TXB0104 Voltages superimposed?

Dennis Bauer

Other Parts Discussed in Thread: TXB0104

We are using the TXB0104 to for SPIO but somehow the voltages are superimposed and don't reach 0 volt when the voltage translator is activated

VCCB = 5 Volt VCCA = 3.3Volt 100nF on supply voltage input.

The output VCCA low level signals do not reach 0 Volt,

What could cause this?

0 Hattie over 13 years ago

What voltage are you seeing? The device is spec'ed to have a maximum output low voltage(VOL) of 0.4V, so a 0.25V VOL is not unusual.

Do you have pull-up resistors on the output?

0 Dennis Bauer over 13 years ago in reply to Hattie

The VOL high level is ok about 3.3Volt but the superimposed level is about 2.32 Vol the low level is around 1.6.

No pull ups at the moment, we are have a serial to wifi board connected to output but we don't have a schematic for it.

Could the low pull ups on that board cause this?

0 Hattie over 13 years ago in reply to Dennis Bauer

Dennis,

Sorry for the delay, I was out of office. How is this going?

Pull-up resistors could cause this. Do you have a schematic of the system?

0 Dennis Bauer over 13 years ago in reply to Hattie

I found out the connected device we use has 10K pull upps integrated, this could cause the problem, we will change the IC to TXS104E version.

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