AD7226 Analog Devices, AD7226 Datasheet - Page 10

• Manufacturer Part Number: AD7226
• Description: LC2MOS Quad 8-Bit D/A Converter
• Manufacturer: Analog Devices

AD7226
STAIRCASE WINDOW COMPARATOR
In many test systems, it is important to be able to determine
whether some parameter lies within defined limits. The staircase
window comparator of Figure 18a is a circuit which can be
used, for example, to measure the V
TTL device under test. Upper and lower limits on both V
and V
jacent pair of comparators forms a window of programmable
size. If V
dow will be high. With a reference of +2.56 V applied to the
V
The circuit can easily be adapted to allow for overlapping of
windows as shown in Figure 19a. If the three outputs from this
circuit are decoded then five different nonoverlapping program-
mable windows can again be defined.
REF
input, the minimum window size is 10 mV.
OL
TEST
can be programmably set using the AD7226. Each ad-
Figure 18a. Logic Level Measurement
lies within a window then the output for that win-
Figure 18b. Window Structure
OH
and V
OL
thresholds of a
OH
–10–
VARYING REFERENCE SIGNAL
In some applications, it may be desirable to have a varying sig-
nal applied to the reference input of the AD7226. The AD7226
has multiplying capability within upper and lower limits of refer-
ence voltage when operated with dual supplies. The upper and
lower limits are those required by the AD7226 to achieve its lin-
earity specification. Figure 20 shows a sine wave signal applied
to the reference input of the AD7226. For input signal frequen-
cies up to 50 kHz the output distortion typically remains less
than 0.1%. Typical 3 dB bandwidth figure is 700 kHz.
Figure 20. Varying Reference Signal
Figure 19a. Overlapping Windows
Figure 19b. Window Structure
REV. A