TDA1387 and TDA1545A

A project log for Audiophile-sounding DAC for almost no money

0DAC - delivers engaging, immersive sound with a pricetag at least two orders of magnitude from commercial audiophile DACs

richard-dudleyRichard Dudley 05/29/2023 at 05:050 Comments

I've decided to abandon DAC development with TDA1387 after a decade or so of interesting designs using it and instead, go over to TDA1545A.

The reason is - TDA1545A offers better bang-for-the-buck in designs with more than a half-dozen or so paralleled chips. The key metric of interest for a DAC chip is SNR and by virtue of its 2mA maximum output current the 1545 delivers better numbers in this regard than the 1mA 1387. The 1387 can of course be 'overclocked' (I have gone up to 1.5mA) but so can the 1545. What's more, the 1545 delivers its output current at the cost of slightly less supply current. When paralleling large numbers (many dozens) of overclocked 1387s in a small space, heat dissipation became a significant problem, calling for a cooling fan. Using 1545 relaxes the thermals somewhat.

TDA1545A's downside is its use of a right-justified input format rather than I2S so it eats up 2 or 3 more logic chips converting from I2S to its native format. For this reason, 1387 is still the best choice for an entry-level design like Toscanini. Moving ever onward, I have been working on a design with 16 paralleled TDA1545A which is sounding excellent and that'll be the subject of the next log entry.