SN74LXC8T245-Q1: 300Mbps@VCCA=1V8,VCCB=3V3 choice

Ryan Wang

Part Number: SN74LXC8T245-Q1
Other Parts Discussed in Thread: SN74AXC8T245-Q1, TXV0108-Q1

Tool/software:

Team,

Customer wants 8 channel automotive level shift which can support 300Mbps@VCCA=1V8,VCCB=3V3. Input transition rate 10ns/V.

I find SN74LXC8T245-Q1, SN74AXC8T245-Q1, SN74AVC8T245-Q1 in ti.com.

However, I'm not so sure they all can meet 300Mbps@VCCA=1V8,VCCB=3V3 for A->B and B->A.

Up to 420-Mbps support for 3.3 V to 5.0 V for SN74LXC8T245-Q1.

Up to 380Mbps support when translating from 1.8V to 3.3V for SN74AXC8T245-Q1.

But SN74LXC8T245-Q1 is much cheaper than SN74AXC8T245-Q1, why?

Could you confirm for me?

Thanks

7 months ago

0 Clemens Ladisch 7 months ago

Guru 318700 points

Please note that the maximum speed depends mainly on the output voltage; the LXC datasheet specifies only 40 Mbps for 3.3 V → 1.8 V.

AVC/AXC devices are optimized for lower voltages. But the datasheets are not very helpful and just say "380 Mbps for 1.8 V → 3.3 V". We have to assume that the maximum for 3.3 V → 1.8 V is lower, and most likely below 300 Mbps.

As far as I know, the TXV0108-Q1 is fast enough for your application.

0 Ryan Wang 7 months ago in reply to Clemens Ladisch

TI__Expert 7610 points

Clemens,

TXV0108-Q1 is faster than AXC8T245 but why it is cheaper than AXC8T245 in 1Ku price? What is its weakness?

0 Clemens Ladisch 7 months ago in reply to Ryan Wang

Guru 318700 points

It has a narrower supply voltage range, and is more modern. A higher price does not necessarily imply higher performance (for a specific application).

+1 Joshua Salinas 7 months ago in reply to Ryan Wang

TI__Mastermind 28240 points

Hello Ryan,

I agree with Clemens on part recommendation and price. Price is not a good indication on how well a part will perform.

Regards,

Josh

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SN74LXC8T245-Q1: 300Mbps@VCCA=1V8,VCCB=3V3 choice