Contents
What are ADC inputs?
An ADC converts a continuous-time and continuous-amplitude analog signal to a discrete-time and discrete-amplitude digital signal. The conversion involves quantization of the input, so it necessarily introduces a small amount of error or noise.
What is ADC input range?
The ADC range is the maximum and minimum ADC input (e.g., 0 to +3.3V). The resolution is the change in input that causes the digital output to change by 1. Range(volts) = Precision(alternatives) • Resolution(volts) Figure 14.4. A 12-bit ADC converts 0 to 3.3V on its input into a digital number from 0 to 4095.
What is input protection?
Input protection is implemented in power supplies and DC-DC converters to ensure safe operation. The input fuse fitted within a power supply is not intended to be field-replaceable, it is rated such that only a catastrophic failure of the power supply will cause it to fail.
What is output overvoltage protection?
Over voltage protection is a power supply feature which shuts down the supply, or clamps the output, when the voltage exceeds a preset level. Most power supplies use an over-voltage protection circuit to prevent damage to the electronic components.
What is the difference between analog and digital inputs?
Digital input signals are used to represent items that only have two (2) states, such as… So, a digital signal is something like telling if a door is open or not. Analog signals are variable, they have multiple states. Analog input signals can represent such items as temperature or level or rate of flow.
How to protect ADC inputs from overvoltage?
A common issue that arises when designing an ADC circuit is how to protect the ADC inputs from overvoltage. The protection of ADC inputs has many scenarios and potential solutions. ADCs from all vendors have similar needs in this respect.
How does the series resistor protect the ADC?
The series resistor after the Schottky diodes also helps limit the current into the ADC if the internal diodes turn on slightly. For extra protection, if the reference has little to no sink current capability, a Zener diode or clamp circuit could be used on the reference node to guarantee the reference voltage cannot be pulled too high.
Can a strong driver circuit damage an ADC?
If the REF node is not driven by a strong driver circuit, then the voltage at the REF node (and input) will rise above the absolute maximum rated voltage and the ADC may be damaged if the voltage exceeds the breakdown voltage of devices on that process.
When does overdrive of ADC inputs take place?
Overdrive of ADC inputs generally occurs when the rails of the driving amplifier are significantly greater than the max input range of the ADC—for example, if the amplifier runs from ±15 V and the ADC input is 0 V to 5 V.