ADS4245: ADS4245EVM

Hi Jae-heung,

Looking at your attached captures, I see that the amplitude is >-1 dBFs for all captures. From this, I believe your input power may be too high, which may be overloading the ADC. Please try sending an input tone corresponding to an amplitude of around -7 dBFs and seeing if you can achieve better captures. Generally, I believe you may run into these overloading issues when your input amplitude >-1 dBFs.

Thanks,

Aman

Hi Aman

I tested by changing the input power level.

I found that the dBFs is always 0dB regardless of the power.

However, the noise floor is changed according to the input power.

Hi, Aman

The above figure is captured from an input level of -20dBm.

 The below figure is captured from an input level of -40dBm.

These show the same dBFS but different noise floor levels.

Best Regards

Jae-Heung

Hi Jae-Heung,

This is a sign of mismatch of selection of two's complement vs. offset binary format. By default, the HSDC PRO accepts two's complement format. Please set up your ADS424x EVM to output two's complement.

Please

1. Change your current setup to two's complement

2. advise how different your setup compare to section 2.4 of the user's guide: https://www.ti.com/lit/ug/slau333a/slau333a.pdf

Below is the format for the ADS424x ini file in HSDC PRO. You can change to two's complement through data postprocessing feature. 

3. Please also advise the time domain waveform as well. This will help us identify the problem. You can switch the HSDC PRO view from FFT to Time Domain.

Hi Kang

1. As you said, ADS4245 EVM seems to be set as two's complement, and HSDC PRO is set as offset binary.

I obtained -8185 for ant B where there is no input signals.

2. ADS42xx GUI does not connect to ADS4245EVM. 

The USB Status light is dark and the values are not applied.

How can I know GUI is connected to ADS4245EVM?

Is there any method to change the ADS4245 register?

3. In addition, I cannot find any setting related to Data format.

How can I change HSDC PRO setting?

TSW_Controller.ini

[TSW_Controller]
server.app.propertiesEnabled=True
server.ole.enabled=True
server.tcp.serviceName="My Computer/VI Server"
server.vi.propertiesEnabled=True
WebServer.TcpAccess="c+*"
WebServer.ViAccess="+*"
DebugServerEnabled=False
DebugServerWaitOnLaunch=False

allowmultipleinstances = TRUE
HideRootWindow=True

High Speed Data Converter Pro,ini

[High Speed Data Converter Pro]
server.app.propertiesEnabled=True
server.ole.enabled=True
server.tcp.paranoid=True
server.tcp.serviceName="My Computer/VI Server"
server.vi.callsEnabled=True
server.vi.propertiesEnabled=True
WebServer.TcpAccess="c+*"
WebServer.ViAccess="+*"
DebugServerEnabled=False
DebugServerWaitOnLaunch=False
server.tcp.enabled = TRUE
server.tcp.port = 6655
server.vi.access = "+*"
server.tcp.access = "+127.0.0.1"
useLocaleDecimalPt=False

Hello

Jae-heung Yeom said:

2. ADS42xx GUI does not connect to ADS4245EVM. 

The USB Status light is dark and the values are not applied.

How can I know GUI is connected to ADS4245EVM?

Is there any method to change the ADS4245 register?

You should be able to press "RESET USB" to connect to the software:

One quick way to configure two's complement vs. offset binary in the ADS42xx family is through the parallel GPIO configuration:

You will need to make sure the SEN is properly configured per Table 6 and Table 9 of the datasheet

https://www.ti.com/lit/ds/symlink/ads4249.pdf

To do so on the EVM, please follow the ADS42xx EVM schematic and user's guide:

https://www.ti.com/lit/ug/slau333a/slau333a.pdf

Jae-heung Yeom said:

3. In addition, I cannot find any setting related to Data format.

How can I change HSDC PRO setting?

You can go to the following directory:

C:\Program Files (x86)\Texas Instruments\High Speed Data Converter Pro\1400 Details\ADC files

open up the .txt file for the ADS424x.ini file

You can then uncomment the following highlighted line. To convert two's complement to offset binary (vice versa), simple XOR the most significant bit