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PGA309 Vout error

Loki Liang
Prodigy 75 points
Other Parts Discussed in Thread: PGA309

Recently, I use the PGA309 for my application. And I use the microcontroller to control the PGA309 through IIC .And I can read/write the PGA309 register successfully.But the Vout is still wrong. This makes me carzy!!! Here is my step:

1、Tied the TEST PIN to a microcontroller IO port, and before the registers' configuration I pull down the test pin.

2、 After the configuration set the test pin is high and enable the Vout.

The circuit diagram refer to the User‘s guide F3-5. The signal is 0.9125V but my Vout is just 25mV. I don't kown what is wrong with it.

so I ask for help here.

  • 0
    TI__Mastermind 27715 points

    Hello Loki,

    Are you using an EEPROM in your final system, or do you plan on writing directly to the PGA309 using the microcontroller? When you pull the TEST pin high it will attempt to read from an external EEPROM before allowing VOUT to enable. If it cannot read good EEPROM data (for example, if there is no EEPROM connected), VOUT will never turn on. I believe this is what's happening in your case.

    If you leave the TEST pin low and write your register configuration, are you able to get a different VOUT?

    Best regards,

    Ian Williams
    Applications Engineer
    Precision Analog - Op Amps 

  • 0 in reply to Ian Williams
    Prodigy 75 points

    Hi lan .

    Thanks for your reply.I have bees solved this problem and now I am interested in the software that uesd the serial port .Where can I download it? Or can you send it to me?

    Best regards.

  • 0 in reply to Loki Liang
    TI__Mastermind 27715 points

    Hi Loki

    Congratulations on solving this issue! I have attached the software and source code for the older serial port version of the PGA309EVM.

    Best regards,

    Ian Williams

    PGA309EVM Serial.zip