AD736-EVALZ Analog Devices Inc, AD736-EVALZ Datasheet - Page 14

• Manufacturer Part Number: AD736-EVALZ
• Description: BOARD EVALUATION FOR AD736
• Manufacturer: Analog Devices Inc

Specifications of AD736-EVALZ

• Main Purpose: Interface, RMS to DC Converters
• Utilized Ic / Part: AD736
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Secondary Attributes: -
• Embedded: -
• Primary Attributes: -

AD736
SELECTING PRACTICAL VALUES FOR INPUT
COUPLING (C
(C
Table 5 provides practical values of C
common applications.
The input coupling capacitor, C
8 kΩ internal input scaling resistor, determine the −3 dB
low frequency roll-off. This frequency, F
Table 5. Capacitor Selection Chart
Application
General-Purpose RMS Computation
General Purpose
Average
Responding
SCR Waveform Measurement
Audio Applications
1
Settling time is specified over the stated rms input level with the input signal increasing from zero. Settling times are greater for decreasing amplitude input signals.
Speech
Music
F
) CAPACITORS
F
L
=
2π
(8000)(
C
), AVERAGING (C
Value
AC COUPLING
CAPACITOR
V
900kΩ
OPTIONAL
1
IN
90kΩ
10kΩ
9MΩ
of
C
C
C
, in conjunction with the
0.01µF
1kV
in
Farads
200mV
2V
20V
200V
AV
AV
and C
L
47kΩ
, is equal to
RMS Input Level
0 V to 1 V
0 mV to 200 mV
0 V to 1 V
0 mV to 200 mV
0 mV to 200 mV
0 mV to 100 mV
0 mV to 200 mV
0 mV to 100 mV
), AND FILTERING
1W
)
–V
S
Figure 25. AD736 with a High Impedance Input Attenuator
+V
–V
F
S
S
for several
1N4148
1N4148
C
C
V
–V
C
IN
1µF
F
S
1
2
3
4
8kΩ
Rev. H | Page 14 of 20
SECTION
BIAS
Low Frequency
Cutoff (−3 dB)
20 Hz
200 Hz
20 Hz
200 Hz
20 Hz
200 Hz
20 Hz
200 Hz
50 Hz
60 Hz
50 Hz
60 Hz
300 Hz
20 Hz
AMPLIFIER
INPUT
RECTIFIER
CORE
rms
Note that at F
( – 3 dB) of the reading. To reduce this error to 0.5% of the
reading, choose a value of C
lowest frequency to be measured.
In addition, if the input voltage has more than 100 mV of dc
offset, then the ac-coupling network shown in Figure 27 should
be used in addition to C
WAVE
10µF
33µF
10µF
+
FULL
C
C
C
AV
C
F
+
+
(OPTIONAL)
(OPTIONAL)
Max Crest
Factor
5
5
5
5
5
5
5
5
3
10
AD736
AMPLIFIER
8kΩ
OUTPUT
L
, the amplitude error is approximately −30%
8
7
6
C
5
+V
OUTPUT
AV
S
C
C
(μF)
150
15
33
3.3
None
None
None
None
100
82
50
47
1.5
100
COM
.
AV
C
1µF
that sets F
+V
OUTPUT
S
C
(μF)
10
1
10
1
33
3.3
33
3.3
33
27
33
27
0.5
68
F
L
Settling Time
360 ms
36 ms
360 ms
36 ms
1.2 sec
120 ms
1.2 sec
120 ms
1.2 sec
1.0 sec
1.2 sec
1.0 sec
18 ms
2.4 sec
at one-tenth of the
1
to 1%