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SN74AVCH8T245: Can I use VCCA and VCCB as 3.3V?

Shanu V
Prodigy 130 points
Part Number: SN74AVCH8T245
Other Parts Discussed in Thread: SN74LVC07A, SN74LVC06A

Hi,

I use SN74AVCH8T245PWR  level shifter for driving LEDs.
Presently I use this for for enabling the LEDs with 1.8V IO. The GPIO_LED signals are driven by processor.

Page 13 of datasheet shows switching characteristics with VCCA=3.3V and VCCB=3.3V.

I want to confirm whether I can use  VCCA=VCCB=3.3V for my application.

  • 0
    TI__Guru* 96722 points
    Technically you can do this. There are other ways to drive indicator LEDs that would be lower cost and simpler to implement. Is there a reason why you want to use the translator?
  • 0 in reply to Emrys Maier
    Prodigy 130 points

    I did prototyping in FPGA board with 1.8V IO and wanted to retain the circuits/layout as much as possible in SoC final board.
    Could you please suggest other simpler options without using FETs/Transistors? I have many instances of this circuit used in the design.

  • 0 in reply to Shanu V
    TI__Guru* 96722 points
    The SN74LVC07A is an open-drain buffer that can operate with a 1.8V supply (which means the inputs trigger at 1.8V levels) or it can operate with a 3.3V supply -- and the outputs can be tied to a diode and resistor connected to any supply up to 5.5V. This setup would invert your logic, however.

    If you want to keep the same logic, use the SN74LVC06A instead (open drain inverter).

    Please see section 9.2 of the datasheet for a schematic/explanation of how this works: www.ti.com/.../sn74lvc07a.pdf