SN74AVC4T774: Current Consumption to High

Pascal Engelhard

Part Number: SN74AVC4T774

We are using this Level Shifter for the communication between the micro controller and an ASIC.

On the most recent PCB's when the ASIC isn't used e.g. no communication, the current consumption is between 10mA and up to 35mA. But on the prototypes we made 2 years ago it is below 1mA. Since the current consumption of the PCB is quite important, this causes some problems.

There is a 51kOhm pull up resistor on the enable pin.

over 5 years ago

0 ShreyasRao over 5 years ago

TI__Guru 57390 points

Hi Pascal,

Welcome to e2e.
What changed from the old PCB to new PCB? Which supply is consuming the higher current. Did you isolate the device to confirm if this is leaking the additional current? could there be manufacturing soldering shorts /flux causing this? Maybe a wash of the PCB could help?
Are there any floating inputs when there is no communication happening?

0 Pascal Engelhard over 5 years ago in reply to ShreyasRao

Prodigy 20 points

Hi Shreyas

There was no change on the PCB. We are producing the devices and now the higher current occurred. And to verify that the leakage current isis caused by the level shifter we switched the chip of a prototype and a new PCB. And the current consumption moved with the level shifter.

Thanks
Pascal

0 ShreyasRao over 5 years ago in reply to Pascal Engelhard

TI__Guru 57390 points

Hi Pascal,

Alright. Do you have the full schematic of the system? Which Vcc is causing this higher Icc and what are the ports connected to? Any scope shots of the supply and the A/B channels available during the higher current consumption?

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SN74AVC4T774: Current Consumption to High