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.

questions about pipeline adc mechanism

Status
Not open for further replies.

airboss

Member level 3
Joined
May 1, 2006
Messages
64
Helped
6
Reputation
12
Reaction score
2
Trophy points
1,288
Activity points
1,821
Hi,

i've seen this block diagram for pipelined adc in many places but i'm really confused. please help me to understand this. we know this will be implemented by S/H capacitor circuit.

1)we see a 2X here. i guess this is because of capacitor charging transferring from sample phase to holding phase. is this correct?
2)many books mention that Vout = 2Vin-Vref. however, from the diagram i uploaded, it seems to me Vout=2*(Vin-Vref). what is my mistake? i know subtraction of output from DAC is done in holding phase. or should Vout=2*(2Vin-Vref)?

thank you!!
 

mince

Member level 5
Joined
Feb 19, 2005
Messages
82
Helped
10
Reputation
20
Reaction score
4
Trophy points
1,288
Location
Texas
Activity points
1,894
If you look at the topology of the MDAC and do the analysis on the switch cap circuit, you can find that the output will be Vo = 2Vin - Vref for the 1.5 bit/stage architecture.
 

    airboss

    Points: 2
    Helpful Answer Positive Rating

satyasiva

Full Member level 1
Joined
Nov 9, 2006
Messages
99
Helped
5
Reputation
10
Reaction score
2
Trophy points
1,288
Activity points
1,724
this fig. does not correspond to 2vin-vref. it is for 1.5bit/stage.
 

    airboss

    Points: 2
    Helpful Answer Positive Rating

ronialeonheart

Junior Member level 1
Joined
Aug 7, 2006
Messages
15
Helped
3
Reputation
6
Reaction score
0
Trophy points
1,281
Activity points
1,352
The Vout = 2Vin-Vref mentioned by many books is not the Vin in this diagram. You can comprehend it as this, the first stage: Vout1=Vin±Vref, second: Vout2=2Vout1±Vref, ..., and Vout1, Vout2, ..., are not the Vout in your diagram. It's the voltage at the left side of the ×2 block.
 

    airboss

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top