TXB0104: OE timing sequence

Rory Wu

Part Number: TXB0104
Other Parts Discussed in Thread: DRV8353

Hi team,

My customer used TXB0104, and find when OE pulling high quickly after Vcc stable, A1 and B1 will have PWM ringing.

Please refer to attached schematic and waveforms. VccA and VccB are connected to 1.8V. When delta time between OE and Vcc pulling up is lager than 500ms, it will not find the issue. When Vcc is connected to 3.3V, the issue disappear as well.

Could you please help check if there is time sequence for OE? Thanks.

Rory WuDRV8353.zip

over 6 years ago

0 ShreyasRao over 6 years ago

TI__Guru 61970 points

Hi Rory,

Once the OE is pulled high, the A1 / B1 channels are in Hi-Z and is not being actively driven by the device.
There is no timing for the OE to Vcc, but there are enable and disable times which are given in the datasheet.
The enable time is the time for valid data (either high or low) once the OE is asserted. (tpzl or tpzh)
similarly, disable time is for the output to change from low or high to high-Z.

0 Rory Wu over 6 years ago in reply to ShreyasRao

TI__Intellectual 1050 points

Hi Shreyas,

Forgot to attach waveforms, now the issue is not related to enable time in my opinion. It is related to Vcc and OE enable time. Could you please help kindly check this issue? Thanks.

TXB0104 issue.zip

0 ShreyasRao over 6 years ago in reply to Rory Wu

TI__Guru 61970 points

Hi Rory,

There is no specification for Vcc to OE enable time.
The OE is referenced to Vcca and device will be active if tied to Vcca supply pin.

0 Rory Wu over 6 years ago in reply to ShreyasRao

TI__Intellectual 1050 points

Shreyas,

If there is no specification for Vcc to OE enable time, when OE pulling high quickly after Vcc stable, A1 and B1 will have PWM ringing. I have attached schematic and waveforms in previous email, could you please help check why this issue happened? Customer is pushing for our result, thanks!

BR,

Rory

0 ShreyasRao over 6 years ago in reply to Rory Wu

TI__Guru 61970 points

Rory,
Taken to email.
I will close this thread for now.

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TXB0104: OE timing sequence