Question

For a 10-bit digital ramp ADC using 500 kHz clock, the maximum conversion time is
1. 2048 μs
2. 2064 μs
3. 2046 μs
4. 2084 μs

Answer 1

Correct Answer - Option 3 : 2046 μs

Concept:

Digital ramp ADC conversion time is given as:

 \(= \left( {{2^N} - 1} \right){T_{clk}} \)

Given:

n = 10

f = 500 kHz

Analysis:

\({T_{clk}} = \frac{1}{{500\; \times \;{{10}^3}}}\) 

= 2 μs

Conversion time = (2^N – 1) T_clk

= (1024 - 1) × 2 μs = 2046 μs

 

The conversion time of different types of n-bit ADC is shown :

Type of ADC	No. of Clocks	Time
Counter Type	2n-1	2n-1 Tclk
SAR (Successive Approximation Register)	n	n Tclk
Flash (Parallel comparator)	1	Tclk
Dual Slope	2n+1	2n+1 Tclk