TXS0101: Data after first two bytes not transmitted

Hoong Wei Chew

Part Number: TXS0101

I am using TXS0101 as a level translator between two serial I/O pins. They are 3V to 5V, open-drain, data rate less than 10 kbps. 16 bytes of data were input to the A port but only two bytes were seen in B port. OE is enabled and by-pass caps are 100 nF each. What could be the problem here?

Here are the signals from the input and output pins:

over 6 years ago

0 ShreyasRao over 6 years ago

TI__Guru 62050 points

Hi Hoong,

I see that the output starts off at 5V and gradually goes down, do you have the scopeshots of the supply voltages, both Vcca and Vccb? What are the current limit on the supply?
What is the rise time on the input signal and are there any input side pullup resistors?
What is the output capacitance loading? Please send the schematic of the system which will answer many questions here.

0 Hoong Wei Chew over 6 years ago in reply to ShreyasRao

Prodigy 30 points

Hi Shreyas,

Here is the schematic:

The card adapter plugs into a smart card reader. Pins A and OE connect directly to MCU. Input to pin A. Output from pin B. Vcca 3.3V. Vccb 5V.

Vccb remained stable at 5V and should be able to supply tens of mA. I didn't check Vcca which shared the MCU power supply. The input signal is serial data at 9,600 baud.

Appreciate your help.

0 Hoong Wei Chew over 6 years ago in reply to Hoong Wei Chew

Prodigy 30 points

Hello Shreyas,

Found the problem to be the Vccb supply which was inadequate. Thanks for your help though.

0 ShreyasRao over 6 years ago in reply to Hoong Wei Chew

TI__Guru 62050 points

Hoong,

I am glad that the issue has been resolved. If possible, please explain a little bit more about the Vccb problem here for the benefit for all here in e2e community.

Was the current clamp limiting the Vccb voltage level?

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TXS0101: Data after first two bytes not transmitted