Hi All,
The ADV7280 packaging does look correct. On some of the smaller package sizes (such as 32 lead LFCSP) the Analog Deivce's logo is not printed.
Also note that there is an internal ring oscillator inside the ADV7280. So long as all the power-supply lines are pulled up correctly I2C communication should be possible. Even if the external crystal or oscillator is broken the ADV7280 will still be able to perform I2C communication.
Therefore this is probably a voltage supply issue or a I2C communication issue.
Some comments/suggestions:
1) Could you please probe every power supply pin as well as reset and powerdown. Please measure this at the pins of the ADV7280 device itself. i.e. not at the output of the voltage regulator.
- Pin2 (DVDDIO) should be 3.3V. (1.8V is also possible)
- what voltage is DVDDIO on your board.
- Pins 3, 13 (DVDD) should be 1.8V
- Pin 16 (PVDD) should be 1.8V
- Pin 21 (AVDD) should be 1.8V
- Pin 28 (reset) should be pulled up to DVDDIO
- Pin 32 (Powerdown) should be pulled up to DVDDIO
2) The SDA and SCL pins need pull-up resistors to DVDDIO
- i.e. you cannot have DVDDIO at 1.8V and try and feed 3.3V I2C lines into the ADV7280.
4) Ensure you are using a common ground plane. i.e. digital and analog grounds should be connected together to a common PCB ground plane.
3) Ensure that the back paddle of the ADV7280 is soldered properly to the ground.
- You can check this using an X-ray device
5) I advise sticking with using a 400 kHz I2C speed.
6) What device are you using as an I2C master?
7) Are you following the I2C communication recommendations as described in the I2C PORT DESCRIPTION section of the ADV7280 datasheet.
8) How do you know that the I2C communication is not working?
- Are you unable to get an acknowledge from the ADV7280 or are you unable to read registers from the ADV7280?
9) Could you please share an oscilloscope plot of the SDA and SCL lines when you are trying to perform a read operation on the ADV7280
Please try reading from User Map register 0x11.
Thanks and Regards,
Robert Hinchy
Senior Applications Engineer,
Analog Devices Inc,