# What is the role of voltage divider in flash ADC?

## What is the role of voltage divider in flash ADC?

The circuit of a flash A–D converter. A potential divider defines the quantization levels. Each stage of the divider is connected to one input of a comparator and the input signal is applied in parallel to the other input of all the comparators.

## How does flash ADC work?

A flash ADC (also known as a direct-conversion ADC) is a type of analog-to-digital converter that uses a linear voltage ladder with a comparator at each “rung” of the ladder to compare the input voltage to successive reference voltages.

How many comparators are required in a 7 bit flash ADC?

With each additional output bit, the number of required comparators doubles. Considering that eight bits is generally considered the minimum necessary for any practical ADC (255 comparators needed!), the flash methodology quickly shows its weakness.

### What are the limitations of flash ADC?

The main disadvantage of flash ADC is that it need large area and dissipate large amount of power. To overcome this complexity number of comparators are reducing by using multiplexers. Here the multiplexers are used to generate reference voltages.

### Which type of ADC is fastest?

The flash ADC is the fastest type available. A flash ADC uses comparators, one per voltage step, and a string of resistors. A 4-bit ADC will have 16 comparators, an 8-bit ADC will have 256 comparators.

Advantages: 1)It is the fastest type of ADC because the conversion is performed simultaneously through a set of comparators, hence referred as flash type ADC. Typical conversion time is 100ns or less. 2)The construction is simple and easier to design.

Block diagram of Flash ADC The advantage of this converter is the speed with which one conversion can take place. The disadvantage of the Flash ADC is the area and power requirements of the 2 N-1 comparators. The speed is limited by the switching of the comparators and the digital logic.

#### How do you convert ADC to voltage?

ADC has a resolution of one part in 4,096, where 212 = 4,096. Thus, a 12-bit ADC with a maximum input of 10 VDC can resolve the measurement into 10 VDC/4096 = 0.00244 VDC = 2.44 mV. Similarly, for the same 0 to 10 VDC range, a 16-bit ADC resolution is 10/216 = 10/65,536 = 0.153 mV.

Analog to Digital Converter (ADC) is an electronic integrated circuit used to convert the analog signals such as voltages to digital or binary form consisting of 1s and 0s. Most of the ADCs take a voltage input as 0 to 10V, -5V to +5V, etc., and correspondingly produces digital output as some sort of a binary number.

## What is the reference voltage of a flash ADC?

Figure 1 shows a typical flash ADC block diagram. For an N-bit converter, the circuit employs 2 N -1 comparators. A resistive-divider with 2 N resistors provides the reference voltage. The reference voltage for each comparator is one least significant bit (LSB) greater than the reference voltage for the comparator immediately below it.

How does a 3 bit flash ADC circuit work?

It is formed of a series of comparators, each one comparing the input signal to a unique reference voltage. The comparator outputs connect to the inputs of a priority encoder circuit, which then produces a binary output. The following illustration shows a 3-bit flash ADC circuit:

### Which is the fastest type of flash ADC?

Flash ADC Applications Flash analog to digital converter is the fastest type of ADC among all the other ADCs. It is also known as a parallel analog to digital converter. It comprises high-speed comparators, resistive voltage divider circuits along with a priority encoder.

### How is a priority encoder circuit formed in flash ADC?

It is formed of a series of comparators, each one comparing the input signal to a unique reference voltage. The comparator outputs connect to the inputs of a priority encoder circuit, which then produces a binary output.