I don't know what you mean by "UWB" (use standard or common abbreviations, no I'm not going to look it up, it's your job to explain), but many many micros have 10 bit A/Ds and SPI hardware. Even without the SPI hardware, SPI is simple to do in firmware by controlling the I/O lines directly.
In the Microchip line, there is a wide spectrum that meet these requirements. A low end PIC 16 can be small, cheap, and very low power. A fast dsPIC33 can run up to 40 MIPS but of course will use more power. There are various PIC 18 and PIC 24 in between.
What you need to explain is how fast you need to sample the 10 bit A/D and what the micro needs to do to these 10 bit values before passing them on via SPI.
This "answer" is more of a comment because too much important information is lacking. It can be turned into a answer if you cooperate and answer the specific questions asked, not what you feel like answering or or you think is important. As it stands, this question is too vague to be reasonably answered and should be closed. People will come by and close it as they encounter it. When 5 close votes are cast, it's over. The clock is ticking. You may have only minutes to a few hours. Do what I said exactly as I said quickly and you may get your answer. Ignore it and not cooperate and you'll be sent home without a cookie.
Added:
You have now added that the A/D sample rate is 500 kHz and that this raw A/D data is to be passed on via SPI. Since the A/D is 10 bits, this is apparently where you got the 5 Mb/s SPI data requirement from.
This is doable, but will require a reasonably high end micro. The limiting factor is the 10 bit A/D at 500 kHz sample rate. That's quite fast for a micro, so that limits the available options. Another thing to consider is that there is more to SPI than just sending the bits. Bytes may need to be transferred in chunks with chip select asserted and de-asserted per chunk. For example, how will this 10 bit data be packed into 8 bit bytes, or will it at all?
The main operating loop of the firmware will be quite simple. You probably set up the A/D to do automatic periodic conversions and interrupt every 2µs with a new value. Now you've got most of 2µs to send it out the SPI. If the device really can just accept a stream of bits, then it might be easier to do the SPI in firmware. Most SPI hardware wants to send 8 or 16 bits at a time. You'd have to buffer bits and send a 16 bit word 5 out of every 8 interrupts. It might be easier to just send 10 bits each interrupt in firmware.
Sending SPI bits in firmware if you only need to control clock and data out is pretty easy. Per bit, you have to:
- Write bit value to data line.
- Raise clock
- Lower clock
It would make sense to unroll this loop with preprocessor logic or something. A PIC 24H can run at up to 40 MIPS, so you have 80 instructions per interrupt. Obviously you can't use 8 instructions to send each bit. If you can do it in 6 it should work. There is some overhead to get into and out of each interrupt, so you might make the whole thing a polling loop waiting for the A/D, but then the processor can't do anything else. I'd probably try to cram this into the A/D interrupt routine using every possible trick so that at least a few forground cycles are left over for background tasks like knowing when to stop, etc.
Check out the Microchip PIC 24H line. I think most if not all have A/Ds that can do 500 kbit/s, and they can all run at least up to 40 MIPS. The new E series is even faster, but I'm not sure how real that is yet.
Best Answer
The cheapest solution from a hardware point of view would be to use a MCU that includes a USB interface (there are a lot of them in the PIC32MK/MZ/MX ranges), and just make the MCU responsible for all the communication to/from both the SD card and the USB interface. Implement the Mass Storage USB device class (or, alternatively, the Media Transfer Protocol class) in software on the MCU (there are a lot of examples and resources around: e.g. Microchip AN1169), and it will allow a computer to be able to browse and read the files when connected to the board.
This solution, however, will require heavier software development. But it is both the simplest in terms of hardware architecture, and the most flexible (if you want to implement other services through the USB port, you can. If you want the MCU to forbid some operations under specific conditions, or filter/preprocess the data on the way from the SD card to the computer, you can. And any modification on these features can be made with a simple firmware update).
This software solution would definitely be the route I'd be following if I were you.
Now, if you want this to be implemented in hardware, it is still possible: you need some USB SD card reader chip (the level shifting will typically be done by this chip). There are a handful of those: Microchip USB2660, MAX14502, and lots of them from Taiwanese manufacturers: GL823U, MA8121, ... Not sure FTDI is a good choice: they have some USB to SPI bridge, but they don't directly implement the USB Mass Storage device class, so you'd need some dedicated software on the PC to be able to browse files (maybe they have a specific firmware/chip somewhere implementing mass storage but I couldn't find it).
Then you need a way to switch the SD card bus to be connected either to the card reader chip or to your MCU. Some 1:2 analog multiplexer can do the job here (better use an analog multiplexer because the SD pins can be bidirectional). Choose one that can handle the frequency required by your SD card speed.
The MAX14502 card reader chip is particularily interesting because it is supposed to act as a middle-man between the USB/SD ports and the MCU, so you can choose to bypass the MCU and go through the reader chip, or go through the MCU. In short, the above multiplexer is builtin (see datasheet page 18), and it even includes a similar multiplexer for the USB port. That will simplify the hardware in your specific case.