TLV5604: TLV5604 output query

Star Xu

Genius 9645 points

Part Number: TLV5604
Other Parts Discussed in Thread: LM3880

Please help check the attached schematic and waveform. The problem is out A~D ripple high voltage.

The change of CS and FS (Linux system, the system will start to work after 10s power on) :

Thanks

Star

over 9 years ago

0 Uttam Sahu over 9 years ago

TI__Genius 14220 points

Hi Star,

Thank you for your query. Could you please explain the waveforms?

Regards,
Uttam Sahu
Applications Engineer, Precision DACs

0 user4864714 over 9 years ago in reply to Uttam Sahu

Prodigy 40 points

Hi Uttam

Fig 2 and Fig 3 are waveforms of TLV5604 Pin-OUTA(or OUTB,OUTC,D) when TLV5604 is power on.

Waveforms of Pin-OUTA(or OUTB,OUTC,D) are also diffrent .

0 Uttam Sahu over 9 years ago in reply to user4864714

TI__Genius 14220 points

Hi Star,

Could you please share a scope shot of the output alongwith the SPI, in a single screen? This will help us debug the issue easily.

Regards,
Uttam

0 user4864714 over 9 years ago in reply to Uttam Sahu

Prodigy 40 points

Hi Uttam,

The output alongwith the SPI is Fig1 and Fig 2.

Fig1 is SPI BUS without OUTA of TLV5604;and Fig 2 has SPI Bus and OUTA of TLV5604,but without CLK

when Power up, level of pin OUTA is from 0v to 5v （Voltage of ref is 5.0v）。

Fig 1

Fig 2

0 Star Xu over 9 years ago in reply to user4864714

TI__Genius 9645 points

Attached waveform for your reference.

0 Uttam Sahu over 9 years ago in reply to Star Xu

TI__Genius 14220 points

Hi Star,

Could you please measure/plot the Reference ripple along with the output ripple. We need to know the source. Please note that as the reference is generated from a power supply using a shunt, sometimes it may have ripple.

Regards,
Uttam

0 user4864714 over 9 years ago in reply to Uttam Sahu

Prodigy 40 points

Above picture show waveform of power （inclued DVDD，RefCD，AVDD）and OUTD when TLV5604 Power on

but waveform of OUTD is different with yesterday measured，and I don't understand why？

and waveform that yesterday measured is showed following。

0 user4864714 over 9 years ago in reply to Uttam Sahu

Prodigy 40 points

The reason of problem(outA~D has high level or high pulse） is “AVdd and RefCD firstly are powered on,and then DVdd is powered on”,is it right?

0 Uttam Sahu over 9 years ago in reply to user4864714

TI__Genius 14220 points

Hi Star,

The correct power sequence should be DVDD, AVDD and then REF. Please look at the absolute max ratings.

You can refer to the following training video for details of power sequencing in precision DACs:

training.ti.com/lessons-precision-dacs-power-sequencing

As the power supplies are external to the schematics you have shown, I can't suggest you how exactly to achieve the sequencing. However, you can use some power sequencing devices for this purpose in case you are not able to sind a simple solution. One of such devices for example is LM3880.

Regards,
Uttam

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TLV5604: TLV5604 output query