AD7398 Analog Devices, AD7398 Datasheet - Page 18

• Manufacturer Part Number: AD7398
• Description: Quad, Serial-Input 12-Bit DAC
• Manufacturer: Analog Devices

Specifications of AD7398

• Resolution (bits): 12bit
• Dac Update Rate: 167kSPS
• Dac Settling Time: 6µs
• Max Pos Supply (v): +5.5V
• Single-supply: Yes
• Dac Type: Voltage Out
• Dac Input Format: Ser,SPI

AD7398/AD7399
APPLICATIONS INFORMATION
STAIRCASE WINDOWS COMPARATOR
Many applications need to determine whether voltage levels are
within predetermined limits. Some requirements are for
nonoverlapping windows and others for overlapping windows.
Both circuit configurations are shown in Figure 33 and
Figure 34, respectively.
V
REF
Figure 33. Nonoverlapping Windows Comparator
V
V
V
V
REF
REF
REF
REF
Figure 34. Nonoverlapping Windows Range
AD7398/
AD7399
A
B
C
D
GND
V
DD
V
V
V
V
OUT
OUT
OUT
OUT
V
GND
V
V
V
V
REF
OUT
OUT
OUT
OUT
A
B
C
D
A
B
C
D
WINDOW 1
WINDOW 2
WINDOW 3
WINDOW 4
WINDOW 5
V
TEST
AD8564
AD8564
AD8564
1/2
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
+
–
V+
10kΩ
V+
10kΩ
V+
10kΩ
V+
10kΩ
V+
10kΩ
WINDOW 1
WINDOW 2
WINDOW 3
WINDOW 4
WINDOW 5
Rev. C | Page 18 of 24
The nonoverlapping circuit employs one AD7398/AD7399 and
ten comparators to achieve five voltage windows. These windows
range between V
Similarly, the overlapping circuit employs six comparators to
achieve three overlapping windows (see Figure 36).
V
REF
V
V
V
V
Figure 35. Overlapping Windows Comparator
REF
REF
REF
REF
AD7398/
AD7399
V
V
V
V
Figure 36. Overlapping Windows Range
A
B
C
D
REF
OUT
OUT
OUT
OUT
V
GND
GND
V
REF
DD
and analog ground as shown in Figure 34.
B
A
D
C
V
V
V
V
OUT
OUT
OUT
OUT
A
B
C
D
V
TEST
WINDOW 2
AD8564
AD8564
WINDOW 1
WINDOW 3
+
–
+
–
+
–
+
–
1/2
+
–
+
–
V+
10kΩ
V+
10kΩ
V+
10kΩ
WINDOW 1
WINDOW 2
WINDOW 3