AD8600AP-REEL Analog Devices Inc, AD8600AP-REEL Datasheet - Page 11

• Manufacturer Part Number: AD8600AP-REEL
• Description: IC DAC MULT 16CH 8BIT 44-PLCC
• Manufacturer: Analog Devices Inc

Specifications of AD8600AP-REEL

• Rohs Status: RoHS non-compliant
• Settling Time: 1µs
• Number Of Bits: 8
• Data Interface: Parallel
• Number Of Converters: 16
• Voltage Supply Source: Analog and Digital, Dual ±
• Power Dissipation (max): 175mW
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 44-PLCC

REV. 0
Unipolar Output Operation
The AD8600 is configured to give unipolar operation. The full-
scale output voltage is equivalent to the reference input voltage
minus 1 LSB. The output is dependent upon the digital code
and follows Table III. The actual numbers given for the analog
output are calculated assuming a +2.5 V reference.
DAC
Binary Input
MSB
1 1 1 1 1 1 1 1
1 0 0 0 0 0 0 1
1 0 0 0 0 0 0 0
0 1 1 1 1 1 1 1
0 0 0 0 0 0 0 1
0 0 0 0 0 0 0 0
Bipolar Output Operation
The AD8600 can be configured for bipolar operation with the
addition of an op amp for each output as shown in Figure 20.
The output will now have a swing of V
IV. This modification is only needed on those channels that re-
quire bipolar outputs. For channels which only require unipolar
output, no external amplifier is needed. The OP495 quad am-
plifier is chosen for the external amplifier because of its low
power, rail-to-rail output swing, and DC accuracy. Again, the
values calculated for the analog output are based upon an as-
sumed +2.5 V reference.
Figure 20. Circuit for Bipolar Output Operation
LSB
AD8600
Table III. Unipolar Code Table
V
V
REF
REF
10k
R1
Analog Output
+V
+V
+V
+V
+V
+V
OUT
REF
REF
REF
REF
REF
REF
ø
(255/256) = +2.49 V
(129/256) = +1.26 V
(128/256) = +1.25 V
(127/256) = +1.24 V
(001/256) = +0.01 V
(000/256) = +0.00 V
OP495
1/4
+5V
–5V
10k
R1
REF
, as detailed in Table
V
OUT
–11–
DAC
Binary Input
MSB
1 1 1 1 1 1 1 1 +2 V
1 0 0 0 0 0 0 1 +2 V
1 0 0 0 0 0 0 0 +2 V
0 1 1 1 1 1 1 1 +2 V
0 0 0 0 0 0 0 1 +2 V
0 0 0 0 0 0 0 0 +2 V
Interfacing to the 68HC11 Microcontroller
The 68HC11 is a popular microcontroller from Motorola,
which is easily interfaced to the AD8600. The connections be-
tween the two components are shown in Figure 21. Port C of
the 68HC11 is used as a bidirectional input/output data port to
write to and read from the AD8600. Port B is used for address-
ing and control information. The bottom 4 LSBs of Port B are
the address, and the top 4 MSBs are the control lines (LD, CS,
EN, and R/W). The microcode for the 68 HC11 is shown in
Figure 22. The comments in the program explain the function
of each step. Three routines are included in this listing: read
from the AD8600, write to the AD8600, and a continuous loop
that generates a saw-tooth waveform. This loop is used in the
application below.
Figure 21. Interfacing the 68HC11 to the AD8600
DIGITAL GROUND
MOTOROLA
68HC11
GND
LSB Analog Output
PC0–PC7
PB0–PB3
Table IV. Bipolar Code Table
PB4
PB5
PB6
PB7
REF
REF
REF
REF
REF
REF
4
(255/256) – V
(129/256) – V
(128/256) – V
(127/256) – V
(001/256) – V
(000/256) – V
8
DB0–DB7
A0–A3
LD
EN
R/W
CS
REF
REF
REF
REF
REF
REF
ANALOG GROUND
DGND1, DGND2
= –0.02 V
= –2.48 V
= –2.50 V
= +2.49 V
= +0.02 V
= +0.00 V
DACGND
AD8600
AD8600