Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

2-GHz 3-input analog switch for DAC - Please help

Status
Not open for further replies.

chickenvlsi

Newbie level 6
Joined
Jun 4, 2009
Messages
12
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,397
Hi All,
Currently, I am designing a DAC for a high speed SAR ADC. In this DAC, a 2-GHz 3-input analog switch is needed (Please enlarge the below figure for more details).
Unfortunately, I failed to find any paper about switch operating at that frequency or thereabout.
I also tried with IEEE explore but still could not find any relevant documents about this kind of switch.

Could you please let me know some basic documents or papers about high speed multi-input analog switch. Here, the term "high speed" means frequency of control signal of the switch is approximately 2GHz.

Thank you very much.
 

dick_freebird

Advanced Member level 5
Joined
Mar 4, 2008
Messages
7,293
Helped
2,128
Reputation
4,261
Reaction score
1,988
Trophy points
1,393
Location
USA
Activity points
58,493
Few, or no RF switches are going to let you commutate
at 2GHz. They try to isolate RF from the control ports.
But they will pass / block 2GHz (50 ohm system).

An old-school analog switch, forget it.

There are only a few topologies - simple, T, Pi. I think
the simple switch (pass only) may suffice since the
input signals are probably not moving very fast (T is
for HF isolation w/o leakage, Pi for isolation and low
port impedance).

You will want Ron*Cmsb to be << 1/freq or that will
become your settling-time bind for sample rate. You
will want to design for minimum charge injection to
further tamp down settling time.

Beyond that there is nothing special about 2GHz on the
control pins, you either have the intrinsic speed in your
process or you don't. Might just see how fast one inverter
can drive another and still have full rail-rail swing. If that
isn't 2GHz, then you're probably hosed.
 

Status
Not open for further replies.

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top