Data converters

Data converters forum

State
Locked Locked
Replies 7 replies
Subscribers 47 subscribers
Views 226 views
Users 0 members are here

Support feedback

Options

Options

Similar topics

LMP92066: Power Supply Sequencing

Christopher Monroy

Prodigy 100 points

Part Number: LMP92066

Hello. I have been using the LMP92066 in a few IRAD programs and now hopefully in production hardware. In two boards the -5V pin has shorted (1.7 ohms) and the devices are drawing excessive DC current. Those devices are now damaged. Is the device turn on dependent on power supply sequence? Should I turn on -5V first, then +5 or +5V first and then -5V? Your help is appreciated.

over 3 years ago

0 Akhilesh K over 3 years ago

TI__Mastermind 19066 points

Hi,

Are you talking about VDDB (+5V) and VSSB(-5V) supplies here?

For -5V operation, VDD should be +5V, VDDB should 0V, and VSSB should -5V. At POR the output should follow the VSSB supply to -5V.

Basically VDDB - VSSB should be max 5V

Regards,

AK

0 Christopher Monroy over 3 years ago

Prodigy 100 points

Yes, I have the connections as you indicated so my question is should VSSB (-5V) be turned on prior to VDD (+5V) or the other way around VDD, then VSSB?

0 Paul_Frost over 3 years ago in reply to Christopher Monroy

TI__Guru 53573 points

Hi Christopher, can you confirm that you have grounded VDDB? Connected VDDB to +5V will likely damage the device as you described.

0 Christopher Monroy over 3 years ago in reply to Paul_Frost

Prodigy 100 points

VDDB is connected to ground in my application

0 Paul_Frost over 3 years ago in reply to Christopher Monroy

TI__Guru 53573 points

Hi Christopher,

The device does not require a specific sequence for the supply ramps. Can you share your schematic? Maybe that would give us some hints.

Thanks,

Paul

0 Christopher Monroy over 3 years ago in reply to Paul_Frost

Prodigy 100 points

Here is the schematic

0 Akhilesh K over 3 years ago in reply to Christopher Monroy

TI__Mastermind 19066 points

Hi,

In your schematics, VIO is connected to 5V (P5P0V) ?

Recommended VIO voltage max is 3.6V. Please change the same to 3.3V. Also VDD power supply must be capable of sourcing at least 50mA current.

Regards,

AK