reference resistance in adc design

[tuza2000]

which kind of resistance in 6bit flash adc can i use ,in tsmc 0.18 technology？

rnploy/rnlploy /rnplus?

why?

i want to parallel resistance to gain a little and accurate one,

is it avilable?

 

[Humungus]

Use the one that offers you the best tradeoff matching-low power consumption. If power consumption is lees than an issue, the use the one that gives you the best matching.

 

[sunking]

poly res is better than rnplus for better match and voltage char.
rnploly is maybe better

 

[mists]

non-salicide p-poly in n-nwell is a low noise resistor, but large resistor value. in flash adc, metal resistor can also consider.

 

[adam79416]

" want to parallel resistance to gain a little and accurate one" If u dont concider the area of the circuit.

 

[tuza2000]

my resistance valule is 20-40 ohm,
is it better that i use parrel rnploy resistance that the area are acceptable?

 

[ocarnu]

6 bit flash uses metal resistors most of the time. I see you don't want speed (20-40 ohms means a "slow" ADC), in this case rnpoly (high resistance, 160-180 oh./sq.) has the best matching.

 

[jiangwp]

The criterial aspects are as below:

1. sheet value percent square;

2. temperature coeffecient;

3. voltage coeffecient;

4. the offect of comparator;

5. the speed of adc;

6. area or matching;

 

[tuza2000]

i use the 20-40 ohm resistance because of the kickback noise .

 

[ocarnu]

This makes it worse, isn't it? You don't have preamps? Is the middle of the ladder decoupled?

 

[suria3]

Hi Tuza2000,

Can you explain to me what is that "kickback noise"?

regards,
suria3

 

[feier0251]

take care of the vdd and grounding routing
regards