ADC 0808



ADC0808 is an 8 bit analog to digital converter with eight input analog channels, i.e., it can take eight different analog inputs. The input which is to be converted to digital form can be selected by using three address lines. The voltage reference can be set using the Vref+ and Vref- pins. The step size is decided based on set reference value. Step size is the change in analog input to cause a unit change in the output of ADC. The default step size is 19.53mV corresponding to 5V reference voltage. ADC0808 needs an external clock to operate unlike ADC0804 which has an internal clock. The ADC needs some specific control signals for its operations like start conversion and bring data to output pins. When the conversion is complete the EOC pins goes low to indicate the end of conversion and data ready to be picked up.




Pin Description: 


 Pin No  Function  Name
1 Analog input pins IN3
2 IN4
3 IN5
4 IN6
5 IN7
6 Start conversion; input pin; a low to high pulse is given SC
7 End of conversion; output pin; goes low when the conversion is over EOC
8 Digital output bit 4 D3
9 Input pin; a low to high pulse brings data to output pins from the internal registers at end of conversion Output enable
10 Clock input; to provide external clock Clock input
11 Supply voltage; 5V Vcc
12 Positive reference voltage Vref(+)
13 Ground ()v) GND
14 Digital output bit D1
15 D2
16 Negative reference voltage Vref(-)
17 Digital output bits D0
18 D4
19 D5
20 D6
21 D7
22 Address latch enable; Input pin; low to high pulse is required to latch in the address ALE
23 Address lines AddressC
24 AddressB
25 AddressA
26 Analog inputs IN0
27 IN1
28 IN2


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