Philips Semiconductors
Product data
CMOS 8-bit A/D converters
ADC0803/0804
V
CC
20
V
REF
(5V)
V
REF
R
V
REF
/2
9
FS
OFFSET
ADJUST
DIGITAL
CIRCUITS
ZS
OFFSET
ADJUST
–
+
330
Ω
0.1
µF
TO V
REF
/2
R
ANALOG
CIRCUITS
TO V
IN
(–)
SL00022
Figure 7. Offsetting the Zero Scale and Adjusting the Input
Range (Span)
8
10
NOTE:
The V
REF
/2 voltage is either 1/2 the V
CC
voltage or is that which is forced at Pin 9.
SL00021
Figure 6. Internal Reference Design
+5V
+5V
V
CC
V
IN
(+)
A/D
V
REF
/2
V
IN
(–)
VOLTAGE
REFERENCE
V
REF
/2
V
IN
(–)
2 kΩ
+
+5V
V
CC
V
IN
(+)
10
µF
A/D
2 kΩ
V
REF
/2
100
Ω
+
10
µF
2 kΩ
2 kΩ
a. Fixed Reference
b. Fixed Reference Derived from V
CC
c. Optional Full
Scale Adjustment
SL00023
Figure 8. Absolute Mode of Operation
2002 Oct 17
11
PHILIPS [ NXP SEMICONDUCTORS ]
