3
DATEL, Inc., Mansfield, MA 02048 (USA)
• Tel: (508)339-3000, (800)233-2765 Fax: (508)339-6356 • E–mail: sales@datel.com • Internet: www.datel.com
ADC-30634-30720
®
®
5. The process that is used to fabricate the ADC-
30634/30720 eliminates the latchup phenomena that
has plagued CMOS devices in the past. These
converters do not require external protection diodes.
6. For clock rates less than 100kHz, there may be
some degradation in offset and differential nonlinearity.
Performance may be improved by increasing the clock
duty cycle (decreasing the time spent in the sample
mode).
7. Connect the converter appropriately; a typical
connection circuit is shown in Figure 2. Then apply an
appropriate clock input.The reference input should be
held to ±0.1% accuracy or better. Do not use the +5V
power supply as a reference without precision regulation
and high-frequency decoupling capacitors.
8. Zero Adjustment - Adjusting the voltage at
–REFERENCE (pin 3) adjusts the offset or zero of the
device. Pin 3 can be tied to GROUND for operation
without adjustments
9. Full Scale Adjustment - Adjusting the voltage at
+REFERENCE (pin 9) adjusts the gain of the device. Pin
9 can be tied directly to a +5V reference for operation
without adjustment.
Table 1. ADC-30634/ADC-30720 Output Code
Note:
Values shown here are for a +5.12Vdc reference. Scale other refereces
proportionally. (+REF=+5.12V, –REF=GND, ¼, ½, and ¾ References
FS=No Connection)
10.Integral Nonlinearity Adjustments - Provision is made
for optional adjustment of Integral Nonlinearity through
access of the reference's ¼, ½, and ¾ full scale points.
For example, the REF. MIDPOINT (pin 6) can be tied to
a precision voltage halfway between +REFERENCE and
–REFERENCE. Pins 6, 18 and 20 should be bypassed
to GROUND through 0.1µF capacitors for operation
without INL adjustments
Figure 2. ADC-30634 and ADC-30720 Typical Connection Diagram
ANALOG
DATA
DATA
INPUT
CODE
1234
5678
DECIMAL HEX
0.00V
Zero 0000
0000
0000
0
00
+0.02V
+1 LSB
0000
0001
1
01
+1.28V
+¼ FS
0100
0000
64
40
+2.54V
+½ FS-ILSB
0111
1111
127
7F
+2.56V
+½ FS
1000
0000
128
80
+2.58V
+½ FS+ILSB
1000
0001
129
81
+3.84V
+¾ FS
1100
0000
192
C0
+5.10V
+FS
1111
1111
255
FF
REF. D2
20MHz CLOCK
VIN 5,7
R¾
CLOCK 2
HP2811
+5V
+5V
+15
+15V
+15V
–15
11
20
18
12
+
+
+
+
+
+
+
5
5
6
4
2
2
9
6
7
5
12
13
14
10
8
1
3
10
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
0.1µF
10
Ω
10k
Ω
2k
Ω
1k
Ω
1k
Ω
1k
Ω
1.5k
Ω
1.5k
Ω
2k
Ω
0.1µF
0.01µF
4.7µF
4.7µF
4.7µF
4.7µF
4.7µF
4.7µF
4.7µF
HA-5033
LM324
1+N
1-N
LM324
1+N
1-N
LM324
1+N
1-N
LM324
1+N
1-N
24 (LSB)
23
22
21
17
16
15
14 (MSB)
B8
B7
B6
B5
B4
B3
B2
B1
R¼