DAC084S085: VoutC output pin high during power up

Damesh Kumar

Part Number: DAC084S085

I been using this dac for my design. Vout3 output is would go to high (2.2V) then to low (0) each time i power up the DAC. My dac is connected to external 2.V supply which power up before microprocessor power up.

The SPI lines are connected via voltage translator (1.8V to 2.8V) from microp to DAC.

Im expecting the Vout 3 to stay low during power up but it goes to high in short period before going low.

The only time i can keep the vout3 low is by disconnecting clk line from dac while keep the rest of the spi and supply line connected.

over 5 years ago

0 Paul_Frost over 5 years ago

TI__Guru 53563 points

Hi Damesh,

Can you share your schematic? In addition, it is important to verify that the absolute maximum table values are not being violated during power up as some pins may become a higher voltage than the VDD supply. In addition, can you very that the circuit that VOUT3 is connected to is not driving the pin before the device is powered on?

Thanks,
Paul

0 Damesh Kumar over 5 years ago in reply to Paul_Frost

Prodigy 20 points

There are op amp connected to dac 3, base on power tree the op amp turn on before dac supply. Will it cause any issue?

0 Paul_Frost over 5 years ago in reply to Damesh Kumar

TI__Guru 53563 points

Hi Damesh,

It is difficult for me to know that without a schematic. If you disconnect the external circuitry (amplifier?) from DAC3, and measure the pin, does it still go high?

Thanks,
Paul

0 Paul_Frost over 5 years ago in reply to Paul_Frost

TI__Guru 53563 points

Hi Damesh,

Can you share the requested data?

Thanks,
Paul

Data converters

Data converters forum

DAC084S085: VoutC output pin high during power up