What kind of ADC should I choose?

• Jul 19, 2006

• #1

B

benchen

Member level 2

Joined

Sep 9, 2005

Messages

42

Helped

2

Reputation

4

Reaction score

0

Trophy points

1,286

Activity points

1,605

The resolution is 8bit, Clock Freq is about 1MHz.
Which structure should I choose to realize low power consumption and small area?
Thanks a lot.

 

• Jul 19, 2006

• #2

M

mists

Full Member level 5

Joined

May 14, 2002

Messages

275

Helped

22

Reputation

44

Reaction score

9

Trophy points

1,298

Location

China

Activity points

1,281

I think SAR ADC is suitable!

 

• Jul 19, 2006

• #3

E

eezou

Member level 5

Joined

Nov 17, 2005

Messages

90

Helped

7

Reputation

14

Reaction score

3

Trophy points

1,288

Activity points

1,791

Flash ADC

 

• Jul 19, 2006

• #4

polymath

Full Member level 4

Joined

May 2, 2006

Messages

231

Helped

28

Reputation

56

Reaction score

4

Trophy points

1,298

Location

England

Activity points

3,105

Hi benchen

Is the 1MHz a clock that you system has available or did you mean you want 1Msps?

A res. of 8bit - OK, but what accuracy? ±0.5Lsb? ±1Lsb? ± 2Lsb? .....

Low power - how low?
Input voltage range?
Input number & type single/double ended?
What type of output serial/parallel?
What supply voltage? single rail/double rail?
What reference - internal/external?
What control - command/autorun?
What package - dip/smt

better definition => better solution

... Polymath

 

• Jul 19, 2006

• #5

E

ericliu

Member level 1

Joined

Dec 31, 1999

Messages

39

Helped

2

Reputation

4

Reaction score

0

Trophy points

1,286

Activity points

153

I think the two-step subranging arhitecture is good.

 

• Jul 20, 2006

• #6

P

pfd001

Advanced Member level 1

Joined

Jul 23, 2005

Messages

409

Helped

45

Reputation

90

Reaction score

10

Trophy points

1,298

Activity points

3,214

SAR is the best choice if the high frequency clock is already available

 

• Jul 20, 2006

• #7

C

cinvo

Newbie level 5

Joined

Mar 14, 2006

Messages

9

Helped

1

Reputation

2

Reaction score

1

Trophy points

1,283

Activity points

1,325

Charge Redistribution SAR ADC

 

• Jul 20, 2006

• #8

Z

zenisle

Full Member level 2

Joined

Sep 11, 2005

Messages

127

Helped

4

Reputation

8

Reaction score

2

Trophy points

1,298

Activity points

1,987

sigma-delta or sar adc

 

• Jul 20, 2006

• #9

M

manissri

Full Member level 5

Joined

Apr 16, 2005

Messages

281

Helped

9

Reputation

18

Reaction score

3

Trophy points

1,298

Activity points

3,279

hi sar adc will be good ..

 

• Jul 20, 2006

• #10

polymath

Full Member level 4

Joined

May 2, 2006

Messages

231

Helped

28

Reputation

56

Reaction score

4

Trophy points

1,298

Location

England

Activity points

3,105

Hi All
How can any of you sincerely recommend any type of ADC WITHOUT knowing the application or requirement? - or do you post to confuse?

The UNKNOWING-SEEING-BLIND LEADING THE IGNORANT-BLIND.

Is it little wonder there are so many confused readers on EDAboard.

... Polymath

 

• Jul 21, 2006

• #11

S

sankudey

Full Member level 3

Joined

Sep 6, 2005

Messages

176

Helped

37

Reputation

74

Reaction score

11

Trophy points

1,298

Location

India

Activity points

3,513

along with the question of polymath...I want to add one more...which i think is importatnt one....

what is the technology and technology node......

BTW: why the question originator is silent for so long


sankudey

 

• Jul 21, 2006

• #12

B

benchen

Member level 2

Joined

Sep 9, 2005

Messages

42

Helped

2

Reputation

4

Reaction score

0

Trophy points

1,286

Activity points

1,605

Sorry for reply so lately. I can not log in today, it is strange

Vdd=1.8, single suply. process: 0.18um.
Vin is from 0~Vdd, single ended.
Clock 1MHz. Resolution:8bit, effective bit >7bit
the power consumption should be less than 6mW.
Reference: internal, (from bandgap and it is also needed to be designed bymyself)
The package and control type is not clear up to now.

Is SAR the best choice?

If using pipleline, is it possible?(I mean the power consumption)
Does the single ended to differential circuit needed in pipeline?
and the range of Vin is also a problem, it is from 0~Vdd, is it OK for pipeline?

thanks a lot.

Added after 1 minutes:

If high freq clock is not available, which ADC should I choose?

 

• Jul 22, 2006

• #13

A

asping

Newbie level 6

Joined

Jan 7, 2006

Messages

12

Helped

0

Reputation

0

Reaction score

0

Trophy points

1,281

Activity points

1,338

Is 6mw the total power of ADC and bandgap ?

 

• Jul 22, 2006

• #14

B

benchen

Member level 2

Joined

Sep 9, 2005

Messages

42

Helped

2

Reputation

4

Reaction score

0

Trophy points

1,286

Activity points

1,605

do not include bandgap. Is it possible? It sounds too hard.

 

• Jul 26, 2006

• #15

S

sankudey

Full Member level 3

Joined

Sep 6, 2005

Messages

176

Helped

37

Reputation

74

Reaction score

11

Trophy points

1,298

Location

India

Activity points

3,513

Hi,
I guess ur spec of 6mW power consumption halted the discussion for a long.....

I just can say one thing from my experiance.....u should avoid to chose a architecture who potentially requires S/H or T/H circuits...because...in CMOS.....as generally closed loop architecture is followed (other than like HBT/BJT...where openloop is preffered for higher frequency).....an OP-AMP comes as mandatory......and it is highly possible that one S/H or T/H pursuing 8(+) bit of resolution ... may consume a potential part of 6mW.....I told 8-bit as for higher accuracy u may have to employ boot-strapping etc....ultimately increasing transistor count......


u keep on updating on this issue....it seems to be a real challenge.....

gd luck...

sankudey