LTC1562 Linear Technology, LTC1562 Datasheet - Page 14

• Manufacturer Part Number: LTC1562
• Description: Very Low Noise/ Low Distortion Active RC Quad Universal Filter
• Manufacturer: Linear Technology

LTC1562
TYPICAL APPLICATIONS
14
V
V
IN2
IN1
5V
0.1 F
R
R
IN3
IN1
Notes: f
Example: Butterworth response, f
= 40k. R
R
Quick Design Formulas for Some Popular Response Types:
R21, R23, R
R22, R24, R
0.1dB passband ripple up to 0.95 f
Q2
SCHEMATIC INCLUDES PIN NUMBERS FOR 20-PIN PACKAGE.
PINS 4, 7, 14, 17 (NOT SHOWN) ALSO CONNECT TO V
= R
R23
R
R
R21
Q3
C
Dual 4th Order Lowpass Filters
Q4
Q1
Q1
is the cutoff frequency: For Butterworth and Bessel, response is 3dB down at f
= 13.07k(100kHz/50kHz) = 26.14k. Use nearest 1% values.
= R
R
R
IN1
IN2
Q1
Q2
Q3
10
, R
, R
, R
, R
1
2
3
5
6
8
9
= 5.412k(100kHz/50kHz) = 10.82k. R22 = R24 = R
IN3
IN4
INV B
V1 B
V2 B
V
SHDN
V2 A
V1 A
INV A
Q3
Q4
+
=
=
=
=
LTC1562
R
R
IN2
IN4
(Maximally Flat Passband)
AGND
INV D
INV C
V2 D
V1 D
for f
5.412k
13.07k
V1 C
V2 C
V
U
–
10k
10k
C
C
20
19
18
16
15
13
12
11
Butterworth
10kHz to 140kHz
= 50kHz. from the formulas above, R21 = R23 = R
C
100kHz
100kHz
100kHz
100kHz
, use LTC1562 “A” grade.
1562 TA03a
(Basic)
R
R22
R24
R
C
C
C
C
Q2
0.1 F
Q4
–
2
2
V
V
–5V
OUT2
OUT1
for f
14.24k
7.097k
17.53k
(Equiripple Passband)
7.26k
IN2
C
Chebyshev
20kHz to 120kHz
= R
100kHz
100kHz
100kHz
100kHz
IN4
C
C
C
C
–10
–20
–30
–40
–50
–60
–70
–80
10
= 10k(100kHz/50kHz)
0
2
2
10k
IN1
C
. For Chebyshev filters with
= R
Amplitude Response
IN3
FREQUENCY (Hz)
= 10k(100kHz/50kHz)
(Good Transient Response)
100k
3.951k
5.066k
4.966k
3.679k
2
for f
= 40k.
C
BUTTERWORTH
f
– 3dB
10kHz to 70kHz
100kHz
100kHz
100kHz
100kHz
Bessel
1562 TA03 TABLE
= 100kHz
C
C
C
C
1562 TA03b
2
2
2
1M