SN74AVC4T245: VCCA and Ax input tolerant issues

? ?

Part Number: SN74AVC4T245
Other Parts Discussed in Thread: SN74AXC4T245

Hi ti team,

Can SN74AVC4T245 work normally when:

1) VCCA=VCCB=1.8V, this is not for level shift but for hardware compatibility.

2) VCCA=1.2V, VCCB=1.8V, can all the A port pins work as input accept 1.8V input as logic "1". I am not sure 1.8V can damage A port input when refer to VCCA=1.2V.

3) VCCA=1.2V, VCCB=1.8V, can all the OE pins accept 1.8V input as logic "1"?

4) One VCC supply is available early than another. For example, VCCB is in 1.8V when VCCA is 0.

over 1 year ago

0 Clemens Ladisch over 1 year ago

Guru 285410 points

Yes.

See [FAQ] Can the input voltage (Vi) to my logic device be higher than the supply voltage (Vcc)?

To avoid glitches during power up, use the SN74AXC4T245 instead.

0 ? ? over 1 year ago in reply to Clemens Ladisch

Prodigy 120 points

If the design is able to guarantee VCCA is available early than VCCB, can these glitches be avoid when using SN74AVC4T245?

+1 Michael Ikwuyum over 1 year ago in reply to ? ?

TI__Mastermind 33805 points

Hi,

Please help refer to the power up sequence per the datasheet to help clarify.

If the recommendation is not feasible, please note that the AXC suggestion is newer and designed with glitch suppression circuitry allowing for a more robust power up to help eliminate glitches, thanks.

Best Regards,

Michael.

Logic

Logic forum

SN74AVC4T245: VCCA and Ax input tolerant issues