AD7839 Analog Devices, AD7839 Datasheet - Page 8

• Manufacturer Part Number: AD7839
• Description: Octal 13-Bit, Parallel Input, Voltage-Output D/A Converter
• Manufacturer: Analog Devices

Specifications of AD7839

• Resolution (bits): 13bit
• Dac Update Rate: 33kSPS
• Dac Settling Time: 30µs
• Max Pos Supply (v): +15.75V
• Single-supply: No
• Dac Type: Voltage Out
• Dac Input Format: Par

AD7839
Unipolar Configuration
Figure 11 shows the AD7839 in the unipolar binary circuit
configuration. The V
AD586, a +5 V reference. V
gives the code table for unipolar operation of the AD7839.
Other suitable references include the REF02, a precision +5 V
reference, and the REF195, a low dropout, micropower preci-
sion +5 V reference.
Offset and gain may be adjusted in Figure 11 as follows: To
adjust offset, disconnect the V
DAC with all 0s and adjust the V
For gain adjustment, the AD7839 should be loaded with all 1s
and R1 adjusted until V
8192) = 9.99878 V.
Many circuits will not require these offset and gain adjustments.
In these circuits R1 can be omitted. Pin 5 of the AD586 may be
left open circuit and Pin 2 (V
Binary Number in DAC Register
MSB
NOTES
V
For V
Bipolar Configuration
Figure 12 shows the AD7839 set up for 10 V operation. The
AD588 provides precision 5 V tracking outputs that are fed to
the V
for bipolar operation of the AD7839 is shown in Table III.
In Figure 12, full-scale and bipolar zero adjustments are pro-
vided by varying the gain and balance on the AD588. R2 varies
the gain on the AD588 while R3 adjusts the offset of both the
+5 V and –5 V outputs together with respect to ground.
For bipolar-zero adjustment, the DAC is loaded with
1000 . . . 0000 and R3 is adjusted until V
scale is adjusted by loading the DAC with all 1s and adjusting
R2 until V
1
1
0
0
0
REF
= V
REF
1 F
REF
C1
REF
(+) = +5 V, 1 LSB = +10 V/2
1111
0000
1111
0000
0000
(+) and V
Table II. Code Table for Unipolar Operation
(+); V
8
OUT
Figure 11. Unipolar +10 V Operation
SIGNAL
AD586
GND
REF
= 10(4095/4096) V = 9.997559 V.
4
2
*ADDITIONAL PINS OMITTED FOR CLARITY
(–) = 0 V for unipolar operation.
1111
0000
1111
0000
0000
REF
6
5
REF
(–) inputs of the AD7839. The code table
OUT
(+) input of the DAC is driven by the
R1
10k
LSB
1111
0000
1111
0001
0000
REF
= 2 V
REF
REF
V
V
13
(–) is tied to ground. Table II
REF
REF
REF
(–)) of the AD7839 tied to 0 V.
+15V
= +10 V/8192 = 1.22 mV.
V
(–) input from 0 V, load the
AD7839*
REF
DD
(+)
(–)
(–) voltage until V
–15V
V
(+) – 1 LSB = 10 V(8191/
SS
DUTGND
+5V
V
CC
V
GND
Analog Output
(V
2 V
2 V
2 V
2 V
0 V
OUT
OUT
OUT
REF
REF
REF
REF
= 0 V. Full
)
SIGNAL
(8191/8192) V
(4096/8192) V
(4095/8192) V
(1/8192) V
GND
V
(0 TO +10V)
OUT
OUT
= 0 V.
–8–
When bipolar-zero and full-scale adjustment are not needed, R2
and R3 can be omitted. Pin 12 on the AD588 should be con-
nected to Pin 11 and Pin 5 should be left floating.
Binary Number in DAC
Register
MSB
1
1
1
0
0
0
NOTES
V
For V
20 V/8192 = 2.44 mV.
CONTROLLED POWER-ON OF THE OUTPUT STAGE
A block diagram of the output stage of the AD7839 is shown in
Figure 13. It is capable of driving a load of 5 k in parallel with
50 pF. G
power on voltage present at V
also used in conjunction with the CLR input to set V
user defined voltage present at the DUTGND pin. When CLR
is taken back high, the DAC outputs reflect the data in the DAC
registers.
100k
REF
R2
= (V
Figure 13. Block Diagram of AD7839 Output Stage
REF
100k
1111 1111
0000 0000
0000 0000
1111 1111
0000 0000
0000 0000
(+) = +5 V, and V
REF
DAC
R3
Table III. Code Table for Bipolar Operation
1 F
1
(+) – V
C1
to G
Figure 12. Bipolar 10 V Operation
10
11
7
9
5
6
REF
12 8 13
are transmission gates used to control the
G
G
*ADDITIONAL PINS OMITTED FOR CLARITY
(–)).
1
AD588
2
4
1111
0001
0000
1111
0001
0000
REF
DUTGND
LSB
6
39k
R
(–) = –5 V, V
R1
2
3
1
14
15
16
G
4
OUT
Analog Output
(V
2[V
2[V
2[V
2[V
2[V
2[V
G
G
V
V
R = 60k
3
5
OUT
. On power up G
REF
REF
REF
REF
REF
REF
REF
REF
+15V
REF
V
AD7839*
(+)
(–)
DD
14k
)
(–) + V
(–) + V
(–) + V
(–) + V
(–) + V
(–)] V
–15V
= 10 V, 1 LSB = 2 V
V
SS
DUTGND
G
+5V
6
V
CC
V
GND
OUT
REF
REF
REF
REF
REF
(8191/8192)] V
(4097/8192)] V
(4096/8192)] V
(4095/8192)] V
(1/8192)] V
SIGNAL
1
GND
and G
V
(–10V TO +10V)
OUT
OUT
V
OUT
REF
REV. 0
to the
V/2
2
are
13
=