TXS0102 common signal malfuntion

TS Yang

Genius 4800 points

Other Parts Discussed in Thread: TXS0102

Hi,

I composed a circuit with TI's TXS0102 as below.

Voltage level of B1 & B2 signal line(100MPHY, MAC) is 3.3V,

and A1 & A2 (10GPHY) is 1.8V.

The voltage translate from B1 to A1, and B2 to A2 operate well,

BUt from B1 to B2 signal is abnormal.

Please review our schematic if there's any problem.

Thanks for your support as always.

over 9 years ago

0 TS Yang over 9 years ago

Genius 4800 points

sorry for the typo.
From B1(3.3V) to A1(1.8V) is OK , and from B2(3.3V) to A2(1.8V) is OK.
But From B2(3.3V) to B1(3.3V) is abnormal.

0 Clemens Ladisch over 9 years ago in reply to TS Yang

Guru 316380 points

What do you mean with "abnormal"? What did you expect? What did you observe?

0 TS Yang over 9 years ago in reply to Clemens Ladisch

Genius 4800 points

I mean the signal before B2 pin is not good.

please see my block below.

4263.TXS0102_block.png.pptx

signal from MAC to 10GPHY through TXS0102 is OK,

but befor pin1 (B2) of TXS0102, signal from MAC to 100MPHY is fail.

I tested without TXS0102, then both signals are good.

I think the pin B2 of TXS0102 influence the communication between MAC and 100MPHY.

0 Clemens Ladisch over 9 years ago in reply to TS Yang

Guru 316380 points

Do those other two devices use push-pull or open-drain signals? What is their drive strength?

0 TS Yang over 9 years ago in reply to Clemens Ladisch

Genius 4800 points

both MAC & 100MPHY connected with pull-up resistor. (4.7K)
What is drive strength? Is it VOD? frequency of MAC is 976kHz, and voltage level is 3.3V as you know.

0 Clemens Ladisch over 9 years ago in reply to TS Yang

Guru 316380 points

Drive strength, or output impedance, specifies how much of a voltage drop you get, depending on the output current.

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TXS0102 common signal malfuntion