SN74LVC8T245: Dears ,The SN74LVC8T245 , OUTPUT A--B. 3.3V TO 5V , output one 5us square wave when B side 5V power on ,without input , if there any wrong ? how to eliminate it ,the SCH and square as below

Andrew Liu74

Intellectual 970 points

Part Number: SN74LVC8T245

over 5 years ago

0 Clemens Ladisch over 5 years ago

Guru 316920 points

Which wave is which signal?

What is the value of OE?

0 Andrew Liu74 over 5 years ago in reply to Clemens Ladisch

Intellectual 970 points

Dears

Thanks for your help ,

the OE PIN is high ,5V.

the wave : red is output pin B5 ,the green is output Pin B6 ,

0 Clemens Ladisch over 5 years ago in reply to Andrew Liu74

Guru 316920 points

What is the yellow channel?

How is the ENABLE signal controlled? Can you show waveforms of ENABLE and VCCB?

0 user4868856 over 5 years ago

Prodigy 20 points

0 user4868856 over 5 years ago in reply to user4868856

Prodigy 20 points

the channel1 is B5 ; the channel 2 is VCCB ; the channel3 is Enable ; the channel 4 is VCCA.

0 Dylan Hubbard over 5 years ago in reply to user4868856

TI__Mastermind 45835 points

Hi,

The architecture of direction controlled level shifters can cause the device to glitch during power-up. It has to do with how and when the control circuitry gets powered. The direction circuitry switch a certain port to an output can cause this pulse.

Are you able to power the VCCA side before the VCCB?

Logic

Logic forum

SN74LVC8T245: Dears ,The SN74LVC8T245 , OUTPUT A--B. 3.3V TO 5V , output one 5us square wave when B side 5V power on ,without input , if there any wrong ? how to eliminate it ,the SCH and square as below