adc0800pd National Semiconductor Corporation, adc0800pd Datasheet - Page 8

• Manufacturer Part Number: adc0800pd
• Description: 8-bit A/d Converter
• Manufacturer: National Semiconductor Corporation

Typical Applications
The digital output LED display can be decoded by dividing
the 8 bits into the 4 most significant bits and 4 least signifi-
cant bits Table I shows the fractional binary equivalent of
these two 8-bit groups By adding the decoded voltages
which are obtained from the column ‘‘Input Voltage Value
with a 10 240 V
value of the digital display can be determined For example
for an output LED display of ‘‘1011 0110’’ or ‘‘B6’’ (in hex)
the voltage values from the table are 7 04
HEX
E
D
C
B
A
F
9
8
7
6
5
4
3
2
1
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
BINARY
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
REF
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
’’ of both the MS and LS groups the
FIGURE 5 Error Plot of a Perfect A D Showing Effects of Quantization Error
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1 2
3 4
1 4
TABLE I DECODING THE DIGITAL OUTPUT LEDs
MS GROUP
(Continued)
FRACTIONAL BINARY VALUE FOR
7 8
5 8
3 8
1 8
a
15 16
13 16
11 16
9 16
7 16
5 16
3 16
1 16
0 24 or
1 32
8
7 280 V
ues of a perfect A D converter The input voltage has to
change by
ty’’ of an A D to obtain an output digital code change The
effects of this quantization error have to be accounted for in
the interpretation of the test results A plot of this natural
error source is shown in Figure 5 where for clarity both the
analog input voltage and the error voltage are normalized to
LSBs
3 64
1 64
LS GROUP
DC
g
7 128
5 128
3 128
1 128
These voltage values represent the center val-
LSB (
15 256
13 256
11 256
g
9 256
7 256
5 256
3 256
1 256
20 mV) the ‘‘quantization uncertain-
TL H 5670 – 8
MS GROUP
9 600
8 960
8 320
7 680
7 040
6 400
5 760
5 120
4 480
3 840
3 200
2 560
1 920
1 280
0 640
0
INPUT VOLTAGE
VALUE WITH
10 24 V
REF
LS GROUP
0 600
0 560
0 520
0 480
0 440
0 400
0 360
0 320
0 280
0 240
0 200
0 160
0 120
0 080
0 040
0