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OPA2227: Abnormal signal at 0'C_FCT failure

Amira Roslan
Prodigy 70 points
Part Number: OPA2227


Tool/software:

Hi TI team, 

Recently our production team facing a few issues on DDS LO board at cold temperature chamber (0°C) which is the alignment failure occur on DUT at first boot up at cold. The alignment shows the calibrator level signal is too low. 

Symptoms: 

  1. Chamber is seeing spikes in failures with multiple alignment failures starting with AifVariableAttenuatorAlign.
  2. When failing, both Ecal and the "front end" paths see 50Mhz signal low, @ ~ -55dBm at COLD conditions
  4. The Cal signal tends to recover with alignment run when the temperature gets higher.
  5. Signal was measured solid out of Ref Plus, but low out of LODDS output. The fact that Ecal also failed narrowed the scope down to few boards, primarily LODDS.

The failure can be duplicate when install the defect component on another good DDS LO board. And our production tried to swap the component by take from the good old DDS LO board and from the bin stock, and both are pass. 

There is a body marking on failure component which is A BB 0P A 2227U K 39APGN

Block Diagram

Defect part was sent to FA, and TI conclude TNI (Trouble Not Identified). They confirm these return units are within the data sheet specification for IQ parameters, but for applications which is failure abnormal signals require application review. 

Please kindly help to advise.

Regards,

Amira

  • 0
    TI__Intellectual 2990 points

    Hey Amira,


    We’re going to need more time to look into this, but I should have an update for you tomorrow. In the meantime, we’re going to need some additional context about the application of the part. Could you send a scope plot of the working amp as well as the problematic part, with the scope DC coupled? 

    Best Regards,

    Alex Curtis

  • 0 in reply to Alex Curtis
    TI__Intellectual 2990 points

    Hi Amira,

    The GBW of the OPA2227 is 8MHz, and from your post, it sounds like the input signal to the device is 50MHz, which exceeds this rating.

    Could you provide more information? 

    Thanks,

    Alex Curtis 

  • 0 in reply to Alex Curtis
    Prodigy 70 points

    Hi Alex, 

    This is the only pictures we have since the part already sent to TI's FA.

    1) Chamber reading for 25 Degree Celsius

    2) Chamber reading for cold temperature 0 Degree Celsius

    3) Voltage measurement on Good and Bad part, referring to block diagram above

    **Remark: U88 IC is the OPA2227. The failure can be duplicate when install the defect component on another good LODDS board. When take the other OPA2227 component from another good LODDS board and from bin stock, both are pass. Means the component from good LODDS board is good, with same setting input etc. 

    I will feedback to production team on the input signal of 8MHz. Do you have any other thoughts or concerns you'd like to share?  

    Regards,

    Amira

  • 0 in reply to Amira Roslan
    TI__Intellectual 2990 points

    Hi Amira,

    Thanks for your patience.

    • Can you verify the node TTN (+5VRF) is at 0V when the problem occurs?
    • Can you check pin 2 of the opamp while the problem occurs and verify that when pin 2 < pin 3, the output hits the negative rail? 
    • If you can verify that the inverting terminal is sitting at a lower voltage than the noninverting terminal and the output is still at the negative rail, then there may be a problem with this amplifier.
    • Additionally, can you verify that the amplifier operates as expected at 25C?
    • Can you provide information on the FA report so I can locate it on my end?

    Best Regards,

    Alex Curtis