SN74LV1T125 power issue

Nat Wong

Genius 3070 points

Other Parts Discussed in Thread: SN74LV1T125

Dear Sirs

I need your help to confirm the SN74LV1T125 design. Thanks.

U2.A: UART Output(3.3V level)

U2.Y: UART Output via level shifter(1.8V level)

DUT Tx & Rx has a 1.8V level signal already (connected by J1)

We do not supply the VCC for U2 and U3 (SN74LV1T125 ).

1.Why connect to our DUT (by J1), U2.VCC will has a fixed 3.3V or 1.8V power on it ?

2. Could you provide the internal structure of SN74LV1T125 for VCC and Y?

Thanks

BRS

Nat

over 10 years ago

0 ShreyasRao over 10 years ago

TI__Guru 64290 points

Hi Nat ,

I will take a look at the schematic and get back to you soon .

0 ShreyasRao over 10 years ago in reply to ShreyasRao

TI__Guru 64290 points

Hi Nat ,

In the schematic , the U2 Vcc is not powered up ? Basically , SOUT and UART_Rx will be isolated and Rx should be floating . U2 should be powered up to 1.8Vcc to have 3.3V SOUT to 1.8V level .

1) I couldn't understand your query precisely , please elaborate .

2) I don't have the access to the internal structure of the device , although I can provide you the functional block diagram .

Logic

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SN74LV1T125 power issue