LTC1595A not working

Hi Bareil76 ,

Let me further check your query and get back to you soon. For the meantime can you try these basic troubleshooting methods that might be able to help:

1. Verify that the LTC1595A is properly powered. Make sure that the LTC1595A is receiving the correct voltage and that it is properly grounded.

2. Try to replace the LTC1595A with a known good one, if it works with a different unit then this means the previous DUT is faulty, if it still doesn't work with several other DUTs, the set-up or code might be wrong.

3. Try to change the clock frequency and correct SPI mode (phase and polarity)

Best Regards,

Den

Thanks for your help. 

1) I checked that the 5V was properly set on the VDD pin. Ref pins sees 10V. Ground is also ok

2) I have tried 2 board so far and both behaves the same way.

3) I also tried it without success

I tried looking at the direct current output of the DAC. When sending:

a) 0x0000 I get 0.154mA

b) 0xFFFF I get 1.388mA

c) 0x8001 I get 0.802mA

d) 0x8000 I get 0.805mA

e) 0x7FFFF I get 0.802mA

So the SPI communication seems to be working. What seems to fail is the rest of the circuit, provided that the current numbers I see are what I should expect!

Hi Bareil76 ,

Thanks for providing additional information. Based on what you have said, it seems that DUT is might not be the problem since you tried two of them and they behave the same way. Since an external set-up is used there are number of things that might be causing the issue hardware-wise, with that kindly:

1. Double check the resistor values and connections in the output stage. Make sure the resistors match the datasheet values and are connected properly for the circuit configuration you are using. Small errors here can lead to incorrect output voltages.

2. Verify the op-amp supply voltages. The op-amp needs proper supplies (e.g. +/-15V) to output the full voltage range.

3. Measure voltages at the op-amp output, DAC output, and reference inputs. This can help narrow down where in the output stage the issue may be occurring.

If you try isolating the issue on the hardware part and you can't find any fault, maybe it's time to check software-wise in terms of the code you are using.

Best Regards,

Den

OMG, I made such a dumb mistake! This was a simple board and did not pay attention. 

I will make the modif and it'll work.

Thanks for your help.