The time it takes in an ADC (Analog-to-Digital Converter) for a sample of an Analog input to be converted to its equivalent Digital value.

Enter:

- Sample and Hold time
- Conversion time

## Formula

**Sampling Time = Conversion time + S/H time**

**Sampling Rate = 1/Sampling Time**

**Example Calculation**

If the S/H time is 10 μs and the Conversion time is 55 μs, then the total sampling time is 65 μs.

The ADC Sampling Rate is 15.4 kHz or 15.4 kSPS.

The value of the input impedance can negatively impact the sample and hold time. Most ADC vendors make recommendations on the maximum value of the input impedance. In the **case of the Arduino **for instance, **Atmel **recommends a max value of **10 kΩ**. Anything higher will increase the settling time and result in an inaccurate reading of the voltage level.

**Related Calculators**

- ADC resolution calculator – the greater the number of bits the higher the voltage resolution
- Sample Rate – at a very basic level, what does this term mean?
- ADC digital output – what’s the bit (1 and 0) equivalent of an analog input for an n-bit ADC?