SN74LVC1T45: Dual Supply Bus Transceiver with DIR and OE

Yaron Rahamim1

Part Number: SN74LVC1T45
Other Parts Discussed in Thread: TMUX1511, SN74AHC125, SN74AVC2T245, SN74LVC2T45

Hi,

My project includes a CPLD which is connected to external IOs. Each IO can be set as INPUT or OUTPUT - at 10MHz.

I have to implement a bi-directional level shifting between the two sides. Each of them can be set to a different voltage level: 1.8V/2.5V/3.3V/5V (although the CPLD will be probably set only to 3.3V)

TI's SN74LVC1T45 device is good solution, but because I have to implement a current limit of 10mA to each IO, I need a similar device but with OUTPUT ENABLE.

The DIR (direction) pin is required. I can't use the auto-direction sensing devices.

Is there any good candidate device for this design?

Thanks,

Yaron.

over 5 years ago

0 Clemens Ladisch over 5 years ago

Guru 316690 points

There is no level shifter with one OE per channel.

You could add separate 3-state buffers like the SN74AHC125 (with additional logic to handle the input direction), or analog switches like the TMUX1511.

0 Yaron Rahamim1 over 5 years ago in reply to Clemens Ladisch

Prodigy 170 points

Hi, Clemens,

Thanks for your answer. I'm going to check your suggestions.

Basically I could use the dual-bit device SN74AVC2T245 and use only one channel of it. The problem is that its max. voltage is 3.6V and not 5V.

Is there any other dual-bit device which can support 5V?

Thanks,

Yaron.

0 Dylan Hubbard over 5 years ago in reply to Yaron Rahamim1

TI__Mastermind 45725 points

Hi Yaron,

The one option you could use for this is the SN74LVC2T45 however it does not have the OE pin you require. Clemens' suggestion may be the best route here.

0 Yaron Rahamim1 over 5 years ago in reply to Dylan Hubbard

Prodigy 170 points

Hi, Dylan,

Thank you.

Yaron.

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SN74LVC1T45: Dual Supply Bus Transceiver with DIR and OE