Analogic / Digital converter

Analogic / Digital converter This integrated circuit (AD 7821) allows to convert an analogic signal in a 8 bits value with a 1 µs conversion time, thus with a 1 MHz frequency. There are faster converters allowing to obtain a better resolution (10, 12, 14 or 16 bits).
Pin Assignments for AD7821 Input Data bit 3 Data bit 2 Data bit 1 Data bit 0 WR/RDY Mode RD INT Ground Vref - Vref + CS Data bit 4 Data bit 5 Data bit 6 Data bit 7 OFL Vss +Vcc		Components List Pot. : P1 = 20 kΩ A/D Converter = AD7821 trigger inverter = 1/4 CD4093
The signal resulting from the amplifier is applied to the pin 1 (Input). The reference voltage is adjusted by means of P1. It is very summary but that works. We can also use a specific component to obtain this reference voltage (zener diode for ex.). The pulse "start of conversion" results from the clock generator (having a 5 V level compatible with the converter) and the pulse "End of conversion" is sent to the PC interface, as well as 8 bits data. We can also send these data through buffer circuits (74245 by eg) to secure the exchanges interface-converter. The logic gate (1/4 CD4093) can be another inverter.