AFE882H1EVM: IOVDD current consumption related issue

Hi Mitesh,

We are reviewing now and will get back to you shortly. 

Best,

Katlynne Jones

Hi Mitesh,

Can you provide a picture your EVM so I can compare the removed components?

IOVDD on the EVM is used for the AFE882H1, used to enable the internal reference, and is used to power the DUT side of the 3 level shifters (U7, U8, U9).

Thanks,
Lucas

Hi Lucas,

KIndly find EVM image.

Regards,

Mitesh

Hi Mitesh,

Is the customer seeing this issue on startup, or only when configuring the AFE?
Also, can the customer be more specific with how IOVDD is being provided and measured?

I removed just U7, U8, U9 (level shifters), and D1 and only saw 6 uA on IOVDD on startup.

Thanks,
Lucas

Lucas,

Can you meaure with the devices (U7, U8 & U9 and D1), no need to remove just measure the current with external IoVDD.

Customer is applying 1.8V externally as mentioned in previous thread & J26 and J27 are open, as they are using power from microcontroller board hardware.

PVDD is 3.5V and IOVDD is 1.8V.

I will ask customer to remove U7, U7, U9 & D1 so extra consumption can be revlidated.

Regards,

Mitesh

Hi Mitesh,

I was measuring around 200 uA on IOVDD before removing the components. After removing those 4 components, I saw 6 uA.

I saw in the picture of the customer's board that they have removed U7, U7, U9 & D1, as well as other components.
Is this board measuring 200 uA on IOVDD? Would there be any chance of something being improperly shorted when they removed the components?

Thanks,
Lucas

Hi Lucas,

In their EVM board the level shifters U7, U8, U9 & D1 are already removed.

They have  measured current again for 1.8V. It is still same 195uA. It is same from initial configuration of AFE882H1 to HART communication.

Please confirm the configuration you checked is same as below.

1. PVDD is 3.5V and IOVDD is 1.8V
2. HART communication is continuously working.
3. Ground is same across the board.

I will ask customer to share their observation in this forum.

Regards,

Mitesh

Hi Mitesh,

I am using 3.5 V and 1.8 V respectively for PVDD and IOVDD.

I am also using a uniform GND for the entire board.

When I continuously transmit HART, I'm only seeing 4 - 6 uA of current on IOVDD.

Are they seeing this high current as soon as the board is connected to power?

Thanks,
Lucas

Hi Lucas,

We are using following features also from the chip. Can you check with following things also

1. DAC enabled and working, using internal reference for it.
2. Used internal (On chip) filter J4 pin 1-2 for HART communications.

Thanks & Regards,

Umakant

Hi Umakant,

I was using the internal HART filter during my measurements, let me try varying the DAC and seeing if I notice any changes.

Thanks,
Lucas

Hi Umakant,

I'm not seeing much of a deviation from my previous measurements.

The high current reading is constant, correct?
Is there any chance of something being shorted when the components were removed?

Thanks,
Lucas

Hi Lucas,

Hi current is constant from start.

I have checked on second board also, still current is same.

Hi Mitesh,

Can you arrange FAE visit to my office to get better idea on this issue.

Thanks & Regards,

Umakant

Hi Umakant,

Can you verify with a multimeter that IOVDD and the "3.3V" net are not shorted?

Thanks,
Lucas

Hi Lucas,

I checked, IOVDD (1.8V) and PVDD(3.5V) not shorted.

Thanks & Regards,

Umakant

Hi Umakant,

I was referencing the nets on J27, where there is a "3.3V" and 1.8V" net. These are typically only powered by the optional USB connection, but if there is a short or faulty connection on the board, there could be additional current consumption.

You should just be able to measure TP19, TP17, TP18 on the top left of the board. These should not be powered in this scenario.

Thanks,
Lucas