[SOLVED] ADC Datasheet

[Max01800]

sorry wrong thread

 

[Max01800]

Guys I need to do a project for an exam. I need to use the ADC from Texas Instruments ADS131B26-Q1 (I attached the datasheet pdf). The problem is that i don't understand the specifications. Specifically. in the image below, I don't understand what's the Power supply Voltage range for AGND, because it appears several times. Also, what does it mean when it says 'APWR to AGND', 'DPWR to DGND' ecc...? Is the power supply voltage for AVDD from -0.3 V to 4 V? If that's so, why do they write 'AVDD to AGND' if AGND has a voltage range from -0.3 V to 20 V?

I have the same problem here. Above all when it says APWR=AVDD to AGND? I swear I'm gonna scream.

Can someone please tell me what's the Input voltage range ?

 

[FvM]

In the first step you'll look for Recommended Operating Conditions, the second table in your post, title stripped off, unfortunately.

The ADC has low voltage (nominal 3.3V) and high voltage (4 -16V) supply terminals. High voltage is for external supply only, ADC circuitry is supplied by low voltage (AVDD) node. Respectively all input voltages are derived from AVDD, input voltage range is however smaller than AVDD as specified above.

 

[Max01800]

In the first step you'll look for Recommended Operating Conditions, the second table in your post, title stripped off, unfortunately.

The ADC has low voltage (nominal 3.3V) and high voltage (4 -16V) supply terminals. High voltage is for external supply only, ADC circuitry is supplied by low voltage (AVDD) node. Respectively all input voltages are derived from AVDD, input voltage range is however smaller than AVDD as specified above.

But for example in the second table-> power supply, it says AGND should be between -0.2 and 0.2 V and 0 V nominal, and ok i get it. After it says AGNDy (where y stands for A or B) to DGND should be between -0.2 and 0.2 V and 0 V nominal, the problem is the 'to'. What does that mean?

 

[KlausST]

Hi,

I don't understand what's the Power supply Voltage range for AGND, because it appears several times.

For voltage measurement you always need two nodes.
* one is the voltage you want to measure
* the other is the reference node. they often are called: GND, AGND (analog GND), DGND (digital GND), 0V. Since it is the reference point it always is considered to be zero.
You also will see the abbreviation "w.r.t." which means: with respect to....
example: APWR w.r.t. AGND.

what does it mean when it says 'APWR to AGND', 'DPWR to DGND' ecc...?

Same as above.
Two nodes. Simple example is to use a voltmeter. It has two cables. The black one (-), minus, 0V or GND. The red one (+) to the voltage you want to measure.
here:
* APWR to AGND --> red cord to APWR, black cord to AGND.
* DPWR to DGND --> red cord to DPWR, black cord to DGND.
note: AGND, DGND, APWR, DPWR ... all are pins of the IC.

Klaus

--- Updated Jan 5, 2024 ---

Is the power supply voltage for AVDD from -0.3 V to 4 V?

This is the section "Absolute maximum ratings"
It is the maximum allowed range. It means: If you go beyond this range it is likely you kill the device.
It does not mean: it is operable at his whole range!
You measure AVDD with AGND as reference (zero level)

If that's so, why do they write 'AVDD to AGND' if AGND has a voltage range from -0.3 V to 20 V?

No! AGND never has a range of -0.3V to 20V! AGND always is nominally zero.
AVDD may be in the range of -0.3V .. 20V ... referenced to AGND = 0V.

But for example in the second table-> power supply, it says AGND should be between -0.2 and 0.2 V and 0 V nominal, and ok i get it.

AGND is considered zero. (for the analog section)
DGND is considered zero (for the digital section)
So the difference between tehm is also zero. Nominally.
On a real circuit / PCB it is unavoidable that there is a small voltage difference between both GNDs. Usually it is in the millivolts. But the IC allows a maximum difference of 0.2V in both directions.