AFE5809: AFE5809 C-bypass on INM pins Question.
Part Number: AFE5809
For AFE5809, DVDD_LDO 1/2, it is digital power for modulator. It can be internally generated. also , external higher performance 1.4-V supply can be applied to N4 and N6 for minimizing digital noise emission.
What is the requirement for this power supply if we use external spply? Such as, current it consumes, noise requirement, and so on?
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In reply to Chen Kung:
In reply to yi xiao:
How are you?
For AFE5809, DVDD_LDO 1/2, it is digital power for modulator.
According to the AFE5809 data sheet:
Please take a look at the following:
Thank you and best regards,
Thanks for reply.
I read Section 7.6 on datasheet, and found it is ADDITIONAL power consumption, 90mW/CH means 8*90/1.8 = 400mA [additional ] for one AFE5809. with 30% margin, it is max. 520mA.
And in Section7.5(Page15), DVDD_1.8V current is max. 110mA.
Here is question about power supply designing: When we enable the demodulator :
1. If we use Internal 1.4V for DVDD_LDO1/2, we should provide 520mA +110mA = 630mA for DVDD_1.8V per chip. Is this perception correct?
2. If we use External 1.4V for DVDD_LDO1/2, the external 1.4V power should provide 520mA per chip, and DVDD_1.8V is still 110mA. Is this perception correct?
How are you?\
Both are right!
and best regards,
We have another question For DVDD_LDO1/2: we use External power supply for them.
In Pin Description Page9 of Datasheet, it writes: "These two pins should be separated on the PCB and decoupled respectively with 0.1-µF capacitors".
How to understand this requirement? My understanding is, although these two pins are connected together INSIDE the IC, BUT still require Independent Traces on PCB, and Independent 0.1uf decouple-caps. Is it so?
Should we use TWO external LDO to supply for DVDD_LDO1/2?
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