ADC0848BCJ National Semiconductor, ADC0848BCJ Datasheet - Page 13

• Manufacturer Part Number: ADC0848BCJ
• Description: IC ADC 8BIT MPU W/MUX OPT 20CDIP
• Manufacturer: National Semiconductor

Specifications of ADC0848BCJ

• Number Of Bits: 8
• Sampling Rate (per Second): 25k
• Data Interface: Parallel
• Number Of Converters: 1
• Power Dissipation (max): 875mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Through Hole
• Package / Case: 20-CDIP (0.300", 7.62mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Other names: *ADC0848BCJ

grounding the V
itive voltage to the V
between actual DC input voltage which is necessary to just
cause an output digital code transition from 0000 0000 to
0000 0001 and the ideal ½ LSB value (½ LSB=9.8 mV for
V
4.2 Full-Scale
The full-scale adjustment can be made by applying a differ-
ential input voltage which is 1 ½ LSB down from the desired
analog full-scale voltage range and then adjusting the mag-
nitude of the V
1111 1110 to 1111 1111.
The full-scale adjustment should be made [with the proper
V
which is given by:
REF
IN
(−) voltage applied] by forcing a voltage to the V
=5.000 V
DC
REF
−
).
input and applying a small magnitude pos-
input for a digital output code changing from
+
input. Zero error is the difference
FIGURE 2. Referencing Examples
b) Absolute with a Reduced Span
IN
(+) input
a) Ratiometric
13
4.3 Adjusting for an Arbitrary Analog Input Voltage
Range
If the analog zero voltage of the A/D is shifted away from
ground (for example, to accommodate an analog input signal
which does not go to ground), this new zero reference should
be properly adjusted first. A V
desired zero reference plus ½ LSB (where the LSB is calcu-
lated for the desired analog span, 1 LSB = analog span/256)
is applied to selected “+” input and the zero reference voltage
at the corresponding “−” input should then be adjusted to just
obtain the 00
where V
V
are ground referenced.)
The V
change from FE
procedure.
MIN
=the low end (the offset zero) of the analog range. (Both
REF
MAX
(or V
=the high end of the analog input range and
HEX
CC
HEX
to 01
) voltage is then adjusted to provide a code
501616
to FF
HEX
HEX
code transition.
. This completes the adjustment
501617
IN
(+) voltage which equals this
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