LP2981: To know the concern of connect the LP2891 pin4 (NC) to ground

Eric Lai

Expert 4940 points

Part Number: LP2981

Hi Expert,

The engineer already connected the LP2891 pin4 (NC) to ground in the design.

May we know the concern and why the datasheet defined the Pin 4 (NC) must be left open?

Best regards,

Eric Lai

Field Application Engineer

Texas Instruments Taiwan Limited

O: +886-2-2175-2582

M: +886-909-262-582

E-Mail:Eric.Lai@ti.com

over 2 years ago

0 Jason Song over 2 years ago

TI__Mastermind 23361 points

Hi Eric,

I checked the bonding diagram, and pin 4 does have a bond wire connect to the die of the chip. Let me try to reach to the design team to see if they could help to provide an answer. Please allow 3 business days for us to check the design.

Regards,
Jason Song

+1 Jason Song over 2 years ago in reply to Jason Song

TI__Mastermind 23361 points

Hi Eric,

Having NC pin connected to the ground would result in voltage accuracy change. For a similar device, having the NC to the ground would move up the output voltage by about 0.75% and we expect something similar on LP2981. If the output accuracy is critical in their application, they will need to revise the design.

Regards,

Jason Song

0 Jason Song over 2 years ago in reply to Jason Song

TI__Mastermind 23361 points

Hi Eric,

We were able to confirm that for LP2981, when NC is grounded, you could expect the output shift by 0.75%.

Regards,
Jason Song

Power management

Power management forum

LP2981: To know the concern of connect the LP2891 pin4 (NC) to ground