resistor when use the push-pull type,

is there any suggest that can be use for the push-pull type and can reach 50M (Hz) bandwidth?

0 Clemens Ladisch over 3 years ago in reply to Tommy Tzeng

Guru 317000 points

What protocol is this?

Consider using TXS0102/TXS0108E, which has edge accelerators.

(Please note that long traces or cables with fast bidirectional signals is not possible.)

Logic

Logic forum

LSF0108: pull up resistor