SN74AUCH244: level shifter/ Buffer, SPI , 3.3V <=> 1.2V, CLK=50MHz, drive 16ea device

Gordon Liu

Intellectual 825 points

Part Number: SN74AUCH244
Other Parts Discussed in Thread: PSPICE-FOR-TI, SN74AXC4T774

Hi ,

I' searching a 3,3V => 1.2V SPI buffer and it will drive 16ea device by a buffer.

I find out LSF108 + SN74AUCH244 but it don't have speed and drive spec.

Could you give us any suggestions??

The MCU is 3.3V level and it parallel connect to CLK, Data.

The SPI client have 16ea, CLK=50MHz, load=100Kohm/ 10pF.

11 months ago

0 Clemens Ladisch 11 months ago

Guru 244020 points

AUC devices have overvoltage-tolerant inputs; you can drive them directly with 3.3 V. (But take care to not exceed the absolute maximum rating of 3.6 V.)

0 Gordon Liu 11 months ago in reply to Clemens Ladisch

Intellectual 825 points

Hi Clemens,

About the speed and drive ability, does it OK??

0 Clemens Ladisch 11 months ago in reply to Gordon Liu

Guru 244020 points

This device supports more than 270 Mbps at 1.2 V. The DC drive strength is 3 mA (more during transitions).

In any case, I am not aware of any device that is stronger or faster at 1.2 V.

0 Gordon Liu 11 months ago in reply to Clemens Ladisch

Intellectual 825 points

Hi Clemens,

Do you mention its on the LSF108 for 270M bps / 3mA ??

0 Clemens Ladisch 11 months ago in reply to Gordon Liu

Guru 244020 points

No; the LSF is a passive switch. I was talking about the AUC buffer alone.

0 Gordon Liu 11 months ago in reply to Clemens Ladisch

Intellectual 825 points

Hi Clemens,

Could you share the Ti- Tina model of SN74AUCH244 ??

0 Clemens Ladisch 11 months ago in reply to Gordon Liu

Guru 244020 points

I am not a TI employee.

As far as I know, it is possible to import the PSpice model into TINA. There also is PSPICE-FOR-TI.

0 Albert Xu1 11 months ago in reply to Gordon Liu

TI__Mastermind 20555 points

Hey Gordon,

I did a bit of digging and it seems that it may be possible to import PSpice into Tina. Otherwise the easiest way to simulate this is to download PSpice.

PSpice to Tina import

0 Gordon Liu 10 months ago in reply to Albert Xu1

Intellectual 825 points

Hi Albert,

Please cehck the attach files: SN74AUCH244.TSM and SN74AUCH244_0529v1.TSC.

I find out it have a big ring noise on the Y port when I put a 10pF.

Does the Macro model OK??

SN74AUCH244_0529v1.TSC

SN74AUCH244.TSM

0 Albert Xu1 10 months ago in reply to Gordon Liu

TI__Mastermind 20555 points

Hey Gordon,

Due to today being a US holiday, our team will look into this and respond back tomorrow.

0 Albert Xu1 10 months ago in reply to Gordon Liu

TI__Mastermind 20555 points

Hi Gordon,

To address your original question, I have gotten some input from the team and they recommend the AXC4T774. This should cover both directions for the SPI signal. This has a 3 + 1 configuration directly targeted for SPI translation.

0 Gordon Liu 10 months ago in reply to Albert Xu1

Intellectual 825 points

Hi Albert,

I don't find out the PSPICE mode of SN74AXC4T774, could you share it??

0 Albert Xu1 10 months ago in reply to Gordon Liu

TI__Mastermind 20555 points

Hi Gordon,

This is under the translation team. I recommend you to go ask on their forum.

Logic

Logic forum

SN74AUCH244: level shifter/ Buffer, SPI , 3.3V <=> 1.2V, CLK=50MHz, drive 16ea device