AD7628KRZ Analog Devices Inc, AD7628KRZ Datasheet - Page 7

• Manufacturer Part Number: AD7628KRZ
• Description: IC DAC 8BIT DUAL W/BUFF 20-SOIC
• Manufacturer: Analog Devices Inc

Specifications of AD7628KRZ

• Settling Time: 400ns
• Number Of Bits: 8
• Number Of Converters: 2
• Voltage Supply Source: Single Supply
• Power Dissipation (max): 450mW
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 20-SOIC (7.5mm Width)
• Resolution (bits): 8bit
• Input Channel Type: Parallel
• Data Interface: Parallel
• Supply Voltage Range - Analogue: 10.8V To 15.75V
• Supply Current: 2mA
• Digital Ic Case Style: SOIC
• No. Of Pins: 20
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

MICROPROCESSOR INTERFACE
PROGRAMMABLE WINDOW COMPARATOR
Figure 13. Digitally Programmable Window Comparator
(Upper and Lower Limit Detector)
PROGRAMMABLE STATE VARIABLE FILTER
REV. A
In this state, variable or universal filter configuration (Figure
14) for DACs A1 and B1 control the gain and Q of the filter
characteristic, while DACs A2 and B2 control the cutoff fre-
quency, f
expression for f
AD7628. Op amps are 2
effects of op amp gain-bandwidth limitations.
Figure 11. AD7628 Dual DAC to 6800 CPU Interface
C
. DACs A2 and B2 must track accurately for the simple
C
to hold. This is readily accomplished by the
Figure 14. Digitally Controlled State Variable Filter
AD644. C3 compensates for the
–7–
In the circuit of Figure 13, the AD7628 is used to implement a
programmable window comparator. DACs A and B are loaded
with the required upper and lower voltage limits for the test,
respectively. If the test input is not within the programmed lim-
its, the pass/fail output will indicate a fail (logic zero).
The filter provides low pass, high pass and band pass outputs
and is ideally suited for applications where microprocessor con-
trol of filter parameters is required, e.g., equalizer, tone con-
trols, etc.
Programmable range for component values shown is f
to 15 kHz and Q = 0.3 to 4.5.
Figure 12. AD7628 Dual DAC to 8085 CPU Interface
CIRCUIT EQUATIONS
C
f
Q =
A
NOTE
DAC equivalent resistance equals
C
256
O
1
=
= C
= –
2 R
R
R
DAC Digital Code
3
4
2
DAC Ladder resistance
, R
. R
R
1
R
1
R
F
S
C
FBB1
1
1
F
= R
AD7628
2
, R
C
4
= 0 kHz
= R
5