TXS0108E: Query on VOH logic level of Level translator

Nandhini KS

Part Number: TXS0108E

Hi, we are using TXS0108E device in our application. We have connected A side to 1.8V & B side to 3.3V signals. In Datasheet , VOHA is mentioned as VCCA*0.67 = 1.206V and our receiver device has 1.26V VIH. VOH & VIH levels are not meeting since VOH of TXS0108E device is only 1.206V. Can you please confirm VOH level of translator?

over 4 years ago

0 Clemens Ladisch over 4 years ago

Guru 243920 points

What current will you circuit sink? That V_OH is specified for a current of 20 µA; a smaller current will result in a smaller voltage drop. A CMOS input should have a leakage current much smaller than 1 µA.

0 Nandhini KS over 4 years ago in reply to Clemens Ladisch

Prodigy 250 points

Hi, Thank you for your response. In Datasheet, VOH is specified only for a current of 20uA. We need to know that TXS0108E level translator will support 50uA current ?

0 Nandhini KS over 4 years ago in reply to Nandhini KS

Prodigy 250 points

In Datasheet, IOH is mentioned as 20uA. But as per internal Pull Up 4k mentioned, it will source upto 100uA current. Will this device supports more than 20uA IOH current?

0 Clemens Ladisch over 4 years ago in reply to Nandhini KS

Guru 243920 points

The TXS has open-drain outputs, which are not supposed to be able to source any considerable current. Where does the 50 µA requirement come from?

0 ShreyasRao over 4 years ago in reply to Nandhini KS

TI__Guru 56070 points

Hi Nandhini,

As Clemens mentioned here TXS is passive switching device without drive of its own( not considering the oneshot edge circuitry).

What is given on the datasheet (20uA) is through the internal pullup resistor. Sourcing more than 20uA current may not meet the Voh as guaranteed by the datasheet. During low to high, the internal pullup is 4kohm, whereas high to low, internal pullup is 40kohm.

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TXS0108E: Query on VOH logic level of Level translator