ADC0804 is an 8-bit analog to digital converter IC which can measure up to 8 analog input simultaneously. That means the digital output value can vary between 0 to 255. It uses a successive approximation converter which is based on the differential potentiometric ladder.
Every device cannot perform each and every operation. There are always different devices that can perform the different operations and convert them for other devices to perform another’s function. The basic problem we face is the translation of data between these devices.
In Electronics Most of the time, different methods of communication between different devices were invented so different devices could perform efficiently with two or multiple different objects and devices.
Why Do We Need to Use ADC?When it comes to real-life or we can say in the time domain the output of different events can always represent in mathematical form or mathematical values. These mathematics values are always in continuous form. In other words, we can say these values always have starting and ending point but between these two points, they have infinite values.
These analog values are easy to read in the time domain (real life). When it comes to machines or electronic devices most of them are unable to read them properly. They could read their starting or may ending point but most of the cases they are unable to read them properly. Machines and Electronic devices always perform their operations in the “frequency domain”. To solve this kind of issues we usually use Analog to Digital Converters (ADC).
ADC0804 IntroductionThere are multiple kinds of Analog to Digital Converters (ADC) which are used to convert the analog signal for microprocessors or controllers. Every “ADC” has its own specification and advantages on the basis of the requirement. Here we are going to discuss “ADC0804 IC” which is known as the low voltage 8-bit analog to Digital Converter.
ADC0804 is a low voltage IC use to convert the low voltage analog signal to an 8-bit digital signal. It works with 0-5 Volts, has 1 Analog input and 8 output pins. ADC0804 comes with an internal clock but to increase or change the clock cycle we could use the external clock. Always keep in mind that conversion speed cannot be faster than 110us either we are using an internal clock or external clock.
Internal CircuitLike other electronic devices ADC0804 also has a little complex internal circuit. ADC0804 translates the analog signal to Digital but to convert the analog signal it uses Gates, Flipflops, Shift Register, Tristate, Clock, latch and Ladder and Decoder, etc. But the main components used in ADC0804 to convert the signal is SAR Latch.
SAR Latch converts continuous analog signal to digital signal/discrete signal through a binary search by using all possible quantization/mapping levels. Other components in “ADC0804” like tri-state, 8-bit shifter, etc are used to give the proper output according to the given input. Tri-state is an internal register that is used to hold the data until a high to low pulse is given. An 8-bit shift register is used to give the output in a sequence so other devices could read in the form of 8-bits.
ADC0804 ADC PinoutThe followin picture shows the pinout diagram of ADC0804. It consists of 20 pins.
Pin ConfigurationADC0804 could be used at any point where we are receiving an analog value with a Potential Difference of 2.5 – 6.5. To use the ADC0804 there are some rules and regulations which we need to follow. DC power source of 5 volts will be attached to the Vcc and GND will be attached to the ground pin.
To turn the device ON apply the ground at the CS pin. Also, to make the device readable and writeable for data also apply the ground at RD and WR pin. To use the internal Clock just use the RC circuit with a 10K resistor and 100pF capacitance at the clock pin. By using these standards ADC0804 will be able to operate.
Example Circuit ProteusHere is an example circuit of how ADC0804 in proteus. This example circuit could be used to convert the voltages into a digital value. First, complete the basic circuit as mentioned above of ADC0804 and then follow these instructions.
At the end you will get the following circuit:
After completing the circuit run it and see the output.
Whenever voltage will be change using variable resistor than it will show the value in Binary form.
Here we are getting the value of “11001100” by giving 4 volts at the input.
Converting binary to Digital:
(11001100) ₂ = (1 × 2⁷) + (1 × 2⁶) + (0 × 2⁵) + (0 × 2⁴) + (1 × 2³) + (1 × 2²) + (0 × 2¹) + (0 × 2⁰) = 204
Analogue value = Step size x Decimal Value
Step Size: When Vref = 5V, for every 19.53mV increase in analogous value cause the increase in one bit on digital side.
Analogue Value = 19.53 x 51 = 393.7mV = 3.9
The actual voltage we are getting after digital conversion is 3.9 and the voltage on the input, we are getting is 4 which is close to the digital voltage. The voltage conversion is the only single example. There are many more applications in real life in which ADC0804 could be used to perform operations. Like temperature sensors, heat sensors, etc. For real example check this article:
ApplicationsIf you want to know about types of ADCs, you can read these articles:
Other ADC and DAC IC’s:
HX711, ICL7107, ADS1115, DAC0808, DAC0832
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