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Re: [Discuss-gnuradio] FrontEnd4702 take 2
From: |
Matt Ettus |
Subject: |
Re: [Discuss-gnuradio] FrontEnd4702 take 2 |
Date: |
Tue, 24 Feb 2004 21:17:05 -0800 |
User-agent: |
Internet Messaging Program (IMP) 4.0-cvs |
Quoting cfk <address@hidden>:
The changes relate to trying to make the board per the USRP mechanical
> constraints firstly. I made the board 2000 mils hi X 2450 mils wide. The
> growth is on the left side as viewed from the top of the USRP with the board
> in the upper left slot. I made the mounting holes per the 150mil setback
> (first three) and the 300mil setback (bottom right corner).
Sounds good
> I did add 10uf, 0.1uf and 1000pf on dvdd, avdd and +5. Additionally, I
> put an opamp in place of the MAX518 and am driving it from aux_dac_a from
> the USRP. Currently I am thinking MAX406, but I may change to a Linear
> Technology LT1678. If anyone has a better idea, I am all ears (even have my
> Mickey Mouse hat available with extra ears).
All good choices.
> There are now two 4702 tuners on the board. The first one has its MA0
> pin grounded so it should respond to I2C address 0xC0 and the second has its
> MA0 pin left open so it should respond to I2C address 0xC2.
While we're at it, let's really go all out -- the 4702 can handle 4 different
addresses. Thus, we could put 2 of these boards, with 2 4702s each, on the
USRP at once, necessitating the 4 addresses. With a pair of 2-pin jumpers we
can accomodate that. If you give the address select pin on one 4702 a 15K R to
+5V, and then provide a jumper which can pull that to ground, it will be
selectable. Similarly the other one could have a jumper to +5V, and would be
open otherwise.
>The agc voltages
> are common, although if you think the opamp should be a dual and use the
> aux_dac_b, that is OK with me.
I would go with a dual opamp and use both DAC outputs.
> The schematic has grown to two B size pages and they are
> http://home.pacbell.net/cfk/frontend4702_1.pdf and
> http://home.pacbell.net/cfk/frontend4702_2.pdf
They look good.
> The layout is shown as an Xray view through the board and is at
> http://home.pacbell.net/cfk/frontendcomponent.pdf . Please view it as a
> parts placement idea only at this time as it isnt routed yet. I am hopeful
> that I will be able to make it just a double sided board. That is, the
> component side will have most of the traces. This leaves the majority of the
> solder side as a ground plane with traces as required in it. I will route
> the power supply lines as wide traces. Currently, signal traces are planned
> at 12mils and the power supply traces at 25mils or in a couple of long
> cases, 50mils.
That file seems to be missing from your site.
> side p.s to Matt: Is the schematic file available for study by me?
Yes, I'll get you a copy of the schematics.
Matt
- [Discuss-gnuradio] intel on radio spectrum policy, Eric Blossom, 2004/02/20
- [Discuss-gnuradio] frontend4702 schematic and layout, cfk, 2004/02/22
- Re: [Discuss-gnuradio] frontend4702 schematic and layout, Matt Ettus, 2004/02/23
- Re: [Discuss-gnuradio] frontend4702 schematic and layout, cfk, 2004/02/23
- Re: [Discuss-gnuradio] frontend4702 schematic and layout, Eric Blossom, 2004/02/24
- Re: [Discuss-gnuradio] frontend4702 schematic and layout, Matt Ettus, 2004/02/24
- [Discuss-gnuradio] FrontEnd4702 take 2, cfk, 2004/02/24
- Re: [Discuss-gnuradio] FrontEnd4702 take 2,
Matt Ettus <=
- Re: [Discuss-gnuradio] FrontEnd4702 take 2, John Gilmore, 2004/02/25
- Re: [Discuss-gnuradio] FrontEnd4702 take 2, Eric Blossom, 2004/02/25
- Re: [Discuss-gnuradio] FrontEnd4702 take 2, Matt Ettus, 2004/02/25
- Re: [Discuss-gnuradio] FrontEnd4702 take 29, Eric Blossom, 2004/02/25
- Re: [Discuss-gnuradio] FrontEnd4702 take 29, Matt Ettus, 2004/02/25
- Re: [Discuss-gnuradio] FrontEnd4702 take 2, Matt Ettus, 2004/02/25
- [Discuss-gnuradio] Better link to front end layout, cfk, 2004/02/25
- Re: [Discuss-gnuradio] Better link to front end layout, Matt Ettus, 2004/02/26
- [Discuss-gnuradio] New FrontEnd Schematic & Layout, cfk, 2004/02/26
- Re: [Discuss-gnuradio] New FrontEnd Schematic & Layout, Eric Blossom, 2004/02/27