THS4552: High Pass problem

Michael Liesenberg85

Mastermind 7560 points

Part Number: THS4552

Hi,

i am having an issue using the THS4452 as a high pass filter.

I designed the high pass filter with FilterPro from TI and here is the schematic:

My schematic looks like this : Power Supply +5V and GND and VCOM is 2,5V

The problem is that the Opamp is drawing 140mA current. Once i take the C62/C61 and C16/C17 its not drawing almost any current.

Is the Opamp instabel? Is it oscillating?

Obs: Low pass filter is working fine, i have 4x THS4552 as Low pass fitler configuration.

over 7 years ago

0 Bonnie%2520Baker over 7 years ago

Prodigy 40 points

Hello Michael,
I was looking at your FilterPro diagram and noticed that you copied it as shown in the software. This diagram is incorrect. If you look at the circuit carefully you will see that Vout1 is connected to Vout2. There in lies the error. I can't see what you have done with these output lines in Cadnce, so all I can say is If you disconnect that trace you may find that the circuit works fine.

0 Michael Liesenberg85 over 7 years ago in reply to Bonnie%2520Baker

Mastermind 7560 points

Hi Bonnie,

yes i know this graphic issue on FilterPro. VOUT1 and VOUT2 are not connected in my schematic.

0 Micah B Brouwer over 7 years ago in reply to Michael Liesenberg85

TI__Intellectual 1910 points

Hey Michael,

What is the input signal? Is the amplifier drawing 140 mA when there is no input applied as well?

0 Michael Liesenberg85 over 7 years ago in reply to Micah B Brouwer

Mastermind 7560 points

Hi,
yes when there was no input signal it was drawing that much.
I manage to clean and replace all SMD componetes and the IC itselgf on the board.
It looks like some components had pulled the ouput to GND with a short cut.
Not it is working! Assembly problems. My vias are too close to SMD components and they are not covered with mask.

Soldering it carefully worked out. Now netx time i will order PCB with vias covered minimizing short cuts.

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THS4552: High Pass problem