Completed board available in the shop – https://tomwatsonaudio.co.uk/product/es9023-minidac/
This is the first of a series of little DAC boards for use with simple projects. The MiniDAC boards all use simple DACs and have direct outputs with no output opamps or I/V conversion needed. They have a standardised size, connector location and pinout for easy swapping.
The ES9023 from ESS is a nice sounding DAC chip and is very cheap (about £1 each from Mouser). It’s not hard to use and is easy to solder with hot air.
You can buy cheap pre-made boards based on the ES9023 but I don’t trust that the support components are any good and it’s much more interesting to design your own.
I’ve split the schematic and details into 2 sections as shown below
3.3v power supply
The TPS7A4901 linear regulator is low noise and perfect for this application, there is no need to go with anything ultra fancy like an LT3042 for a low-cost DAC. The 4901 can take up to 36v input voltage, but bear in mind your input caps would need to rated appropriately and heat dissipation would need to be considered.
You could use something like a TPS7A2033 which would also work perfectly but the reason I didn’t use it in my design is I wanted input voltages of up to about 16V which the TPS7A2033 does not support (It has a maximum input of 6V).
The resistors on the feedback pin (R10 and R11) set the output voltage to 3.3V.
Any 3.3V regulator would work, but i’d avoid noisier ones like the TPS1117A for best performance.
DAC
Here is the schematic for the ES9023 DAC, pretty much copied from the datasheet. A few points of note
- R1 and R6 (the 100R on the outputs) ideally should be thin film SMD or metal film through hole
- C3 and C4 (2n2 to GND) should be C0G/NP0 dielectric ceramic if SMD or film if through hole
- There is no need for an MCLK input, the 50MHz crystal generates it
- All other caps are X7R and resistors are thick film
I use this DAC board in various battery/DC powered applications and it sounds great. Highly recommended.
Kicad 3D render and screenshot of the layers
Gerber file is available to download here:
https://github.com/smileym4n-collab/es9023/releases/download/v1.0/9023.zip
BOM download with Mouser part numbers:
https://github.com/smileym4n-collab/es9023/releases/download/v1.0/9023v2.csv
TPS7A4901 datasheet – https://www.ti.com/lit/ds/symlink/tps7a49.pdf
ES9023 datasheet – https://www.esstech.com/wp-content/uploads/2022/09/ES9023-Datasheet-v0.72.pdf
Keep an eye out for some more in the MiniDAC series, boards are planned for the PCM5102, AK4432, WM8524 and UDA1334A.
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