adc0800pd National Semiconductor Corporation, adc0800pd Datasheet - Page 9

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

Typical Applications
A low speed ramp generator can also be used to sweep the
analog input voltage and the LED outputs will provide a bi-
nary counting sequence from zero to full-scale
The techniques described so far are suitable for an engi-
neering evaluation or a quick check on performance For a
higher speed test system or to obtain plotted data a digital-
to-analog converter is needed for the test set-up An accu-
rate 10-bit DAC can serve as the precision voltage source
for the A D Errors of the A D under test can be provided as
either analog voltages or differences in two digital words
A basic A D tester which uses a DAC and provides the error
as an analog output voltage is shown in Figure 6 The 2 op
amps can be eliminated if a lab DVM with a numerical sub-
traction feature is available to directly readout the difference
voltage ‘‘A – C’’
Connection Diagram
(Continued)
FIGURE 6 A D Tester with Analog Error Output
FIGURE 7 Basic ‘‘Digital’’ A D Tester
See NS Package Number D18A
Order Number ADC0800PD
Dual-In-Line Package
or ADC0800PCD
Top View
9
For operation with a microprocessor or a computer-based
test system it is more convenient to present the errors digi-
tally This can be done with the circuit of Figure 7 where the
output code transitions can be detected as the 10-bit DAC is
incremented This provides
under test If the results of this test are automatically plotted
with the analog input on the X axis and the error (in LSB’s)
as the Y axis a useful transfer function of the A D under
test results For acceptance testing the plot is not neces-
sary and the testing speed can be increased by establishing
internal limits on the allowed error for each code
All R’s
e
0 05% tolerance
TL H 5670 – 9
TL H 5670 – 17
LSB steps for the 8-bit A D
TL H 5670 – 16