Current for AFE5808 in Evaluation Module

Hello Prsna,

We have received your post regarding the AFE5808EVM and I have assigned it to the device application expert.

He will get back to you with a response as soon as he can.

Hello Prsna,

Thanks for using our AFE5808/08A device (AFE5808/08AEVM and TSW1400 board).
Yes, we follow your description and did the same measurement on the positive +5V current and negative -5V current.
Initially the positive +5V current is about 0.33A.
Then we turned on all 8 channels (= ON) and connected all 8 channels to
5MHz input signals with fundamental amplitude to -1dBFS level.
and also we set AFE5808/08A device with 65MSPS data rate (using external Clock source =65MHz)
and set up 14 bit data mode on the data capture.
We observed the positive +5V current = 0.815 Amp and the negative -5V current = 0.023Amp.
So could you please double check your AFE5808/08A GUI register settings on your side?

Thank you and best regards,
Chen

Hello Prsna,

How are you?
Could you please also try the following steps:
1) Please turn off AFE5808/08A GUI (software).
2) Turn off all AFE5808/08A EVM power supplies including +5V, -5V and GND.
3) Re-turn on all AFE5808/08A EVM power supplies including +5V, -5V and GND.
4) Re-start AFE5808/08A GUI.
This can guarantee all the system are reset.

Thank you very much.

Best regards,
Chen

Dear Chen,

I repeated as per your setting and got the same current as you mentioned. The board seems to work fine.

Does external clocks are mandatory?

I have one more query, I connect an external trigger from my laser source(J11). The trigger signal is a negative pulse trigger with duration of 5ns and signal level of 4V.

The board only acquires the correct signal once in 30 times trail, rest of the time it just getting some unwanted data. (I think there is a not a stable capturing of the trigger signal or am I missing something). 

  

Thanks

Prsna

Hello Prsna,

How are you?

Thanks for letting us know the AFE5808_08A EVM is working fine for you.

Using external clock is not mandatory for using this EVM.

This is only used for comparison because we are using it because the external clock freq can be changeable.

You can also use the on-board osc clock which is 40MHz fixed freq for your purpose.

Then you need to reconnect the Jumper JP9 and make sure JP10 is connected as well.

The other question related to the SMA connector J11 (as you mentioned).

According to the AFE5808_08A User's Guide, this J11 SMA connector is connected to AFE5808 device's pin L7.

Also please look at the AFE5808_08A Data Sheet, this device pin L7 is DNC (Do not connect. Must leave floated).

So please do not use this J11 connector and please leave it floated.

Thank you very much!

Best regards,

Chen

Hello Prsna,

How are you?
Yes, I have confirmed with other engineer here.
When you are using AFE5808_08A EVM,
then no need to use the J11 connector.

Thank you!

Best regards,
Chen

Dear Chen,

It was J11 pin (EXT_TRG_INPUT) in TSW1400 board.

I'm sorry that I didn't mention it properly.

I connect the trigger signal from my laser source to this pin in TSW1400. The AFE5808 collect the signal from eight channel and transfers it to the TSW1400 via the P10(AFE5808). 

Thanks

Prsna

Hello Prsna,

Thanks for letting us know.

Yes, you are right TSW1400 board has a connector J11 which can be used for trigger IN signal purpose.

However the other EVM (such as AFE5808 EVM) also needs this trigger IN option as well.

Could you please let me double confirm with other engineer here?

I will let you know again.

Thank you!

Best regards,

Chen

Hello Prsna,

When you connect your trigger signal to TSW1400 board pin J11,

you also need to do the following on TSW1400 GUI:

1) connect your cable to J11.

2) select TSW1400 GUI

3) check the following two options:

Check "Trigger mode enable"

Check "Arm on next capture button press"

Then after these changes, please run "Capture" from TSW1400 GUI again.

And please observe the captured data after running "Capture" button.

Thanks and best regards,

Chen

Dear Chen,

I did followed the 'high speed data converter pro GUI' user guide(section 3.1.3.3) and used the same setting before.

It acquires the correct signal once in many number of trail.

Thanks

Prsna

Prsna, 5ns is too small. I have trouble with anything less than about 125ns pulse. Can you try this with any other trigger source or lengthen your pulse? I think you mean the pulse is 4V and then goes to 0V for 5ns, right? Can your trigger source also take an input? The TSW1400 could be the master source and then trigger your laser source. Would that work?

Dear CSmyth,

Yes you are right my signal goes from 4V to 0V.

I can make LED as my trigger source and lengthen the pulse (I will try this, if this ain't working I can make TSW1400 as the master source).

Will let you know soon.

Thanks

Prsna