DAC7578: I2C NO ACK

chen xuelong

Prodigy 60 points

Part Number: DAC7578

Tool/software:

Hi TI expert:

I get a problem in my design when I try to use MCU I2C communicate with DAC7578SPWR.

The following pictures are the waveforms get from the pins of DAC7578SPWR:

As the picture shows, the master I2C data has been sent to DAC7578SPWR(I2C slave address 0x98), but no ACK signal was got.

Also the power on sequence waveform and hardware schematic were attached, please help me find out if I'm missing anything.

over 1 year ago

0 Katlynne Jones over 1 year ago

TI__Mastermind 42253 points

Hi Xuelong,

Can you try using 5V logic? It looks like your I2C high voltage is ~3.4V. The VIH threshold for this device is 0.7*VDD and you're using a 5V VDD.

Best,

Katlynne Jones

0 chen xuelong over 1 year ago in reply to Katlynne Jones

Prodigy 60 points

Hi Jones,

Thanks for your reminder! But after I adjust the DAC supply power to 3.8V, MCU still not get the ACK signal. Any other suggestion?

0 Katlynne Jones over 1 year ago in reply to chen xuelong

TI__Mastermind 42253 points

Hi Xuelong,

Are SCL and SDA powered on before the DAC? It looks like that is the case and AVDD and CLR are being pulled up before the DAC actually powers up. Can you remove this condition? This could potentially be damaging the DAC.

Best,

Katlynne Jones

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DAC7578: I2C NO ACK