ADS7957-Q1: Operation Question

CHO SR

Part Number: ADS7957-Q1

Hi,

The customer is testing the ADS7957QDBTRQ1 circuit after designing it.

The Max value should be output when it is about 5V input based on the ADC 1024 value with the 10bit resolution specification.

Currently, the Max value is coming out at about 1.5V input level.

I would like to ask if there are any additional parts that need to be set up.

11 months ago

+1 Tom Hendrick 11 months ago

TI__Guru**** 176421 points

Hi Cho,

In your schematic snippet, it appears as though REFM (pin 3) of the ADS7957-Q1 is 'open circuit'. This pin needs to be tied to AGND. Please ensure that pin 3 is grounded and verify that you get the correct ADC results.

0 CHO SR 11 months ago in reply to Tom Hendrick

Genius 3415 points

Hi Tom,

Thank you for your support.

The customer tested REFM(pin 3) by connecting it to AGND, but it is the same.

0 Tom Hendrick 11 months ago in reply to CHO SR

TI__Guru**** 176421 points

Please send over screen shots showing the interface (/CS, SDI, SDO, SCLK) and details of the register settings. Is there something missing from the schematic? Every input from what I see should be ~5V.

0 CHO SR 11 months ago in reply to Tom Hendrick

Genius 3415 points

Sorry, they said there was a problem with the A GND connection.

After A GND reconnection, it works normally.

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ADS7957-Q1: Operation Question