I've used x=03 giving 11mm between board surfaces. There are two reasons for this: a) This clears the CF socket area with height for components in this area. The CF socket sticks out about 6.5mm so this gives 4.5mm for components under the CF area. b) The Hydra daughter board is bigger than the Balloon and extends up above the back of the CF socket (the lower, bus connector, edge is coincident). Many CF cards fatten after they clear the socket (particularly WLAN cards) (Also note that it is a Type I socket), so it was important to give as much space in this area as possible. There were a number of different physical design constraints that forced this particular arrangement for the Hydra daughter boards. One being that I needed to stack several cards together, in different combinations, so the connectors on each side of the board needed to be in the same plane. In a design that is less constrained I'd suggest making the daughterboard so that its upper edge is coincident with the loon edge from which the CF card protrudes, this would allow better clearance for CF cards. If the daughter board needs to be larger than the Balloon board it may be better to extend it in the opposite direction i.e. below the Bus connector. This has the advantage that PCB tracks to the Bus connector have more routing space (i.e. both above and below the connector) and this may allow a cheaper daughter board to be made where via size is larger and with possibly fewer layers, even if this is not the case routing will be much easier. Cheers David. -----Original Message----- From: balloon-admin@balloonboard.org [mailto:balloon-admin@balloonboard.org] On Behalf Of Laurie van Someren Sent: 21 June 2004 16:58 To: balloon@balloonboard.org Subject: [Balloon] Question for Dave Bissett I think Dave Bissett may have actually used the CF socket and the large GPIO connector on a Balloon, so he is well placed to answer this query. The standard connector QTE-100-01-L-D-A-K is the one standing lowest off the board surface, and so a PCB attached to its counterpart QSE connector interferes with the CF socket. Connectors which stand further off are available; the -01- is 5mm thick and 8mm and 11mm and more are options. It looks as if the -02- part with its additional 3mm height will hold a PCB clear of the CF socket, (though there would be almost no room for components on it where the CF socket is). Dave, what value of X have you used for a QTE-100-0X- >with< CF socket, please ? Thanks LvS _ ASCII | -- ( ) ribbon | Laurie van Someren at Aleph One Ltd X campaign | Old Courthouse Bottisham CAMBRIDGE CB5 9BA UK / \ against | Tel +44 (0)1 223 811 679 Fax +44 (0)1 223 812 713 HTML e-mail | http://www.aleph1.co.uk/ mailto:laurie@aleph1.co.uk _______________________________________________ Balloon mailing list Balloon@balloonboard.org http://balloonboard.org/mailman/listinfo/balloon