SN74LVC245A: SN74LVC245A

Yogendran Kasi Perumal

Prodigy 30 points

Part Number: SN74LVC245A
Other Parts Discussed in Thread: TXB0104, , LSF0204, SN74LVC2T45, SN74LVC1T45

Would like to connect the interface device having 5V with Raspberry pi SPI (3)

is that possible to use level shifter (SN74LVC245A) or should we use TxB0104 bi-directional level Shitfer ?

Interface device breakout board with 5V communicate with RPI over SPI 4 Wires

SCK
MISO
MOSI
SS to

Level Shifter SN74LVC245A is also meant for SPI communication.

over 6 years ago

0 Emrys Maier over 6 years ago

TI__Guru* 96681 points

Hi Yogendran,
I'm guessing that you're interfacing to the Pi via wires? What frequency are you operating at?

You can probably get away with using the TXB0104, however it has a weak output drive, and long wires could cause problems (large capacitive loads definitely will cause trouble). Another possibility would be LSF0204 (also an auto-bidirectional translator).

I would recommend using the SN74LVC2T45 (2 channel) and the SN74LVC1T45 (1 channel) in some combination to have unidirectional translation (ie the translator never switches directions). This will guarantee better signal integrity than the TXB or LSF device.

FYI, there's a very useful video series on the LSF series of translators avialable here: training.ti.com/LogicMinute

0 Yogendran Kasi Perumal over 6 years ago in reply to Emrys Maier

Prodigy 30 points

Hi There - Thanks for taking time on this query... Appreciate your input and comments.

Yes RPI and interface (breakout board) is connected thru Standard Jumper wires max length of 300mm.

0 Emrys Maier over 6 years ago in reply to Yogendran Kasi Perumal

TI__Guru* 96681 points

With short wires like that, you probably won't see any problems. I would still recommend using the active drive translators though.

0 Yogendran Kasi Perumal over 6 years ago in reply to Emrys Maier

Prodigy 30 points

Thanks again

in that case can i use this ? SN74AXC8T245 8-Bit Dual-Supply Bus Transceiver With Configurable http://www.ti.com/product/sn74axc8t245?qgpn=sn74axc8t245

0 Emrys Maier over 6 years ago in reply to Yogendran Kasi Perumal

TI__Guru* 96681 points

That device doesn't operate at 5V, but if you need a lower voltage translator, I would definitely recommend it.

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SN74LVC245A: SN74LVC245A