SN74LV4T125: SPI repeater

John Liu59

Part Number: SN74LV4T125
Other Parts Discussed in Thread: SN74LVC125A, SN74AHC367

Dear all,

We have application using SPI communication with 40cm long distance form CPU to other devices, need add SPI repeater to guarantee the normal communication, can SN74LV4125 used in this application? the communication rate is 50MHz, and the input voltage is 3.3V and Vcc also should be 3.3V.

Thanks.

over 7 years ago

0 ShreyasRao over 7 years ago

TI__Guru 62320 points

Hi John,

Since this is a repeater (buffer), you do not need the SN74LV4T125 device. This device can be used as a buffer, however, primarily it is used as translation device.

I would recommend using SN74LVC125A which is quad buffer or SN74AHC367 which is hex buffer.
Let me know if this works.

0 John Liu59 over 7 years ago in reply to ShreyasRao

TI__Intellectual 2735 points

Hi ShreyasRao,

Thanks for your reply, I have a question below:
Since the communication rate is 50MHz, can this device support the rate?

Thanks.

0 Dylan Hubbard over 7 years ago in reply to John Liu59

TI__Mastermind 46135 points

John,

Please refer to question 2 on the FAQ page linked below. Thanks!

e2e.ti.com/.../3540.05-timing

0 Michael J Schultis over 3 years ago in reply to Dylan Hubbard

TI__Mastermind 24985 points

Hello,

In addition to the recommendation above, there is a newly released device that is optimized for SPI buffering or level shifting:

https://www.ti.com/product/TXU0304 (commercial)

https://www.ti.com/product/TXU0304-Q1 (automotive)

It can support 1.1 to 5.5V supply configurations and can share a supply on both VCC rails for buffering or have different supplies on each VCCA and VCCB for level shifting SPI interfaces.

For even lower voltage applications down to 0.65V, you may also consider the following devices which can be configured for SPI interface directionality

https://www.ti.com/product/SN74AXC4T774

https://www.ti.com/product/SN74AXC4T774-Q1

For the most up to date recommendations on Level Translation devices by interface such as SPI, UART, etc... please refer to the following FAQ:
Are there voltage level translation / level shifter device recommendations for the industry standard interfaces like GPIO, SPI, UART, I2C, MDIO, RGMII, I2S etc?

Best,
Michael