OPA549: Slew Rate

Sathish Vallamkonda

Part Number: OPA549
Other Parts Discussed in Thread: BQ24780S,

Hi,

I am using OPA549 to do a line transient test from 19V to 23V. The slew rate i want is >=1V/us. When i connected the output of OPA549 to input of my EVM it took about 15us to go from 19V to 23V. What causing the slew rate to slow down and how can i increase it to what i want? When i disconnect my EVM, it takes only 1us to go from 19V to 23V. The VIN of EVM has only 2.2uF cap. The EVM i am using is BQ24780S EVM. I am driving OPA549 witha function generator.

Sathish

over 4 years ago

0 Thomas Kuehl over 4 years ago

TI__Guru* 93105 points

Hello Satish,

The unloaded output test you performed indicates that the OPA549 slew rate is high as it should be (9 V/us). Therefore, the increased slewing time is likely related to charging the 2.2 uF cap, and whatever else is attached to the OPA549 output. What do you have the OPA549 current limiting set to?

It would be helpful if you could provide us your OPA549 circuit schematic, the details of the 19 V to 23 V input transient, and the complete output load information.

Regards, Thomas

Precision Amplifiers Applications Engineering

0 Sathish Vallamkonda over 4 years ago in reply to Thomas Kuehl

TI__Prodigy 20 points

Hi Thomas,

i will send you the files to your email.

Sathish

0 Thomas Kuehl over 4 years ago in reply to Sathish Vallamkonda

TI__Guru* 93105 points

Hi Sathish,

Since we continued and resolved this discussion off line I would appreciate it if you could close this e2e inquiry.

Regards, Thomas

Precision Amplifiers Applications Engineering

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OPA549: Slew Rate