SN74LVC8T245: Power supply requirements

Jeff Smith

Part Number: SN74LVC8T245
Other Parts Discussed in Thread: TLV741P

Tool/software:

Can you explain how you can determine the power supply requirements for the SN74LVC8T245?

I am using several of these to translate from a 3.3V logic domain to a 5V logic domain. I want to choose the smallest DC-DC converter to generate the 3.3V Voltage rail.

6 months ago

0 Michael Ikwuyum 6 months ago

TI__Mastermind 36955 points

Hi Jeff,

The power supply requirement should not be re-defined as it is already specified in the data sheet for 1.65 V up to 5.5 V.

3.3 V on VCCA or VCCB and 5 V on VCCA or VCCB works fine, within the recommendation, thanks.

Best Regards,

Michael.

0 Jeff Smith 6 months ago in reply to Michael Ikwuyum

Prodigy 10 points

Hi Michael,

I probably did not explain very well. I need to generate the 3.3V from the 5V power source. I wanted to understand more about the current consumption of the device to define my power budget for the 3.3V generation.

Best Regards,

Jeff

0 Michael Ikwuyum 6 months ago in reply to Jeff Smith

TI__Mastermind 36955 points

Hi Jeff,

I see. Please see below for the Icc spec specified as the current consumption.

You may also see [FAQ] How do I Calculate Power Consumption or Current Consumption for my CMOS Logic Device? for more information, thanks.

Best Regards,

Michael.

0 Clemens Ladisch 6 months ago in reply to Michael Ikwuyum

Guru 294230 points

The power consumption of CMOS devices is negligible. If any of the pins on the 3.3 V side is used as an output and sources current, then the supply must also supply that.

Just use a cheap LDO like the TLV741P.

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SN74LVC8T245: Power supply requirements