We have a project using some LDOs on DAC, ADC, Clock Gen., such as TPS74701, TPS79301, TPS72501...
I want to know:
how can I build up a good power/ground plane with decoupling caps using TI TINA.
Thanks
David
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Hi David,
Are you asking for guidelines for power / ground planes and decoupling caps (like an Application Note or tutorial)? I'm not sure what you mean by "using TINA" since TINA is a simulation tool and is not for PCB layout.
I found the following information which may be useful to you if you are looking for tutorial on regulator layout next to high performance data acquisition components:
http://www.ti.com/lit/an/snva602/snva602.pdf
http://www.ti.com/lit/ml/slup224/slup224.pdf
http://www.ti.com/litv/pdf/slua534
http://www.ti.com/lit/wp/snaa113/snaa113.pdf
Thanks,
Hooman
Hi Hooman,
Sorry, it is my fault.
For example, DAC3482 need a 1.2V and 3.3V for digital and analog power supply. External supply can provide 5.0V to the board. So we will need some LDO (such as TPS79301, TPS72501) to transfer the voltage to proper voltage level. But DAC needs a high performance and clear supply, usually we will need some decoupling caps to be a filter. That can reduced noise and impedence of power plane.
So I want to know:
How can I make sure the combination of LDOs and decoupling caps that is good for high speed DAC?
Can TI TINA help to do this task?
Thanks and Best Regards,
David
Hi David,
I found the following reference designs with respect to the regulators you had noted, which allows you to do "load transient" simulation:
TPS74701: http://www.ti.com/litv/tsc/slim253
Here is the link to all the TINA reference designs, for your reference:
http://www.ti.com/adc/docs/midlevel.tsp?contentId=55102&DCMP=hpa_hpa_elabs&HQS=Tools+OT+spicerack
However, since TINA is not a PC board layout tool, for layout optimization, you'd need to consulate some of the application note links I provided before (or other tutorial material).
Hope this helps you.
Regards,
Hooman
David,
You can use your PCB tools to derive the via inductance and board capacitance. Also, you can use the capacitor manufacturer's datasheet to derive the ESR, ESL, etc. Once you have all these models, you can use TINA to simulate the impedance over frequency. See attached example.
You may also refer to this article describing the use of single value capacitors to eliminate peaking due to ESR. The use of board capacitance for broadband filtering is helpful for high speed systems.
-KH