Hello all,
I would appreciate a check over from a more experienced engineer, to change the input sensitivity of the ClassDaudio TAS5630 board.
Its based on the TAS5630DKD2EVM (Datasheet here), which shows the OPA1632 on the inputs (Datasheet here).
I require it to match a MiniDSP which outputs 0.9v. In order to reach the full output with a 50V supply / 48V output voltage, then the gain needed (I believe) is 35dBv, or a 56x voltage multiplier. I have contacted ClassDaudio and all they are able to say is that it matches the evaluation board at 23dBv.
Below is my thought process:
TAS5630 datasheet - 5v input for full output
OPA1632 datasheet- As far as I can see I would be aiming for a voltage multiplier of 5.6x for full output (5v into TAS5630 / 0.9v into opamp).
OPA1632 datasheet- The opamp Datasheet shows Rg and Rf here
OPA1632 datasheet- Example layout matches with schematic
TAS5630 datasheet- I assume Rf are R63/65 and Rg are R62/66
Own photo -
On the board I measure R26/28/29/32 to be 2.2k each and <1R to the op-amp input pins, indicating they're Rg.
The components R25/21/22/33 measure to be 10K resistors. I can't see the traces exactly, but resistances are <1R to where they're meant to go if they're Rf.
In which case 10k/2k2 = 4.54x gain rather than the ideal 5.6x.
Changes to board-
Am I right in thinking replacing the Rg resistors (R26/28/29/32) with 1.78k (1% E96) will yield the desired input sensitivity?
Thanks for checking this over.. I have seen warnings of incorrect values leading to burned ICs and appreciate your time taking a look!
I would appreciate a check over from a more experienced engineer, to change the input sensitivity of the ClassDaudio TAS5630 board.
Its based on the TAS5630DKD2EVM (Datasheet here), which shows the OPA1632 on the inputs (Datasheet here).
I require it to match a MiniDSP which outputs 0.9v. In order to reach the full output with a 50V supply / 48V output voltage, then the gain needed (I believe) is 35dBv, or a 56x voltage multiplier. I have contacted ClassDaudio and all they are able to say is that it matches the evaluation board at 23dBv.
Below is my thought process:
TAS5630 datasheet - 5v input for full output
OPA1632 datasheet- As far as I can see I would be aiming for a voltage multiplier of 5.6x for full output (5v into TAS5630 / 0.9v into opamp).
OPA1632 datasheet- The opamp Datasheet shows Rg and Rf here
OPA1632 datasheet- Example layout matches with schematic
TAS5630 datasheet- I assume Rf are R63/65 and Rg are R62/66
Own photo -
On the board I measure R26/28/29/32 to be 2.2k each and <1R to the op-amp input pins, indicating they're Rg.
The components R25/21/22/33 measure to be 10K resistors. I can't see the traces exactly, but resistances are <1R to where they're meant to go if they're Rf.
In which case 10k/2k2 = 4.54x gain rather than the ideal 5.6x.
Changes to board-
Am I right in thinking replacing the Rg resistors (R26/28/29/32) with 1.78k (1% E96) will yield the desired input sensitivity?
Thanks for checking this over.. I have seen warnings of incorrect values leading to burned ICs and appreciate your time taking a look!
Last edited:
Although, if my maths is also correct, then this is only an additional 1.8dB headroom with output rail voltages going from 39V to 48V