SN74AXC4T774: Using SN74AXC4T774 for I2 S level translation.

Shibin Varghese

Part Number: SN74AXC4T774
Other Parts Discussed in Thread: SN74LVC125A, SN74AUC17, SN74LVC125A-Q1, SN74LVC126A-Q1

Hello Team,
I am using an audio interface with I2S signals.
The MCU will be operating in 3.3V logic and the audio amplifier is in 1.8V logic.
1). Is the level translator CAXC4T774QBQBRQ1 a good choice for my application?.
2). Do I really need a bidirectional voltage translator to communicate with the audio amplifier?.
3). I have a pin shortage in the MCU. So can I pull up or pull down the direction control pins?
4). The pin description for the I2S audio amplifier I am using says they are input only. So I hope I can pull those direction control pins to low or high to enable the communication only in one direction.
Please correct me if I am wrong

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 243180 points

Yes, the SN74AXC4T774-Q1 can be used, and you can connect the DIR inputs directly to V_CC.

But for translating down, you can simply use any buffer with overvoltage-tolerant inputs, such as the SN74LVC125A-Q1/SN74LVC126A-Q1, or SN74LVC125A/SN74AUC17 if you do not need automotive qualification.

0 Shibin Varghese over 1 year ago in reply to Clemens Ladisch

Intellectual 835 points

Hello Clemens,
Thank you for your reply.
All the level translators you suggested are unidirectional. So I believe we don't require a bidirectional level translator there.
Please correct me if I am wrong.
The SN74LVC125ADRG3 seems like a good choice for I2S signals.
I believe the OE signals can be pulled down completely since I don't have enough pins in my controller

0 Clemens Ladisch over 1 year ago in reply to Shibin Varghese

Guru 243180 points

Yes, the /OE inputs can be grounded to have the outputs always enabled.

Logic

Logic forum

SN74AXC4T774: Using SN74AXC4T774 for I2 S level translation.