TXB0108: Device only works in one direction and marking does differ from marking given in datasheet.

Mark Bolduan

Part Number: TXB0108

I'm using the TXB0108YZPR2 "Bidirectional Voltage-Level Shifter with Auto Direction Sensing" for shifting 3,0V levels (B-side) to 2,5V levels (A-side). 3 of the connected signals have the direction B-> A and 5 signals A->B. Unfortunately the part does only work in the direction B->A and not in the direction A->B. The circuitry around the part should correspond to the datasheet. But as I noticed, the device marking "25REK1" differs from the one given in the datasheet "5M". The part is bought from a big distributor and not from a broker.

- Is "25REK1" a correct marking?

- Did anybody have similar problems? If yes, what was the reason?

over 2 years ago

0 Clemens Ladisch over 2 years ago

Guru 317370 points

The TXB has many limitations; problems are usually caused by violating them. Please show the schematic.

The marking for the YZPR2 package is "EK".

0 Joshua Salinas over 2 years ago

TI__Mastermind 23600 points

Hello Mark,

If using the TXB0108YZPR2 the correct device marking is "EK"

As Clemens mentioned, please include schematics and waveforms so our team can better assist you.

Regards,

Josh

0 Mark Bolduan over 2 years ago in reply to Clemens Ladisch

Prodigy 30 points

0 Mark Bolduan over 2 years ago in reply to Clemens Ladisch

Prodigy 30 points

0 Mark Bolduan over 2 years ago in reply to Clemens Ladisch

Prodigy 30 points

Regarding the Oszi-Screenshot: Ch4 shows MISO on B6(Pin E1, side of MCU) side of the MCU (Master) and Ch2 shows MISO on A6 (Pin E4, side of the FPGA)

Regarding the schematic: There are no pull-ups or pull-downs connected to the signals.

You are right - according to the datasheet the marking is "EK" and not "5M". But what about "25REK1"?

0 Mark Bolduan over 2 years ago in reply to Clemens Ladisch

Prodigy 30 points

Regards

Mark

0 Clemens Ladisch over 2 years ago in reply to Mark Bolduan

Guru 317370 points

This looks as if the signal is shorted to another pin, probably a soldering error. Does this happen only on one board?

0 Joshua Salinas over 2 years ago in reply to Mark Bolduan

TI__Mastermind 23600 points

Hello Mark,

The other values around "EK" represent Year/Month data codes, day of laser mark and assembly site code. The 25REK1 still represents the TXB0108YZPR2.

Regards,

Josh

0 Mark Bolduan over 2 years ago in reply to Clemens Ladisch

Prodigy 30 points

Thanks Clemens, there indeed seems to be some kind of soldering problem. With another board I tested it works. To be sure I will test other boards too.

0 Mark Bolduan over 2 years ago in reply to Joshua Salinas

Prodigy 30 points

Thanks Josh, do you know if the format of the device marking is described somewhere?

+1 Joshua Salinas over 2 years ago in reply to Mark Bolduan

TI__Mastermind 23600 points

Hello Marl,

Yes, there is a format we use. Please see the information below. Hope this helps.

+-------------+
! O !              YM = YEAR MONTH DATE CODE
! YMDEKS !               D = DAY OF LASER MARK
! ! S = ASSEMBLY SITE CODE
! !
! !
+-------------+

Regards,

Josh

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TXB0108: Device only works in one direction and marking does differ from marking given in datasheet.