ADC17I_15 Datasheet, PDF (1/2 Pages) Analog Devices – DUAL SLOPE A/D CONVERTERS

DUAL SLOPEAID CONVERTERS
ADC-14I, A'DC-17I, ADCIIOO
GENERAL DESCRIPTION
Dual slope integrating AID converters perform a conversion by
first integrating the input signal for.a fixed period of time, and
then measuring the time required to return the integrator to
OBSOLETE zero when it is integrated in the opposite direction with a
fixed reference 'Signal. A major benefit of this technique is that
it results in very high rejection of normal mode noise when the
signal integration time period is set equal to one cycle of the
power line.
ADC-141 and ADC-171
These two high resolution converters are identical except for
output coding. The ADO-141 has 14-bit binary plus sign coding,
while the ADC-171 has 4Y2digits plus sign output coding. Both
feature a normal mode rejection ratio of 70dB; an aut9matic
zero correction cycle, and a gainTC of only :!:10ppm/uC.
ADCllOO
The ADCll00 is a new dual slope AID converter in a compact
2" x 4" x 0.4" module. It can be triggered externally, or inter-
nally at a rate of about 4 conversions/sec, or it can be wired to
start a new conversion'when the conversion in progress is com-
pleted. It is ideal for driving a display, or feeding data .to a
computer, or for doing both jobs simultaneously. Since it re-
quires only +5V power, and has a normal mode noise rejection
ratio of 40dB minimum, it is a natural choice for installation
at transducer locations.
BLOCK DIAGRAM
ADC-141 & ADC-171
BLOCK DIAGRAM
ADCllOO
72 INPUT
POLAR ITV
1
2
~OAO
-
3
4
0 ~RRANGE
'"aooo--
5
""4000
6
~--
7
B
9
10
11
12
13
~0--- 1B00O0O
400
o ,c,o
<0->-
0--
TB"OOo-
-
,==~II
II
40
14
0-------
15
D ²₁'⁰-₀'-- -
16
17
0o
,,~
4
-~ ^u
1B _{0 ,- --}
19
0---,-'"
~-
20
0--~----
RAMP DOWN
21
0 SIATUS -~
-,,-_...._-
CONTROL
22
23
24
- ^{~P .~~.:-:-:======--}
~r<
ClOCK OUT
LOGIC
25
26
~V-ERTCM}J- -~1"
48
47
36
REF IN
37
'REF OUT
36
I--~
35
~G-<)
'15V _<>
32
"'-"<>
31
l:2':o
29
~^~~;;'~K~
28
27
NOT[
ON THE ADC 141 PINS 6 ) AND 8 ARf OMITT[ 0 THE MSB IS ON PIN 4 AND BIT 2
IS ON PIN 5 BITS 3 THROUGH 14 AAE ON PINS 9 THROUGH 20 AESPfCTIVELY
HOLD B
POLARITY 9
READY 10
TRIGGER 11
1 14
215
4 16
6 17
DATA
OUTPUTS
1022
20 23
40 24
80 25
100 31
200 32
400 33
BOO 34
1000 35
67 ANALOG GRD
66 OFFSET
65 OVERLOAD
64 REF IN
43 RAMP DOWN
42 FREO. ADJ
40 DIGITAL GRD
39 ClOCK IN
3B CLOCK OUT
---<> I 37 "VDC
N(
1.
2.
3.
94 CONVERTERS