SPI Level-Shift "SN74AXC4T774BQB"

Derek Liu

Other Parts Discussed in Thread: SN74AXC4T774

I found the USB to SPI bridge solution, but the SPI voltage level of the USB-SPI bridge is 3.3V, so I need the level-shift (1.8V-3.3V) component. I chose the "SN74AXC4T774BQB", would you help check if the SN74AXC4T774BQB is workable?

Thanks.

over 4 years ago

0 Derek Liu over 4 years ago

Prodigy 130 points

I have another question about the signal data rate. In the datasheet description, The translated signal data rate can be up to 310 Mbps when the signal is translated from 1.8V to 3.3V. but I would like to know if the translated signal data rate can also be up to 310 Mbps when the signal is translated from 3.3V to 1.8V? Thanks

Derek.

0 Clemens Ladisch over 4 years ago in reply to Derek Liu

Guru 316690 points

Yes, the SN74AXC4T774 can translate SPI signals at these voltages.

As shown in sections 6.11 and 6.13 of the datasheet, the maximum propagation delay for 1.8 V to 3.3 V is 7 ns, while for 3.3 V to 1.8 V, it is 5 ns or 6 ns. So you should be able to get the same speed. What frequency do you need?

0 Derek Liu over 4 years ago in reply to Clemens Ladisch

Prodigy 130 points

Hi Clemens,

Got it.

The SPI clock max frequency is 13MHz for our fingerprint device. so I can use the SN74AXC4T774, is it correct?

Thanks

Derek.

0 Clemens Ladisch over 4 years ago in reply to Derek Liu

Guru 316690 points

13 MHz indeed is slower than 310 Mbps.

0 Dylan Hubbard over 4 years ago in reply to Clemens Ladisch

TI__Mastermind 45725 points

Hey Derek,

This device should have no issue with that frequency and is a great fit for the SPI directionality.

Logic

Logic forum

SPI Level-Shift "SN74AXC4T774BQB"