Hello,
Need some help understanding what i do wrong here.
Long story short.
We have made some PCB for the 9028PRO chip. Works perfect and sounds good.
For 1.2V DVDD we use this: input 5V -> 1uF X7R-> ADP-151 1.2V -> 1uF X7R. This provide the 1.2V to chip and we have some 0,1uF around the legs of the chip.
ADP-151 can provide 200mA output current and input volt can be up to 5.25V and 9028PRO spec say 82mA at the DVDD. I have looked at DimDIm's post and I know that higher input kHz takes up to 200mA, But we only use 44.1kHz.
All fine up to here.
Anyway, we tried to put in a 9038PRO in the same PCB (AVCC is ok and can handle up to 600mA).
With the 9038PRO the ADP-151 can't provide to output 1.2V, We get something like 0,9V.
So our first ide was that for some reason 9038 need more then 200mA current for DVDD. In the spec it say something like 128mA.
But if we "break" the PCB circuit and lower the input volt to ADP-151 to around 3.7V (from 5V to 3.7V) it's working ok and we have 1.2V.
How can that be? Lower input gives ok output (1.2V), but 5V input only gives 0,9V output.
Sorry if the "story" is impossible to understand....
BR//
Daniel
Need some help understanding what i do wrong here.
Long story short.
We have made some PCB for the 9028PRO chip. Works perfect and sounds good.
For 1.2V DVDD we use this: input 5V -> 1uF X7R-> ADP-151 1.2V -> 1uF X7R. This provide the 1.2V to chip and we have some 0,1uF around the legs of the chip.
ADP-151 can provide 200mA output current and input volt can be up to 5.25V and 9028PRO spec say 82mA at the DVDD. I have looked at DimDIm's post and I know that higher input kHz takes up to 200mA, But we only use 44.1kHz.
All fine up to here.
Anyway, we tried to put in a 9038PRO in the same PCB (AVCC is ok and can handle up to 600mA).
With the 9038PRO the ADP-151 can't provide to output 1.2V, We get something like 0,9V.
So our first ide was that for some reason 9038 need more then 200mA current for DVDD. In the spec it say something like 128mA.
But if we "break" the PCB circuit and lower the input volt to ADP-151 to around 3.7V (from 5V to 3.7V) it's working ok and we have 1.2V.
How can that be? Lower input gives ok output (1.2V), but 5V input only gives 0,9V output.
Sorry if the "story" is impossible to understand....
BR//
Daniel
Higher input voltage creates higher losses Pl= (Uin-Uot)*Iout, so maybe it is a thermal protection of ADP-151?
P.S. ES9038Pro have more than one 1.2V power pin, someone uses more than one 1.2V regulator - the losses are distributed across multiple ICs.
P.S. ES9038Pro have more than one 1.2V power pin, someone uses more than one 1.2V regulator - the losses are distributed across multiple ICs.
Probably a single ADP151 was the wrong choice all along as it is only 200 mA capable. The 9028PRO already comes too close to that value and 9038PRO is apparently over that value. There is not enough headroom with regards to current/power.
I only know ES9028K2M of the more recent ESS DACs and that one already has peak currents that disturb some 1.2V regulators. You could try out LDOs that are in the 500 ...800 mA range.
I only know ES9028K2M of the more recent ESS DACs and that one already has peak currents that disturb some 1.2V regulators. You could try out LDOs that are in the 500 ...800 mA range.
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Yes, how importen is it to use a low-noise reg for Dvdd?
Or can a 1117 be used in this position?
BR// Daniel
Or can a 1117 be used in this position?
BR// Daniel
Good question. I don’t know as I haven’t really compared regulators, I only solved issues with non suitable regulators and used AMS1117-ADJ. Rock stable with either 5 or 3.3V input voltage.
Why that? The solution is already in that "500 mA". The 5V will also already be regulated so please explain the extra step in-between.
The current is variable but with a nominal 128 mA it will be 0.48W nominal dissipation. Dividing that dissipation does not make a shocking difference as the total will stay 0.48W.
But don't listen to me, I don't have that much experience with ES9038PRO.
The current is variable but with a nominal 128 mA it will be 0.48W nominal dissipation. Dividing that dissipation does not make a shocking difference as the total will stay 0.48W.
But don't listen to me, I don't have that much experience with ES9038PRO.
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it was most to lower the heat in the 1.2v reg. You think it’s unnecessarily?
Then i go directly with 5v to 1.3v
BR// Daniel
Then i go directly with 5v to 1.3v
BR// Daniel
With enough copper for cooling and an already regulated 5V I don't think it is necessary. If you want relatively cool regs and dissipation bothers you then use the extra 3.3V regulator or use separate AMS1117 for DVDD and the others.
I recall SMSL also uses 3.3V regs between 5V and 1.2V regs.
I recall SMSL also uses 3.3V regs between 5V and 1.2V regs.
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Probably your regulator is dissipating too much power, so it is protecting itself. The power dissipated by the regulator is the current though it times the voltage drop across it. You can lower the voltage drop, the current, or both, until the regulator operates normally. If you suspect the self-protection mechanism is from it going over temp due to high power operation then some freeze spray might make it temporarily recover. It might also feel hot when touched with a finger. In that case redesigning the board to carry away more heat and or using a glue-on heat sink might help.
Thanks. Yes a redesign for the 9038.
For now we put the 9028 back and all works fine.
BR// Daniel
For now we put the 9028 back and all works fine.
BR// Daniel