AD7523, AD7533
Offset Adjustment
1. Adjust V
REF
to approximately +10V.
2. Connect all digital inputs to “Logic 1”.
3. Adjust I
OUT2
amplifier offset adjust trimpot for 0V
±1mV
at
I
OUT2
amplifier output.
4. Connect MSB (Bit 1) to “Logic 1” and all other bits to “Logic 0”.
5. Adjust I
OUT1
amplifier offset adjust trimpot for 0V
±1mV
at
V
OUT
.
Gain Adjustment
1. Connect all digital inputs to V+.
2. Monitor V
OUT
for a -V
REF
(1 - 2
-9
) volts reading.
3. To increase V
OUT
, connect a series resistor of up to 250Ω
between V
OUT
and R
FEEDBACK
.
4. To decrease V
OUT
, connect a series resistor of up to 250Ω
between the reference voltage and the V
REF
terminal.
CALIBRATE
10K
4.7K
6.8V
(2)
+15V
V
DD
NC
1K
-
A2
6
+
10K 1%
10K 1%
SQUARE
WAVE
MSB
DIGITAL FREQUENCY
CONTROL WORD
LSB
15
4
14
16
C1
1
2
OUT1
OUT2
AD7523/
AD7533
13
3
-
A1
6
+
TRIANGULAR
WAVE
FIGURE 5. PROGRAMMABLE FUNCTION GENERATOR
V
REF
+15V
V
IN
R
FB
16
14
2
4
AD7523/
AD7533
1
11
15
3
BIT 1
MSB
LSB
DIGITAL
INPUT
“D”
BIT 1
MSB
DIGITAL
INPUT
“D”
15
4
+15V
R1
OUT2
-
6
+
R2
V
OUT
14 16
OUT1
BIT 8 (10) (AD7533)
AD7523/
AD7533 1
LSB
13
3
2
-
6
+
V
REF
BIT 8
(10) (AD7533)
-
6
+
V
OUT
V
OUT
= -V
IN/D
Where:
Bit 8
Bit 1 Bit 2
D
= ------------- + ------------- +
…
-------------
2
2
1
2
2
2
0
≤
D
≤
255
---------
-
256
FIGURE 6. DIVIDER (DIGITALLY CONTROLLED GAIN)
R2
R1 D
VO UT
=
V REF
---------------------
–
---------------------
-
-
R1
+
R2
R1
+
R2
Bit 8
Bit 1 Bit 2
-
Where D
= ----------- + ----------- +
…
-----------
-
-
8
1
2
2
2
2
0
≤
D
≤
255
---------
-
256
FIGURE 7. MODIFIED SCALE FACTOR AND OFFSET
10-14
INTERSIL [ INTERSIL CORPORATION ]
