[gta02-core] Caps for bass fix (ECN0022)

Werner Almesberger werner at openmoko.org
Thu Aug 20 18:58:39 CEST 2009

Rene Harder wrote:
> Why don't we use the 100uF caps from the big-C buzz fix (C4306/4307
> GTA02-A7) so we don't have any component change. It's a Tantalum Solid
> Electrolytic Chip Capacitor [3] (TLJA107M006R0500)

Are 500 mOhm ESR still okay ? If yes, that looks like a decent choice
as far as the electrical characteristics are concerned. It's too tall
(1.8 mm) for going into the can, though. We'll have plenty of space in
the can while the space outside the can probably remains largely the
same. (Depends a bit on how we're doing with the Calypso and WLAN

My non-electrical criteria are, in this order:

- can be sourced: compatible (*) parts from at least two different
  vendors in stock at Digi-Key and available in small quantities
  (minimum order <= 10)

- low profile: if possible, low enough to fit inside the can (height <=
  1.7 mm)

- smallest possible surface

(*) A small tolerance of capacity or an imperfect footprint match are
    okay. If we select a height <= 1.7 mm, the second source must be
    <= 1.7 mm too.

> And at the end we are just designing a cell phone with music playback
> ability and no high class audio amplifier so i would not expect an
> outstanding THD at all. ;-)

Yeah, we're not exactly building the B&O phone ;-)

- Werner

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