TXB0106 and TRSF3223E Interaction Problems?

Hi,

As you described, I try to figure out the simple schematic. Please check  it.

Could you give more information about this diagram?

1. What is power supply of the MPC and TRSF2332E?

2. Is the voltage value of MPC output high signal level as same as power supply?

3. Could you add some loading (as described on page 8 in TXB0106 datasheet ) at output port and repeat the test?

Thanks

Lawrence

8400.Autopilot.pdf

I have attached our full schematic.

The MPC is a PhyTec phyCORE-MPC565. It is powered from 2.6 vdc, 3.3 vdc and 5.0 vdc. The TTL lines we have connected are 5.0V levels. They are connected to the "B" side. Please note that the MPC and other modules are not in circuit when I check this, only the TXB0106 and the TRSF3223E.

/OE on the TXB0106 is connected to 3.3V per your data sheet.  The TRSF3223E is powered from 5.0Vdc.

The voltages we see on the TXB0106 are as follows: A1 = 3.3V, B1 = 5.0V, A2 = 5.0V, B2 = 3.3V, A3 = 3.3V, B3 = 3.3V, A4 = 5.0V, B4 = 3.3V, A5 = 5.0V, B5 = 3.3V, A6 = 3.3V, B6 = 5.0V.

M1, U4 (MPC) and U6 are NOT in the circuit. When we install the MPC (U4) we see 5.0V on both the B5 and B6 lines.

Thanks in Advance.

We are also finding that the /OE pin DOES have to be toggled on power up to clear the J-K states at get it to sort of work. It is taking Milliamps to pull up, not Microamps as the data sheet says.We tried a 1K ohm to 3.3V and only got it to 1.7 vdc unless you pull it up hard. What we may end up with is a transistor to toggle power and a pull-down.

We may just end up pulling it out of the circuit altogether.

Could your provide some inforamtion about power-up sequence?

Thanks

Lawrence

Hi,

For TXB0106, the input current should be  microamps as desribed in datasheet. Could you mearsue the resistance between OE and GND when power is zero.

If it is possible to test TXB0106 only? Please obersve port A5 when B5 is pull up to 5V.

Thanks

Lawrence

Lawrence,

We took the device out of the circuit. As one of our personnel in the Physics department told us, it depends which input has the harder pull as to which way the circuitry flows and who gets priority. He has had experience with another device which is similar or a copy of and he said it never worked correctly either. It comes up in various states.

We tried pulling down the /OE pin and then releasing it to clear the states. It still did the same thing.

We really don't have time to play with this device to get it to work. We pulled it out and wired in a separate circuit board from SparkFun electronics. https://www.sparkfun.com/products/11978  It appears to be working correctly.

It sounds like you need to remove this part from your inventory if it is so temperamental to use.

George Blake

Hi,George

First thanks for using this part and took the time to do the test on it.

Actually, the TXB series parts have been used in many work scenarios and many customers for long time. and this kind of directional auto sensing part have some special thing need to be care when using it.

When you did the measurement, please make sure the input pin will not be floating.

as your result, the

 "The voltages we see on the TXB0106 are as follows: A1 = 3.3V, B1 = 5.0V, A2 = 5.0V, B2 = 3.3V, A3 = 3.3V, B3 = 3.3V, A4 = 5.0V, B4 = 3.3V, A5 = 5.0V, B5 = 3.3V, A6 = 3.3V, B6 = 5.0V.

M1, U4 (MPC) and U6 are NOT in the circuit. When we install the MPC (U4) we see 5.0V on both the B5 and B6 lines. "

You can check whether when the input is floating, then the voltage is not correct. One example is for B5, when you install the U4, then B5 is correct , in your design, B5 is the output to TRSF3223E. and for B6 A6 correct, because B6 is the input comes from the driver TRSF3223E, not floating.

For the input floating, we can not make sure the part works well. so that is the reason we put the notes in the datasheet which is "The A and B sides of an unused data I/O pair must be held in the same state, i.e., both at VCCI or both at GND."  

Also for the /OE pin, the spec in the datasheet must be meet, we make sure it is correct. if you are OK, please put it in the no floating pins and then retest it.

Also one more thing, for fully check whether the part works well, except not folating input, the other is better to toggle the signal and then monitor it by probe with less capacitive load.

If you are OK to redo the test, any update, please let us know.

By the way except found your issue by doing the check without M1, U4 and U6, any actual working issue when the part in the system? or only the check is the first step and found issu?

if have, maybe we can dig into your issue direcly and see any help we can do here.

BR

Junjie