Vasile Surducan wrote:
> On Thu, Feb 16, 2012 at 2:50 PM,  <alan.b.pearce@stfc.ac.uk> wrote:
> > > > Hi all,
> > > >
> > > > I need to interface an 120Msps serial ADC with LVDS output to an US=
B
> > > > 2.0. Does anyone knows a small ASIC, DSP or whatever which allows t=
his
> > > > simple task. I thought also to USB to SATA bridge, however I need a
> > > > few programmable IOs for controlling the A2D,
> > >
> > > Classic application for a small FPGA, plus FTDI FTx232H hi-speed USB
> > > interface. FPGA will handle LVDS conversion, some RAM for buffering a=
nd
> > > handshaking.
> >
> > When you say LVDS, what format is it? Does it work just like an SPI dev=
ice
> > (LVDS really is only the differential hardware layer). If it does work
> > like an SPI device then a Microchip 2210 USB-SPI with an LVDS driver an=
d
> > receiver chip may do what you want.
>=20
> It's 14 bit serial output in one lane (one bit a time) or two lane
> (two bits at a time) and frame, all LVDS output.
> Also has a SPI for commands. See for example LTC2268.

Clearly, this is anything but a "simple task". Given that high-speed USB ca=
n
only support about 40 MBps sustained, you'd only be able to operate this ch=
ip
at 20 Msps or so with a "bare-bones" interface. If you want to burst data a=
t
higher sample rates, you're going to need a significant amount of high-spee=
d
buffer memory between the ADC and the USB.

Just as an example, look at Linear's DC1371A board, which performs the
function you are asking for. It includes a rather hefty Virtex-5 FPGA along
with a couple of high-speed ZBT SRAMs. Granted, this board supports many mo=
re
features than you probably need, but the basic data handling is going to be
very similar.

You're going to have to give us a better idea of what you're trying to do w=
ith
this chip before we can offer meaningful suggestions. BTW, this is exactly =
the
sort of FPGA design work that I do. If you'd like to discuss this project
off-list, send a message to dtweed at dtweed dot com.

-- Dave
--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.