AD713 Analog Devices, AD713 Datasheet - Page 15

• Manufacturer Part Number: AD713
• Description: Precision, High Speed, BiFET Quad Op Amp
• Manufacturer: Analog Devices

Specifications of AD713

• -3db Bandwidth: 4MHz
• Slew Rate: 20V/µs
• Vos: 300µV
• Ib: 40pA
• # Opamps Per Pkg: 4
• Input Noise (nv/rthz): 16nV/rtHz
• Vcc-vee: 9V to 36V
• Isy Per Amplifier: 3mA
• Packages: DIP,SOIC

GIC AND FDNR FILTER APPLICATIONS
The closely matched and uniform ac characteristics of the AD713
make it ideal for use in generalized impedance converter (GIC)/
gyrator and frequency dependent negative resistor (FDNR)
filter applications. Figure 47 and Figure 48 show the AD713
used in two typical active filters. The first shows a single AD713
simulating two coupled inductors configured as a one-third
octave band-pass filter. A single section of this filter meets
ANSI Class II specifications and handles a 7.07 V rms signal
with <0.002% THD (20 Hz to 20 kHz).
Figure 48 shows a seven-pole antialiasing filter for a 2× over-
sampling (88.2 kHz) digital audio application. This filter has
<0.05 dB pass-band ripple and 19.8 μs ± 0.3 μs delay, at dc to
20 kHz, and handles a 5 V rms signal (V
overload at any internal nodes.
The filter of Figure 47 can be scaled for any center frequency by
using the following formula:
where all resistors and capacitors scale equally. Resistors R3 to
R8 should not be greater than 2 kΩ in value to prevent parasitic
oscillations caused by the amplifier’s input capacitance.
If this is not practical, add small lead capacitances (10 pF to
20 pF) across R5 and R6. Figure 45 and Figure 46 show the
output amplitude vs. frequency of these filters.
V
IN
V
DD
f
C
17
4
=
2
14
. 1
AD7528
π
DB0 TO
DATA 1
DAC A1
DB7
11
RC
R
S
7
2
3
2
A1
AD713
CS
+V
20
15
4
1/4
S
+
1µF
DAC B1
WR
16
1
R
F
19
DAC A/
DACB
10kΩ
R3
6
18
1
5
S
6
5
= ±15 V) with no
A2
30kΩ
AD713
R4
V
Figure 44. A Programmable State Variable Filter Circuit
1/4
DD
17
7
4
14
DB0 TO
DATA 2
HIGH
PASS
OUTPUT
DAC A2
DB7
30kΩ
33pF
R5
C3
R1
Rev. F | Page 15 of 20
7
2
AD7528
10
9
1000pF
A3
CS
18
15
AD713
C1
1/4
DAC B2
Figure 46. Relative Output Amplitude vs. Frequency of Antialiasing Filter
WR
–100
–110
–120
16
–10
–20
–30
–40
–50
–60
–70
–80
–90
R2
8
0
10k
–10
–20
–30
–40
–50
–60
–70
Figure 45. Output Amplitude vs. Frequency of 1/3 Octave Filter
DAC A/
DAC B
0
6
0
20
1
5
10
13
12
1000pF
A4
–V
11
20
C2
S
1µF
AD713
+
FREQUENCY (MHz)
30
14
BAND PASS
OUTPUT
1/4
FREQUENCY (MHz)
40
100k
–1
18
19
20
21
22
DAC EQUIVALENT RESISTANCE EQUALS
256 × (DAC LADDER RESISTANCE)
3
2
1
0
LOW PASS
OUTPUT
50
200
200
–1
–2
–3
–4
–5
DAC DIGITAL CODE
0
60
500
500
FREQUENCY (MHz)
16 18 20
OUTPUT AMPLITUDE
1k
GROUP DELAY
1k
CIRCUIT EQUATIONS
C
f
Q =
A
70
C
1
O
=
= C
= –
2k
2π R
R
R
2k
3
4
2
80
, R
R
R
1
×
F
S
22 24
1
1
R
5k
5k
C
= R
FBB1
R
1
90
F
1M
2
10k 20k
10k 20k
AD713
, R
100
4
= R
5